Encyclopaedia of Biological Disaster Management: vol. 8. Biological Control and Disaster Management

BIOLOGICAL DISASTER MANAGEMENT

Vol. 8

CONTENTS Preface

1. Disaster Management-role of Forensic Expert

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2. Biological Warfare Mass Casualty Management

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3. Biological Warfare

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4. Chemical Warfare

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5. Ricin

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6. Disaster Management Cycle

86

7. Public Health Statement for Acetone

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Bibliography

281

Index

284

PREFACE The twentieth century witnessed the creation and development of Weapons of Mass Destruction: nuclear, chemical, and biological. While such weapons have been used in major wars, regional conflicts, and terrorism, this chapter will focus on the latter. Weapons of Mass Destruction all have the potential to create mass casualties, public panic, and enormous property destruction. They represent an existing and growing security and safety risk for all the citizens of the world. Terrorists now have an improved ability to collect information, raise money, and disseminate rhetoric. Advanced information technology available through the Internet allows extremists to communicate widely and efficiently. Additionally, publicly available databases serve as repositories for technical information relating to weapons production. Another important factor is that Weapons of Mass Destruction, together with the materials and technology used to make them, are increasingly available. Many of these materials are widely available for legitimate commercial purposes. Moreover, the disintegration of the former Soviet Union has increased concerns about the protection, control, and accountability of Weapons of Mass Destruction, related materials and technologies, and the potential unemployment and proliferation of thousands of scientists skilled in the field. Afinal factor is the relative ease of manufacture and delivery of Weapons of Mass Destruction. Facilities required to produce radiological, biological, and chemical weapons are small and hard to detect, compared with those associated with nuclear weapons. In this book we will discuss about the Biological Disaster and their impacts on the environment, society and coming generations. — Author

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1 DISASTER MANAGEMENT-ROLE OF FORENSIC EXPERT Disasters have existed ever since the existence of the mankind. The ‘Hindu Philosophy’ and ‘Greek’ philosopher Empedocles presumed that Universe consists of five elements: Earth, Fire, Air, Sun, and Water, from there comes the manifestation of violence like Earthquakes, Volcanoes, Cyclones, and Floods. The focus of nature has been relentlessly violent and Natural Disasters have been called the greatest destroyer of lives and property. With the development of Chemical Processes and Manufacturing Industry, “Nuclear Bomb Explosion” in 1945, “Bhopal Gas Tragedy” in India on 3rd December 1984, and “Terrorist Attack on World Trade Center” in USA on 9/11th September 2001, and continuing technological advances, it is inevitable that Biological and Chemical Disasters are just round the corner and community must prepare themselves for these disasters. The growing “Terrorism” in the World over has added to ever increasing list and severity of Man Made Disasters. INTRODUCTION Disaster literally means ‘Catastrophe’, ‘Calamity’, or ‘Aapada’. The Second Wednesday of every October during the Decade was observed as “World Disaster Reduction Day”. National Day for Disaster Reduction was observed on 11th October. Theme for the year 2000 was “Community Participation and Public Awareness”. The United Nations observed the Nineties as the “International Decade For Natural Disaster Reduction” (IDNDR), in order to focus on International Initiatives for minimizing the adverse impact

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of natural calamities particularly in the developed countries like India. The period of 1970 alone accounted for death of over 1 million persons and destruction of property over 46 billion dollars by Cyclones, Hurricanes, Tornados, Earthquakes, Floods and other disasters. In Past Century more than 10 million people have died due to Floods, Earthquakes and Tropical Storms. Man Made Disasters as a result of Toxic Chemicals; Explosions, Fire Incidents; High Rising Building’s Collapse; And Hazardous Waste etc. have been the cause of many deaths and casualties. The increase in Chemical Processes and Manufacturing Industry inevitably carries the risk of accidents. Enrico Fermi and his associates in the year 1944 at the University of Chicago developed the First Atomic Reactor and when proved that chain reaction was in fact a reality the world was introduced to new and terrifying dimensions, in the cause and scope of disasters. The Nuclear Bomb was dropped in Hiroshima and Nagasaki in1945, since then the threat of Nuclear War is ever increasing. Increasing Nuclear Power Plants the world over inevitably carries the risk of accidents like manifested in the Three Mile Island and Chernobyl. One of the worst Industrial Disaster in the World “Bhopal Gas Tragedy” in the Night of 3rd –4th December, 1984 which killed 2500 victims and 17500 victims were hospitalized, besides, incapacitating thousands. Many deaths, morbidity and suffering of thousands could have been saved in Bhopal with proper disaster management. The ‘Chemical Disaster Prevention Day’ being observed all over India on 4th December every year is a grim reminder of the worst recorded accident in the history of Chemical Industry. A powerful Earthquake on 26th December 2003 strikes Bam (an Ancient Silk Road City) in South- Eastern Iran, killing some 40000 people and injuring some 30000 others. The Interior Ministry of Iran estimates 20000 deaths in Bam Earthquake (27-12-2003). Thus, disaster management plan is a must for every hospital as a disaster can happen anywhere anytime. No one can claim that, “It cannot happen here”. The fact is that it can happen here, anywhere, not necessarily a nuclear bomb but it could be a riot, road traffic accident, fire incident, building collapse, or any of natural disasters or an act of man that can suddenly bring about a localized or widespread state of disaster.

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AIMS & OBJECTIVES To create a medical community, which is adequately knowledgeable about the disasters, natural or otherwise, it is likely to face and the safe ways of surviving community affected. The ultimate aim of disaster management plan is to save as many lives as possible by providing best possible medical care under those circumstances. WHAT IS A ‘DISASTER’? Before going into discussion about actual topic, I would like to discuss what disaster means for medical fraternity? The Oxford Dictionary describes disaster as “A sudden Calamitous Event bringing great damage, loss or destruction”. WHO Definition: “A situation, which implies unforeseen serious and immediate threat to public health”. Colin Grant’s Definition: “Catastrophe causing injury or illness simultaneously to at least thirty people who will require hospital emergency treatment”-(Colin Grant’s-1973). Rutherford’s Definition: “An emergency of such magnitude as to require extraordinary mobilization of emergency service”(Rutherford-1974). Jenkins A’s Definition: “Disaster needs declaration when immediate patient load in the emergency medical services system is greater than normal, operator can care for” (Jenkins An-1978). No definition seems to be complete which is suited to every Hospital / Institution.

WHAT IS MY PERCEPTION? A disaster involves following Ingredients: • Unforeseen, Serious and Immediate Threat to Public Health i.e. Suddenness in terms of time; • An Emergency, Calamity, Catastrophe, Misadventure, Tragedy, Epidemic, Cataclysm etc.; • Where number of casualties far exceeds medical facilities in normal situation that disrupts the normal routine of life i.e. Magnitude in terms of severity of damage or deaths.

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Disaster Management-Role of Forensic Expert

2) MAN MADE DISASTERS: i) CAUSED BY WARFARE: (a) Conventional Warfare. (b) Nuclear, Biological & Chemical Warfare. ii) CAUSED BY ACCIDENTS: (a) Vehicular Accidents, (Plane, Train, Ship and Motor Car etc.). (b) Drowning. (c) Collapse of Building. (d) Explosion. (e) Fires. (f) Biological. (g) Chemical Including Poisoning.

In other words declaration of disaster depends on gravity or magnitude of situation, number of victims involved, time factor i.e. Suddenness of an event, availability of medical care in terms of space, equipments, medical and paramedical staff, medicines and other basic human needs i.e. food, shelter and clothing, weather conditions in the locality of incident etc. Thus, enhancing human sufferings and create human needs that the victims cannot alleviate without assistance. DISASTER CLASSIFICATION Disasters have been classified in various ways but the most convenient method used in classificationof disasters is in two distinct categories according to their causes. 1. Natural Disaster. 2. Man Made Disaster. Western Countries classified disasters as follows: 1) NATURAL DISASTERS: i) NATURAL PHENOMENON BENEATH EARTH’S SURFACE: (a) Earthquakes. (b) Volcanic eruptions. ii) NATURAL PHENOMENA AT EARTH’S SURFACE: (a) Land slides. (b) Avalanches. (c) Metrological / Hydrological Phenomenon. (d) Wind Storms (Cyclones, Typhoon, Hurricane). (e) Tornadoes. (f) Hail Storms and Snow Storms. (g) Sea Surges, Flash Floods or Cloud Burst. (h) Floods. (i) Droughts. iii) BIOLOGICAL PHENOMENA: (a) Locusts Worms. (b) Epidemics of Diseases.

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SOME OF THE MAJOR DISASTER EVENTS Year

Place Of Disasters World Wide

Casualties Reported

1348 1556 1919 1949 1956 1962 1963 1963 1985 1985 1987 1988 1988 1988 1988 2001 2003 2004 2004

Epidemic (Bubonic Plague) World Wide 25,000,000 Earthquake China 8,30,000 Epidemic (Influenza) World Wide 20,000,000 Mini disaster Germany 3,000 Hurricane China 2,000 Avalanches Ranrahivca Peru 3,500 Air Crashes Canada 118 Dam Collapse Valout, Italy 3,000 Volcanic Eruption Colombia, USA 23,000 Air Crashes (Air India) Montreal, Canada 348 Nuclear Plant Disaster Chernobyl, USA 29 Earthquakes Armenia, USSR 55,000 Train Accident South-West, London (Injured) 36(115) Earthquakes Unan, China 900 Earthquakes Tazakistan, USSR 1,415 Terrorist’s Attack on WTC, USA 3,000 Earthquake Bam, Iran 20,000 MEENA, NEAR MACCA SAUDI ARABIA 244 MADRID BLAST, SPAIN 198 (1400 Injured.)

6 1737 1961 1977 1979 1984 1988 1988 1993 1998 2001 2003 2003 2003 2003 2002 2003

Disaster Management-Role of Forensic Expert Earthquake Calcutta, India Floods India Cyclone Andhra Pradesh, India Flash Flood Gujrat, India Chemical Disaster Bhopal, India Train Accident Quilon, India (Injured) Air Crash Ahmedabad, India 13 Bomb Blasts In Mumbai, India. Train Accident Khanna, Pusa, India. Earthquake Bhuj Gujrat, India. Frontier Mail Fire Ludhiyana, Punjab, India. 2 Bomb Blasts In Mumbai, India. Cloud Burst Himanchal Pradesh, India. Stampede At Kumbh, Nasik, India. Terrorist’s Attack Kaluchak, Jammu. Terrorist’s Attack on Railway Station, Jammu.

3,00,000 1,000 10,000 2,500 2,500 300(500) 135 250 211 10,000 36 (14) 45 41 35 (75) 23 20

2004 Terrorist’s Attack on Railway Station, Jammu.

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DISASTER MANAGEMENT PLAN AIM OF DISASTER MANAGEMENT The ultimate aim of disaster management is basically the prevention and minimization of death, disability, sufferings and losses. There are certain fundamental principles, which should be thoroughly understood by everyone who may have responsibility for helping the victim of a disaster. Furthermore, it is important that these principles be applied in the proper sequence; otherwise they loose effectiveness or cause even more deaths and injuries(Grab & Eng. -1969). PRINCIPLES Disaster management means a planned and systemic approach towards understanding and solving problems in the wake of disasters. Some general principals of disaster planning are: • It should be a continuous process. • It should reduce the unknown in a problematic situation.

Disaster Management-Role of Forensic Expert • • • • • • •

Plan Plan Plan Plan Plan Plan Plan

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must evoke appropriate action. must foresee what is likely to happen. must be based on valid knowledge. must focus on general principles. should serve as an educational activity. for overcoming resistance. must be tested.

Adjust planning to people rather than expecting people to change their behavior in order to conform to the planning. These principles include following steps: • “Prevent” the occurrence of the disaster whenever possible. • “Minimize The Number Of Casualties” if the disaster cannot be prevented. • “Prevent Further Casualties”. • “Rescue The Victims”. • “Provide First Aid To The Injured”. • “Evacuate The Injured To Medical Installation”. • “Provide The Definite Medical Care”. • “Promote The Reconstruction Of The Lives Of Victims”. Thus, Disaster Management involves: Disaster Prevention: Described as measures to prevent natural phenomena from causing or resulting in disaster or other related emergency situations. Prevention concerns the following: • To prevent or eliminate the occurrence of disaster, need for Formulation and Implementation of long-term policies and programs, • On the basis of vulnerability analysis of all risks, prevention includes legislation and regulatory measures, principally in the field of physical and urban planning, public works and building. Disaster Preparedness: Described as action designed to minimize loss of life and damage and to organize and facilitate timely effective rescue relief and rehabilitation in case of disaster:

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Disaster Management-Role of Forensic Expert • Preparedness is supported by the necessary legislation and means a readiness to cope with disaster or similar emergencies, which could not be avoided. • Preparedness is concerned with forecasting and working, the education and training of population, staff, organization for and management of disaster, including preparation of operational plan, training of relief group, the stock piling of supplies and the earmarking of the necessary funds.

Continuous preparedness to provide quick and effective relief, together with the adoption of such preventive measures as are possible to save life, lessens personal suffering and loss when a calamity strikes -(Skeet, 1979). Disaster Mitigation: Mitigation means reducing the actual or probable effects of an extreme hazard on man and his environment. ROLE OF FORENSIC EXPERT Role of Forensic Expert is of immense value due to medicolegal nature of all the cases especially in ‘Man Made Disasters’ like terrorist attack etc., and when MCI Recommendations are that emergency services to be brought under the supervision of Forensic Medicine Department and posting of Inters for two weeks in the casualty under the supervision of Forensic Experts. TRIAGE Need for Emphasis on ‘Triage’ and plan for allocation or extension of emergency department space.The concept of ‘Triage’ or ‘Sorting’ was originally developed for Mass Casualty Disaster or Battle Field Situations in which decision had to be made about the allocation of resources and Medicare. This concept was being expanded to emergency department in which unscheduled patients arrive by ambulance or other means seeking urgent care. Triage is a core process in the emergency department. The origin of Modern Triage is attributed to Baron Dominique Jean Larry in the Napoleonic Wars who created a system for sorting the thousands of French causalities into groups with different priorities for evacuation and treatment, not based on soldiers rank, but on the nature of their injuries.

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The patient presenting to casualty in the late 1960’s were not always triaged. Ambulance cases were generally afforded priority with the walking wounded being seen in order of arrival. In the mid 1970’s staff at the Bore Hill Hospital in Melbourne developed a five tired time based scale and used different colored stickers on the medical record to indicate priority. This scale was slightly modified by Fitzgerald who demonstrated the validity of the scale in describing the urgency for need of medical care by testing its correlation with a range of actual and surrogate measures of injury and illness severity. AIMS AND OBJECTIVES An effective ‘triage’ system will achieve the following: • To ensure immediate medical intervention in life threatening situation. • To expedite the care of patients through an accurate initial assessment of urgency. • To ensure that patients are prioritized for treatment in accordance with the severity of their medical condition. • To reduce the morbidity associated with medical conditions through early intervention. • To assist patient requiring treatment in another hospital, department, or community health services. • To improve public relations by communicating accurate information to friends and relatives who accompany patients. • To improve patients flow within Emergency Department. • To provide supervised learning for appropriate personnel’s (like Interns, J.R.’s etc.). • To assist with all aspects, in performance measurement in Emergency • Sorting of dead from injured. • Fixing of identity is a great challenge for Forensic Expert, and in almost all cases autopsy is to be performed as unknown, unclaimed dead bodies. • Post mortem examination of all the casualties is must to confirm the cause of death.

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Disaster Management-Role of Forensic Expert • Fixing Identity and confirmation of event by Preservation and collection of evidences for Forensic Examination. • Almost all wounded patients need Casualty Services. • For Post Mortem Examination, Demarcation of additional staff & space and rapid disposal of cases is the need of hour in cases of Mass Casualties. • For creating Temporary Mortuary, use of tents, folding tables & adequate quantity of equipments may be needed. • Mobile vans may be used for ‘On the Site Post Mortem Examination’. • Facility of ‘Cold Storage Cabinets’ or arrangement of Ice Cubes (blocks) for keeping the dead bodies till waiting for relatives or final disposition of dead bodies may be available. • Provision for adequate water supply, arrangement of lights must be ensured before performing ‘On the Site Post Mortem Examination’. • Another important point needs emphasis here is to ask for adequate security arrangements to avoid ‘Secondary Disaster’ due to Law and Order problems.

Role as a Leader Forensic Expert being an expert of medico legal nature of cases and also having administrative e knowledge and experience of working with law enforcement persons, must come forward and play a role as a Leaderin such disastrous situations.

Role as a Doctor The primary role of doctors should be to function as a doctor and they should not be diverted, to other functions, and keeping in mind the directions of S.C. regarding treatment offered to a patient in emergency situation. No patient left unattended & treatment must not be delayed in the name of medico-legal nature of the cases. ROLE AS A COORDINATOR Forensic Expert must act as a Coordinator of following’s activities:

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• Nursing staff, • NGO’s (like Red Cross for ambulance services, setting up first aid team, help in providing food, drink, and temporary shelters for victims and rescuers, supply of drugs and equipments, help in rehabilitation, supply of cloths blankets etc.) • Volunteers (like NCC, NSS etc.) for rescue, first aid, evacuation etc. the volunteer’s should act in coordination with professionally trained persons. The volunteer’s help should correspond as closely as possible to his training and experience. PUBLIC HEALTH WORK PERSONNEL • To perform any work that would lessen the chance of a ‘Secondary Disaster’ and then take other activity to support the rescue operation. The usual task to be performed includes: • Removing traffic jams or road blocks so that clear passage may be available for relief vehicles, ambulance, and fire brigade vehicles etc. • Prevention of any untoward effects like break down of electric, water, and gas supply. • To assist Fireman in obtaining adequate water for Fire Fighting. • Rescue operations particularly of removing victims from under debris etc. PREVENTION OF HEALTH PROBLEMS Prevention of ‘Secondary Disaster’: ‘Secondary Disaster’ means ‘Disaster After Disaster’ or ‘Disaster Over Disaster’ due to law and order problems during treatment or at nay stage of disaster management, like public outrage, conflicts between hospital staff and attendants of patient’s or so called self made local leaders, creating strike like situation. NEED FOR CHANGE OF ATTITUDE “Delusion Of Personal Invulnerability”: Most people believe

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that a disaster is something that happens to someone else not to themselves or their families. This is called the “Delusion Of Personal Invulnerability”. As a result they are likely to ignore or minimize warning and refrain from taking preventive measures. Students can be trained in ‘first aid’ and remain in a constant state of preparedness. The idea that assumes the supreme importance is –the elimination of the critical difference between ‘runaway’ to ‘run-in’, in case of any disaster.

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damage, losses to the property, and human sufferings along with prevention of human lives on one hand and reduce the cost of relief, rehabilitation and reconstruction on the other hand. No master plan can be evolved to fit every emergency situation but a general schedule of emergency activity could prove extremely helpful in times of disaster, if executed in a coordinated and disciplined fashion.

FUTURE TRENDS IN DISASTER MANAGEMENT

The better awareness for disaster preparedness and mitigation is expected to result in coordinated extensive efforts to ensure better disaster management.

The disaster management has come a long way from disgraceful history. The scientific development in many discipline have made significant breakthrough in better prediction, preparedness and mitigation.

Adequate procedures to deal with disaster should be formulating in every country of the world as no country is completely immune from both natural and man made catastrophe (Skeet, 1979).

The use of satellite, computers, electronics, better communication facilities are going to make significant difference in disaster management. The data processing and computers are providing a useful tool in decision making in disaster. SUMMARY AND CONCLUSIONS When the disaster strikes, power goes out, all modes of communication (Telephone etc.) becomes inoperable, lifts stop functioning, when drinking water becomes contaminated, when normal modes of transportation suddenly becomes impossible, when casualties start coming in groups that is not the time for planning but that is the time of acting. This fact makes it imperative for community disaster preparedness and particularly health care system with its critical component “the hospital” which are to be prepared consistently to mobilize all their facilities for maximum use. Creating public awareness about safety from disasters by organizing workshops, symposium, seminars etc. There is need for amending, enacting & effectively enforcing legislations for safety from disasters like Protection of habitations from adverse impacts of disasters, constructing new buildings safe from disasters and retrofitting existing buildings for improving disaster resistance. Need for change of strategy from ‘post-disaster reactive approach’ to ‘pre-disaster pro-active approach’ to reduce the

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• Signs and symptoms of illness will be delayed from hours to weeks and initially may mimic minor nonspecific illnesses or naturally produced disease syndromes. • Arrival of assistance from state or federal agencies will be delayed from 24-72 hours after request and may take longer for full operation. PRE-EVENT PROCEDURES

BIOLOGICAL WARFARE MASS CASUALTY MANAGEMENT INTRODUCTION Other articles in the CBRNE section discuss the specific clinical management issues involved with treatment of patients exposed to potential bioterrorism pathogens and toxins. This article focuses on the larger logistic and emergency management issues of such an event. The complex relationships among various medical disciplines and with the rest of the response community cannot be overemphasized. Medical support falls within the realms of public health, emergency medical services, and traditional fixed site health care. Appreciating that a bioterrorist event is a hybrid disaster, with similarities to a public health emergency and a traditional disaster, is important.

ASSUMPTIONS The following assumptions must be made concerning a bioterrorist event to effectively and realistically plan for response: • With or without advanced warning, the actual time and location of the release of a biological agent most likely will be covert. • Terrorists desiring maximum effect will opt for aerosolized release of the pathogen. • Exposed individuals will have minimal physical and immunologic protection.

THREAT AWARENESS AND PRE-EVENT SURVEILLANCE Successful treatment of patients exposed to many of the biological agents is exquisitely time dependent. Morbidity and mortality increase significantly with any delay. Barring discovery by law enforcement or intelligence communities or terrorist announcement of an impending release, the determination that a bioterrorism event has occurred most likely falls to the medical community. The determination of a bioterrorism event by the medical community is through the following: • Presumptive diagnoses by astute clinicians • During an autopsy or as the result of specific diagnostic tests ordered based on a patient’s clinical condition • Result of epidemiologic investigations PRE-EVENT COMMUNICATION WITH LAW ENFORCEMENT Communication between the medical and law enforcement communities has been rare in the past. Physicians are reluctant to breach patient confidentiality. Law enforcement personnel do not wish to compromise ongoing investigations or unduly alarm the public, especially when evidence or information is not explicit enough to validate suspicions. Nonetheless, information sharing between these disciplines should be explored. Terrorist activities, thefts from biological laboratories, or information received from police agencies may impart forewarning if provided in a timely, discrete manner to appropriate offices of the local health care network. Conversely, if a diagnosis associated with pathogen production is made, passing this information on to the appropriate authorities for further investigation may be prudent. Since entry into the

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health care system is often through emergency departments and primary care clinics, open dialogue between these providers and law enforcement personnel is advisable and encouraged.

capabilities: the Centers for Disease Control and Prevention (CDC) and the US Army Medical Research Institute of Infectious Diseases (USAMRIID). Other organisms, such as Yersinia pestis, require Biosafety Level III capabilities for appropriate safety.

EVENT DISCOVERY

Many viral pathogens require sophisticated testing, such as enzyme-linked immunosorbent assay or polymerase chain reaction, that is not widely available. Finally, definitive diagnosis of those pathogens not requiring sophisticated testing or extreme safety precautions requires time for culture growth. Still, certain pathogens can be identified in local laboratories, at least to the degree to justify empiric treatment and health care network alert. Y pestis is a bipolar gram-negative rod that can be identified through Gram stain. The identification of Brucella species in conjunction with a suggestive clinical picture may trigger expedient actions based on a presumptive diagnosis only.

EVENT DISCOVERY BY CLINICAL PROVIDERS Frontline clinicians may be singularly positioned to first identify a possible bioterrorism attack. However, sole reliance on this method of discovery is fraught with problems. Many pathogens produce early symptoms that mimic naturally occurring diseases. Some findings are so ubiquitous that a rare provider orders further laboratory or radiographic tests early in the course of the disease, unless significant physiologic derangements are present or the index of suspicion is raised due to prior intelligence information. Most physicians have not evaluated or treated patients with many of the diseases produced by these agents. Since a delay occurs between exposure and symptoms, patients present at various times, to various care providers, rather than simultaneously to one location. EVENT DISCOVERY BY DIAGNOSTIC TESTS OR AT AUTOPSY Most diagnostic studies performed early are nonspecific, and few laboratories are equipped to provide the sophisticated testing required to identify the specific pathogens used in a bioterrorist attack. A patient presenting with findings consistent with early Venezuelan equine encephalitis looks remarkably similar to any other patient with aseptic meningitis, and routine testing of cerebrospinal fluid does not alter this picture. This exact problem occurred during the initial outbreak of West Nile virus encephalitis in New York City in the summer of 1999. Findings and initial tests were consistent with St. Louis encephalitis, and several months passed before the causative agent was determined to be West Nile virus. Laboratory workers attempting to isolate certain pathogens without the proper equipment or safeguards are at risk. In general, smallpox and the various viral hemorrhagic fever viruses should be isolated only in laboratories with Biosafety Level IV capabilities. Currently only 2 facilities in the United States have such

Only anthrax produces nearly pathognomic radiographic findings; suspect anthrax in any previously healthy patient with rapidly progressive sepsis and an unexplained widened mediastinum on routine chest film. Unless accompanied by acral or digital necrosis due to small vessel thrombosis or by hemoptysis and gram-negative rods in the sputum of large numbers of previously healthy patients, the lobar pneumonia of inhalational plague may be misdiagnosed in the clinical setting. In fact, pathologists may be the first clinicians to consider bioterrorism. Unfortunately, many pathogens produce nearly identical gross and microscopic findings at necropsy, and further tests are required. However, very few pathogens produce the extensive necrotizing hemorrhagic mediastinitis found in a patient who has succumbed to inhalational anthrax.

DISCOVERY THROUGH POPULATION-BASED SURVEILLANCE Two distinct subsets of evaluations may assist in accelerating the discovery of a bioterrorist release of a pathogen: syndromic surveillance and analysis of mined data. In syndromic surveillance, data are collected from likely portals of entry into the health care system on patients who present with specific, prospectively identified clinical syndromes. If an

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unexpected variation in the incidence of these syndromes appears, a more intense but expedient epidemiologic investigation may be warranted. Problems with this method include the requirement for cooperation by caregivers in providing this information in a timely fashion and balancing the sensitivity and specificity of the analytic method. Data collection and reporting can be labor intensive for a relatively low yield, and few incentives exist for a health care system already strapped for resources. Data mining is a method only now being evaluated fully as a possible investigative tool. Since many of these pathogens produce symptoms or discomfort in victims before specific diagnoses are entertained, affected persons may exhibit predictable behavioral patterns that, if identified, can trigger full-scale investigations. Statistical analysis may identify trends earlier than traditional methods by capturing information such as school or work absenteeism; use of specific over-the-counter medications; use of emergency departments, emergency medical services, or primary care clinics for nontraumatic complaints; raw incidence of animal illnesses; poison center data; and nontrauma deaths. Should either of these methods identify a significant trend, expedient epidemiologic investigations may be warranted. These investigations require establishing a case definition, identifying those patients who meet established criteria, and determining that the incidence of the particular disease is out of the ordinary. Influenza is a disease of the winter months, and finding it during the winter is expected. Plague, although rare, still is found episodically in certain western states. The finding of even one patient with plague in the Northeast United States, particularly the inhalational form, should trigger, at a minimum, enhanced epidemiologic surveillance. Epidemiologic investigation is resource intensive, and, barring significant augmentation of staff to collect and analyze data, this method alone may not be responsive enough to serve as the primary means of determining that an event has occurred. Epidemiologic investigation does have great value as the disaster unfolds, as is discussed later.

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BIOTERRORIST EVENT

INDICATORS

OF A

POSSIBLE BIOTERRORIST EVENT

High index of suspicion on the part of clinical providers and an epidemiologic surveillance system that is rapidly responsive, sensitive, and specific are important to early recognition of an event. If a communications network exists that allows free exchange of information, a variety of clues may promote such early recognition. These clues include the following: • Large numbers of patients with similar symptoms of disease • Large numbers of patients with unexplained symptoms, diseases, or deaths • Higher than expected morbidity and mortality associated with a common disease and/or failure to respond to traditional therapy • A single case of a disease caused by an uncommon agent • Multiple unusual or unexplained clinical syndromes in the same patient • Disease with an unusual geographic or seasonal distribution • Unusual typical patient distribution • Unusual disease presentation • Similar genetic type among pathogens from temporally or spatially distinct sources • Unusual, atypical, genetically engineered, or antiquated strains of pathogens • Endemic disease with a sudden unexplained increase in incidence • Simultaneous clusters of similar illness in noncontiguous areas • Pathogens or toxins transmitted through aerosol, food, or water contamination, suggestive of sabotage • Ill persons presenting at nearly the same time from a point source (eg, a tight cluster of patients meeting case

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Biological Warfare Mass Casualty Management definition), with a compressed epidemiologic curve (the rate of change of new cases is significantly higher than predicted based on historical or modelling data) • No illness in persons not exposed to common ventilation systems when illness is observed in those in proximity to those systems • Death or illness among animals that may be unexplained or attributed to an agent of bioterrorism that precedes or accompanies illness or death in humans

DIAGNOSIS Exact diagnosis of diseases caused by biological warfare or terrorism is important for a number of reasons, beyond treating an individual patient. These reasons include the ability to predict the spread of the disease, generate prognoses, and attribute responsibility. Without explicit criteria for identifying cases, these efforts are undermined. The concept of case definitions, used by public health departments and the CDC, is very important in this effort. Some syndromes do not have confirmatory laboratory tests, although laboratory evidence may be a component of the case definition. Other diseases have such characteristic presentations that diagnosis may be based on these findings alone. Some are diagnosed on the basis of epidemiologic data. For many, substantial amounts of information must be collected before a final case classification is possible. Finally, for forensic purposes, the identification of as many of the specific characteristics of the pathogen as possible is important. Gathering the necessary information and diagnostic testing for classic case definition requires time, especially if sophisticated laboratory tests are required. In the case of a rapidly progressive virulent outbreak, a delay in instituting treatment until definitive diagnosis has been made results in increased morbidity and mortality. Therefore, “diagnosis to treat” becomes a viable and necessary option. This option is most valuable once occurrence of an attack has been determined, but it is also valuable for postprophylactic treatment of the population at risk. Standardized diagnosis to treat criteria have not been developed, but clinicians should work with emergency planners and public health officials

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to prospectively identify those criteria necessary to commence treatment of large segments of the population prior to definitive diagnosis.

EMERGENCY RESPONSE TO A BIOTERRORIST EVENT The demand placed on the health care system (e.g., public hospitals, for-profit hospitals, community health centers, emergency medical services) following a bioterrorism attack will be unprecedented. Indeed, most disasters in US history have been marked by relatively little loss of life in comparison to infrastructure destruction; only 6 disasters in US history have resulted in more than 1000 fatalities. Due to public health initiatives, the concept of major epidemics likewise has been modified. The available model that is closest to an overwhelming, rapidly progressive, infectious disease epidemic is the Spanish influenza epidemic of 1918, in which an estimated 650,000 Americans died and approximately 40% of the population was affected. Community health care systems must plan ahead to cooperate and expeditiously expand personnel, resources, and facilities to handle the additional demand for services that such an event would cause. All states and local areas have emergency response plans that are geared toward natural disasters. A bioterrorism event poses a series of unique challenges. Unlike the typical focal disaster, an epidemic due to a bioterrorism attack will be unpredicted, progressive, and widespread. The following will overwhelm local health services very quickly: • Shortfalls of ICU beds, ventilators, and other critical care needs • Shortages of chemotherapeutic agents • Needs for ancillary or nontraditional treatment centers • High demand for mortuary and/or funeral services • High demand for social and counseling services • Shortages of health care workers due to absenteeism Demands on medical care may last weeks to months after the initial onslaught. Essential community servants (e.g., medical care personnel, police, firefighters, ambulance drivers, other first responders) may be affected. Elderly and other high-risk

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populations may be fearful of leaving their homes and seeking proper medical attention for chronic medical conditions and may require home visits for health care. Once an event has been discovered, medical management of the ensuing disaster will be focused on alerting the appropriate officials, containing the epidemic, providing postexposure prophylaxis to the population at risk, treating ill patients, handling deceased individuals, and addressing the psychological needs of the community. Because of the criminal nature of such an attack, forensic and law enforcement issues also have to be addressed. Both medical and public health disaster response activities are coordinated through one organizational structure, the Incident Command System (ICS). Many different organizations participate in the response to a disaster. The ICS provides a common organizational structure and language that allows different kinds of agencies and/or multiple jurisdictions of similar agencies to work together effectively in response to a disaster.

ICS STRUCTURE AND HIERARCHY The organizational structure of ICS is built around 5 major management activities. Note: Not all activities are used for every disaster. • Incident command • Operations • Planning • Logistics • Financial/administrative Functional requirements, not titles, determine ICS hierarchy. IMPORTANT PRINCIPLES • An important part of disaster planning is the identification of the incident commander and other key positions before a disaster occurs. • ICS must be started early, before an incident gets out of control. • Medical and public health responders, often used to working independently, must adhere to the structure of

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the ICS in order to avoid potentially negative consequences, including the following: o Death of personnel due to lack of training o Lack of adequate supplies to provide care o Staff working beyond their training or certification • The structure of ICS is the same regardless of the nature of the disaster. The only difference is in the particular experience of key personnel and the extent of the ICS utilized in a particular disaster.

ALERTING AND NOTIFICATION During planning sessions well before an event, address the timing of release of information to the public, the content of information provided, and the methods of release. Many natural disasters (e.g., hurricanes, flooding) allow sufficient forewarning that area evacuation may be possible. For others, such as tornadoes, evacuation may not be possible, but additional precautions and shelter-in-place actions may be taken to lessen the impact of the event. Terrorists are unlikely to afford a community that luxury, and equally doubtful is that local governments will order evacuation based on even a credible threat, given the increasing frequency of biological terrorism hoaxes that have plagued communities across the country in recent years. CONTAINMENT In all probability, the realization that a major epidemic is at hand will precede the exact identification of the pathogen involved. Nonetheless, identification is of utmost importance, since the transmissibility of infection must be known to contain the spread of the disease. Diseases that are transmissible through casual contact, by nonhuman vectors, or by respiratory droplets, such as smallpox or pneumonic plague, carry high rates of secondary infections, whereas other diseases pose little risk to those not initially infected. Barring identification of the time and location of release and the amount and virulence of the pathogen, determination of the area of exposure and population at risk is very difficult and requires the expeditious and concerted efforts of local public health

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investigators and epidemiologists supported by state and federal agencies. Agent characteristics may be helpful, since certain pathogens are exquisitely fragile outside a host, regardless of meteorologic conditions. Analysis of activities of initial victims during the prodromal or incubation period is necessary to estimate time and location of release. As more epidemiologic information becomes available, these determinations may be refined. Once estimates of the area of exposure and population at risk are determined, forced or voluntary isolation and quarantine may reduce the spread to secondary contacts. Isolation is the process of separating infectious persons from others. As a practical point, isolation primarily occurs within the confines of hospitals. Quarantine, originally applied to the maritime industries, is the limitation on freedom of movement to prevent the spread of a disease. Animal and vector control also may be important determinants in containing the spread of certain diseases. Disease transmission through tainted water supplies is highly unlikely, since routine water purification systems effectively kill most pathogens, and those that survive are not in concentrations sufficient to cause disease. However, one or two notable exceptions exist, such as Cryptosporidium parvum. This organism is quite resistant to chlorine, and very small swallowed doses can cause infection. Recently, several widespread outbreaks involving municipal water supplies and public swimming pools have occurred.

MASS PROPHYLAXIS Postexposure prophylaxis serves 2 purposes: to prevent secondary infections in the case of transmissible diseases and to improve community morbidity and mortality. The prognosis in patients with active disease caused by the common pathogens of warfare or terrorism is uniformly poor, with mortality rates approaching 100% if treatment is delayed until patients become symptomatic. Additionally, very little treatment beyond supportive care is available for many of these patients. The importance of postexposure prophylaxis is obvious and cost effective. Most hospitals and pharmacies have gone to “just in time” pharmaceutical procurement, and stockpiles to handle surge

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demand are meager at best at most locations. As part of the federal initiative to address deficiencies in the capability to respond to a bioterrorism attack, the Office of Emergency Preparedness of the Department of Health and Human Services established 4 National Medical Response Teams, and the CDC instituted the National Pharmaceutical Stockpile (NPS) program. Three National Medical Response Teams, in North Carolina, Colorado, and California, are capable of providing medical treatment after a chemical or biological terrorist event. The response teams are fully deployable within 6 hours to incident sites anywhere in the country with a cache of specialized pharmaceuticals to treat as many as 1000 patients. A fourth team is dedicated to the National Capital Area. The Strategic National Stockpile (SNS) program consists of a 2-tier response. The first tier consists of eight 12-hour “push packages” of pharmaceuticals and supplies that can be delivered to the scene within 12 hours of the federal decision to deploy the assets. These packages allow for the treatment or prophylaxis of disease caused by a variety of threat agents, including anthrax, tularemia, plague, smallpox, and botulism preparedness. The second tier is the Vendor-Managed Inventory, which arrives at the scene 24-36 hours after activation. The Vendor-Managed Inventory packages consist of additional pharmaceuticals and supplies, tailored to a specific agent, and are sent if needed. Logistics of mass prophylaxis are magnified by the difficulties in determining the population at risk, and initial estimates are likely to be high. Community emergency planners must have an accurate inventory of pharmaceuticals and medical supplies on hand. They also must have detailed plans and procedures for safeguarding, distributing, and dispensing community stores; for patient screening and tracking; and for receiving, distributing, dispensing, and providing security for arriving SNS supplies. Ambulatory, home-ridden, and homeless patients require provisions. Establish sufficient dispensing locations to prevent an additional burden on hospitals and to ensure delivery of these medications in a timely fashion. The difficult ethical issue of prioritizing who receives critical medications, especially if shortages are anticipated, should be resolved prior to an event.

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MASS PATIENT CARE Another Herculean task is addressing the needs of patients requiring treatment or requesting evaluation for possible treatment. Anticipate a large number of individuals requesting evaluation and treatment who have little or no risk of exposure and who are completely asymptomatic. These latter patients, referred to frequently as the “worried well,” result in a significant additional burden, possibly 5-10 times as great as the number of actual ill or injured. Primary components of mass patient care include the following: (1) personnel and material resource protection, (2) decontamination, (3) triage, (4) treatment, and (5) disposition.

FACILITY AND/OR MEDICAL PERSONNEL PROTECTION Although frequently omitted as first responders in most documents concerning weapons of mass destruction, the true first responders in a covert bioterrorism attack are the health care providers and ancillary staff at hospitals, clinics, and private physician offices. Consider both collective and personal protection. Collective protection includes positive pressure ventilation systems and high-efficiency particulate air filtration. Both require major modifications in existing facilities and are cost prohibitive. Unless the health care facility is directly downwind from the release site, virtually no risk of major contamination of the facility by airborne spread is present. However, these systems may be considered for new construction. Expedient collective protection may include shutting off ventilation systems and closing and sealing all exterior doors and windows. Since a bioterrorism attack is most likely to occur at some time prior to discovery, these actions may have little effect on facility personnel protection. Personal protection includes vaccinations and postexposure chemoprophylaxis, personal protective equipment, and augmented standard infectious disease protocols. Provide chemoprophylaxis to all health care personnel as soon as a diagnosis is known. Although many ultimately do not need this treatment, staff shortages at a time of greatly increased demand translate into a further degradation of health care response and increased community morbidity.

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Controversy continues to exist about the level of personal protective equipment required for hospital personnel. With the exception of the T-2 mycotoxins, intact skin provides an adequate barrier to infection. Re-aerosolization has not been well studied and was considered to be negligible in the past. However, as was demonstrated in the anthrax attacks that occurred in 2001, reaerosolization may occur in certain situations. Unless a patient presents immediately after a release, little risk exists to health care providers from exposure to residual weaponized pathogens. However, some agents are highly contagious through respiratory droplets; add these precautions to standard precautions until the exact diagnosis is made. Personnel involved with decontamination of a suspected bioagent should wear respiratory and splash protection, at a minimum (ie, Occupational Safety and Health Administration Level C).

DECONTAMINATION Most patients who have been infected with a pathogen by a bioterrorism attack do not develop symptoms until 1 day to several weeks after the attack. The exceptions to this are patients exposed to biological toxins, who may develop symptoms several hours after exposure. At present, most biological agents do not survive for long periods outside a host. Even the relatively hardy spore of anthrax is degraded by direct exposure to UV light; consequently, decontamination is not necessary unless the attack is overt and recent. Several cidal and static decontamination solutions are under investigation, but for mass decontaminations, copious amounts of soap and water are probably sufficient. The issue of capture of effluent from decontamination is more significant with chemical than with biological agents, since these pathogens and toxins are denatured through water treatment facilities. TRIAGE Traditional triage from a mass casualty event involving trauma primarily is based on physiologic parameters, anatomic sites of injury, and attempts to separate patients requiring minimal effort to stabilize from those who require immediate surgery or further life-saving interventions. Patients with physical injuries or vital signs incompatible with life without extensive use of resources are

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identified as expectant. Triage in the wake of a bioterrorism attack may require triage based on prognosis alone. In the case of anthrax or pneumonic plague, a patient with any symptoms has a very poor prognosis, despite vigorous treatment, and, in the presence of an overwhelming number of patients, these minimally ill patients may need to be triaged to the expectant category based on their poor prognosis. As with postexposure prophylaxis, give some consideration to these potentially difficult decisions prior to the crisis.

TREATMENT Local health care systems have little time to prepare for a bioterrorism event after the fact. These organizations also may suffer significant staff shortages due to absenteeism or illness among medical personnel. All health care systems must modify operations significantly to reduce routine demand while increasing the supply of health care. Health care systems must have prospectively developed plans for a graduated expansion of available health care. Methods may include the following: • Diversion of patients with minor complaints or health problems to other sites of care • Public service announcements: Announcements requesting telephone triage may prove beneficial and may protect individuals not affected by the bioterrorist pathogen. • Cancellation of elective appointments, procedures, and surgery: In addition to freeing up space, hospital gurneys, and beds, this method makes available staff who may be used to augment other departments and services. • Early discharge of unexposed but hospitalized patients to skilled nursing facilities, home health care, or remote health care facilities: Patient’s families may be able to provide initial posthospitalization care under the direction of visiting nurses or through telephonic direction from hospital care providers. • Doubling up of single or even shared hospital rooms • Using open wards in auditoriums, cafeterias, or other locations within the confines of the health care facilities or establishing expansion facilities near existing hospitals

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• •

• o o

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o Although certain aspects of patient privacy and comfort are sacrificed, this method of expansion of facilities was used effectively during the influenza epidemic of 1918. o Its purpose primarily is to extend nursing services to more patients than can be accomplished on wards with private rooms. Temporary doubling of shifts for staff Recruitment of volunteers, retired health care workers, or students from medical, nursing, dental, lab tech, and other allied health care schools from the community: Whether or not volunteers will come in the case of a bioattack cannot be predicted, but volunteers from these sources may serve to expand the pool of available health care providers for the expected surge of patients. Expeditious credentialing mechanisms will need to be developed. Many functions in hospitals do not require allied health care providers, and volunteers may be of great value in freeing up more skilled personnel. Evacuation of affected patients (may prove problematic) The National Disaster Medical System claims to have nearly 100,000 beds available nationwide. The wisdom of evacuating patients who may transmit the disease to new communities must be balanced with the need to contain the spread of the disease and the desires of family members to remain close to their relatives. This decision ultimately may have to be made by elected state or federal officials in the interest of national security.

MASS FATALITY MANAGEMENT A bioterrorist event is likely to produce significant numbers of fatalities, especially during the early phases of response. Local medical examiners, morgues, and funeral homes most likely will not be able to absorb the surge. Once activated and mobilized, the National Disaster Medical System includes a number of deployable Disaster Mortuary Operations Response Teams. At least one of these teams has

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additional training in handling contaminated or infected remains. Issues involved with fatality management include the following: • Infection control o Enforce the same precautions required for live victims while handling deceased patients, during autopsy, and during disposal or disposition of the remains. o Survivability of all potential pathogens in corpses has not been studied. • Victim identification and tracking o Even in a massive catastrophe, legal, moral, ethical, psychological, and religious reasons exist to identify the dead. o Release or cremation of remains will be delayed unless positive identification occurs or, at a minimum, enough evidence is collected (eg, dental radiographs, fingerprints, photographs, potentially DNA samples) for determination later. • Establishment of temporary morgues o In the event of mass fatalities, the ability of hospitals and medical examiners to maintain all remains is doubtful. o Without safeguards and training, local funeral homes may be resistant to accepting contaminated bodies. Processes must be in place prospectively to augment the existing system through the use of temporary morgues. o These sites require temperature and biohazard control, adequate water, lighting, rest facilities for staff, and viewing areas and should be in communication with patient tracking sites (probably the American Red Cross) and the emergency operations center. o Security also may be an issue. • Disposal or release of remains o Many moral, cultural, and religious issues are involved with disposal of the deceased. Although under a declared disaster, the governor and the President have

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extraordinary powers, at some point a decision must be made concerning the release of remains to families for interment or cremation or to the state for chemical cremation or incineration. o Develop appropriate plans and decision algorithms in advance. AFTERMATH

PSYCHOLOGICAL ISSUES In any disaster, the tendency is to underplay the importance of addressing the psychological needs of the community—the victims and their families, survivors, and response personnel. Failure to address this important aspect of response and recovery impedes effective response during disaster operations and may have important long-term effects on the community well after recovery operations have been completed. The loss of property or family members and friends under traumatic conditions is difficult at best, and disasters are no exception. When an entire community is affected by a disaster of any nature, the entire community may suffer short-term psychological effects, and a significant percentage of these individuals may develop posttraumatic stress disorder. Shortterm mass crisis counseling may improve overall function and reduce the incidence of posttraumatic stress disorder among the population. First responders and health care workers tend to deny their feelings and not deal with their own psychological trauma, especially during the actual crisis. Critical incident stress debriefing and interventional counseling for these personnel are required to reduce the incidence of long-term sequelae. LEGAL AND FORENSIC ISSUES Superimposed on the ensuing disaster that a bioterrorist event creates are the myriad diverse legal and forensic issues that are involved in community response to the event. Many of these have not been resolved yet, at either the state or federal level, and, because of different state and local statutes, no standardized templates address them all.

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During the planning process, address the major law enforcement and forensic issues that may affect health care operations, including the following: • Declaration and enforcement of quarantine • Legal requirements for community immunization or forced postexposure prophylaxis • Security at health care facilities, temporary morgues, neighborhood treatment centers, and antibiotic dispensing stations • Evidence collection (both physical and testimonial) • Patient privacy • Interstate licensing of providers and liability

RECOVERY FROM THE EVENT In most disaster planning processes, the tendency is to focus on disaster response to the exclusion of recovery. A biological event does not cause physical destruction, and the community material resources remain intact. The 2 primary issues facing community governments and the local health care systems are environmental surety and long-term community mental health. Most biological pathogens cited in bioterrorism research have very short life spans outside a host. Plague may become endemic among the rodent population of an area, posing a continued threat to the community. Anthrax spores have maintained viability under extreme environmental conditions for decades. Although not cited as a typical bioterrorist pathogen, the virus that causes animal foot-and-mouth disease is one of the hardiest known. Depending upon the pathogen released, ensuring that areas of high concentration are safe for use is necessary. Schools, auditoriums, or other sites used as inpatient expansion facilities require confirmation of contamination removal, if for no reasons other than legal liability and peace of mind of the community. This also may apply to traditional fixed site treatment facilities. Should a major event occur, psychological problems would remain an issue for the community and possibly for the entire United States. An interesting anecdote from the Spanish influenza epidemic of 1918 is the paucity of literature or coverage of this

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disaster, both after the event and in historical documentation. A variety of reasons for this have been postulated, but estimates state that as much as one third of the population had a close friend or relative die from this epidemic. Apply the lessons learned in recent hurricanes, in which whole communities were displaced, to any community that suffers a bioterrorist attack. SUMMARY A terrorist event presents unique challenges and obstacles to the health care system, well beyond those typically observed in US disasters. Bioterrorism represents the most extreme example. Material and human resource deficiencies at a time of greatly increased demand require unique and innovative solutions if death, disability, and major psychological impairment are to be ameliorated. Only through cooperative, comprehensive planning, across communities and vertically through all levels of government, is this able to be accomplished.

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3 BIOLOGICAL WARFARE HISTORY OF BIOLOGICAL WARFARE Biological weapons include any organism (such as bacteria, viruses, or fungi) or toxin found in nature that can be used to kill or injure people. (Toxins are poisonous compounds produced by organisms.) The act of bioterrorism can range from a simple hoax to the actual use of these biological weapons, also referred to as agents. A number of nations have or are seeking to acquire biological warfare agents, and there are concerns that terrorist groups or individuals may acquire the technologies and expertise to use these destructive agents. Biological agents may be used for an isolated assassination, as well as to cause incapacitation or death to thousands. If the environment is contaminated, a long-term threat to the population could be created. History: The use of biological agents is not a new concept, and history is filled with examples of their use. Attempts to use biological warfare agents date back to antiquity. Scythian archers infected their arrows by dipping them in decomposing bodies or in blood mixed with manure as far back as 400 BC. Persian, Greek, and Roman literature from 300 BC quotes examples of dead animals used to contaminate wells and other sources of water. In the Battle of Eurymedon in 190 BC, Hannibal won a naval victory over King Eumenes II of Pergamon by firing earthen vessels full of venomous snakes into the enemy ships. During the battle of Tortona in the 12th century AD, Barbarossa used the bodies of dead and decomposing soldiers to poison

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wells. During the siege of Kaffa in the 14th century AD, the attacking Tatar forces hurled plague-infected corpses into the city in an attempt to cause an epidemic within enemy forces. This was repeated in 1710, when the Russians besieging Swedish forces at Reval in Estonia catapulted bodies of people who had died from plague. During the French and Indian War in the 18th century AD, British forces under the direction of Sir Jeffrey Amherst gave blankets that had been used by smallpox victims to the Native Americans in a plan to spread the disease. Allegations were made during the American Civil War by both sides, but especially against the Confederate Army, of the attempted use of smallpox to cause disease among enemy forces. Modern Times: Biological warfare reached sophistication during the 1900s. During World War I, the German Army developed anthrax, glanders, cholera, and a wheat fungus specifically for use as biological weapons. They allegedly spread plague in St. Petersburg, Russia, infected mules with glanders in Mesopotamia, and attempted to do the same with the horses of the French Cavalry. The Geneva Protocol of 1925 was signed by 108 nations. This was the first multilateral agreement that extended prohibition of chemical agents to biological agents. Unfortunately, no method for verification of compliance was addressed. During World War II, Japanese forces operated a secret biological warfare research facility (Unit 731) in Manchuria that carried out human experiments on prisoners. They exposed more than 3000 victims to plague, anthrax, syphilis, and other agents in an attempt to develop and observe the disease. Some victims were executed or died from their infections. Autopsies were also performed for greater understanding of the effects on the human body. In 1942, the United States formed the War Research Service. Anthrax and botulinum toxin initially were investigated for use as weapons. Sufficient quantities of botulinum toxin and anthrax were stockpiled by June 1944 to allow unlimited retaliation if the German forces first used biological agents. The British also tested

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anthrax bombs on Gruinard Island off the northwest coast of Scotland in 1942 and 1943 and then prepared and stockpiled anthrax-laced cattle cakes for the same reason.

In 1995, 2 members of a Minnesota militia group were convicted of possession of ricin, which they had produced themselves for use in retaliation against local government officials.

The United States continued research on various offensive biological weapons during the 1950s and 1960s. From 1951-1954, harmless organisms were released off both coasts of the United States to demonstrate the vulnerability of American cities to biological attacks. This weakness was tested again in 1966 when a test substance was released in the New York City subway system.

In 1996, an Ohio man attempted to obtain bubonic plague cultures through the mail.

During the Vietnam War, Viet Cong guerrillas used needlesharp punji sticks dipped in feces to cause severe infections after an enemy soldier had been stabbed. In 1979, an accidental release of anthrax from a weapons facility in Sverdlovsk, USSR, killed at least 66 people. The Russian government claimed these deaths were due to infected meat, and maintained this position until 1992, when Russian President Boris Yeltsin finally admitted to the accident. Bioterrorism and biowarfare today: A number of countries have continued offensive biological weapons research and use. Additionally, since the 1980s, terrorist organizations have become users of biological agents. Usually, these cases amount only to hoaxes. However, the following exceptions have been noted: In 1985, Iraq began an offensive biological weapons program producing anthrax, botulinum toxin, and aflatoxin. During Operation Desert Storm, the coalition of allied forces faced the threat of chemical and biological agents. Following the Persian Gulf War, Iraq disclosed that it had bombs, Scud missiles, 122mm rockets, and artillery shells armed with botulinum toxin, anthrax, and aflatoxin. They also had spray tanks fitted to aircraft that could distribute agents over a specific target. In September and October of 1984, 751 people were intentionally infected with Salmonella, an agent that causes food poisoning, when followers of the Bhagwan Shree Rajneesh contaminated restaurant salad bars in Oregon. In 1994, a Japanese sect of the Aum Shinrikyo cult attempted an aerosolized (sprayed into the air) release of anthrax from the tops of buildings in Tokyo.

In 2001, anthrax was delivered by mail to US media and government offices. There were 4 deaths. In December 2002, 6 terrorist suspects were arrested in Manchester, England; their apartment was serving as a “ricin laboratory.” Among them was a 27-year-old chemist who was producing the toxin. Later, on January 5, 2003, British police raided 2 residences around London and found traces of ricin, which led to an investigation of a possible Chechen separatist plan to attack the Russian embassy with the toxin; several arrests were made. On February 3, 2004, 3 US Senate office buildings were closed after the toxin ricin was found in mailroom that serves Senate Majority Leader Bill Frist’s office.

HOW BIOLOGICAL AGENTS ARE DELIVERED AND DETECTED Although there are more than 1200 biological agents that could be used to cause illness or death, relatively few possess the necessary characteristics to make them ideal candidates for biological warfare or terrorism agents. The ideal biological agents are relatively easy to acquire, process, and use. Only small amounts (on the order of pounds and often less) would be needed to kill or incapacitate hundreds of thousands of people in a metropolitan area. Biological warfare agents are easy to hide and difficult to detect or protect against. They are invisible, odorless, tasteless, and can be spread silently. DELIVERY Biological warfare agents can be disseminated in various ways. Through the air by aerosol sprays: To be an effective biological weapon, airborne germs must be dispersed as fine particles. To be infected, a person must breathe a sufficient quantity of particles into the lungs to cause illness. Used in explosives (artillery, missiles, detonated bombs): The use of an explosive device to

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deliver and spread biological agents is not as effective as the delivery by aerosol. This is because agents tend to be destroyed by the blast, typically leaving less than 5% of the agent capable of causing disease. Put into food or water: Contamination of a city’s water supplies requires an unrealistically large amount of an agent as well as introduction into the water after it passes through a regional treatment facility. Absorbed through or injected into the skin. This method might be ideal for assassination, but is not likely to be used to cause mass casualties.

DETECTION Biological agents could either be found in the environment using advanced detection devices or after specific testing or by a doctor reporting a medical diagnosis of an illness caused by an agent. Animals may also be early victims and shouldn’t be overlooked. Early detection of a biological agent in the environment allows for early and specific treatment and time enough to treat others who were exposed with protective medications. Currently, the US Department of Defense is evaluating devices to detect clouds of biological warfare agents in the air. Doctors must be able to identify early victims and recognize patterns of disease. If unusual symptoms, a large numbers of people with symptoms, dead animals, or other inconsistent medical findings are noted, a biological warfare attack should be suspected. Doctors report these patterns to public health officials. PROTECTIVE MEASURES Protective measures can be taken against biological warfare agents. These should be started early (if enough warning is received) but definitely once it is suspected that a biological agent has been used. To read more about protective clothing, see Personal Protective Equipment. Masks: Currently, available masks such as the military gas mask or high-efficiency particulate air (HEPA) filter masks used for tuberculosis exposure filter out most biological warfare particles

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delivered through the air. However, the face seals on ill-fitting masks often leak. For a mask to fit properly, it must be fitted to a person’s face. Clothing: Most biological agents in the air do not penetrate unbroken skin, and few organisms stick to skin or clothing. After an aerosol attack, the simple removal of clothing eliminates a great majority of surface contamination. Thorough showering with soap and water removes 99.99% of the few organisms that may be left on the victim’s skin. Medical Protection: Health care providers treating victims of biological warfare may not need special suits but should use latex gloves and take other precautions such as wearing gowns and masks with protective eye shields. Victims would be isolated in private rooms while receiving treatment. Antibiotics: Victims of biological warfare might be given antibiotics orally (pills) or through an IV, even before the specific agent is identified. Vaccinations: Currently, protective vaccines (given as shots) are available for anthrax, botulinum toxin, tularemia, plague, Q fever, and smallpox. The widespread immunization of nonmilitary personnel has not been recommended by any governmental agency so far. Immune protection against ricin and staphylococcal toxins may also be possible in the near future. BACTERIA ANTHRAX Anthrax bacteria occur worldwide. The organisms known as Bacillus anthracis may ordinarily produce disease in domesticated as well as wild animals such as goats, sheep, cattle, horses, and swine. Humans become infected by contact with infected animals or contaminated animal products. Infection occurs mainly through the skin and rarely by breathing spores or swallowing them. Spores exist in the soil and become active when the organisms in the carcass are exposed to air. Apart from biological warfare, anthrax in humans is rare. In the United States, only 127 cases of anthrax appeared in the early years of the 20th century and dropped to about 1 per year during the 1990s.

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SIGNS AND SYMPTOMS Skin anthrax (cutaneous): Infection begins when the spores enter the skin through small cuts or abrasions. Spores then become active in the host (human or animal) and produce poisonous toxins. Swelling, bleeding, and tissue death may occur at the site of infection. More than 95% of the cases of anthrax involve the skin. After a person is exposed, the disease first appears in 1-5 days as a small pimple-looking sore that progresses over the next 1-2 days to contain fluid filled with many organisms. The sore is usually painless and it may have swelling around it. Sometimes the swelling affects a person’s entire face or limb. Victims may have fever, feel tired, and have a headache. Once the sore opens, it forms a black area of tissue. The black appearance of the tissue injury gives anthrax its name from the Greek word anthrakos meaning coal. After a period of 2-3 weeks, the black tissue separates, often leaving a scar. With adequate treatment, less than 1% of people infected with skin anthrax die. Inhalation anthrax: In inhalation anthrax, the spores are inhaled into the lungs where they become active and multiply. There they produce massive bleeding and swelling inside the chest cavity. The germs then can spread to the blood, leading to shock and blood poisoning, which may lead to death. Historically known as woolsorter’s disease (because it affected people who work around sheep), inhalation anthrax can appear anywhere within 1-6 days, or as long as 60 days after exposure. Initial symptoms are general and can include headache, tiredness, body aches, and fever. The victim may have a nonproductive cough and mild chest pain. These symptoms usually last for 23 days. Some people show a short period of improvement. This is followed by the sudden onset of increased trouble breathing, shortness of breath, bluish skin color, increased chest pain, and sweating. Swelling of the chest and neck may also occur. Shock and death may follow within 24-36 hours in most people with this type of infection. Anthrax is not spread from person to person. Inhalation anthrax is the most likely form of disease to follow a military or

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terrorist attack. Such an attack likely will involve the aerosolized delivery of anthrax spores. Mouth, throat, GI tract (oropharyngeal and gastrointestinal): These cases result when someone eats infected meat that has not been cooked sufficiently. After an incubation period of 2-5 days, victims with oropharyngeal disease develop a severe sore throat or sores in the mouth or on a tonsil. Fever and neck swelling may occur. The victim may have trouble breathing. GI anthrax begins with nonspecific symptoms of nausea, vomiting, and fever. These are followed in most victims by severe abdominal pain. The victim may also vomit blood and have diarrhea.

DIAGNOSIS Doctors will perform various tests, especially if anthrax is suspected. With skin anthrax, a biopsy is taken of the sore (lesion), and lab tests are performed to look at the organism under a microscope and confirm the diagnosis of anthrax. The diagnosis of inhalation anthrax is difficult to make. A chest x-ray may show certain signs in the chest cavity. Cultures (growing the bacteria in a lab and then examining them under a microscope) are minimally helpful in making the diagnosis. Blood tests may also be performed. GI anthrax also is difficult to diagnose because the disease is rare and symptoms are not always obvious. Diagnosis usually is confirmed only if the victim has a history of eating contaminated meat in the setting of an outbreak. Once again, cultures generally are not helpful in making the diagnosis. Meningitis (brain swelling) from anthrax is difficult to distinguish from meningitis due to other causes. A spinal tap may be performed to look at the person’s spinal fluid in identifying the organism. The most useful microbiologic test is the standard blood culture, which is almost always positive in victims with anthrax throughout their bodies. Blood cultures should show growth in 6-24 hours and if the laboratory has been alerted to the possibility of anthrax, biochemical testing should provide a preliminary

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diagnosis 12-24 hours later. However, if the laboratory has not been alerted to the possibility of anthrax, there is the chance that the organism may not be identified correctly. Rapid diagnostic tests for anthrax and its proteins include polymerase chain reaction (PCR), enzyme-linked immunosorbent assay (ELISA), and direct fluorescent antibody (DFA) testing. Currently, these tests are only available at national reference laboratories.

TREATMENT Inhalation anthrax: As previously stated because inhalation anthrax moves quickly throughout the body, doctors will begin antibiotic treatment right away even before a firm diagnosis is made through lab testing. Ciprofloxacin (Cipro), doxycycline (Vibramycin), and penicillin are FDA-approved antibiotics for treatment of anthrax. Experts currently recommend ciprofloxacin or other drugs in the same class for adults who are assumed to have inhalation anthrax infection. Penicillin and doxycycline may be used once organism culture sensitivities are known. Traditionally, ciprofloxacin and other antibiotics in that class are not recommended for use in children younger than 16-18 years because of a weak theoretical link to permanent joint disorders. Balancing these small risks against the risk of death and the possibility of infection with a resistant strain of anthrax, experts recommend that ciprofloxacin nonetheless be given to children in appropriate doses. Because there is a risk the infection will recur, victims are treated with antibiotics for at least 60 days. Skin Anthrax: Treatment of skin anthrax with antibiotics generally prevents the disease from progressing to the entire body although the black tissue and scar continue to form. Although previous guidelines have suggested treating skin anthrax with 710 days of therapy, recent recommendations suggest treatment for 60 days in the setting of bioterrorism, thus assuming the person may also have been exposed to inhalational anthrax. In pregnant women, experts recommend that ciprofloxacin be given after exposure as a preventive medication following exposure to an anthrax attack.

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PREVENTION After exposure, the antibiotics ciprofloxacin, or doxycycline may be prescribed by a doctor and the medications are usually taken for 60 days. A vaccination series to protect against anthrax consists of 6 injections given over a period of 18 months, followed by booster shots every year. If a biological warfare attack is expected or may have occurred, people who have not had the vaccine may be given ciprofloxacin or doxycycline for at least 4 weeks. PLAGUE Plague is another infection that can strike humans and animals. It is caused by the bacteria Yersinia pestis, which has been the cause of 3 great human pandemics in the 6th, 14th, and 20th centuries. Throughout history, the oriental rat flea has been largely responsible for spreading bubonic plague. After the flea bites an infected animal, the organisms can multiply inside the flea. When an infected flea attempts to bite again, it vomits clotted blood and bacteria into the victim’s bloodstream and passes the infection on to the next victim, whether small mammal (usually rodent) or human. Although the largest outbreaks of plague have been associated with the rat flea, all fleas should be considered dangerous in areas where plague may be found. The most important vector (a vector is an animal that can transmit the disease) in the United States is the most prevalent flea of rock squirrels and California ground squirrels. The black rat has been most responsible worldwide for the continuing spread of plague in urban epidemics.

SIGNS AND SYMPTOMS People infected with plague may suddenly develop high a fever, painful lymph nodes, and have bacteria in their blood. Some victims with the bubonic form of the disease may develop secondary pneumonic plague (a disease similar to pneumonia). Plague is contagious and when the victim coughs, plague can spread. Pneumonic plague is the most severe form of the disease and if untreated, most people die. As few as 1-10 organisms are enough to infect humans or other animals including rodents.

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During the early phase, the germs usually spread to lymph nodes near the bite, where swelling occurs. The infection then spreads to other organs such as the spleen, liver, lungs, skin, mucous membranes, and later, the brain. In the United States, most victims with human plague have the bubonic form. If the organisms were used as a biological warfare agent, it most likely would be spread through the air and inhaled by victims. The result would be primary pneumonic plague (epidemic pneumonia). If fleas were used as carriers of disease, bubonic or septicemic (blood infection) plague would result. Bubonic Plague: Swollen lymph nodes (called buboes) develop 1-8 days after exposure. Their appearance is associated with the onset of sudden fever, chills, and headache, which often are followed by nausea and vomiting several hours later. The buboes become visible within 24 hours and cause severe pain. Untreated, septicemia (blood poisoning) develops in 2-6 days. Up to 15% of bubonic plague victims develop secondary pneumonic plague and thus can spread illness from person to person by coughing. Septicemia Plague: Septicemia plague may occur with bubonic plague. The signs and symptoms of primary septicemic plague include fever, chills, nausea, vomiting, and diarrhea. Later, bleeding in the skin may develop, hands and feet may lose circulation, and tissue may die. Pneumonic Plague: Pneumonic plague may occur primarily from inhaling organisms in the air or from exposure to infected blood. Victims typically have a productive cough with bloodtinged sputum within 24 hours of symptom onset.

DIAGNOSIS The diagnosis of bubonic plague may be made if the victim has painful lymph glands and other common symptoms, especially if the victim has been exposed to rodents or fleas. But if the victim is not in an area where plague is present and symptoms are typical of other illnesses, the diagnosis may be difficult. The doctor may view under a microscope a sample of sputum from a productive cough or the fluid from a swollen lymph gland. Samples may grow in the laboratory and indicate plague within 48 hours and blood tests may also be performed.

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TREATMENT Victims of suspected plague will be isolated for the first 48 hours after treatment begins. If pneumonic plague is present, isolation may last for 4 more days. Since 1948, streptomycin has been the treatment of choice for plague but other antibiotics may be given. If treated with antibiotics, buboes typically become smaller in 10-14 days and do not require drainage. Victims are unlikely to survive primary pneumonic plague if antibiotic therapy is not begun within 18 hours of the beginning of symptoms. Without treatment, 60% of people with bubonic plague die, and 100% with pneumonic and septicemic forms die. PREVENTION Fleas always must be targeted for destruction before the rodents, because killing rodents may release into the environment massive amounts of infected fleas, which will be hungry for a blood meal and, in the absence of rodents, the fleas will seek out any warm-blooded animal including humans and infect them. Pesticides have been successful in getting rid of rats and other animal hosts. Public education about how plague spreads is an important part of prevention. People who have been exposed to pneumonic plague and those who have been exposed to organisms in the air may be treated with antibiotics such as tetracycline or doxycycline for 6 days. Contacts with victims who have bubonic plague do not need preventive medication. But people who were in the same environment as those who are infected may need preventive antibiotics. A previously FDA-approved plague vaccine is no longer manufactured. It was useful against the bubonic form of plague but not the more serious pneumonic (lung) form of plague, which is the kind most often expected in a terrorist incident. A new vaccine effective against all varieties of plague is under development. Only those at high risk for plague should be given the vaccine. This might include military troops and personnel working in areas where plague exists and lab personnel working with the

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organism. The current vaccine against bubonic plague by flea bite does not have the same effectiveness against the organisms released in the air. CHOLERA Cholera is an acute and potentially severe gastrointestinal disease (stomach and intestines) caused by the bacteria Vibrio cholerae. This agent has been investigated in the past as a biological weapon. Cholera does not spread easily from human to human, so it appears that major drinking water supplies would have to be profusely contaminated for this agent to be effective as a biological weapon. Cholera normally can infect water or food that becomes contaminated by human bowel waste. The organism can survive for up to 24 hours in sewage and as long as 6 weeks in certain types of relatively impure water containing organic matter. It can withstand freezing for 3-4 days, but it is killed readily by dry heat, steam, boiling, short-term exposure to ordinary disinfectants, and chlorination of water. The toxin causes a person’s intestines to create massive amounts of fluid that then produces thin, grayish brown diarrhea.

SIGNS AND SYMPTOMS Depending on how many organisms a person drinks or eats, the illness could begin within 12-72 hours. The symptoms start suddenly with intestinal cramps and painless (rice-water appearing) diarrhea. Vomiting, feeling ill, and headache often accompany the diarrhea, especially early in the illness. Fever is rare. If untreated, the disease generally lasts 1-7 days. During the illness, the body loses great amounts of fluid, so it is important during recovery to replace fluids and balance electrolytes (such as sodium and potassium). Children may experience seizures and cardiovascular imbalances severe enough to cause heart problems. The rapid loss of body fluids often leads to more severe illness. If not treated, up to half of children with cholera may die. DIAGNOSIS The doctor may examine a sample of the stool under a microscope to confirm the diagnosis. Symptoms alone are usually enough to identify cholera.

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TREATMENT Fluids and electrolytes need to be replaced because the body has lost large amounts of fluids through the vomiting and diarrhea. Doctors may encourage the person to drink, but if someone continues to vomit or has frequent stools, an IV may be used to replace the fluid lost. Antibiotics such as tetracycline or doxycycline shorten the duration of diarrhea and reduce fluid losses. The antibiotics ciprofloxacin or erythromycin also may be used for a few days. PREVENTION A live vaccine is available for use in those considered to be at risk for exposure. The vaccine is protective for only about half of those immunized, and protection lasts for no more than 6 months. The vaccination schedule is an initial dose followed by another dose 4 weeks later, with booster doses every 6 months. An inactivated oral vaccine is safe and provides rapid shortterm protection. It requires 2 doses and has about 85% efficacy lasting 2-3 years for 2 different types of cholera. TULAREMIA Tularemia is an infection that can strike humans and animals. It is caused by the bacterium Francisella tularensis. The disease causes fever, localized skin or mucous membrane ulcerations, regional swelling of lymph glands, and occasionally pneumonia. G.W. McCay discovered the disease in Tulare County, California, in 1911. The first confirmed case of human disease was reported in 1914. Edward Francis, who described transmission by deer flies via infected blood, coined the term tularemia in 1921. It has been considered an important biological warfare agent because it can infect many people if dispersed by the aerosol route. Rabbits and ticks most commonly spread tularemia in North America. In other areas of the world, tularemia is transmitted by water rats and other aquatic animals. The bacteria are usually introduced into the victim through breaks in the skin or through the mucous membranes of the eye, respiratory tract, or GI tract. Ten virulent organisms injected under

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the skin from a bite or 10-50 organisms breathed into the lungs can cause infection in humans. Hunters may contract this disease by trapping and skinning rabbits in some parts of the country.

SIGNS AND SYMPTOMS Tularemia can be divided into 2 forms: the ulceroglandular (75% of cases) and typhoidal (25% of cases). Victims with the ulceroglandular type have sores on the skin or mucous membranes, large lymph nodes, or both. Those with typhoidal tularemia have smaller lymph nodes and no skin sores. After 3-6 days, people with the ulceroglandular form of the disease develop a group of symptoms: fever, chills, headache, cough, and muscle aches. They may also have chest pain, vomiting, joint pain, sore throat, abdominal pain, diarrhea, shortness of breath, back pain, or neck stiffness. A sore up to an inch across may appear on the skin in about 60% of people and is the most common sign of tularemia. If the bite associated with infection was from an animal carrying the disease, the sore is usually on the upper part of a person’s body, such as on the arm. If the infection came from an insect bite, the sore might appear on the lower part of the body, such as on the leg. Enlarged lymph nodes are seen in about 85% of victims and may be the initial or the only sign of infection. Although enlarged lymph nodes usually occur as single lesions, they may appear in groups. Enlarged lymph nodes may come and go and last for as long as 3 years. When swollen, they may be confused with buboes of bubonic plague. Sore throat and other complications may occur in up to 25% of people with tularemia. People with either type of tularemia may develop pneumonia. They may have a productive or nonproductive cough and possibly chest pain, shortness of breath, and vomit blood. DIAGNOSIS Tularemia can be diagnosed by growing the bacteria in the laboratory from samples taken of blood, ulcers, sputum, and other body fluids. Blood tests may not be helpful.

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TREATMENT Victims with tularemia who do not receive appropriate antibiotics may have a prolonged illness with weakness and weight loss. Treated properly, very few people with tularemia die. A 14day course of streptomycin is effective treatment for tularemia. Gentamicin is also effective. Although tetracycline and chloramphenicol have also been found effective, they are associated with significant relapse rates. Although laboratory-related infections with this organism are common, human-to-human spread is unusual. Victims do not need to be isolated from others. PREVENTION An antibiotic given after exposure to tularemia is difficult, because the ideal drug, streptomycin, must be given by injection. Tetracycline is effective after exposure to an aerosol of tularemia if given within 24 hours of the exposure and taken for 14 days. A vaccine has been developed and used in humans since 1940. In the 1960s, a more purified vaccine was developed. Extensive studies have demonstrated that the vaccine protects humans against the organism released into the air. Immunization with the vaccine prevents the typhoidal type and lessens the effects of the ulceroglandular form of tularemia. BRUCELLOSIS Brucellosis is an infection of domesticated and wild animals that can be transmitted to humans. It is caused by an organism of the genus Brucella. The organism infects mainly cattle, sheep, goats, and other similar animals causing death of developing fetuses and genital infection. Humans, who usually are infected incidentally by contact with infected animals, may develop numerous symptoms in addition to the usual ones of fever, general illness, and muscle pain. The disease often becomes long-term and may return, even with appropriate treatment. The ease of transmission through the air suggests that these organisms may be useful in biological warfare. Each of 6 different species may tend to infect certain animal species. Four are known to cause illness in humans. Animals

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may transmit organisms during a miscarriage, at the time of slaughter, and in their milk. Brucellosis is rarely, if ever, transmitted from human to human. Certain species can enter animal hosts through skin abrasions or cuts, the eye membranes, the respiratory tract, and the GI tract. Organisms grow rapidly and eventually go to the lymph nodes, liver, spleen, joints, kidneys, and bone marrow.

SIGNS AND SYMPTOMS Victims may have a fever or a long-term infection or just a local inflammation. The disease may appear suddenly or develop slowly anywhere from 3 days to several weeks after exposure. Symptoms include fever, sweats, fatigue, loss of appetite, and muscle or joint aches. Depression, headache, and irritability occur frequently. In addition, infection of bones, joints, or the genitourinary tract may cause pain. Cough and chest pain also may be noted. Symptoms often last 3-6 months and occasionally for longer than a year. Different species of the organism can cause different symptoms from skin sores to low back pain to liver disease. DIAGNOSIS The doctor will want to know about any exposure to animals, animal products, or environmental exposures in making the diagnosis. Military troops exposed to a biological attack and who have fever are likely candidates for this illness. Environmental samples may show the presence of this organism in the attack area. Laboratory tests and cultures of blood or body fluid samples including bone marrow may be performed. TREATMENT Therapy with a single drug has resulted in a high relapse rate, so a combination of antibiotics should be prescribed. A 6-week course of doxycycline along with streptomycin for the first 2 weeks is effective in most adults with most forms of brucellosis. PREVENTION Animal handlers should wear appropriate protective clothing when working with infected animals. Meat should be well cooked,

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and milk should be pasteurized. Laboratory workers need to take appropriate cautions in handling the organism. In the event of a biological attack, the standard gas mask should protect adequately from airborne species. No commercially available vaccine exists for humans. Q FEVER Q fever is a disease that also affects animals and humans. It is caused by the bacteria Coxiella burnetii. A sporelike form of the organism is extremely resistant to heat, pressure, and many cleaning solutions. This allows the germs to live in the environment for long periods under harsh conditions. In contrast, the disease it causes in humans is usually not harmful, although it can be temporarily disabling. Even without treatment, most people recover. The organism is extremely infectious. The potential of the organism as a biological warfare agent is related directly to its ability to infect people easily. A single organism is capable of producing infection and disease in humans. Different strains have been identified worldwide. Humans have been infected most commonly by contact with domestic livestock, particularly goats, cattle, and sheep. The risk of infection is increased greatly if humans are exposed while these animals are giving birth to young. Large numbers of the germs may be released into the air as an animal gives birth. Survival of the organism on surfaces, such as straw, hay, or clothing, allows for transmission to other people who are not in direct contact with infected animals. People can become infected by breathing the organisms.

SIGNS AND SYMPTOMS Humans are the only hosts that commonly develop an illness as a result of the infection. The illness may begin within 10-40 days. There is no typical pattern of symptoms, and some people show none at all. Most people appear mildly to moderately ill. Fever (can go up and down and last less than 13 days), chills, and headache are the most common signs and symptoms. Sweating, aches, fatigue, and loss of appetite are also common.

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Cough often occurs later in the illness. Chest pain occurs in a few people. Sometimes there is a rash. Other symptoms such as headache, facial pain, and hallucinations have been reported. Sometimes problems in the lungs are seen on chest x-rays. And some people may seem to have acute hepatitis because of their liver involvement. Others may develop a heart condition called endocarditis.

DIAGNOSIS Blood tests may help in making the diagnosis of Q fever. TREATMENT Tetracycline has been the main drug used since the 1950s. When initiated within the first few days of the illness, treatment significantly shortens its course. Other antibiotics, such as erythromycin and azithromycin, are also effective. People with chronic Q fever who develop endocarditis may die, even with appropriate treatment. PREVENTION Although an effective vaccine (Q-Vax) is licensed in Australia, all Q fever vaccines used in the United States are under study. Q fever can be prevented by immunization. SMALLPOX Variola (the virus that causes smallpox) is the most notorious of the poxviruses. Smallpox was an important cause of illness and death in the developing world until recent times. In 1980, the World Health Organization (WHO) declared that smallpox had been completely wiped out. The last case was noted in Somalia in 1977. Variola represents a significant threat as a biological warfare agent. Variola is highly infectious and is associated with a high death rate and secondary spread. Currently, the majority of the US population has no immunity, vaccine is in short supply, and no effective treatment exists for the disease. Two WHO-approved and inspected repositories remain: One is at the Centers for Disease Control and Prevention in the United States; the other at Vector

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Laboratories in Russia. It is widely believed that clandestine stockpiles exist in other countries such as Iraq and North Korea. Variola virus is highly infectious when released into the air. It is environmentally stable and can retain its ability to infect people for long periods. Infection through contaminated objects such as clothing is infrequent. After a person is exposed to aerosolized virus, the virus multiplies in the person’s respiratory tract. After a period of 7-17 days, variola is spread through the bloodstream to lymph nodes where it continues to multiply. Variola then moves into smaller blood vessels near the surface of the skin where the inflammatory changes occur. The classic smallpox rash then begins. Two types of smallpox generally are recognized. Variola major, the most severe form, may cause death in up to 30% of unvaccinated people who develop it. (3% of people vaccinated people may also develop variola major). Variola minor, a milder form of smallpox, produces death in 1% of unvaccinated people.

SIGNS AND SYMPTOMS The symptoms of variola major occur after a 7- to 17-day incubation period. They begin acutely with high fever, headache, chills, aches, vomiting, abdominal and back pain. During the initial phase, 15% of people develop delirium (hallucinations), and 10% of light-skinned people may develop a fleeting rash. After 2-3 days, the rash develops on the face, hands, and forearms and extends gradually to the trunk and lower part of the body. The sores progress all at once into fluid-filled sacs. The distribution of the rash is important in making the diagnosis of smallpox. A greater number of lesions will appear on the face arms and legs compared to the trunk. People with smallpox are most infectious on days 3-6 after the fever begins. Virus is spread to others through coughing and sneezing or by direct contact. With the milder form of smallpox, variola minor, the skin sores are similar but smaller and fewer in number. People are not as ill as those who have variola major.

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DIAGNOSIS Most doctors have never seen a case of smallpox and may have difficulty diagnosing it. Other viral illnesses with rash, such as chickenpox or allergic contact dermatitis, can look similar. Smallpox is different from chickenpox because of the distribution of the lesions and because they are all at the same stage of development everywhere on the body. With chickenpox, sores may be forming while others are scabbing over. The failure to recognize mild cases of smallpox in people with partial immunity permits rapid person-to-person transmission. Exposed people may shed virus through coughing without ever showing the signs and symptoms of the disease. The doctor may look at scrapings of tissue under a microscope but will be unable to tell the difference between smallpox and monkeypox or cowpox. Advanced PCR techniques have been developed and may provide for more accurate diagnosis in the near future. TREATMENT People with smallpox are usually isolated from people without smallpox for 17 days. Anyone exposed to either weaponized variola or people infected with smallpox must be vaccinated immediately; this may lessen or prevent the illness if done within 4 or 5 days of infection. Treatment of smallpox is mainly to help relieve symptoms. The antiviral agent, cidofovir, may be effective in treating symptoms. For more on smallpox, see Smallpox. PREVENTION Smallpox vaccine is used to prevent people from getting smallpox. The vaccine is given as a type of shot, but a 2-pronged needle is used to place the medication into the skin. This leaves a permanent scar, which many adults may still have from smallpox inoculations given to them when they were babies. Once the shot is given, a small fluid-filled pimple usually appears 5-7 days later. A scab forms over the site during the next

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1-2 weeks. Common side effects include low-grade fever and swollen lymph glands. People with weakened immune systems should not have the smallpox vaccination. This includes people with HIV, anyone with a history of eczema, and pregnant women. MONKEYPOX The monkeypox virus is a naturally occurring relative of variola, which is found in Africa. The first case of human monkeypox was identified in 1970, but fewer than 400 cases have been diagnosed since. Some concern exists that monkeypox may be weaponized, however, human monkeypox is not as potent as smallpox. Pneumonia due to monkeypox may cause death in about half of people who develop it. VIRAL ENCEPHALITIDES The viral encephalitides, Venezuelan equine encephalitis (VEE) virus, western equine encephalitis (WEE) virus, and eastern equine encephalitis (EEE) virus, are members of the Alphavirus genus and are regularly associated with encephalitis. These viruses were recovered from horses during the 1930s. VEE was isolated in the Guajira peninsula of Venezuela in 1930, WEE in the San Joaquin Valley of California in 1930, and EEE in Virginia and New Jersey in 1933. Although natural infections with these viruses occur following bites from mosquitos, the viruses are also highly infectious when spread through the air. If intentionally released as a small particle aerosol, this virus may be expected to infect a high percentage of people exposed within a few miles. VEE virus has the capacity to produce epidemics. Outcomes are significantly worse for the very young and the very old. Up to 35% of people infected may die. WEE and EEE typically produce less severe and widespread disease but are associated with death rates as high as 50-75% in those with severe illness.

SIGNS AND SYMPTOMS VEE: After an incubation period of 2-6 days, people with VEE develop fevers, chills, headache, aches, sore throat, and sensitivity to light (eyes). They may become mildly confused, have seizures

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or paralysis, or go into a coma. For those who survive, their nervous system functions usually recover completely. EEE: The incubation period for EEE varies from 5-15 days. Adults may have certain early symptoms up to 11 days before the onset of nervous system problems such as mild confusion, seizures, and paralysis. Signs and symptoms include fever, chills, vomiting, muscle rigidity, lethargy, slight paralysis, excess salivation, and difficulty breathing. Children frequently develop swelling on their face and near their eyes. Up to 30% of survivors of severe disease have permanent nervous system problems such as seizures and various degrees of confusion (dementia). WEE: The incubation period is 5-10 days. Most people have no symptoms, or they might develop a fever. Other symptoms include nausea, vomiting, headache, a stiff neck, and drowsiness. Up to 90% of victims younger than 1 year have seizures. Typically, adults recover completely. Children, especially newborns, may have lasting nervous system problems.

DIAGNOSIS Laboratory tests, including nasal swab samples, may show any of the 3 viruses. TREATMENT No specific treatment is available. Doctors will help control symptoms. For some people that may include medications to control fever and seizures or help breathing. PREVENTION A vaccine for VEE can be given as an injection for those at high risk, such as laboratory field personnel. About 20% of those who receive the vaccine fail to respond to it, meaning they would not be protected by the vaccine. An additional 25% of those vaccinated develop high fever, chills, and feel sick enough to be in bed. A different vaccine was developed for those who did not develop protection from the initial activated vaccine. It is an inactivated vaccine, which produces only mild tenderness at the injection site. Shots are given at 2- and 4-week intervals until the person responds and develops antibodies as protection.

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The EEE vaccine is inactivated and given as an injection (1 to start and another 28 days later). There are no serious side effects or long-term problems with this vaccine. Boosters are required. VIRAL HEMORRHAGIC FEVERS Viral hemorrhagic fevers are caused by 4 families of viruses. Arenaviridae (Lassa, Argentine, Bolivian, Brazilian, Venezuelan hemorrhagic fevers) Bunyaviridae (Rift Valley, Crimean-Congo, Hantaan) Filoviridae (Marburg, Ebola) Flaviviridae (Yellow, Dengue, Kyasanur Forest, Omsk HFs) The best known of the viral hemorrhagic fevers is Ebola virus. First recognized in Zaire in 1976, the virus has been linked to 3 outbreaks in Africa. Up to 92% of people who contract Ebola will die. A related virus was discovered in Reston, Virginia, in 1989 in association with an outbreak of illness among monkeys imported from the Philippines. No human cases occurred with this outbreak. These viruses are each characterized by an acute generalized illness that includes feeling quite ill (flulike illness) with profound exhaustion and often associated internal bleeding. All agents are highly infectious via the aerosol route, and most are stable as respiratory aerosols. Thus, they possess characteristics that may make them attractive for use by terrorists. The agents that produce viral hemorrhagic fever are all simple RNA viruses. They are able to survive in blood for long periods, which means they can infect people who are around animals slaughtered domestically. These viruses are linked to the rodent or insect that helps to spread them, which helps in searching for a diagnosis. The specific viral hemorrhagic fever that develops depends on many factors such as the strength of the virus, its strain, and the route of exposure.

SIGNS AND SYMPTOMS All viral hemorrhagic fevers primarily target blood vessels. They damage the blood vessels and produce internal bleeding. Victims may have fever, aches, exhaustion, infected eyes, low

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blood pressure to severe shock, and bleeding in tiny blood vessels such as in the eye. More severe cases will have serious problems with the nervous system, liver, and lungs. Depending on the type of virus, symptoms can include deafness, severe internal bleeding, kidney failure, rash, black (bloody) vomit, and other life-threatening symptoms.

DIAGNOSIS It is important for the doctor to know a person’s travel history in making a diagnosis of viral hemorrhagic fever. These agents are linked tightly with their natural geographic area and the ecology of the species and vectors found in that specific locale. Victims often recall exposures to rodents (Arenavirus, Hantavirus), mosquitoes (Rift Valley fever virus, yellow and dengue fever viruses), or even slaughtered horses (Rift Valley fever virus, Crimean-Congo virus). Laboratory tests may be helpful. Testing can be conducted at the CDC in Atlanta or the US Army Medical Research Institute of Infectious Disease (USAMRIID) at Fort Detrick in Frederick, Maryland. TREATMENT Treatment for viral hemorrhagic fevers is largely directed at easing the discomfort of the symptoms. Victims benefit from being placed in a hospital setting immediately. Air transport is not advised. Sedative and pain-relieving medications are helpful, but aspirin and similar drugs should not be given because of their tendency to make bleeding worse. Doctors will also not usually use IV lines or catheters because of bleeding problems. The treatment for bleeding is controversial. Generally, mild bleeding is not usually treated, but severe bleeding requires appropriate replacement therapy (blood through an IV line). Specific treatment with ribavirin has been used and is currently under investigation as a therapy for Lassa fever, Hantavirus, Crimean-Congo, and Rift Valley Fever. Treatment is most effective if begun within 7 days. Ribavirin has poor activity against the filoviruses and flaviviruses.

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PREVENTION The only established and licensed virus-specific vaccine against any of these viruses is the yellow fever vaccine. It is mandatory for those traveling into areas of Africa and South America where the disease is commonly found. Current trials are underway for further vaccines and antibody therapies. TOXINS STAPHYLOCOCCAL ENTEROTOXIN B Staphylococcal enterotoxin B (SEB) is one of the best-studied and, therefore, best-understood toxins. Staphylococcal enterotoxin is one of the most common causes of food poisoning. Nausea, vomiting, and diarrhea normally occur after someone eats or drinks contaminated food. The toxin creates different symptoms when exposure is through the air in a biological warfare situation. Only a small, inhaled dose is necessary to harm people within 24 hours of inhalation.

SIGNS AND SYMPTOMS After exposure, signs and symptoms begin in 2-12 hours. Mild-to-moderate exposure to SEB produces fever, chills, headache, nausea, vomiting, shortness of breath, chest pain, body aches, and a nonproductive cough. Severe exposures can lead to a toxic shock -type picture and even death. Depending on the severity of exposure, the illness may last 3-10 days. DIAGNOSIS Diagnosis of SEB can be difficult. Laboratory tests and a chest x-ray may be performed. Nasal swabs may show the toxin for 1224 hours after exposure. TREATMENT Doctors provide care to relieve symptoms. Close attention to oxygenation and hydration are important. People with severe SEB may need help breathing with a ventilator. Most victims are expected to do well after the initial phase, but the time to full recovery may be long.

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PREVENTION No approved human vaccine exists for SEB, although human trials are ongoing. Passive immunotherapy agents have demonstrated some promise when given within 4 hours of exposure, but such therapy is still being tested. RICIN Ricin, a plant protein toxin derived from the beans of the castor plant, is one of the most toxic and easily produced of the plant toxins. Although the lethal toxicity of ricin is about 1000fold less than botulinum toxin, the worldwide ready availability of castor beans and the ease with which the toxin can be produced give it significant potential as a biological weapon. Since ancient times, more than 750 cases of ricin intoxication have been described. Ricin may have been used in the highly published killing of Bulgarian exile Georgi Markov in London in 1978. He was attacked with a device in an umbrella that implanted a ricin-containing pellet into his thigh.

SIGNS AND SYMPTOMS The toxicity of ricin varies greatly with the way it is given. Ricin is extremely toxic to cells and acts by inhibiting protein synthesis. Inhalation exposure causes primarily breathing and lung problems. If eaten, ricin causes symptoms in the GI tract. If injected, the reaction takes place in that area. Following inhalation exposure of ricin, toxicity is characterized by the sudden onset of nasal and throat congestion, nausea and vomiting, itching of the eyes, itching, and tightness in the chest. If exposure is significant, after 12-24 hours severe breathing problems may set in. In animal studies, death occurs 36-48 hours after severe exposure. Ingestion of ricin is generally less toxic because it is not absorbed well and may degrade in the digestive tract. Out of 751 ingestions recorded, only 14 resulted in a death. At low doses, injection exposures produce flulike symptoms, body aches, nausea, vomiting, and localized pain and swelling at the injection site. Severe exposure results in tissue death and GI bleeding, as well as widespread liver, spleen, and kidney problems.

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DIAGNOSIS The diagnosis of ricin poisoning is made on the basis of symptoms and whether exposure was possible. In biological warfare, exposure is likely to occur by inhalation of a toxin aerosol. Victims may have certain signs on a chest x-ray. The diagnosis can be confirmed by lab tests on samples from a nasal swab. Ricin can be identified for up to 24 hours after exposure. TREATMENT Treatment is mainly to relieve symptoms. If exposure was by inhalation, the person may need help breathing. Those who ingested the poison may need to have their stomachs pumped (gastric lavage), or they might be given activated charcoal to soak up the material. PREVENTION Currently, no vaccine is available for ricin exposure. Test vaccines have proven effective in animals. Other drugs are being studied as well. BOTULINUM TOXIN Botulinum toxins are the most deadly toxins known. Because botulinum toxin is so lethal and easy to manufacture and weaponize, it represents a credible threat as a biological warfare agent. When used in this manner, exposure is likely to occur following inhalation of aerosolized toxin or ingestion of food contaminated with the toxin or its microbial spores. Iraq admitted to active research on the offensive use of botulinum toxins and to weaponizing and deploying more than 100 munitions with botulinum toxin in 1995. All 7 subtypes (A-G) of botulinum toxin act in similar ways. The toxin produces similar effects whether ingested, inhaled, or via a wound. The time course and severity of illness vary with route of exposure and dose received. Symptom onset is slower after inhalation exposure.

SIGNS AND SYMPTOMS Symptoms may occur hours to several days after exposure. Initial signs and symptoms include blurred vision, dilated pupils,

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difficulty swallowing, difficulty speaking, an altered voice, and muscle weakness. After 24-48 hours, muscle weakness and paralysis may cause the person to be unable to breathe. Varying degrees of muscular weakness may occur.

DIAGNOSIS Paralysis may indicate the presence of this exposure. Laboratory tests generally are not helpful. Infection by inhalation can be diagnosed from nasal swabs up to 24 hours after exposure. TREATMENT The most serious complication is respiratory failure. With attention to symptoms and help breathing, sometimes with a ventilator, death occurs in fewer than 5% of cases. For confirmed exposures, an antitoxin is available from the CDC. This antitoxin has all of the disadvantages of horse serum products, including the risks for shock and serum sickness. Skin testing is performed first by injecting a small amount of the antitoxin into the skin and then monitoring the person for 20 minutes. PREVENTION A toxoid (inactivated toxin that produces immunity) has been used in volunteers and occupationally at-risk workers. It is available through the CDC. It was used to immunize US military troops during the Persian Gulf War. The current schedule for immunization is at 0, 2, and 12 weeks with an annual booster. MYCOTOXINS The trichothecene mycotoxins are highly toxic compounds produced by certain species of fungi. Because these mycotoxins can cause massive organ damage, and because they are fairly easy to produce and can be dispersed by various methods (dusts, droplets, aerosols, smoke, rockets, artillery mines, portable sprays), mycotoxins have an excellent potential for weaponization. Strong evidence suggests that trichothecenes (“yellow rain”) have been used as a biological warfare agent in Southwest Asia and Afghanistan. From 1974-1981, numerous attacks resulted in a minimum of 6310 deaths in Laos, 981 deaths in Cambodia, and

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3042 deaths in Afghanistan. When taken from fungal cultures, the mycotoxins yield a yellow-brown liquid that evaporates into a yellow crystalline product (thus, the “yellow rain” appearance). These toxins require certain solutions and high heat to be completely inactivated.

SIGNS AND SYMPTOMS After exposure to the mycotoxins, early symptoms begin within 5 minutes. Full effects take 60 minutes. If skin exposure occurs, the skin burns, becomes tender, swollen, and blisters. In lethal cases, large areas of skin die and slough (fall off). Respiratory exposure results in nasal itching, pain, sneezing, a bloody nose, shortness of breath, wheezing, cough, and bloodtinged saliva and sputum. If ingested, the person feels nausea and vomits, loses appetite, feels abdominal cramping, and has watery and/or bloody diarrhea. Following entry into the eyes, pain, tearing, redness, and blurred vision occur. Systemic toxicity may occur and includes weakness, exhaustion, dizziness, inability to coordinate muscles, heart problems, low or high temperature, diffuse bleeding, and low blood pressure. Death may occur within minutes to days depending on the dose and route of exposure. DIAGNOSIS Diagnosis of an attack of trichothecene mycotoxin depends on the symptoms and identifying the toxin from biological and environmental samples. Many people with these symptoms may report being in a yellow rain or smoke attack. Initial laboratory tests are not always helpful. Currently, a rapid identification kit for any of the trichothecene mycotoxins does not exist. Gas-liquid chromatography has been used in the past with great success. However, chromatographic methods lack great sensitivity, and presently alternative methods of detection are under investigation. TREATMENT Treatment is mainly to help with symptoms. The immediate use of protective clothing and mask during a mycotoxin aerosol

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attack should prevent illness. If a soldier is unprotected during an attack, the outer clothing should be removed within 4-6 hours and decontaminated with 5% sodium hydroxide for 6-10 hours. The skin should be washed with copious amounts of soap and uncontaminated water. The eyes, if exposed, should be washed out with large amounts of normal saline or sterile water. US military personnel can use a skin decontamination kit effectively against most chemical warfare agents, including the mycotoxins. No specific therapy exists for a trichothecene exposure. After appropriate skin decontamination, victims of inhalation and oral exposures may be given superactivated charcoal orally. Activated charcoal removes mycotoxins from the GI tract. Some victims may need help breathing with a ventilator. Early use of steroids increases survival time by decreasing the primary injury and shock-like state that follows significant poisoning.

PREVENTION No vaccine exists for trichothecene mycotoxin exposure. Currently, 2 topical skin protectants as well as vaccines are in advanced development but have not been approved yet for use in humans.

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4 CHEMICAL WARFARE RISK OF EXPOSURE Injury from chemical weapon agents, known as CWAs, may result from industrial accidents, military stockpiling, war, or a terrorist attack. Industrial accidents are a significant potential source of exposure to chemical agents. Chemicals such as phosgene, cyanide, anhydrous ammonia, and chlorine are used widely. These chemicals are frequently transported by industry. The accidental release of a methylisocyanate cloud (composed of phosgene and isocyanate) was implicated in the Bhopal, India, disaster in 1984. Chemical weapons first were used in 1915, when the German military released 168 tons of chlorine gas at Ypres, Belgium, killing an estimated 5,000 Allied troops. Two years later, the same battlefields saw the first deployment of sulfur mustard. Sulfur mustard was the major cause of chemical casualties in World War I. CWAs have been used in at least 12 conflicts since, including the first Persian Gulf War (Iraq-Iran War). The Iraqi military also used chemical weapons against the Iraqi Kurds during the second Persian Gulf War. Civilians also have been exposed inadvertently to chemical weapons many years after weapon deployment during war. Some 50,000 tons of mustard shells were disposed of in the Baltic Sea following World War I. Since then, numerous fishermen have been burned accidentally while hauling leaking shells aboard

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boats. Leaking mustard shells also have injured collectors of military memorabilia and children playing on old battlefields. Although a number of international treaties have banned the development, production, and stockpiling of chemical weapons, these agents reportedly are still being produced or stockpiled in several countries. Within the last decade, terrorists deployed chemical weapons against civilian populations for the first time in history. The release of sarin in Matsumoto, Japan, in June 1994 by the extremist Aum Shinrikyo cult left 7 dead and 280 injured. The following year, the Aum Shinrikyo cult released sarin vapor in the Tokyo subway system during morning rush hour, leaving 12 dead and sending more than 5,000 casualties to local hospitals. Several characteristics of chemical weapon agents lend themselves to terrorist use. Chemicals used in CWAs are widely available, and recipes for CWA production may be found on the Internet. CWAs are transported easily and may be delivered by a variety of routes. Chemical agents often are difficult to protect against and quickly incapacitate the intended targets. Most civilian medical communities are inadequately prepared to deal with a chemical terrorist attack. TYPES OF CHEMICAL WEAPON AGENTS Chemical weapon agents are hazardous substances. Major categories of CWAs include the following: Nerve agents (such as sarin, soman, cyclohexylsarin, tabun, VX) Vesicating or blistering agents (such as mustards, lewisite) Choking agents or lung toxicants (such as chlorine, phosgene, diphosgene)

CYANIDES Incapacitating agents (such as anticholinergic compounds) Lacrimating or riot control agents (such as pepper gas, chloroacetophenone, CS) Vomiting agents (such as adamsite)

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Physical Properties: CWAs generally are stored and transported as liquids and deployed as either liquid aerosols or vapors. Victims usually are exposed to agents via 1 or more of 3 routes: skin (liquid and high vapor concentrations), eyes (liquid or vapor), and respiratory tract (vapor inhalation). In general, some liquids may be harmful whether inhaled into the lungs or absorbed into the skin. Vapors can be affected by winds. Even a slight breeze can blow a nerve agent vapor away from its intended target. The effects of vapor are enhanced when used within an enclosed space. Clinical Effects: Depending on the agent and the type and amount (concentration) of exposure, CWA effects may be immediate or delayed. Large inhalation exposures to nerve agents or mustards are likely to kill people immediately. Small exposures on the skin to nerve agents and mustards are more dangerous than they seem at first. People exposed to such agents need to be carefully observed for slowly developing or delayed effects. A chart of signs and symptoms is available from the North Carolina Statewide Program for Infection Control and Epidemiology. Medical Management: Ideally, emergency personnel will wear personal protective equipment, decontaminate the victims immediately, provide medical support to the victims and provide specific antidotes to counteract the harmful effects. Personal Protective Equipment: First responders to a chemical attack are at serious risk themselves from the chemically contaminated environment (known as the hot zone). They can come in direct contact with the CWA or inhale the vapor. They are also at risk if they handle skin and clothing of victims if a liquid chemical agent was used. Vapors pose little added risk for anyone outside the hot zone. Decontamination: Decontamination is the physical process of removing the remaining chemicals from people, equipment, and the environment. Residual hazardous chemicals on those who have been exposed directly are a source of ongoing exposure to others and pose a risk of secondary exposure to first responders and emergency care personnel. Immediate decontamination is a major treatment priority for those with CWA exposure. Initial decontamination involves removing all contaminated clothes and

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jewelry from the affected person and then washing the body thoroughly with warm water and soap.

vapors are heavier than air and tend to sink into low places (for example, trenches or basements).

Hot water and vigorous scrubbing may actually worsen the effects by increasing chemical absorption into the skin.

Signs and symptoms: Nerve agents produce various signs and symptoms depending on the agent someone might be exposed to, its concentration, and length of exposure.

Vapor exposure alone may not require decontamination. But if it is not known whether the exposure was to a vapor or liquid, or if exposed people have symptoms, they should undergo decontamination. Ideally, decontamination will take place as close as possible to the site of exposure to minimize duration of exposure and prevent further spread. Hospitals receiving contaminated people may establish an area outside the Emergency Department in which to perform initial decontamination before people and equipment are allowed entry. Portable decontamination equipment with showers and run-off water collection systems are commercially available. All hospitals should have the capacity to safely decontaminate at least 1 person. Supportive and specific therapy: Doctors will first make sure exposed victims are able to breathe. For many chemical warfare agents, doctors can only treat the symptoms they produce. But specific, well-established antidotes are available for nerve agent and cyanide exposures. Lab tests are not widely available in hospitals to rapidly confirm exposure to chemical agents.

NERVE AGENTS The 5 nerve agents, tabun (GA), sarin (GB), soman (GD), cyclohexylsarin (GF), and VX, have chemical structures similar to the common organophosphate pesticide Malathion. These agents initially stimulate and then paralyze certain nerve transmissions throughout the body and cause other toxic effects such as seizures. Physical properties: Under temperate conditions, all nerve agents are volatile liquids, which means they can evaporate quickly. The most volatile agent, sarin, evaporates at about the same rate as water. The least volatile agent, VX, has the consistency of motor oil, which makes it 100-150 times more toxic than sarin when victims are exposed on their skin. A 10 mg dose applied to the skin may cause death in up to half of unprotected people. All nerve agents rapidly penetrate skin and clothing. Nerve agent

Liquid exposure: Liquid agents easily penetrate skin and clothing. Symptoms may begin anywhere from 30 minutes to 18 hours after skin exposure. A small droplet on the skin, for example, may cause local sweating and muscle twitching, followed by nausea, vomiting, diarrhea, and generalized weakness. Even with decontamination, signs and symptoms may last for hours. In contrast, people with severe liquid exposures may show no symptoms (for 1-30 minutes) but rapidly may suffer abrupt loss of consciousness, convulsions, generalized muscular twitching, paralysis, secretions (from the nose, mouth, lungs), difficulty breathing, and death. Vapor exposure: Vapor inhalation produces poisonous symptoms within seconds to several minutes. Effects may be local or throughout the body. Exposure to even a small amount of vapor usually results in at least one of the following categories of symptoms: (1) in the eyes, blurred vision, eye pain, red eyes; (2) runny nose; or (3) difficulty breathing, shortness of breath, excessive productive coughing. Respiratory tract: Nerve agents act on the upper respiratory tract to produce runny nose, drooling, and weakness of the tongue and throat muscles. High-pitched, distressed breathing can occur. A great deal of phlegm production and narrowing of the airways can occur. If untreated, the combination of symptoms rapidly progresses to respiratory failure and death. Cardiovascular system: Nerve agents also act on the heart and may produce abnormal heartbeats, more likely to be too fast rather than slow. Central nervous system: Nerve agents produce a variety of signs and symptoms throughout the central nervous system. People may lose consciousness (sometimes within seconds of exposure) and have seizures. Symptoms such as headache, dizziness, numbness or tingling, anxiety, insomnia, depression, and emotional instability also have been reported.

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Musculoskeletal system: Nerve agents initially stimulate and then paralyze muscles. With minimal exposure, exposed people may complain of vague weakness or difficulty walking. Eyes: Nerve agent liquid or vapor readily penetrates the eye tissues and may cause the pupils to contract, blurred and dim vision, headache, redness, tears, pain, nausea, and vomiting. Although contraction of the pupils is the most consistent clinical finding after vapor exposure to nerve agents (this occurred in 99% of people exposed in the Tokyo sarin attack), it may not occur or occur later if the exposure is on the skin. In severe cases, the pupils of the eye may remain narrowed up to 45 days. Diagnosis: Routine testing is not reliable in identifying nerve agents in blood or urine. So doctors will make their treatment decisions based on the signs and symptoms a person shows and on information about the type of chemical exposure, if known. Treatment: Treatment of victims exposed to nerve gas is similar to the treatment of those poisoned by organophosphate insecticides. Atropine sulfate: Victims with symptoms require immediate treatment with atropine. Atropine helps people breathe by drying secretions and opening their airways to allow them to breathe more freely. Atropine also blocks other effects of poisoning, such as nausea, vomiting, abdominal cramping, low heart rate, and sweating. Atropine, however, does not prevent or reverse paralysis. Adults and children will be given appropriate doses of atropine by IV or injection. Another medication, pralidoxime chloride, may also be given. With adequate decontamination and appropriate initial therapy, serious signs and symptoms of nerve agent toxicity rarely last more than a couple of hours. Mark I kit: The Mark I kit was designed for military selfadministration in the field. It consists of 2 spring-loaded devices to inject yourself, containing atropine and pralidoxime, respectively. These antidote kits are not yet available for civilian use. Prognosis: Peak toxic effects occur within minutes to hours and go away within 1 day. People who were exposed but show no symptoms are usually observed for at least 18 hours because some signs and symptoms can show up later.

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MUSTARDS Sulfur mustard has been used as a chemical weapon since World War I. Nitrogen mustard, a derivative of sulfur mustard, was one of the first chemotherapy agents but never has been used in warfare. These agents cause blistering of exposed surfaces. Both mustard agents rapidly penetrate cells and generate a highly toxic reaction that disrupts cell function and causes cell death. The chemical reaction is both temperature dependent and aided by the presence of water, which explains why warm, moist tissues are affected more severely. Actively reproducing cells, such as skin and blood cells, are most at risk. Physical properties: Mustards are oily liquids with odors of mustard, onion, garlic, or horseradish. Highly soluble in oils, fats, and organic solvents, mustards quickly penetrate skin and most materials, including rubber and most textiles. Sulfur mustard is considered a persistent agent with low volatility at cool temperatures but becomes a major vapor hazard at high temperatures. Exposure to mustard vapor, not mustard liquid, is the primary medical concern. More than 80% of mustard casualties in World War I were caused by exposure to mustard vapor. Mustard vapor is 3 times more toxic than a similar concentration of cyanide gas; however, mustard liquid is also quite toxic. Skin exposure to as little as 1-1.5 teaspoons of liquid (7 g) is lethal to half of those exposed. Signs and symptoms: Mustards injure the skin, eyes, respiratory tract, GI tissues, and blood system. The pattern of toxicity depends partly on whether the person is exposed to liquid or vapor. Liquid exposure primarily damages the skin, producing an initial rash followed by blistering similar to a partial-thickness burn. Vapor exposure damages the upper respiratory tract (skin usually is not affected). Mustards penetrate cells in less than 2 minutes, yet signs and symptoms usually are delayed 4-6 hours (the range can be from 1-24 hours). The time it takes to show symptoms is shorter with high-concentration exposures, such as those occurring at increased room temperature and humidity. Skin: Chemical burns caused by mustard often appear deceptively superficial at first. Earliest symptoms are itching, burning, and stinging pain over exposed areas. Moist, thinner

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skin is affected more severely. Affected areas appear red and swollen. If contamination is more extensive, superficial blisters occur within 24 hours of exposure. Most burns are partial thickness, but full-thickness burns with deep blisters may result from exposure to higher concentrations. Blister fluid does not contain active mustard and is not toxic. Eyes: Eyes are especially sensitive to the effects of mustard. Symptoms begin 4-8 hours after exposure. Earliest symptoms include burning pain, a feeling that something is in the eye, sensitivity to light, tearing, and blurred vision. Permanent corneal scarring and blindness may occur with severe exposures, but is rare. Respiratory tract: Mustards primarily damage tissues in the upper airway through a direct inflammatory effect. Following a period of 2-24 hours after exposure, symptoms may appear. Early symptoms include sinus congestion, a sore throat, and hoarseness. Later, cough, shortness of breath, and trouble breathing may develop. People with severe and extensive contact with mustard gas may develop respiratory complications up to several days after exposure. Gastrointestinal tract: Rarely, mustard damages rapidly growing cells of the intestinal tract. GI involvement results in abdominal pain, nausea, vomiting, diarrhea, and weight loss. Blood system: Rarely, mustards cause unpredictable loss in the production of bone narrow. Certain specialized cells begin dying 3-5 days after exposure reaching its worst point in 3-14 days, depending on the severity of exposure. Diagnosis: Diagnosis of mustard exposure is based on what the doctor observes from the person’s signs and symptoms. No laboratory tests are useful. Personal protective equipment: Liquid mustard contamination poses a risk for emergency care personnel. Ideally, they will be wearing appropriate personal protective gear. Decontamination: Immediate decontamination within 2 minutes of exposure is the most important intervention for people who have skin exposure to mustard, because it rapidly becomes fixed to tissues, and its effects are irreversible. Even if an exposure

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takes place and a person shows no obvious sign and symptoms, decontamination is still urgent. Remove clothing immediately and wash the skin with soap and water. Eye exposure requires immediate washing out with a large amount of saline or water. Decontamination after the first few minutes of exposure does not prevent further damage later but at least prevents spread of the chemical to other parts of the body and protects emergency care personnel from further contact exposure. Treatment: Treatment of mustard exposure is based on symptoms. Because the effects of mustards typically are delayed, people with complaints immediately after exposure may have an additional injury. For those with signs of upper airway obstruction, doctors may treat by using a tube in the person’s throat or perform surgery to open the airway. Mustard-induced burns are especially painful. Doctors will use strong pain relievers. Adequate burn care is essential, because skin lesions heal slowly and are prone to infection. Severe burns may require removal of dead tissue, irrigation, and placement of antibiotics, such as silver sulfadiazine, directly on the burned area. The victim may need a tetanus shot. Severe eye burns may be treated with daily irrigation, topical antibiotic solutions, topical corticosteroids, and drugs that dilate the pupil. Petroleum jelly may be applied to prevent eyelids from sticking together. More severe corneal injuries may take as long as 2-3 months to heal. Permanent visual problems are rare. Although no antidotes currently are available to treat mustard toxicity, several agents are under investigation. Victims with bone marrow suppression following mustard exposure may be treated with medication to stimulate the bone marrow, such as granulocyte colony-stimulating factor. Prognosis: Victims with significant respiratory tract burns usually require admission to the hospital’s intensive care unit. Also, victims with several skin burns will be admitted to the burn

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unit for burn care, pain relief, and supportive care. Blood cell counts will be monitored for 2 weeks following significant exposures. Most people recover completely. Only a small fraction have long-term eye or lung damage. About 2% of those exposed to sulfur mustard in World War I died, mostly due to burns, respiratory tract damage, and bone marrow suppression. Sulfur mustard is known to cause cancer, yet a single exposure causes only a small risk.

Chemical Warfare Phenodichloroarsine (PD) Sesqui Mustard

Blood Chemicals (chemicals acting on the blood) Arsine (SA) Cyanogen Chloride (CK) Hydrogen Chloride Hydrogen Cyanide (AC)

DEFINITION OF CHEMICAL TERRORISM Chemical terrorism: Terrorism using chemical agents. These chemical agents are poisonous gases, liquids or solids that have toxic effects on people, animals or plants. Most chemical agents are capable of causing serious injuries or death. The severity of injuries depends on the type and amount of the chemical agent used, and the duration of exposure. Chemical agents that might be used for terrorism have been divided by the US Centers for Disease Control and Prevention (the CDC) as follows:

Blistering (Vesicant) Chemicals Distilled Mustard (HD) Lewisite (L) Mustard Gas (H)

Choking/Lung/Pulmonary Damaging Chemicals Chlorine (CL) Diphosgene (DP) Nitrogen Oxide (NO) Perflurorisobutylene (PHIB) Phosgene (CG) Red Phosphorous (RP) Sulfur Trioxide-Chlorosulfonic Acid (FS) Teflon and Perflurorisobutylene (PHIB) Titanium Tetrachloride (FM) Zinc Oxide (HC)

Incapacitating Chemicals

Nitrogen Mustard (HN-2)

Agent 15

Phosgene Oxime (CX)

BZ

Ethyldichloroarsine (ED)

Canniboids

Lewisite 1 (L-1)

Fentanyls

Lewisite 1 (L-2)

LSD

Lewisite 1 (L-3)

Phenothiazines

Methyldichloroarsine (MD)

Nerve Chemicals

Mustard/Lewisite (HL)

Cyclohexyl Sarin (GF)

Mustard/T

GE

Nitrogen Mustard (HN-1)

Sarin (GB)

Nitrogen Mustard (HN-3)

Soman (GD)

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Chemical Warfare Tabun (GA) VE VG V-Gas VM VX

Riot Control/Tear Chemicals Bromobenzylcyanide (CA) Chloroacetophenone (CN) Chloropicrin (PS) CNB - (CN in Benzene and Carbon Tetrachloride) CNC - (CN in Chloroform) CNS - (CN and Chloropicrin in Chloroform) CR CS

Vomiting (Emetic) Chemicals Adamsite (DM) Diphenylchloroarsine (DA) Diphenylcyanoarsine (DC) Other Industrial Chemicals EMERGENCY ROOM PROCEDURES IN CHEMICAL HAZARD EMERGENCIES

Preparations 1. Try to determine agent identity. 2. Break out personal protection equipment, decon supplies, antidotes, etc. 3. Is chemical hazard certain or very likely? YES: • Don personal protective equipment. • Set up hot line.

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4. Clear and secure all areas which could become contaminated. 5. Prepare to or secure hospital entrances and grounds. 6. Notify local emergency management authorities if needed. 7. If chemical is a military agent and Army has not been informed. call them. 8. If an organophosphate is involved, notify hospital pharmacy that large amounts of atropine and 2-PAM may be needed. When victim arrives (Note: A contaminated patient may present at an emergency room without prior warning.) 9. Does chemical hazard exist? Known release/exposure (including late notification) Liquid on victim’s skin or clothing Symptoms in victim, EMTs, others Odor (H, L, phosgene, chlorine) M-8 paper, if appropriate YES: Go to 10. NO: Handle victim routinely. 10. Hold victim outside until preparations are completed (don personal protective equipment to assist EMT’s as necessary). 11. If patient is grossly contaminated (liquid on skin, positive M-8 paper) OR if there is any suspicion of contamination, decontaminate patient before entry into building. Initial Treatment and Identification of the Chemical Agent 1. Establish airway if necessary. 2. Give artificial respiration if not breathing. 3. Control bleeding if hemorrhaging. 4. Symptoms of cholinesterase poisoning? Pinpoint pupils Difficulty breathing (wheezing, gasping, etc) Local or generalized sweating

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5. 6.

7. 8.

9.

10.

Fasciculations Copious secretions Nausea, vomiting, diarrhea Convulsions Coma YES: Go to NERVE AGENT PROTOCOL History of chlorine poisoning? YES: Go to CHLORINE PROTOCOL. Burns that began within minutes of poisoning? YES: Go to 7. NO: Go to 8. Thermal burn? YES: Go to 9. Burns or eye irritation beginning 2-12 hours after exposure? YES: Go to MUSTARD PROTOCOL. NO: Go to 9. Is phosgene exposure possible? Known exposure to phosgene Known exposure to hot chlorinated hydrocarbons Respiratory discomfort beginning a few hours after exposure YES: Go to PHOSGENE PROTOCOL. Check other possible chemical exposures: Known exposure Decreased level of consciousness without head trauma. Odor on clothes or breath Specific signs or symptoms.

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5 RICIN RICIN OVERVIEW A maximum credible event is one that could cause a large loss of life in addition to disruption, panic, and overwhelming use of civilian health care resources. This possibility brings about an attempt to evaluate and discuss substances that could be used as agents of biological warfare or as weapons of mass destruction (WMD). An agent considered capable of causing a maximum credible event is highly lethal, inexpensively and easily produced in large quantities, stable in aerosol form, and can be dispersed. The ideal agent is also communicable from person to person and has no treatment or vaccine. Ricin is a potent toxin that could be used as an agent of biological warfare or as a WMD. Derived from the beans of the castor plant (Ricinus communis), Ricin is native to Africa and common in warm climates worldwide. More than 1 million tons of castor beans are processed every year worldwide. It is easily and inexpensively produced, is highly toxic, and is stable in aerosolized form. Ricin has no treatment or vaccine, but it is not communicable from person to person. Although a large amount of ricin would be necessary to produce many casualties, it would be highly effective within a closed environment. Ricin can be disseminated as an aerosol, by injection, or as a food and water contaminant. Its use as a food and water contaminant is a major concern. If ricin were used in that fashion, resultant deaths could overwhelm local health care

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resources. Even use without casualties can be disruptive. Three US Senate office buildings closed on February 3, 2004, after ricin was found in the mailroom that serves Senate Majority Leader Bill Frist’s office. No injuries were reported.

In December 2002, 6 terrorist suspects were arrested in Manchester, England. Their apartment was serving as a “ricin laboratory.” Among them was a 27-year-old chemist who was producing the toxin.

On February 4, 2004, as part of the ongoing investigation as to the source of this most recent ricin attack, the Secret Service acknowledged that ricin had also been found at a White House mail-processing center in early November 2003.

On January 5, 2003, British police raided 2 residences around London and found traces of ricin, which led to an investigation of a possible Chechen separatist plan to attack the Russian embassy with the toxin. Several arrests were made.

A vial containing ricin was also found at a post office in Greenville, South Carolina, in October 2003. The envelope, addressed to the US Department of Transportation, was labeled “caution RICIN POISON.” The letter, protesting a proposed federal limit on the number of truckers’ hours behind the wheel to go into effect in January 2004, was signed “Fallen Angel.” Officials suspect that the attacks in October 2003 and November 2003 are related because both letters were signed “Fallen Angel” and contained ricin of poor quality. The FBI is currently investigating whether these two earlier attacks are at all related to the ricin found in the Senate mailroom. From 1991-1997, 3 cases involving ricin were reported in the United States. In Minnesota, 4 members of the Patriots Council, an extremist group that held antigovernment and antitax ideals and advocated the overthrow of the US government, were arrested in 1991 for plotting to kill a US marshal with ricin. The ricin was produced in a home laboratory. They planned to mix the ricin with the solvent dimethyl sulfoxide (DMSO) and then smear it on the door handles of the marshal’s vehicle. The plan was discovered, and the men were convicted. In 1995, a man entered Canada from Alaska on his way to North Carolina. Canadian custom officials stopped the man and found him in possession of several guns, $98,000, and a container of white powder, which was identified as ricin. In 1997, a man shot his stepson in the face. Investigators discovered a makeshift laboratory in his basement and found agents such as ricin and nicotine sulfate. The use of ricin is not limited to the United States.

RICIN CAUSES Ricin is a protein derived from the beans of the castor plant (R communis). Castor beans are used in the production of castor oil, a brake and hydraulic fluid constituent. Ricin makes up 3-5% of the “waste mash” that is produced during this process. Separating out this protein is not difficult; it only requires chromatography, a common undergraduate chemistry skill. RICIN SYMPTOMS Symptoms from exposure to ricin depend on the route of exposure and the amount of absorption. Routes of exposure are respiratory (inhaled aerosol), gastrointestinal (GI [ingested]), and percutaneous (injected). If exposed to ricin through inhaled aerosol, it will most likely affect numerous individuals simultaneously. In this case, a cluster of people would develop similar symptoms over a brief period, typically within 8 hours following inhalation. Such an occurrence would point to the possibility of an intentional act. People exposed to the ricin may experience symptoms such as fever, nausea and vomiting, a progressively severe cough, and congestion in the nose and the throat. Other symptoms associated with inhalation of ricin include difficulty breathing and tightness in the chest. With significant exposure to ricin, breathing difficulties occur within 12-24 hours. A chest x-ray may reveal excess fluid in the lungs. If exposed to ricin by ingesting contaminated foods or beverages, symptoms may initially mimic food poisoning, usually within 6 hours after ingestion. People who ingested ricin may feel abdominal pain, often accompanied by vomiting

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and diarrhea. Because of this, they may also become dehydrated. Although ingesting ricin is usually less toxic than exposure through inhalation, with significant amounts of the poison, resulting symptoms may become more severe and possibly result in death. People injected with ricin, either in pellet form or with it dissolved in a liquid, may experience pain and swelling at the injection site. They may experience other flulike symptoms as well, such as nausea, vomiting, and body aches. More severe symptoms will occur later and a critical life-threatening syndrome will develop.

WHEN TO SEEK MEDICAL CARE A person exposed to ricin should seek medical attention as soon as possible. If in an area where ricin has been released and people may have been exposed to it, they must immediately leave that area and move to an area with fresh air. If near an area where ricin has been released, people must wait for emergency personnel to advise them regarding appropriate evacuation procedures. In an aerosol attack, people should use protective masks that are effective in preventing toxicity. To avoid possible contamination, people exposed to ricin must remove and dispose of any clothing and thoroughly wash their skin with copious amounts of soap and water. If their eyes are irritated, people must wash them out with water. EXAMS AND TESTS Diagnosing an aerosolized attack or a food and water contaminant with ricin primarily depends on symptoms and the likelihood of such an exposure. In cases of an isolated ricin injection, diagnosis is extremely difficult. In addition, diagnostic testing is of limited value, because no test is currently available to confirm exposure to ricin definitively. Nonetheless, in the case of possible exposure to ricin, a person would most likely undergo a complete physical examination by a doctor. Sophisticated diagnostic tests (not widely available) can identify ricin in the body up to 24 hours after exposure.

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If exposure is from an inhaled aerosol, the presentation is similar to a sudden, rapidly worsening lung injury. The most common findings include labored breathing or difficulty in breathing, tightness in the chest, and rapid heart rate. A chest xray film shows excess fluid in the lungs. If exposure is through ingestion, the physical findings are usually confined to the GI tract. Symptoms include abdominal pain, vomiting, and diarrhea. Dehydration is common. If the dose was sufficient and the disease has progressed, vomiting blood or passing bloody diarrhea or dark-colored tarry stools may occur. If exposure is from an injection, the skin at the injection site is examined for swelling and redness. The affected area may feel painful. The skin is also examined for the possibility of a retained foreign object. The physical findings on the skin from injected ricin may occur prior to or at the time of other flulike symptoms.

EXAMS AND TESTS Diagnosing an aerosolized attack or a food and water contaminant with ricin primarily depends on symptoms and the likelihood of such an exposure. In cases of an isolated ricin injection, diagnosis is extremely difficult. In addition, diagnostic testing is of limited value, because no test is currently available to confirm exposure to ricin definitively. Nonetheless, in the case of possible exposure to ricin, a person would most likely undergo a complete physical examination by a doctor. Sophisticated diagnostic tests (not widely available) can identify ricin in the body up to 24 hours after exposure. If exposure is from an inhaled aerosol, the presentation is similar to a sudden, rapidly worsening lung injury. The most common findings include labored breathing or difficulty in breathing, tightness in the chest, and rapid heart rate. A chest xray film shows excess fluid in the lungs. If exposure is through ingestion, the physical findings are usually confined to the GI tract. Symptoms include abdominal pain, vomiting, and diarrhea. Dehydration is common. If the dose was sufficient and the disease has progressed, vomiting blood or passing bloody diarrhea or dark-colored tarry stools may occur.

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If exposure is from an injection, the skin at the injection site is examined for swelling and redness. The affected area may feel painful. The skin is also examined for the possibility of a retained foreign object. The physical findings on the skin from injected ricin may occur prior to or at the time of other flulike symptoms.

MEDICAL TREATMENT No antidote or vaccine is available for ricin. Regardless of the route of exposure, treatment remains mainly supportive. If exposure is from inhaled aerosol, the person may need assistance with breathing. If particularly severe, the person who was exposed may require intubation and use of a ventilator. If ricin was ingested, the stomach may need to be pumped (called gastric decontamination). Superactivated charcoal may also be given to help soak up the poison. To treat dehydration, intravenous fluids may be given. MEDICATIONS Antibiotics serve no role in the treatment of ricin poisoning. Medications may be given to treat seizures and low blood pressure that are sometimes associated with exposure to ricin. In the case of ricin exposure by injection, antibiotics may serve to prevent infection. A tetanus immunization may also be given as a precautionary measure. SURGERY Surgical care is not necessary for exposure to ricin, unless the ricin was injected. In this instance, the injection site should be treated to assess whether a foreign object is present. If so, the object should be surgically removed. NEXT STEPS

FOLLOW-UP Depending on the severity of the symptoms, a person exposed to ricin may be admitted to the hospital for monitoring. PREVENTION The only effective prevention against a biological attack with ricin is avoidance; unfortunately, no antidote or vaccine exists.

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Currently, investigations are ongoing for possible vaccines and ricin inhibitors. Protective masks have been shown to be effective in preventing toxicity during an aerosol attack. Although ricin is not the ideal biological warfare agent, it remains a threat, primarily as a food and water contaminant. Ricin is widely available and easily produced. With the increasing number of biological threats, hoaxes, and “how to” Internet resources available, this threat has the potential to become reality. Therefore, being familiar with ricin’s characteristics is important.

OUTLOOK Depending on the dose and the route, death can occur within 36-72 hours following the time of exposure. If death has not occurred within 3-5 days from the time of exposure, recovery is likely.

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6 DISASTER MANAGEMENT CYCLE Lets discuss about the definition: “Collection actions/measures taken before, during and after any situation to predict, prevent, reduce or cope with its impact. These measures may be taken at community or household levels.”

Disaster Response Activities that take place when a disaster strikes to reduce loss of life and to deliver relief as quickly as possible to the affected people. The following are the examples: —• Search and Rescue • Need for assessment. • Provide the victims Psychological support. • Emergency food, water, medicines are required. • There should a provison for temporary shelters and other relief activities. • There should also be a scope for restoring the family links.

Recovery (Rehabilitation) After a disaster, there are scenes, which are very heart-rending. The people needs psychological support. Measures taken after a disaster, to bring back the condition within the community to normal even better than before are given below: a. Psychological Rehabiltation: The affected people needs counseling. Their primary needs have to be met. They will be best, when they are in surroundings of their relatives.

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The affected have to be slowly involved in matters which will help them to see Life in a new way. The best thing is proper follow up of the matter. b. Financial Rehabilitation: The most important thing is that if the disaster is big, then the affected victims loses all there finances and this result in more tension. Plans should be made in advance for ‘DISASTER INSURANCE’ in areas, where natural disasters are very common. It will help. The distribution of livelihood kits should be distributed. c. Social Rehabilitation: Places such as Welfare Centers should be established. More emphasis shoould be given to self help groups. Places like ‘HOMES’ should be built, so that the affected people can get traumatic councelling and make a new living.

Risk Reduction (Mitigation) Its actually a long term measure to reduce the risk of a disaster. This means; Strengthening of existing buildings and infrastructures. Raised earth platform in flood prone areas. Taking out insurance policies. Plantation of drought resistant crops. Building of cyclone shelters, reinforcement of river banks in flood prone areas. Public awareness programs should be run. That is the most important part of risk reduction activities. There should be also community based health care/health promotion.

Disaster Preparedness Its the effort to enable a community to cope with and respond quickly and effectively to any further disaster. These can be done by the following: o By Vulnerability and Capacity Assessment (VCA) of the community through mapping exercise. o Deveopment of Early Warning Systems. These can be done with the help of satellite data, through Geographic Information System and Remote Sensing. o Formation of community disaster preparedness and response committee and plan.

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DISASTER MANAGEMENT - INTRODUCTION When one thinks of Disasters, it naturally crosses one’s mind that; if only it had been averted. Disasters are by their very nature unpredictable and happen inspite of the best efforts. It appears to be so sudden and powerful that one attributes it to ones fate. This is what make each of the disasters remarkable and larger than life. Even though all precautions are taken, yet they happen and the sheer ferocity of their occurence brings terror to one’s heart. It is hard to believe that except for a chance event of the affected people being part of the disaster, they might very well be alive. The scene of the disaster is heart-rending and what comes to mind is the horror of what happened and one is compelled to feel sorrow for the victims of the disasters. Whether it is the Hurricane Katrina, Wilma, Recent Earthquake in India, Tsunamis, Chernobyl Nuclear Tragedy, Bhopal Gas Tragedy (India), Hurricane Andrew 1992, cyclone at Darwin Australia (1974) etc; each of the disaster has a unique story to tell: if only it could have been avoided and here lies the imporatnce of pre-disaster management policy. Some times our stereotypial attitudes and lack of proper policy implementation often leads to failure to recognize THAT RELIEF AND DEVELOPMENT are inextricably linked and part of the sae on-going process. It is now being acknowledged that disasters an wipe out years of development and can dramatically increase vulnerability An increasing number of Governments and International Organizations are promoting risk reduction as the only sustainable solution for reducing the Social, Economical and Environmental impacts of disasters. Risk Redution strategies includes vulnerability mapping identification of areas that are safe for settlement and development adoption of building codes

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based on disaster resilient engineering and on local hazard risk assessments and enforcing these plans and codes by economic and other incentives. I want to stress on the points of local capacities and predisaster management to safeguard the precious lives of our brothers and sisters of my planet. One of the most important of these concerns is to build local capacities. The rationale here is based on recognition that local communities have developed their own, indiginous, preparedness and mitigation activities based on their extensive experiences of living with disasters. (All too often in the past, these have been overlooked or undervalued by Disaster Management Specialists from Outside) Let me give some examples: In India, one tribal group living in the Andaman and Nicobar Islands understood the coming of the arrival of the slayer Tsunami and fled to a safer place long before the killer waves would have engulfed them. An art of their own, passed from generations to generations. In Africa, there are a lot of food shortages due to drought; but they are able to prevent full blown famine by employing a variety of ‘coping’ mechanisms that allow them to ride out the hungry season until the next harvset. Also I believe that successful disaster prevention depends partly upon being able to predict these crisis before they happen. Though Disasters happen with great regularity, I believe that we should do research as how to stop these natural calamities rather than forecasting it’s arrival. To that effect, we should stress the need for natural barriers for cyclones and hurricanes, rainwater harvesting methods for continuous suuply of water even in the driest seasons, concepts on recharging of groundwater in the driest part of the world. Stressing the need to use methods for liberatiuon of energy from the faults in the earth-strata, so that the release of the enormous energy from the bottom of the earth will stop earthquakes happening! Also we should stress on the afforestation intiatives in catchment areas basins. I believe this basic research can enable us to undersatnd the water-soil-climate system better. This can lead to new thinking and new avenues of action, which can yield larger stable production within the existing constraints.

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The effort spent in basic research and the policies obtained from those pays for it many times over, though not necessarily immediately. I do believe that you will definitly find this website interesting and it will help you also to create awareness on Pre-Disaster Management and save lives. I welcome you to our website on Disaster Management. I would request you to send your views and suggestions at our e-mail address. Expensive long-term development projects are put at greater risk, if they do not take natural hazards into account. An earthquake can shatter a housing project; a farming scheme, ruined by a hurricane or flood. Disaster statistics are hard to calculate with any accuracy or consisting. Nonetheless, all the evidence points to a steep and continuing rise in deaths and injuries from disasters since the 1960’s and there is a general consensus among researches and insurers that the number of disasters is increasing. This rise can not be explained by a parallel rise in the number of erthquakes, cyclones and the like. What we are seeing is an increase in the effects of disasters on people or in other words, people vulnerability to disasters. It is the social, cultural, economic and political environment that makes people vulnerable. This is most apparent; as eonomic pressures, force many of the poor to live in cheap but dangerous locations such as the flood plains and unstable hillslides. There are also many less visible underlying factors — social, political as well as economic that effect people’s ability to protect themselves against ethnicity, gender, disability and age. In most cases, the rich are affected much less due to better constructed houses and safer locations. Disasters caused by natural hazards such as earthquakes, floods, storms, volcanoes and droughts are major global problems. Between 1971 and 1995, they caused each year on average more than 1,28,000 deaths and affected the lives of 136 million people. Every country is affected by natural hazards to some extent. However, most disasters occur in the poorer countries of the third world; some 97% of deaths and 99% of people affected between 1971 and 1995 were in developing countries and the economic consequences of disasters there were massive.

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To some extent: This is an accident of geography; that many third world countries are in the regions prone to the most severe hazards such as earthquakes, droughts, volcanoes, floods, landslides and cyclones.

SOME FACTS ABOUT DISASTERS Until the 1970’s, the International community considered disasters as exceptional circumstances, when local coping capacities were exhausted and external emergency relief was required. The term Disaster Managment was generally equivalent to disaster response and tended to be within the exclusive competence of organisations such as the Red Cross and Red Cresent Socities or National Civil Defence Institutions. In 1971, the United Nations Disaster Relief Office, now the United Nations Office for the Co-ordination of Humanitarian Affairs ( UNOCHA ), was established to mobilize and co-ordinate relief activities from all sources in times of disaster. The concept of disaster pre-paredness was developed during 1970’s and 1980’s and included training and some cross-sectional activities to increase capacity for rescue , relief and rehabilitation during and after a disaster. But even the most pessinmistic forecasts could not have forseen the upward spiral in negative socio-economic consequences of natural disasters in the closing decades of the 20th Century. The 1990s was declared the International Decade for Natural Disaster Reduction (IDNDR), one of the principal goals of which was to inculcate a culture of disaster prevention; through the wider application of known scientific and technological mechanisms by a better informed population. In the words of United Nations Secretary General Kofi Annan, “We must, above all, shift from a culture of reaction to a culture of prevention. The humanitarian community does a remarkable job in responding to disasters. But the most important task in the medium and long term is to strengthen and broaden programmes which reduce the number and cost of disasters in the first place. PREVENTION IS NOT ONLY MORE HUMAN THAN CURE, IT IS ALSO MUCH CHEAPER” (IDNDR 199b) The IDNDR successfully placed risk reduction higher on the political agenda, as well as setting out a number of priorities to be undertaken by countries and regions in the 21st Century.

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CIVIL CHEMICAL AND BIOLOGICAL WARFARE ATTACK: THE MYTH AND REALITY

of CBW casualties and should be properly informed about the risks and the special handling procedures required.

Following the attacks in New York in September 2001, the spectre of urban attack by terrorists using chemical and biological warfare (CBW) agents again raised its head and led to a wave of speculation and near panic on both sides of the Atlantic Ocean. Newspaper articles about ‘weapons of mass destruction’ abounded, and emergency and hospital medical services made provisions for the management of large numbers of casualties.

Most busy anaesthetists do not have ready access to information about CBW agents. White has produced a useful, comprehensive document detailing a wide range of chemicals, toxins and organisms that have been proven or suspected to be agents of warfare, and more recently of urban terrorist attack. Two points about the extensive range of hazards presented in the review are particularly important.

In the United States, mass ingestion of prophylactic antibiotics began and gas masks were purchased in large numbers. Television pictures of emergency personnel clad in protective suits (many of them totally inappropriate for the real degree of risk) were widely transmitted and for several weeks the public awaited a worldwide chemical/biological Armageddon.

First, despite widespread public and political belief, biological and chemical agents are not strictly weapons of mass destruction but weapons of mass injury, a point recognized by a number of clinical experts including an ex-Soviet source. In this respect, they may lead to mass fatalities where medical resources are limited or non-existent, but with properly organized and equipped medical services the picture may be quite different. Unlike nuclear weapons, biological and chemical agents do not cause mass destruction of material and physical trauma. Biological and chemical agents should therefore be viewed in their own pathophysiological context. The persistence of the Nuclear, Biological and Chemical (NBC) classification owes more to diplomatic manipulation and the balance of military power than medical reality. White has appropriately classified CBW agents as weapons of mass injury rather than destruction, which is a more realistic term for anaesthetists used to the business of supporting life in difficult circumstances. This does not alter the fact that, untreated, CBW agents may lead to substantial loss of life. However, advanced life support and guidelines for longer term treatment do exist, and can radically alter the clinical picture.

In the event, the reality was confined to the distribution of anthrax spores through the US postal system, which fortunately claimed only a few lives. Nevertheless this attack, coming after the use of a military organophosphate nerve agent by terrorists in Japan in 1995, demonstrated that urban chemical and biological attack was possible and posed a problem for emergency and hospital medical services around the world. The risk of deliberate urban release of chemical and biological agents persists and is not new. From the point of view of casualty management, it is important that the momentum generated by the events of last autumn should be sustained. The appearance in this issue of a review concerning the implications of chemical and biological agents for anaesthesia and intensive care is therefore very appropriate. Many clinical specialities may be involved in the management of CBW casualties, but that of anaesthesia and intensive care has a critical role to play since the speciality, more than most others, has the academic background in physiology, applied pharmacology and pathophysiology, and is able to understand the injuries provoked by CBW agents. More importantly, it is able to respond with immediate and continuing life support. It is therefore essential that anaesthetists should be closely involved in the management

Secondly, it is important to realize that not all the hazards listed in the review are equally likely to be used by terrorists. A few have been identified and used, such as sarin and anthrax. Most, however, are still confined to the area of speculation (sometimes backed by intelligence information). The existence of a hazard does not necessarily imply a threat, a term which implies a means of delivery and intention on the part of the assailant, apart from possession of a hazard. In terms of planning and training, it is more realistic and less nihilistic to build from

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experience of chemical hazards that have or could be used by terrorists, backed by experience gained from industrial toxic release. Knowledge of the management of naturally occurring epidemics is equally valuable for the management of a deliberately induced epidemic (a biological weapon attack). For those clinicians who feel they have a lack of experience in such cases, it is worth noting that considerable clinical analogous experience exists, which can be used in the management of unfamiliar pathology. For anaesthetists in particular, the essential life support procedures involved are very familiar from more conventional areas of practice.

CBW ATTACK AS A SPECIAL CASE OF GENERAL HAZARDOUS MATERIAL RELEASE In civil life, populations are at constant risk from accidental exposure to toxic substances, as they are from naturally occurring epidemics. These are the natural equivalents of the intentional toxic release and epidemics that constitute CBW. Accidental civil toxic releases are managed according to the United Nationscontrolled, hazardous materials control system (HAZMAT), which provides detailed information to emergency services about the properties and management of toxic substances at their place of use or while they are in transit. HAZMAT databases provide information for protection and decontamination, and clinical management protocols. The system is designed to manage accidental releases but provides a valuable framework for the management of casualties from deliberate releases. The difference between accidental and deliberate (terrorist) releases is that the identity of the toxic agent may not be known with certainty in the case of the latter, and so measures must be put into place that cover the worst case scenario of the agent being highly toxic, persistent and transmissible. Most HAZMAT incidents involve small numbers of casualties with varying degrees of exposure. Some of these may have the effects of both toxic and conventional trauma, for example after an explosion, such as that which occurred at a chemical factory in Toulouse, France in September 2001. The notion of mass casualties may not always therefore be appropriate, although both chemical and biological accidental releases have occurred in the past, giving rise to large numbers of injured and dead.

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Much information exists about the management of HAZMAT incidents and the author has made good use of the internet sources that are now available. HAZMAT is a valuable model and all anaesthetists involved in disaster management should be aware of the stages in the overall management of a HAZMAT incident, and of the risks related to the toxicity, latency of action, persistency and transmissibility of the agents involved. These four characteristics are common to both chemical and biological agents, and determine the degree of risk as well as the appropriate reponse. Toxicity is a familiar concept in anaesthesia, and toxic effects appear with a specific latency, which is important for the use of agents in deliberate release. In general, chemical agents and toxins have short periods of latency before specific signs and symptoms appear. In contrast, classical biological warfare agents have extended latency periods (usually familiar as incubation periods) before the effects of the induced disease begin to appear. Persistency relates to the ability of a toxic agent to remain in the environment into which it had been released and is a function of the physicochemical properties of the agent. For chemical agents, the persistency may be variable but for most biological warfare agents, with the exception of spore-forming agents such as anthrax, persistency is usually very short. However, transmissibility may take place as a result of the physical contamination of the victim due to a persistent chemical agent or as a result of infection in the case of an airborne agent. Transmissibility is therefore a potential menace in the case of biological warfare agents because of infection down the casualty management line.

WHAT ARE THE HAZARDS LIKELY TO BE FACED? Many known chemical agents (e.g. chlorine, phosgene and hydrogen cyanide) are readily available industrially and their properties are listed in standard sources and databases, which are cited in the review in this issue. Others, such as organophosphates, are familiar as pesticides but are also used by the military as nerve agents that may be synthesized in improvised laboratories. Certain biological warfare agents are recognized as being a more likely threat than others, given the difficulty of delivery and the sensitivity of the agents to meteorological conditions. Thus, anthrax is now an established threat that is more important than the rare viral

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haemorrhagic fevers, which are the domain of specialist physicians. It is important that biological attack should be viewed as a special case of an epidemic.

MEDICAL MANAGEMENT OF CASUALTIES FROM CBW ATTACK: POINTS INVOLVEMENT OF ANAESTHETISTS Following CBW attack, anaesthetists may be involved at several points, and are thus in danger of primary and secondary exposure. In some countries, anaesthetists form part of the primary emergency response and are familiar with the dangers of toxic exposure and the need for protection and decontamination. Anaesthetists may also be involved in management in the emergency room, operating theatre management and the intensive care unit. In France, special plans were put in place for the management of terrorist toxic release following the Japanese sarin attacks in 1995, which have been recently modified as Plan Biotox. The plans provide special mobile medical response teams (with training and protective suits) as well as protected medical teams to receive casualties who escape the HAZMAT cordon. Anaesthetists are involved at both these points and must have a good understanding of the importance of casualty decontamination. In the hospital, anaesthetists must be aware of the effects of certain toxic agents on the conduct of general anaesthesia for the management of accompanying physical trauma. There are effects on the status of the patient before an operation and on the anaesthetic agents themselves. A good example is the effects of exposure to organophosphate anticholinesterases on the action of neuromuscular blocking agents, which is covered by White. Many toxic hazards have long latency effects, which lead to the necessary management of patients in the ICU. Long-term ventilation may be required for neuromuscular problems, toxic pulmonary oedema and associated adult respiratory distress syndrome. Mass toxic casualties will place a heavy burden upon emergency and intensive care services as a result of the short and longer term actions of toxic agents. Attacks using bacterial and viral biological agents essentially pose the problem of epidemic infection, although intensivists are

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required for the management of the resulting complications, including multiple organ failure. There is a long latency in most cases, but there may be ultra-short and intermediate latency effects if a bacterial toxin is used as a toxic agent.

MANAGEMENT OF SPECIFIC PATHOPHYSIOLOGY Toxic agents may attack all somatic systems, but the respiratory system is the most vulnerable in the short and intermediate term, leading to fatality in some cases if resuscitation is not started early and continued. There are many pathophysiological processes leading to respiratory failure after toxic injury, affecting both the airway, and the control and mechanics of breathing. There may be, as in the case of organophosphates, failure of the respiratory centres and paralysis of the muscles of breathing through neuromuscular blockade. The review covers this in some detail. The more water-soluble toxic agents, such as chlorine, cause irritation and the production of secretions in the nasopharynx with laryngeal spasm. There may be blockage of the main airways with bronchial and bronchiolar constriction. Finally, many toxic substances act at the level of the alveoli causing toxic pulmonary oedema. Both the central and peripheral nervous systems may be affected as in the case of sarin poisoning, where the respiratory centres are depressed and there is a depolarizing neuromuscular block. The airways may be affected at both the upper and lower levels with cough and laryngeal spasm, production of secretions and vomitus, bronchospasm, bronchiolitis and toxic pulmonary oedema. Many substances produce ciliary paralysis, which compounds the bronchial problem. Clinically, the combined effects are to produce increased airway resistance and reduced compliance. This leads to a failure of alveolar ventilation, a rise in end-tidal carbon dioxide, hypoxia and cardiac arrest. ANAESTHETISTS—A VOICE TO BE HEARD Anaesthetists clearly have a vital role to play in the management of CBW casualties, but in many countries their involvement with planning and provision of care has been relatively limited, particularly in the prehospital and emergency room areas. Many of the special government CBW advisers are from the public health, toxicology and pathology specialities. They

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do not have first hand experience of the emergency and intensive care life support measures required to break the link between mass injury and mass loss of life. It is important for anaesthetic professional bodies to take an interest in the subject and explain the role anaesthetists have to play in the management of chemical agent injury. For the general public, most of whom are still unaware that anaesthetists are medical practitioners, this may be something of a revelation. Training and close integration of anaesthetists into toxic emergency response teams is essential, but training by exercise is notoriously difficult for busy clinicians who have more than enough real problems to deal with. Nevertheless, it is vital that anaesthetists understand the real risks from CBW and the HAZMAT procedures to avoid becoming the next casualty. Above all, the speciality must give out a clear and positive message about the real dangers of CBW, and the appropriate planning and life support procedures that should form the medical response. This will not only serve to provide some comfort to a frightened general public, but will provide much needed focus for the rational management of casualties from a CBW attack. 1999 WMD Terrorism Chronology: Incidents Involving SubNational Actors and Chemical, Biological, Radiological, and Nuclear Materials. Assessing the threat of terrorism involving chemical, biological, radiological, or nuclear (CBRN) materials, often referred to as “weapons of mass destruction” or “WMD,” remains difficult despite extensive literature bases in terrorism studies and WMD studies. In the absence of sufficient empirical data and analysis, policymakers and analysts often make projections based on assumptions about the increasing spread of WMD-related technology and know-how, and the vulnerability of modern society to WMD attack. However, the threat also depends on the desire of sub-national actors to use WMD-related materials, but the motivations underlying sub-national interest in WMD remain poorly understood.

DATABASE DESCRIPTION In an effort to bridge this gap, staff members at the Center for Nonproliferation Studies (CNS) at the Monterey Institute of

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International Studies in Monterey, California, under the auspices of the Chemical and Biological Weapons Nonproliferation Project, directed by Dr. Jonathan B. Tucker, in 1997 began compiling a Database of Worldwide Incidents 1900-Present Involving SubNational Actors and Chemical, Biological, Radiological, and Nuclear Materials (hereafter, the Monterey WMD Terrorism Database). Chemical agents, such as cyanide and the nerve agent sarin, harm humans, animals, or plants by means of the agents’ toxic effects, as opposed to harm by burning or explosion. Biological agents are disease-causing microorganisms including viruses and bacteria, as well as toxins, such as botulinum toxin and ricin, which are produced by living organisms. Radiological agents, such as cesium-137 and cobalt-60, include materials that are radioactive but that are not capable of sustaining a nuclear chain reaction. Finally, nuclear materials, such as uranium-235 and plutonium, can serve as raw materials in the construction of a nuclear-yield device. The Monterey WMD Terrorism Database began with 129 incidents that had been gleaned from a study by RAND of international terrorism and an unclassified study on chemical and biological weapons (CBW) terrorism by Ron Purver of the Canadian Security Intelligence Service. Since that time, by using an extensive but exclusively open-source collection system focused on capturing news reports from the Internet, CNS staff members have added over 550 incidents. Using a lengthy search string based on specific WMD agents and materials, staff members gather articles of potential interest; approximately 200,000 articles were collected in 1999. Once an incident has been “flagged,” more specific research is conducted in an effort to identify and retrieve all available open-source material on the incident. Each incident is summarized in terms of several categories following standardized coding criteria, supplemented by discussions among staff to resolve ambiguous cases as clearly and consistently as possible. The first category is the incident’s Location. Campaigns throughout the world to acquire WMD, as in the case of Osama bin Laden, are classified as worldwide. Efforts to acquire WMD by a specific group are assigned to that group’s base location, whereas use and possession of materials are assigned to the place

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where the agent was used or discovered. The second category is Motivation: incidents are either politically/ideologically motivated, in that the incident occurred for reasons associated with a political, social, or religious ideology, or criminally motivated, in that the incident occurred for reasons not associated with such ideologies. Two other standardized categories are Group Type, i.e., nationalistseparatist or single issue, and Delivery System. Finally, incidents are also classified according to type of event. Use of Agent means that WMD material was actually used in the incident. Threat with Possession means that while use was only threatened, there is evidence that the perpetrator had the material, making the threat credible. Possession means that the perpetrator had the material, but did not use or threaten to use it. In such a case, there may or may not be evidence that the perpetrators intended to use the material. Attempted Acquisition means that the perpetrators tried, or in some cases tried and succeeded, to acquire the material but were either interdicted or were otherwise unable to acquire the material. Plot means that the perpetrator considered, planned to use, or threatened to use WMD material. Hoax means that although use was threatened, the threat was not credible, or an “empty threat.” For security reasons, access to the Monterey WMD Terrorism Database is restricted to law enforcement agencies and other qualifying entities, including certain international organizations and government agencies. In this report, we present an overview and abridged summary of data from the database in an effort to expand and deepen the publicly available information for making threat assessments of WMD terrorism. We hope that policymakers, analysts, and academics will benefit from the publication of summary information from the database in several ways. First, the standardized categories in the database can be analyzed over time, in the aggregate, and in relation to one another. This type of analysis can be used to focus on one particular category, such as a given group or group type, and to look at the frequency of incidents and level of interest in WMD by that particular group or group type. That information could then be cross-referenced to delivery system and geography to show regional distributions by group type and delivery-system

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technology. Second, analyzing the incidents by standardized category allows the identification of relationships and influences among groups, regions, and ideologies. For example, say that a particular group is involved in a WMD incident. Do other groups learn or mimic this behavior? How is interest in WMD affected? Finally, having empirical data over time creates a basis for identifying key threshold incidents, that is, incidents that may be indicative of new trends in WMD terrorism, such as the 1995 Tokyo subway sarin attack by Aum Shinrikyo. This event stands out as significantly different from other events. In contrast, interest in botulinum toxin, although also threatening, is not a new phenomenon; indeed, there has been interest in botulinum toxin for use as a weapon for at least 85 years. ANALYSIS OF 1999 INCIDENTS

OVERALL GENERAL NUMBERS The Monterey WMD Terrorism Database includes 175 entries for 1999, of which 104 occurred in the United States. The total number for the year is important because as of 23 February 2000, the database contained 687 incidents since 1900. Therefore, the 175 incidents that occurred in 1999 represent over 25 percent of the total. This can be attributed to two causes. First, it is undeniable that reporting and thus the collection of incidents have improved considerably since 1900. The compilation of incidents is undoubtedly more complete for the 1980s, for example, than it is for the 1960s. However, this compilation most accurately reflects incidents reported in the media since 1990, given the relative ease of electronic information collection on events since 1990. Even with this caveat, the findings reported here are significant. Over one quarter of the incidents recorded in the database occurred in a single year, 1999. Of the 494 incidents that occurred 1990 to 1999, 35 percent occurred in 1999. This is largely the result of the second cause: the high number of anthrax hoaxes that were perpetrated in the United States. Of the 104 incidents that occurred in the United States in 1999, 81 involved anthrax threats. This wave of anthrax hoaxes began in October 1998 and continues today, although incidents have declined.

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GEOGRAPHICAL DISTRIBUTION Box 1: INCIDENTS BY REGION US / Canada Asia Europe Middle East & North Africa Latin America Russia / NIS Sub-Saharan Africa Worldwide Australia / New Zealand

107 (104 / 3) 21 15 11 7 7 4 3 -

The geographical distribution of these 175 incidents is also noteworthy. Of the 175 incidents, 104 or 59 percent occurred in the United States. By way of comparison, the region with the next highest number of incidents was Asia with just 21, and then Europe with 15 in 1999. Even without the anthrax threats, the United States would have had more incidents than any other region in the world. This strongly suggests that the fear of WMD terrorism and the publicity associated with each incident within the United States have strengthened the likelihood of more incidents, and that it is therefore in the United States that the threat is most pressing. Indeed, there has been since 1995 an unprecedented focus on the threat of WMD terrorism by senior US policymakers and elected officials. However, the accessibility of US data to CNS staff because of the vast number of local-level US news sources on the Internet, may also partially explain the predominance of US incidents. Box 2: INCIDENTS BY TYPE OF EVENT Use of Agent (20 tear gas) 39 (14 US/13 Asia/5 Europe) Attempted Acquisition 5 Threat with Possession 5 Possession 19 Hoax/Prank/Threat (82 anthrax) 99 (85 US) Plot Only 8 However, the type of incident that occurred in each region

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would appear partially to contradict the conclusion that the threat is most pressing in the United States. The overwhelming trend in the United States was one of hoaxes. These are disruptive and often demand a full emergency response, but they are unlikely to result in casualties. In contrast, 13 of 21 incidents in Asia involved the use of an agent. This could suggest that whereas incidents in the United States were intended to threaten, disrupt, or intimidate, most incidents in Asia were intended to injure. This applies to a lesser extent in other regions: in Europe, five of 15 incidents involved the use of an agent, in the Middle East it was two of 11; Latin America three of seven; and Sub-Saharan Africa one of four. Even so, it was in the United States that there were the most uses of an agent: 15 incidents in 1999. This seems likely to be a consequence of the greater number of incidents, of all types, that occurred in the United States compared to other regions.

TYPES

OF

AGENTS INVOLVED Box 3: INCIDENTS BY TYPE OF AGENT

BW CW Nuclear Radiological Unknown

95 65 5 5 5

Box 4: INCIDENTS BY AGENT Anthrax Tear Gas

83 27

Cyanide

7

HIV

4

Sarin Nuclear facility Ricin Butyric Acid Radiological materials Miscellaneous

2 2 1 1 1 47

(81 US/1 Middle East/1 Worldwide) (8 Europe/8 US/4 Asia/3 Sub-Saharan Africa/2 Middle East/2 Latin America) (3 Asia/2 Latin America/2 US/1 Middle East) (1 Asia/1 Europe/1 Latin America/1 Canada) (1 US/1 Asia) (1 NIS/1 Asia) (1 US) (1 Europe) (1 NIS) (Worldwide)

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The types of agents that were used in each incident is significant. Apart from the anthrax cases in the United States, the next most common agent was tear gas, of which there were 27 incidents in 1999, spread fairly evenly across the world. It is notable that apart from the US anthrax incidents, there were only 14 cases worldwide involving biological agents, about a fifth of the number that involved chemical agents. Most of the agents employed were low-end non-warfare or household agents, raising questions such as: whether their use was a product of opportunism; whether it was intended to set the perpetrators apart from other groups by using a non-conventional weapon; and whether such incidents are truly significant as indicators of the likelihood of WMD terrorism. Of the agents that were used in incidents, tear gas accounted for 20 of the 39 events. The next highest was “poison,” used in three attacks, and then several agents, including cyanide, were used in two attacks. By contrast, tear gas was involved in just one hoax, compared to 82 such incidents involving anthrax. Apart from the hoaxes, there was a single incident involving anthrax: an attempted acquisition. Similarly, there were relatively few incidents of any type that involved other high-end sophisticated agents such as ricin (one threat with possession) or sarin (two hoaxes).

MOTIVATIONS

FOR

INCIDENTS

Box 5: INCIDENTS BY MOTIVATION Politically/Ideologically motivated incidents Criminally motivated incidents By region Political US/Canada 49/1 Asia 6 Europe 6 Middle East & North Africa 7 Latin America 6 NIS 5 Sub-Saharan Africa 3 Worldwide 3 Australia/New Zealand -

86 89 Criminal 55/2 15 9 4 1 2 1 -

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Looking at motivation type, ideological motivations accounted for about half of all incidents, approximately the same as criminally motivated incidents. When incidents are broken down by region or by event type, incidents generally remain split about half and half between ideological and criminal motivations. Although this seems to suggest that perpetrators without a link to an ideology are equally likely to be interested in WMD material, it may be that the media are more likely to report WMD incidents that are linked in some way to an ideology, which would imply that criminal motivations are actually predominant CONCLUSION In conclusion, 1999 saw an apparent continued division between the United States and the rest of the world in numbers and types of incident and in agents used in such incidents. Also, both criminally and ideologically motivated actors appeared equally interested in WMD materials. The trends discussed for 1999 are broadly consistent with the general findings from the database for all years. Analysis from the database, as a whole, reveals at least four significant findings. First, unknown perpetrators were responsible for more incidents recorded in the database (48.7 percent), than any other type of actor. In 1999, the number of incidents with unidentified perpetrators was 91 (52 percent), many of them involving anthrax hoaxes. Most incidents where the perpetrator was known involved lone actors. There were 43 such incidents in 1999, 51 percent of all incidents perpetrated by known actors. The figure was 48.5 percent for the database as a whole. Possibly as a result of this, the majority of incidents in the database (60 percent) were low-end incidents. In 1999, low-end incidents dominated to an even greater degree, propelled by the wave of anthrax hoaxes. Hoaxes alone accounted for 56.5 percent of incidents in 1999, and low-end incidents were 75 percent of all types of incident. Moreover, throughout the database, most uses of an agent (87.3 percent) involved ones that would be considered low-end or household agents. As was noted earlier, the majority of uses of an agent in 1999 involved tear gas. Although this cannot be considered a household agent, it is certainly at the low end of the scale compared to anthrax, ricin, or sarin. After tear gas, most uses in 1999 involved a non-specific

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“poison,” followed by cyanide. None of these should be perceived as high-end agents, so although 1999 was an exceptional year for hoaxes, it was a more standard year for the types of agents being used in attacks. The data for 1999 do not suggest a significant trend among sub-national actors towards using WMD materials to cause mass casualties. INCIDENTS IN 1999

THROUGHOUT 1999 Agent: biological weapons Type of Event: attempted acquisition Summary: Throughout 1999, Osama bin Laden and al-Qaida were reported to have attempted to acquire biological weapons in laboratories in Sudan and Afghanistan. Agent: nuclear device Type of Event: attempted acquisition Summary: Throughout 1999, it was reported that Osama bin Laden and al-Qaida were engaged in a comprehensive plan to acquire nuclear weapons. The first such report surfaced in October 1998. Agent: chemical weapons Type of Event: attempted acquisition Summary: Throughout 1999, Osama bin Laden and al-Qaida were reported to have been engaged in attempts to develop chemical weapons at laboratories in Sudan and elsewhere. Some reports alleged that bin Laden did indeed acquire chemical weapons. Agent: HIV Type of Event: use Summary: In 1999, in Nakhon Nayok, Muang district, China, the 34-year-old widow of a policeman who had died of AIDS went on a rampage, trying to infect 20 policemen from the Muang police station and several politicians with HIV. Agent: chemical and biological weapons Type of Event: plot

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Summary: US security forces allegedly warned their Israeli counterparts that Christian millenarian groups could use biological weapons for an attack in Israel during 2000. Such groups have supposedly been purchasing poisons and bacteria from a variety of sources and have been seeking scientists and engineers to help in the development of “a doomsday weapon.” Agent: sarin Type of Event: hoax Summary: In the first half of 1999, a man robbed a bank in the Chicago, Illinois, area with a bomb that he claimed contained sarin. Agent: anthrax Type of Event: hoax Summary: In 1999, a high school in Mentor, Ohio, received a letter threatening exposure to anthrax. Agent: tear gas Type of Event: possession Summary: During the summer, police in Amsterdam, The Netherlands, arrested 20 gang members on charges of illegal weapons, hash possession, and car theft. The gang members, most of whom came from the countries of former Yugoslavia, had access to a variety of weapons, including tear gas.

JANUARY Agent: poison Type of Event: use Summary: Nine children and three adults were hospitalized during the last week of January after eating poisoned sweets that someone had intentionally scattered over a five-square-mile area in Congzhou, Sichuan province, China. Agent: anthrax Type of Event: hoax Summary: A store in Victorville, California, was evacuated for two hours after an anthrax threat was made in a call to a 911 dispatcher on 2 January.

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Disaster Management Cycle Agent: anthrax Type of Event: hoax

Summary: At around 1 p.m. on 3 January, an unidentified caller telephoned a medical center in Ocala, Florida, claiming anthrax had been released in the emergency room. Agent: cyanide Type of Event: possession Summary: On 4 January, a pistol containing ammunition with cyanide-laced bullets was reportedly found near the cells of commanders of the National Liberation Army (ELN) or Revolutionary Armed Forces of Columbia (FARC), being held in the Itagui, Colombia, jail. Agent: anthrax Type of Event: hoax Summary: On 4 January, a high school in Anaheim, California, received an anthrax threat. Agent: HIV Type of Event: threat with possession Summary: On 6 January, an unmasked assailant robbed a currency exchange office in Zadar, Croatia, using a syringe allegedly containing HIV. Agent: anthrax Type of Event: hoax Summary: At approximately 7 a.m. on 11 January, a threat of anthrax exposure was made against a car dealership located on Wilshire Boulevard in Los Angeles, California. Agent: anthrax Type of Event: hoax Summary: At 3 p.m. on 13 January, an unidentified individual telephoned the City Hall switchboard in Tualatin, Oregon, claiming that anthrax was in the building.

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Summary: On 14 January, an employee of a retail store in Cathedral City, California, received a telephone call threatening the release of anthrax. Agent: anthrax Type of Event: hoax Summary: On 15 January, the United States Attorney’s office in Buffalo, New York, received a letter containing a threat of anthrax exposure. Agent: poison Type of Event: use Summary: According to the mainland Chinese periodical Xian Gongan Shenghuo Bao, on 17 January, authorities arrested two suspects for the poisoning of 17 people, resulting in four deaths, in Ziyang county, China. Agent: anthrax Type of Event: hoax Summary: At 4:00 p.m. on 19 January, an anonymous caller telephoned a restaurant in Palm Desert, California, claiming that the restaurant had been contaminated with anthrax. Agent: anthrax Type of Event: hoax Summary: On 20 January, a high school student in Elma, New York, reportedly perpetrated an anthrax hoax that resulted in the quarantine of around 700 students for nearly 10 hours because he wanted the day off. Agent: anthrax Type of Event: hoax Summary: An anonymous phone call threatening anthrax, placed to the central switchboard of the West Seneca, New York, Town Hall on 21 January, resulted in the building’s closure for the lunch hour.

Agent: anthrax

Agent: anthrax

Type of Event: hoax

Type of Event: hoax

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Summary: A 22 January Buffalo News report stated that Niagara County, New York, sheriff’s deputies arrested two high school students and charged them with falsely reporting an anthrax incident to a high school principal. Agent: anthrax Type of Event: hoax Summary: On 22 January, employees at a food market in East Aurora, New York, found a letter in the rear entrance threatening anthrax exposure. Agent: anthrax Type of Event: hoax Summary: On 24 January, authorities arrested Christopher J. McCoy and charged him with telephoning four anthrax threats over a three-day period, 21-23 January, to a hospital in Sierra Madre, California,

Disaster Management Cycle Agent: attack against biological facility Type of Event: hoax

Summary: In February, Chechen leader Salman Raduyev warned Russia that Chechens would attack Russian biological facilities unless two Chechen prisoners were released. Agent: cyanide Type of Event: plot Summary: In February 1999, information surfaced indicating that the Revolutionary Army Forces of Colombia (FARC) plotted to kill three hostages in Colombia using cyanide. Agent: anthrax Type of Event: hoax Summary: Two 14-year-old boys confessed to phoning in a 2 February anthrax threat to a high school in Lackawanna, New York.

Agent: anthrax

Agent: unknown

Type of Event: hoax

Type of Event: hoax

Summary: At around 6 a.m. on 25 January, an individual telephoned a company in Alden, New York, claiming that anthrax was in the office building.

Summary: On 3 February, UK police identified convicted murderer Michael Sams as the perpetrator of several consumertampering extortion threats against supermarkets.

Agent: unknown

Agent: anthrax

Type of Event: hoax

Type of Event: hoax

Summary: On 27 January, an anonymous phone call was placed to the commercial department of Coca-Cola Beverages Slovakia informing them that Cola-Cola beverages would be poisoned if an extortion fee were not paid.

FEBRUARY Agent: radiological Type of Event: hoax Summary: In February, Chechen leader Salman Raduyev warned Russia that Chechens would attack Russian government targets with radiological materials unless two Chechen prisoners were released.

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Summary: A letter purporting to contain anthrax was received on 3 February, at The Washington Post offices in Washington, DC. Agent: anthrax Type of Event: hoax Summary: The local NBC news offices in Atlanta, Georgia, received a letter containing an anthrax threat at 11:40 a.m. on 4 February. Agent: anthrax Type of Event: hoax Summary: Three boys were arrested on 5 February and charged with aggravated harassment and falsely reporting an anthrax incident the day before in Cattaraugas County, New York.

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Disaster Management Cycle Agent: anthrax Type of Event: hoax

Summary: A letter purporting to contain anthrax was opened on 4 February, at the Old Executive Office Building in Washington, DC. Agent: anthrax Type of Event: hoax Summary: A post office in Columbus, Georgia, received a letter on 4 February addressed to the postal service containing the message, “You have now been exposed to anthrax.” Agent: anthrax Type of Event: hoax Summary: On 5 February, the principal’s office at a middle school in Douglasville, Georgia, received a letter claiming to contain anthrax. Agent: anthrax Type of Event: hoax Summary: On 5 February, a school in East Aurora, New York, was closed following the discovery of an anthrax threat written on the front door. Agent: anthrax Type of Event: hoax Summary: An abortion clinic near Elkins, West Virginia, received an anthrax threat the week of 8 February. Agent: anthrax Type of Event: hoax Summary: On 9 February, a letter threatening anthrax exposure was opened in the US State Department building in Washington, DC, at around 11 a.m. Agent: anthrax Type of Event: hoax Summary: According to the Gwinnett County Police Department, a county resident located near Snellville, Georgia, received a telephone call at 3:30 a.m. on 10 February threatening that an anthrax bomb was in his mailbox.

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Agent: cyanide Type of Event: hoax Summary: On 10 February, a retail company in Taiwan received a letter claiming that the 2,000 stores on the island would be under the threat of cyanide product contamination during the Chinese lunar new year unless a NT $21 million sum was paid to the extortionists. Agent: tear gas Type of Event: use Summary: Police and Metropolitan Atlanta Rapid Transit Authority (MARTA) officials were searching for the identity of a man who walked through a MARTA car on 11 February, at the Oakland City station in Oakland City, Georgia. The man may have been contaminated with an irritant such as tear gas. Twentyone people were treated for injuries. Agent: anthrax Type of Event: hoax Summary: On 12 February, an employee in the mailroom of The Los Angeles Times newspaper office in Los Angeles, California, found and opened a letter containing a small amount of gray powder purported to be anthrax along with a note stating, “If you open this letter, you will be exposed to anthrax.” Agent: tear gas Type of Event: possession Summary: On 13 February, in Aalborg, Denmark, leftist Danish demonstrators protesting a neo-Nazi organization were found in possession of approximately 30 gasoline bombs and an undisclosed number of tear gas canisters stored in two apartments. Agent: anthrax Type of Event: hoax Summary: During the week of 14 February, an abortion clinic in Asheville, North Carolina, received a package with a threatening note attached, causing the employees to suspect anthrax. Agent: anthrax Type of Event: hoax Summary: On 16 February, a letter threatening to use anthrax to kill US and British citizens living in Yemen was faxed to the London, United Kingdom, office of an Arabic newspaper.

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Agent: anthrax

Agent: anthrax

Type of Event: hoax

Type of Event: hoax

Summary: On 17 February, an agency of anti-abortion activist Reverend Ralph Ovadal in Monroe, Wisconsin, received by mail a suspicious letter that contained a white powder. Agent: anthrax Type of Event: hoax Summary: On 18 February, a women’s health organization in Milwaukee, Wisconsin, was the site of an anthrax threat through a letter. Agent: anthrax Type of Event: hoax Summary: On 18 February, a Cincinnati, Ohio, abortion clinic received a letter containing a threat of anthrax exposure and an unidentified powder. Agent: anthrax Type of Event: hoax Summary: On 18 February, a clinic in Rapid City, South Dakota, was shut down at about 12:30 p.m. due to an anthrax threat in a package received through the mail. Agent: anthrax Type of Event: hoax Summary: On 18 February, a clinic in Sioux Falls, South Dakota, was shut down at about 2:00 p.m. due to an anthrax threat in a package received through the mail. Agent: anthrax Type of Event: hoax Summary: On 18 February, an abortion clinic in Washington, DC, received a package with a label on the outside warning that the package contained anthrax. Agent: anthrax Type of Event: hoax Summary: On 18 February, a medical center in Charleston, West Virginia, received an anthrax threat in a letter.

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Summary: On 18 February, a clinic in Manchester, New Hampshire, received and opened an envelope around 11:45 a.m. containing a threat of anthrax exposure and a brown or white powder. Agent: anthrax Type of Event: hoax Summary: On 18 February, a healthcare provider’s headquarters in Burlington, Vermont, received an anthrax threat through the mail. Agent: anthrax Type of Event: hoax Summary: On 18 February, a package allegedly containing anthrax was delivered to the loading dock of the US Court of Appeals in Atlanta, Georgia. Agent: anthrax Type of Event: hoax Summary: On 19 February, an abortion clinic in Nashville, Tennessee, received a suspicious letter in a business-size envelope with a handwritten address and carrying no return address. As the letter was not opened, it is unclear from news reports if the letter truly contained a threat, since it was described as only containing a piece of paper. Agent: anthrax Type of Event: hoax Summary: On 19 February, a Birmingham, Alabama, clinic, the site of a fatal 1998 bombing, received an envelope that appeared to be similar to letters sent to abortion clinics nationwide containing threats of anthrax exposure. Agent: anthrax Type of Event: hoax Summary: On 19 February, the office of a clinic in Des Moines, Iowa, received a letter that, according to the attached message, had been “treated” with anthrax. A Federal Bureau of Investigation (FBI) spokesman stated that it contained a powdery substance.

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Disaster Management Cycle Agent: anthrax Type of Event: hoax

Summary: On 19 February, the Portland, Maine, office of a clinic received a suspicious letter bearing a Kentucky postmark and the return address of a lab not used by the clinic. Agent: anthrax Type of Event: hoax Summary: On 19 February, a clinic in St. Paul, Minnesota, received a letter similar to those sent to other abortion clinics around the country claiming to contain anthrax. Agent: anthrax Type of Event: hoax Summary: On 19 February, a clinic in Minneapolis, Minnesota, received a letter similar to those sent to other abortion clinics around the country claiming to contain anthrax. Agent: anthrax Type of Event: hoax Summary: On 19 February, a clinic in St. Johnsbury, Vermont, received a suspicious envelope similar to envelopes used in an anthrax hoax at a planned parenthood clinic in Burlington, Vermont, on 18 February. Agent: anthrax Type of Event: hoax Summary: On 20 February, a medical center in Cranston, Rhode Island, received an envelope with a Lexington, Kentucky, postmark, similar to anthrax threats received at other clinics. Agent: anthrax Type of Event: hoax Summary: At around 1:20 p.m. on 22 February, the head of the New York, New York, National Organization for Women (NOW) office received an anthrax threat. Agent: anthrax Type of Event: hoax Summary: On 22 February, a clinic in St. Louis, Missouri, received a letter threatening anthrax contamination.

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Agent: anthrax Type of Event: hoax Summary: On 22 February, the administrative office of a family planning organization in Sandy Springs, Georgia, received a suspicious letter with “PAACO” shown as the return address. This clinic was bombed in January 1997, allegedly by Eric Rudolph. Agent: anthrax Type of Event: hoax Summary: At about 8:15 a.m. on 22 February, a dental office adjacent to a clinic in Spokane, Washington, received a Christmas card, postmarked in Lexington, Kentucky, showing a brown stain, but no clear threat of anthrax. The secretary who opened the letter did not read the card after seeing that it contained a “powder.” Agent: anthrax Type of Event: hoax Summary: On 22 February, a clinic in Wood County, West Virginia, received a letter containing an anthrax threat. Agent: anthrax Type of Event: hoax Summary: On 22 February, a letter containing a threat of anthrax exposure was found at a Newark, Delaware, clinic. Agent: anthrax Type of Event: hoax Summary: On 22 February, an anthrax threat was reported by the Motor Vehicle and Licensing Division Administrator and Commander of Hawaii Army National Guard 29th Infantry Brigade, in Honolulu, Hawaii. Agent: anthrax Type of Event: hoax Summary: On 22 February, a center in Washington, DC, received an anthrax threat similar to those received at abortion clinics since October 1998. Agent: anthrax Type of Event: hoax Summary: On 22 February, a clinic in Kansas City, Missouri, received a letter with a Louisville, Kentucky, postmark containing

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a stained piece of paper warning of anthrax exposure, a powdery substance, and a hand-drawn skull and crossbones. Agent: anthrax Type of Event: hoax Summary: On 23 February, a letter possibly threatening anthrax contamination was received at a clinic in Salt Lake City, Utah. Agent: anthrax Type of Event: hoax Summary: On 23 February, an internist based in Honolulu, Hawaii, received an anthrax threat, postmarked in Kentucky. Agent: tear gas Type of Event: use Summary: On 23 February, a bus traveling in Tel Aviv, Israel, was sprayed with tear gas by an unknown assailant. One passenger who had difficulty breathing was taken to a hospital, and six others with only light exposure to the tear gas refused medical attention. Agent: anthrax Type of Event: hoax Summary: On 23 February, a letter that contained an anthrax threat arrived at a women’s center in New York, New York. Agent: anthrax Type of Event: hoax Summary: At 8:30 a.m. on 23 February, an abortion clinic in Pittsburgh, Pennsylvania, received a letter containing an anthrax threat. Agent: anthrax Type of Event: hoax Summary: On 24 February, at a car wash in Spring Hill, Florida, a gallon milk jug was found with the words “Anthrax Saline” written in black marker on the side. Agent: unidentified chemical Type of Event: use Summary: On 24 February, a woman at Orlando International Airport sprayed two security officers with an unknown chemical to escape a search by the guards, before fleeing.

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Agent: anthrax Type of Event: hoax Summary: On 26 February, at a clinic in Boise, Idaho, a worker opened a plain white envelope containing a note stating that the opener of the letter had just been exposed to anthrax.

MARCH Agent: nuclear weapons Type of Event: hoax Summary: In March, Vladimir Mikhaylin and Oleg Tikhonov, from Kaluga, Russia, sent threatening letters via the Internet to approximately 20 countries, including the United States, the United Kingdom, and Israel, threatening nuclear strikes against these states. Agent: chloropicrin Type of Event: possession Summary: On 3 March, Moscow officials arrested Warrant Officer Vladimir Karpov, of the Russian Civil Defense Ministry, for attempting to sell almost 100 liters of what was believed to be chloropicrin. Agent: anthrax Type of Event: hoax Summary: On 3 March, in a church mailroom building in Salt Lake City, Utah, a package was discovered containing a note stating that the opener of the letter had just been exposed to anthrax. Agent: anthrax Type of Event: hoax Summary: According to the city manager of Lumberton, North Carolina, an anonymous phone call on 4 March reported that anthrax had been released in a city clinic. Agent: anthrax Type of Event: hoax Summary: On 5 March, a letter containing an anthrax threat arrived at the office of a Baptist organization in Nashville, Tennessee.

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Agent: nitric acid

Agent: HIV

Type of Event: use

Type of Event: hoax

Summary: On 8 March, 148 persons were poisoned by nitric acid placed in the food of a restaurant in Luoyang City, China. The perpetrators hoped to damage the business of the restaurant. Agent: anthrax Type of Event: hoax Summary: On 12 March, a staff member at a high school in Hamburg, New York, found a note on the floor of one of the classrooms stating that anthrax would be released by the end of classes that day. Agent: unknown Type of Event: hoax Summary: On 15 March, employees at a Chicago, Illinois, clinic discovered what they believed to be a suspicious package. Though there was no confirmation available to suggest that the package threatened anthrax exposure, the assumption by clinic personnel and police was that it was indeed an anthrax threat. Agent: radiological agent Type of Event: possession Summary: By 18 March, Fu’ad ‘Abduh al-Shuwayri and Butrus Michael Najim had been arrested by Lebanese security agents on charges of attempting to sell six kilograms of uranium. Agent: poison Type of Event: hoax Summary: On 18 March, a rumor that the city’s water supply in Istanbul, Turkey, had been contaminated with an unknown poison reached the media. Agent: anthrax Type of Event: hoax Summary: On 20 March, a Spring Hill, Florida, resident found a milk jug with the word “anthrax” written on it in thick black marker.

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Summary: On 21 March, Manuel Basulto and Miguel Quevedo were arrested for mugging people on the streets in Havana, Cuba. The suspects allegedly threatened to expose their victims to HIV by cutting themselves. Agent: tear gas Type of Event: possession Summary: On 23 March, police in Brussels, Belgium, confiscated tear gas canisters belonging to French far-right leader Jean-Marie Le Pen’s bodyguard. The canisters were stored in a vehicle and were intended for Le Pen’s protection in Belgium. Agent: anthrax, Ebola virus Type of Event: hoax Summary: On 26 March, a man placed two plastic vials labeled “anthrax” and “Ebola” on a ticket counter at Pittsburgh International Airport, Pennsylvania. The vials were a practical joke from one of the man’s colleagues. Agent: anthrax Type of Event: hoax Summary: On 26 March, a jogger in Spring Hill, Florida, found a plastic milk jug with the word “anthrax” written on it in pen.

APRIL Agent: anthrax Type of Event: hoax Summary: On 16 April, a note bearing an anthrax threat was handed to a faculty member of a high school in Chautauqua County, New York. Agent: anthrax Type of Event: hoax Summary: A computer-generated note was discovered in the parking lot of the courthouse in Biloxi, Mississippi, on 19 April. The note, found by a sheriff’s deputy in a bag of crumpled napkins,

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alleged that anthrax had been spread throughout the building’s ventilation system. Agent: anthrax Type of Event: hoax Summary: On 19 April, an envelope containing an anthrax threat arrived at the Blackfeet Tribal Office in Browning, Montana.

MAY Agent: chemical weapons Type of Event: hoax Summary: The Kashmiri militant group, Hizbul Mujahiden, claimed that their fighters in Kargil and Drass possessed chemical weapons and napalm bomb-like devices. They threatened to use them against Indian troops if India used napalm bombs against the militants. Agent: unknown chemical weapons Type of Event: plot Summary: On 9 November 1999, the Middle East Newsline reported that members of Hamas, the Islamic Resistance Movement, had planned to attack Israeli targets with chemical weapons in May. Agent: cyanide Type of Event: attempted acquisition Summary: On 12 May, Masanobu Okamura, was arrested for the attempted sale of 450 grams of potassium cyanide in Nishiyodogawa-ku, Osaka, Japan. Agent: tear gas Type of Event: possession Summary: On 12 May in the Gauteng Province of South Africa, police issued arrest warrants for four men suspected of possession of unlicensed firearms, including two detonators, 10 tear gas canisters, six automatic rifles, and 62 handguns. Agent: butyric acid Type of Event: use Summary: On 13 May, the German foreign minister, Joschka Fischer, was hit in the face with butyric acid by a protester in

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Bielefeld, Germany. The attack occurred at a congress of Fischer’s Green Party to discuss the Party’s continued support of NATO air strikes on Yugoslavia. Agent: anthrax Type of Event: hoax Summary: On 15 May, a public library, in Nashville, Tennessee, received an anthrax threat. Agent: tear gas Type of Event: use Summary: On 17 May, a white military policeman sprayed a black colleague with tear gas in Pietersburg, South Africa. Agent: tear gas Type of Event: use Summary: On 18 May, seven police officers were sprayed with tear gas in a pinball parlor in Kashihara, Nara, Japan. Agent: anthrax Type of Event: hoax Summary: On 22 May, a college located in Syracuse, New York, received a letter containing an anthrax threat. Agent: anthrax Type of Event: hoax Summary: On 22 May, a high school located in Syracuse, New York, received a letter containing an anthrax threat.

JUNE Agent: nuclear facility Type of Event: hoax Summary: In June or July, Chechens threatened to attack a nuclear power plant and other nuclear facilities in Russia. Agent: tear gas Type of Event: possession Summary: On 2 June, four teenagers were arrested in Barberton, South Africa, for allegedly having stolen weapons, including tear gas grenades, from a police substation in Emjindini.

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Disaster Management Cycle Agent: tear gas Type of Event: use

Summary: On 6 June, a self-proclaimed grand wizard of the Invisible Empire of Pennsylvania Ku Klux Klan received burns to his face and chest when a tear gas canister was thrown into the living room of his home in Walston, Pennsylvania. Agent: tear gas Type of Event: hoax Summary: On 8 June, a suspicious brown paper bag was discovered by a patrol officer at an elementary school in Bergen County, New Jersey. It was found to hold tubes containing a clear liquid similar to tear gas. Agent: weed killer Type of Event: plot Summary: On 10 and 11 June, three threatening letters were received by public figures in the United Kingdom. The letters demanded the withdrawal of British troops from Northern Ireland by 16 June. The author, Adam Busby, threatened to poison the United Kingdom’s water supply with the herbicidal weed killer paraquat if the British government did not comply with his demand. Agent: tear gas Type of Event: use Summary: On 10 June, a 15-year-old boy, armed with a knife and tear gas spray, held hostage a student at the National Defense Medical College, Tokorozawa, Japan, for five hours. The suspect, who called for the destruction of the Japanese Constitution, also sprayed another student with the tear gas. Agent: unidentified chemical Type of Event: plot Summary: On 19 June, the newspaper Yidyout Ahranout reported that members of Hamas, the Islamic Opposition Movement, had plans to poison water supplies in Israel with “chemical substances.”

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Agent: unidentified chemical Type of Event: use Summary: On 19 June, an unidentified substance was deposited on a merry-go-round at a park in Indianapolis, Indiana. Eleven children and one adult required hospital treatment for chemical burns. Delin Swanigan was subsequently charged in connection with the incident. Agent: tuberculosis bacilli Type of Event: attempted acquisition Summary: On 28 June, a physician reported that a vial of live tuberculosis bacilli that she had brought to a tuberculosis conference had been stolen in San Francisco, California.

JULY Agent: fluorine Type of Event: possession Summary: On 5 July, police arrested Jesse Spurgin after finding six fluorine-based gas bombs hidden outside his Hastings, Nebraska, apartment. Roughly 40 small bottles of chemicals were removed from the apartment, and an Environmental Protection Agency member suggested that Spurgin had been attempting to produce mustard gas. Agent: tear gas Type of Event: use Summary: A tear gas canister was set off in the middle of a gay pride parade in San Diego, California, on 24 July. About 15 people were treated at the scene and another three required hospital treatment. Agent: caustic liquid Type of Event: use Summary: On 30 July, a man splashed an unidentified caustic liquid that injured five postal workers and two customers in a post office in Philadelphia, Pennsylvania. Agent: unknown Type of Event: use Summary: On 30 July, 20 mostly elderly members of a group called Tablig Jamaat became ill after eating contaminated food at

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a mosque in Chandpur, Bangladesh. Apparently, burglars tainted the members’ food, causing the patrons to fall unconscious. The burglars then took the victims’ money and valuables. Seventeen of the 20 did not fully regain consciousness until 6 p.m. on 31 July.

AUGUST Agent: tear gas Type of Event: use Summary: On 6 August, the fans of the Paris Saint Germain soccer team tossed tear gas and other articles during a soccer match in Rennes, France. Agent: anthrax Type of Event: hoax Summary: On 12 August, an Internet service company in Seattle, Washington, received an envelope containing a threatening letter and a white powder purported to be anthrax. Agent: biological agent Type of Event: use Summary: On 17 August, a bag of medical waste bearing a taped-on newspaper picture of Buford O. Furrow and a swastika drawn in marker was found outside of a synagogue in Stamford, Connecticut. Agent: tear gas Type of Event: use Summary: On 18 August, a soccer fan threw a canister of tear gas into the crowd at a soccer match between Yugoslavia and Croatia at the Red Star stadium in Belgrade, Yugoslavia. Agent: biological agent Type of Event: use Summary: On 19 August, a container of medical waste was found by an employee in the parking lot outside of a synagogue in Norwalk, Connecticut. Agent: tear gas Type of Event: use Summary: On 19 August, a tear gas grenade was thrown at the speakers’ podium at a rally attended by 150,000 people in Belgrade, Yugoslavia.

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Agent: phosphorous-32 Type of Event: use Summary: On 19 August, 32-year-old former lab technician Andrew Andris Blakis was arrested and charged with assault with a deadly weapon and unlawful disposal of radioactive material, phosphorous-32, in Los Angeles, California. Agent: Drano Type of Event: use Summary: On 20 August, a woman in Prince Frederick, Maryland, laced soda cans with Drano in an effort to poison coworkers at a mental institution because she felt the workers mistreated the patients at the facility. Agent: HIV Type of Event: threat with possession Summary: On 22 and 23 August, a man held up three people at an automatic teller machine in Vancouver, British Columbia, Canada, and threatened to stab them with a syringe filled with what he claimed was blood tainted with HIV. Agent: uranium Type of Event: possession Summary: On 24 August, the French-language newspaper Cambodge Soir reported that Cambodian anti-drug police had arrested four Vietnamese nationals for attempting to smuggle uranium into the country. Agent: tear gas Type of Event: use Summary: During the course of a post-soccer game riot on 25 August at Amman International Stadium in Amman, Jordan, a member of the Libyan national soccer team allegedly threw a canister of tear gas towards the opposing Palestinian soccer team’s locker room. Agent: nuclear components Type of Event: possession Summary: On 30 August, Shim’on Na’or, Ion Menciu, and Ivan Busuioc were arrested as the middlemen in an illegal operation to smuggle arms, explosives, and nuclear components to and

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through Romania to export-embargoed nations and possibly terrorist organizations.

SEPTEMBER Agent: tear gas Type of Event: use Summary: On 3 September, two men approached a woman walking home and sprayed tear gas in her eyes in the Goi district of Ichihara, Japan. Agent: anthrax Type of Event: hoax Summary: On 13 September, a postal worker in Pittsburgh, Pennsylvania, opened a letter that claimed to contain anthrax. As a precaution, nine postal workers were decontaminated at a nearby hospital. Agent: virus Type of Event: hoax Summary: On 17 September, Diazien Hossencofft, of Albuquerque, New Mexico, threatened to release a code for a virus to the Chinese government that “would kill the entire population except for a few people.” Agent: strontium Type of Event: possession Summary: During the week of 20 September, officials in Uzhgorod, Ukraine, confiscated two lead cylinders containing radioactive strontium (according to early reports) or strontium90 (according to later reports) from a group of Russian and Ukrainian citizens during a routine passport check. Agent: cyanide Type of Event: use Summary: On 23 September, police in the Anantnag district of South Kashmir, India, recovered 3 to 3.5 kilograms of cyanide powder from an abandoned house at Marwan in the city of Qazigund.

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Agent: chemical agent Type of Event: possession Summary: On 27 September, the daily newspaper Jehad-eKashmir, of Pakistan-occupied Kashmir (POK), reported that Islamic separatists in POK possess chemical weapons. Agent: tear gas Type of Event: use Summary: On 28 September, emergency services responded to a reported fire in the basement of a house in Springfield, Massachusetts. One police officer and nine firefighters needed treatment after a tear gas grenade exploded in the basement. The owner of the house was a member of a military unit and kept tear gas for training purposes. The grenade was found and set off by one of the children who lived in the house. Agent: nuclear facility Type of Event: hoax/plot Summary: On 30 September, Yoichi Clark Shimatsu, formerly an editor of the Japan Times Weekly and currently an investigative reporter, authored an article concerning the possible involvement of Aum Shinrikyo in a nuclear accident at Tokaimura, Japan, that occurred in September.

OCTOBER Agent: rat poison Type of Event: threat with possession Summary: In October, the Animal Liberation Front (ALF) mailed envelopes containing razor blades laced with rat poison to over 80 medical researchers working in the vivisection industry in Canada and the United States. Agent: sarin Type of Event: hoax Summary: By 1 October, the mayor of Kunming, Yunnan, China, had received a threatening letter. The author of the letter threatened to release sarin at the World Horticulture Exposition

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that was held in Kunming on 1 October if the city did not pay him five million yuan. Agent: tear gas Type of Event: possession Summary: On 11 October, thieves stole a large amount of tear gas from Taoyuan Air Force Base in Taiwan. Agent: anthrax Type of Event: hoax Summary: On 12 October, a television office in Lexington, Kentucky, received a letter-size package containing an unknown substance and a letter that stated that whoever opened the letter had been exposed to anthrax. Agent: biological Type of Event: plot Summary: On 17 October, Russian soldiers discovered, on the bodies of Chechens killed during fighting in Dagestan, plans to use biological weapons. Agent: CS gas Type of Event: threat with possession Summary: On 17 October, police reported that members of Reclaim the Streets had purchased 34 containers of CS gas over a six-week period, for use at an anti-World Trade Organization (WTO) protest, scheduled for 30 November in London, United Kingdom. Agent: cobra venom Type of Event: possession Summary: On 29 October, The Independent reported that police in Bangladesh had confiscated two shipments of cobra venom in Khaka and Tongi, Bangladesh. Agent: anthrax Type of Event: hoax Summary: On 29 October, an employee at a bank in Concord, New Hampshire, opened an envelope containing an unidentified white powder.

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NOVEMBER Agent: tear gas Type of Event: use Summary: Twice during the week beginning 1 November, a woman used tear gas or pepper spray to rob women in supermarket parking lots in St. Petersburg, Florida. Neither of the victims required treatment. Agent: rat poison Type of Event: use Summary: On 3 November, 48 people were poisoned as a result of eating contaminated meat rolls at a fast food restaurant in Deyang City, China. The meat rolls had been tainted with rat poison, which police believed was deposited in the rolls by an enemy of the restaurant’s owner. Agent: ricin Type of Event: threat with possession Summary: James Kenneth Gluck threatened to poison two Colorado judges using ricin. He was arrested on 5 November, and the raw materials for making ricin were seized from his Tampa, Florida, home. Agent: anthrax Type of Event: hoax Summary: On 8 November, the administration building at a former uranium processing plant in Hamilton County, Ohio, had to be evacuated when an employee found a coffee cup with an attached note that read, “Anthrax sample. Do not touch.” No anthrax was subsequently discovered. Agent: tear gas Type of Event: possession Summary: On 11 November, materials including tear gas canisters were found in the Milwaukee, Wisconsin, house of Kenneth R. Allen, who died in a fire after dousing police officers with burning liquid when they attempted to execute a search warrant.

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Summary: On 12 November, 12 students at a high school in Hat Yai, Thailand, became ill after consuming instant noodles that were contaminated by a classmate with a carbamite-based insecticide. Agent: tear gas Type of Event: possession Summary: Sid Ahmed Rezala was arrested and then released by French customs officials on a train at Pontarlier, France, on 13 November. He was searched and found to be carrying a knife, drugs, and a canister of tear gas. Agent: anthrax Type of Event: hoax Summary: On 18 November, there was an anthrax threat at a high school in New York. The following day, police arrested a juvenile who was charged with falsely reporting the incident. Agent: tear gas Type of Event: use Summary: On 29 November, two robbers sprayed tear gas in the eyes of a saleswoman and a security guard in a store on Avenue Montaigne in Paris, France. Agent: tear gas Type of Event: use Summary: On 30 November, protestors at the World Trade Organization (WTO) meeting in Seattle, Washington, threw back at police officers tear gas canisters that had been used by the police against the protestors.

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faculty member were treated in hospital. Two 17-year-old students were suspended as a result of the incident. Agent: cyanide Type of Event: possession Summary: On 3 December, Kevin Ray Patterson was arrested in connection with a plot to blow up a 24-million-gallon propane storage facility in Elk Grove, California. Explosive materials and cyanide were found during a search of his house. Agent: tear gas Type of Event: use Summary: On 12 December, members of the Revolutionary Armed Forces of Colombia (FARC) attacked a naval base and police station in Jurado, Colombia, with tear gas grenades and other weapons, completely destroying the police garrison. Agent: gas bombs Type of Event: use Summary: On 13 December, rebels from the FARC used “gas bombs filled with shrapnel” to attack a police station in Piendamo, Colombia. Agent: anthrax Type of Event: hoax Summary: On 13 December, a man phoned and claimed he had placed anthrax in a high school in Bedford, Indiana. Agent: toxic gas Type of Event: use Summary: On 14 December, rebels from the FARC attacked the police headquarters in Cubara, Colombia, using “gasoline and toxic gas.”

Agent: pepper spray

Agent: tear gas

Type of Event: use

Type of Event: use

Summary: On 2 December, pepper spray was released in a high school in Overland Park, Kansas. Eleven students and one

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Summary: On 14 December, it was alleged that an individual belonging to the National Movement for the Defense of Sovereignty

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(MONADESO) threw a canister of tear gas during a demonstration that occurred during the rehearsal for the Panama Canal transfer ceremony in Panama City, Panama. Agent: chemical agent Type of Event: use Summary: On 17 December, the Manila Times claimed that rival groups vying for control of gold mining operations in Monkayo, Philippines, had used “poison gas very much like the chemical warfare employed by Saddam Hussein against his enemies in Iraq.” The dispute began on 19 September . Agent: cyanide Type of Event: use Summary: On 18 December, seven students at a law school in Springfield, Massachusetts, became ill after drinking water from a cooler that had been contaminated with potassium cyanide. Agent: cyanide Type of Event: possession Summary: On 25 December, two members of the Mujahedin Khalq (MKO) were killed near Andimeshk, Iran. They, and a third man who was arrested, intended to attack military installations in Iran. All three were found to be carrying cyanide capsules. Agent: poison Type of Event: hoax Summary: During the night of 31 December, individuals drove through the streets of Al Kosheh, Egypt, with a megaphone, warning that Christians had poisoned the village’s tap water in an effort to kill Muslims. The event was part of an escalating dispute between Muslims and Coptic Christians in the village. Agent: chemical agent Type of Event: plot Summary: On 31 December, Angolan Armed Forces (FAA) discovered a bunker filled with military equipment belonging to the rebel group UNITA in Andulo. Among the materiel recovered

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were gas masks and chemical warfare gloves and boots. Angolan government sources claimed that the find reinforced their belief that UNITA had used chemical weapons in the Calosinga region of the state. Agent: chemical agent Type of Event: plot Summary: An FBI affidavit in January 2000 asserted that millennium night attacks planned by Al-Qaida against Westerners at holy sites in Jordan may have included plans to use unconventional gas bombs.

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7 PUBLIC HEALTH STATEMENT FOR ACETONE This public health statement tells you about acetone and the effects of exposure. This information is important because this chemical may harm you. The Environmental Protection Agency (EPA) has identified 1,350 hazardous waste sites as the most serious in the nation. These sites make up the National Priorities List (NPL) and are targeted for long-term federal clean-up. Acetone has been found in at least 560 NPL sites. However, it’s unknown how many NPL sites have been evaluated for this substance. As EPA tests more sites, the sites with acetone may increase. This is important because exposure to acetone may harm you and because these sites are or may be sources of exposure. When a large industrial plant or a small container releases a substance, it enters the environment. This release does not always lead to exposure. You are exposed to a substance only when you come in contact with it by breathing, eating, touching, or drinking. If you are exposed to acetone, many factors determine if you’ll be harmed and how badly. These factors include the dose (how much), the duration (how long), and how you’re exposed. You must also consider the other chemicals you’re exposed to and your age, sex, nutritional status, family traits, lifestyle, and state of health. WHAT IS ACETONE? Acetone is a chemical that is found naturally in the environment and is also produced by industries. Low levels of

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acetone are normally present in the body from the breakdown of fat; the body can use it in normal processes that make sugar and fat. Acetone is a colorless liquid with a distinct smell and taste. People begin to smell acetone in air at 100 to 140 parts of acetone in a million parts of air (ppm), though some can smell it at much lower levels. Most people begin to detect the presence of acetone in water at 20 ppm. Acetone evaporates readily into the air and mixes well with water. Most acetone produced is used to make other chemicals that make plastics, fibers, and drugs. Acetone is also used to dissolve other substances.

WHAT HAPPENS TO ACETONE WHEN IT ENTERS THE ENVIRONMENT? Acetone enters the air, water, and soil as a result of natural processes and human activities. Acetone occurs naturally in plants, trees, volcanic gases, and forest fires. People and animals breathe out acetone produced from the natural breakdown of body fat. Acetone is also released during its manufacture and use, in exhaust from automobiles, and from tobacco smoke, landfills, and certain kinds of burning waste materials. The levels of acetone in soil increase mainly because of acetone-containing wastes being buried in landfills. Acetone is present as a gas in air. Some acetone in air is lost when it reacts with sunlight and other chemicals. Rain and snow also remove small amounts of acetone from the atmosphere and, in the process, deposit it on land and water. About half the acetone in a typical atmosphere at any time will be lost in 22 days. Microbes (minute life forms) in water remove some acetone from water. Some acetone in water will evaporate into air. About half the acetone in a stream will be removed from water in less than a day. Fish do not store acetone from water in their bodies. Microbes in soil remove part of the acetone in soil. Some is lost from soil by evaporation. Acetone molecules do not bind tightly to soil. Rainwater and melted snow dissolve acetone and carry it deeper into the soil to groundwater. HOW MIGHT I BE EXPOSED TO ACETONE? Your body makes small amounts of acetone. You can be exposed to a small amount of acetone by breathing air, drinking water, and eating food with acetone. You can also be exposed by contact with household chemicals with acetone. Several consumer

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products, including certain nail polish removers, particle board, some paint removers, many liquid or paste waxes or polishes, and certain detergents or cleansers, contain acetone. You can also be exposed to acetone if you are exposed to isopropyl alcohol, because isopropyl alcohol changes to acetone in the body. The level of acetone in air and water is generally low. The amount of acetone in the air of cities is generally higher than in remote and rural areas. The typical level of acetone in the air of cities in the United States is about 7 parts of acetone per billion parts of air (ppb). The level of acetone in air inside homes is usually slightly higher than in outside air (8 ppb versus 7 ppb). This is because of household chemical use inside homes. Acetone in drinking water is so low that its levels have not been measured in many samples. In a national survey, the acetone level in drinking water from Seattle, Washington, was 1 ppb. Acetone occurs naturally in many fruits and vegetables. The amount of acetone in food does not increase because of processing or packaging. The average amount of acetone an adult in the United States gets from food is not known. People who work in certain industries that process and use acetone can be exposed to higher levels than the general populace. These industries include certain paint, plastic, artificial fiber, and shoe factories. Professional painters and commercial and household cleaners are also likely to breathe or touch higher acetone concentrations than the general population. As a member of the general public, you may be exposed to higher than normal levels of acetone if you smoke cigarettes, frequently use acetone nail polish removers, live near landfill sites that contain acetone, live near busy roadways (because automobile exhaust contains acetone), or live near other facilities that are known to release acetone, such as incinerators. The exposure from these sources will be mainly from breathing air that contains acetone or by direct skin contact with it. In addition, children can be exposed to acetone by eating dirt or by placing dirty hands in their mouths after exposing their skin to dirt from landfill sites.

HOW CAN ACETONE ENTER AND LEAVE MY BODY? Your body normally contains some acetone because it’s made during the breakdown of fat. Your body will make more acetone

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from body fat if you are on a low-fat diet. In addition to the acetone that your body makes from normal processes, acetone can enter your body if you breathe air that contains acetone, drink water or eat food that contains acetone, or if you touch liquid acetone or soil that contains acetone. The bloodstream absorbs acetone rapidly and completely from the lungs and stomach. The bloodstream can also absorb acetone from the skin, but less rapidly than from the lungs and stomach. Blood carries acetone to all body organs, but it does not stay there very long. The liver breaks down acetone to chemicals that are not harmful. The body uses these chemical to make glucose (sugar) and fats that make energy for normal body functions. The breakdown of sugar for energy makes carbon dioxide that leaves your body in the air you breathe out. These are normal processes in the body. Not all the acetone that enters your body from outside sources is broken down. The amount that is not broken down leaves your body mostly in the air that you breathe out. You also breathe out more carbon dioxide than normal if you are exposed to acetone from sources outside the body because more carbon dioxide is made from the extra acetone. Only a small amount of acetone that is not broken down leaves the body in the urine. The acetone that is not used to make sugar leaves your body within a few days in the air you breathe out and in the urine. The amount of acetone that enters and leaves your body depends on how much you’re exposed to and for how long. The higher the level of acetone and the longer that you are exposed will cause acetone to leave your body more slowly, but almost all the acetone will leave your body within 3 days after your exposure stops. If you exercise or work while exposed to acetone in air, more will enter your lungs because you breathe faster and more deeply during exercise.

HOW CAN ACETONE AFFECT MY HEALTH? Low levels of acetone are normally present in the body from the breakdown of fat. The body uses acetone in normal processes that make sugar and fats that make energy for normal body

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functions. Many conditions can lead to higher-than-average amounts of acetone in the body. For example, babies, pregnant women, diabetics, and people who exercise, diet, have physical trauma, or drink alcohol can have higher amounts of acetone in their bodies. These higher amounts of acetone usually don’t cause health problems. In addition, acetone can prevent convulsions. Most of the information on how acetone affects human health comes from medical exams of workers on a single workday; from lab experiments in humans exposed to acetone in air for a few days; and from cases of people who swallowed acetone-based glue or fingernail polish remover. Workers and people exposed to acetone in the lab complained that acetone irritated their noses, throats, lungs, and eyes. Some people feel this irritation at levels of 100 ppm acetone in the air, and more people feel the irritation as the level in air increases. The workers who complained of irritation were exposed to levels of 900 ppm or more. Workers exposed to acetone at 12,000 ppm or higher also complained of headache, lightheadedness, dizziness, unsteadiness, and confusion depending on how long they were exposed (from 2 minutes to 4 hours). Two workers exposed for 4 hours became unconscious. In addition, some people who had casts applied with acetone were exposed to acetone that evaporated into air during and after the casts were applied. These patients became nauseous, vomited blood, and became unconscious. These cases happened many years ago; modern hospitals have different methods that don’t use acetone when casts are applied. Some people exposed to acetone in the air at about 250 ppm for several hours in the lab had headaches and lacked energy, and they also had some mild behavioral effects. These effects showed up in tests of how long it takes to react to a visual stimulus or the ability to hear different sounds. Some people exposed to 500 ppm in the air for several hours in the lab had effects on the blood, but other studies showed no effects on the blood at even higher exposure levels. Some women exposed to 1,000 ppm for about 8 hours in a lab said that their periods came earlier than expected. Workers are not usually exposed to levels higher than 750 ppm anymore because of current government regulations. The regulation says workroom

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air should contain no more than an average of 750 ppm. Most people can smell acetone in the air at 100 to 140 ppm; that means you will probably smell acetone before you feel effects like headache and confusion. Levels of acetone in air in rural areas and in cities (less than 8 ppb) are generally lower than this. People who swallowed acetone or substances that contained acetone became unconscious, but they recovered in the hospital. The amount of acetone that these people swallowed was not always known, but one man swallowed about 2,250 milligrams of pure acetone per kilogram of body weight (2,250 mg/kg). In addition to becoming unconscious, he had tissue damage in his mouth and he later developed a limp, which eventually cleared up, and symptoms similar to diabetes (excessive thirst, frequent urination). The amount of acetone in water or food would never be high enough to cause these effects, but people, especially children, could accidentally swallow enough acetone in nail polish remover or some household cleaners to cause such effects. In a lab experiment, people who had liquid acetone applied directly on their skin and held there for a half hour developed skin irritation. When the skin was looked at under a microscope, some of the skin cells were damaged. Animals briefly exposed to high levels of acetone in the air also had lung irritation and became unconscious; some died. Exposure at lower levels for short periods also affected their behavior. Pregnant animals that were exposed to high levels of acetone in air had livers that weighed more than usual and had fewer fetuses. The fetuses weighed less than normal and had delayed bone development. We do not know how exposure to acetone in air for longer than 2 weeks affects animals. Animals given large amounts of acetone to swallow or drink for short periods had bone marrow hypoplasia (fewer new cells being made), degeneration of kidneys, heavier than normal livers and bigger liver cells, and collapse and listlessness. Pregnant mice that swallowed acetone had lower body weights and produced fewer newborn mice. More of the newborns of mice that had swallowed acetone died than newborns of mice that were not given acetone. Male rats that swallowed or drank even small amounts of acetone for long periods had anemia and kidney

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disease. The female rats did not have anemia, but they had kidney disease when they swallowed a much larger amount of acetone than the male rats swallowed. The female rats had livers and kidneys that weighed more than normal, and so did the male rats, but only when they swallowed larger amounts of acetone than the females swallowed. The male rats also had abnormal sperm. The female rats did not have any effects in their reproductive organs. Rats also had signs that acetone caused effects on their nervous systems. Acetone is irritating to the skin of animals when it is placed directly on their skin, and it burns their eyes when placed directly in their eyes. One kind of animal (guinea pigs) even developed cataracts in their eyes when acetone was placed on their skin. We do not know whether many of the effects seen in animals would occur in humans. People exposed to acetone were not examined for some effects or could not be examined for effects that can be seen only by looking at internal organs under a microscope. The findings in animals show that male rats are more likely than female rats to get blood and kidney disease and effects on reproductive organs after exposure to acetone. This suggests that men might be more likely to have effects of exposure to acetone than women. One effect of acetone seen in animals is an increase in the amount of certain enzymes (chemicals in the body that help break down natural substances in the body and chemicals that enter the body). The increase in these enzymes caused by acetone exposure can make some chemicals more harmful. This is one reason that people should be concerned about being exposed to acetone; exposure is very likely to mixtures of chemicals in the environment, near hazardous waste sites, or in the workplace is very likely. Acetone does not cause skin cancer in animals when it is applied to their skin. We don’t know whether acetone would cause cancer after breathing or swallowing it for long periods, because no tests have been done. The Department of Health and Human Services and the International Agency for Research on Cancer have not classified acetone for carcinogenic effects. The EPA has determined that acetone is not classifiable as to its human carcinogenicity.

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IS THERE A MEDICAL TEST TO DETERMINE WHETHER I HAVE BEEN EXPOSED TO ACETONE? Acetone can be measured in the air you breathe out, in the blood, and in the urine. Methods for measuring acetone in breath, blood, and urine are available at most modern testing labs. Doctors’ offices may not have the necessary equipment, but your doctor can take blood and urine samples and send them to a testing lab. The measurement of acetone in breath, blood, and urine can determine whether you have been exposed to acetone if the levels are higher than those normally seen. They can even predict how much acetone you were exposed to. However, normal levels of acetone in breath, blood, and urine can vary widely depending on many factors, such as infancy, pregnancy, lactation, diabetes, physical exercise, dieting, physical trauma, and alcohol. The odor of acetone on your breath can alert a doctor that you have been exposed to acetone. An odor of acetone on your breath could also mean that you have diabetes. Because acetone leaves your body within a few days after exposure, these tests can tell only that you have been exposed to acetone within the last 2 or 3 days. These tests cannot tell whether you will experience any health effects related to your exposure. WHAT RECOMMENDATIONS HAS THE FEDERAL GOVERNMENT MADE TO PROTECT HUMAN HEALTH? EPA requires that spills of 5,000 pounds or more of acetone be reported. To protect workers, the Occupational Safety and Health Administration (OSHA) has set a legal limit of 750 ppm of acetone in workroom air. The regulation means that the workroom air should contain no more than an average of 750 ppm of acetone over an 8-hour working shift or over a 40-hour workweek. INTRODUCTION The primary purpose of this chapter is to provide public health officials, physicians, toxicologists, and other interested individuals and groups with an overall perspective of the toxicology of acetone. It contains descriptions and evaluations of toxicological studies and epidemiological investigations and

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provides conclusions, where possible, on the relevance of toxicity and toxicokinetic data to public health. A glossary and list of acronyms, abbreviations, and symbols can be found at the end of this profile. DISCUSSION OF HEALTH EFFECTS BY ROUTE OF EXPOSURE To help public health professionals and others address the needs of persons living or working near hazardous waste sites, the information in this section is organized first by route of exposure - inhalation, oral, and dermal; and then by health effect - death, systemic, immunological, neurological, reproductive, developmental, genotoxic, and carcinogenic effects. These data are discussed in terms of three exposure periods - acute (14 days or less), intermediate (15-364 days), and chronic (365 days or more). Levels of significant exposure for each route and duration are presented in tables and illustrated in figures.

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exposure at which major health effects start to appear. LOAELs or NOAELs should also help in determining whether or not the effects vary with dose and/or duration, and place into perspective the possible significance of these effects to human health. The significance of the exposure levels shown in the Levels of Significant Exposure (LSE) tables and figures may differ depending on the user’s perspective.

The points in the figures showing no-observed-adverse-effect levels (NOAELs) or lowest- observedadverse- effect levels (LOAELs) reflect the actual doses (levels of exposure) used in the studies. LOAEL have been classified into “less serious” or “serious” effects. “Serious” effects are those that evoke failure in a biological system and can lead to morbidity or mortality (e.g., acute respiratory distress or death).

Public health officials and others concerned with appropriate actions to take at hazardous waste sites may want information on levels of exposure associated with more subtle effects in humans or animals (LOAELs) or exposure levels below which no adverse effects (NOAELs) have been observed. Estimates of levels posing minimal risk to humans (Minimal Risk Levels or MRLs) may be of interest to health professionals and citizens alike. Estimates of exposure levels posing minimal risk to humans (Minimal Risk Levels or MRLs) have been made for acetone. An MRL is defined as an estimate of daily human exposure to a substance that is likely to be without an appreciable risk of adverse effects (noncarcinogenic) over a specified duration of exposure. MRLs are derived when reliable and sufficient data exist to identify the target organ(s) of effect or the most sensitive health effect(s) for a specific duration within a given route of exposure. MRLs are based on noncancerous health effects only and do not consider carcinogenic effects.

“Less serious” effects are those that are not expected to cause significant dysfunction or death, or those whose significance to the organism is not entirely clear. ATSDR acknowledges that a considerable amount of judgment may be required in establishing whether an end point should be classified as a NOAEL, “less serious” LOAEL, or “serious” LOAEL, and that in some cases, there will be insufficient data to decide whether the effect is indicative of significant dysfunction. However, the Agency has established guidelines and policies that are used to classify these end points. ATSDR believes that there is sufficient merit in this approach to warrant an attempt at distinguishing between “less serious” and “serious” effects. The distinction between “less serious” effects and “serious” effects is considered to be important because it helps the users of the profiles to identify levels of

MRLs can be derived for acute, intermediate, and chronic duration exposures for inhalation and oral routes. Appropriate methodology does not exist to develop MRLs for dermal exposure. Although methods have been established to derive these levels, uncertainties are associated with these techniques. Furthermore, ATSDR acknowledges additional uncertainties inherent in the application of the procedures to derive less than lifetime MRLs. As an example, acute inhalation MRLs may not be protective for health effects that are delayed in development or are acquired following repeated acute insults, such as hypersensitivity reactions, asthma, or chronic bronchitis. As these kinds of health effects data become available and methods to assess levels of significant human exposure improve, these MRLs will be revised. A User’s Guide has been provided at the end of this profile. This guide should

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aid in the interpretation of the tables and figures for Levels of Significant Exposure and the MRLs.

INHALATION EXPOSURE

Death In a retrospective mortality study of 948 employees (697 men, 251 women) of a cellulose fiber plant where acetone was used as the only solvent, no significant excess risk of death from any cause (all causes, malignant neoplasm, circulatory system disease, ischemic heart disease) compared with rates for the U.S. general population was found. The workers had been employed at the plant for at least 3 months to 23 years. Industrial hygiene surveys found that median time-weightedaverage acetone concentrations were 380, 770, and 1,070 ppm based on job categories. High concentrations of acetone were required to produce death in animals. An 8-hour LC50 value of 21,091 ppm and a 4-hour LC50 value of 31,994 ppm were found for female rats. Inhalation exposure to acetone for a few hours has resulted in death in rats at concentrations ranging from 16, inhalation exposure to acetone for a few hours has resulted in death in rats at concentrations ranging from 16,000 to 50,600 ppm and in guinea pigs from 10,000 to 50,000 ppm. In general, higher concentrations of acetone resulted in death sooner than lower concentrations. That very high concentrations of acetone are required to cause death of animals is reinforced by the fact that no deaths were reported for rats exposed to acetone at 4,210 for 8 hours to 126-129 ppm for 25 minutes or mice exposed to <84,194 ppm for 8 hours. No studies were located regarding death of animals after intermediate- or chronic-duration inhalation exposure to acetone.

Systemic Effects The systemic effects of inhalation exposure to acetone in humans and animals are discussed below. Respiratory Effects. The only effect on the respiratory system observed in humans exposed to acetone vapors is irritation of the nose, throat, trachea, and lungs. The irritating properties of acetone in humans have been noted both in workers who were exposed to acetone occupationally and in volunteers under controlled

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laboratory conditions. Complaints of irritation were reported by workers with average exposures to acetone in the workroom of e”901 ppm. In controlled situations, the volunteers had been asked to give their subjective complaints, and some of the volunteers reported that exposure to 100 ppm for 6 hours was irritating, with more subjects reporting irritation at increasing exposure levels. Subjective symptoms also included the loss of the ability to smell acetone as exposure proceeded. In another controlled experiment, the majority of subjects, although exposed for only 3-5 minutes, estimated that they could tolerate an exposure level of 200 ppm for an 8-hour workshift. Pulmonary function testing of volunteers exposed <1,250 ppm acetone intermittently for various durations in a complex protocol revealed no abnormalities caused by the exposure. The volunteers did experience throat irritation sporadically. Exposure of animals to much higher concentrations of acetone than those reported in humans has resulted in respiratory effects. Pulmonary congestion, edema, and hemorrhage of the lungs were observed in guinea pigs that died after exposure to 10,000 ppm continuously for 1 or 2 days, to 20,000 ppm continuously for 1 day, or to 50,000 ppm for a few hours. The congestion and edema were attributed to the irritating effects of acetone on the mucosa. The hemorrhage may have been a consequence of death. Respiratory rates also decreased in the guinea pigs during exposures, but the decrease was probably a consequence of the narcotic effects of acetone. In mice exposed to acetone for 10 minutes, the calculated concentration of acetone that decreased the respiratory rate 50% (RC50) was 77,516 ppm. The decrease in respiratory rate was considered to be due to sensory irritation, but adaptation to the irritant properties developed. The RC50 for acetone was higher than the values calculated for other solvents, indicating that acetone is a weak irritant. In mice exposed to 6,000 ppm acetone for 0.5 hours/day for 1 or 5 days, no effects on the time of inspiration, time of expiration, time between breaths, or tidal volume were found . In addition, acetone exposure caused no changes in lung weight, lung volume displacement, or histological evidence of pulmonary pathology. Histological examination of the lungs of rats exposed

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intermittently to a high concentration of acetone (19,000 ppm) for 2-8 weeks revealed no evidence of treatment-related lesions. Cardiovascular Effects. Information regarding cardiovascular effects in humans following inhalation exposure to acetone is limited. High pulse rates (120-160/minute) were commonly found in patients exposed to acetone by inhalation and/or dermally after application of casts for which acetone was used in the setting solution. In a controlled laboratory study using a complex protocol, electrocardiography of volunteers exposed to <1,250 ppm acetone intermittently for various durations revealed no alterations, compared with their preexposure electrocardiograms. A retrospective mortality study of 948 workers (697 men, 251 women) employed for at least 3 months to 23 years at a cellulose fiber plant where acetone was used as the only solvent found no significant excess risk of death from circulatory system disease or ischemic heart disease compared with rates for the U.S. general population. Industrial hygiene surveys found that median time-weightedaverage acetone concentrations were 380,770, and 1,070 ppm based on job categories. Reduced heart rates were observed in guinea pigs exposed to various high concentrations of acetone for various acute durations, but were probably a consequence of the narcotic effects of acetone . Necropsy of the guinea pigs revealed no effects on the heart, but histological examination was not performed. Histological examination of the hearts of rats exposed intermittently to a high concentration of acetone (19,000 ppm) for 2-8 weeks revealed no evidence of treatment-related lesions. Gastrointestinal Effects. Case reports have described vomiting of blood and gastrointestinal hemorrhage in patients who had hip casts applied with acetone present in the setting fluid. As the vomitus contained blood several hours after vomiting first commenced, the gastrointestinal hemorrhage may have been due to the trauma of repeated vomiting. These patients had a strong odor of acetone in their breath, and acetone was detected in the urine and blood. These patients were exposed to acetone by inhalation during cast application and from evaporation from the casts after the applications. In addition, the possibility of contribution from dermal exposure could not be ruled out. In one case, exposure was considered to be mainly dermal. Necropsy of

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guinea pigs that died after exposure to various high concentrations of acetone for various acute durations revealed no effects on the stomach, but histological examination was not performed. Hematological Effects. In a health evaluation survey of 168 men and 77 women employed at a cellulose fiber production plant where acetone was used as the only solvent, all hematological parameters were within normal limits. The workers had been employed at the plant for at least 3 months to 23 years. Industrial hygiene surveys found median time-weightedaverage acetone concentrations of 380, 770, and 1,070 ppm, based on job categories. Hematological effects have been observed in humans after inhalation exposure to acetone in controlled laboratory studies of volunteers. Statistically significant increased white blood cell counts and decreased phagocytic activity of neutrophils, compared with controls, were observed in the volunteers after a 6-hour exposure or repeated 6-hour exposures for 6 days to 500 ppm. No significant difference was seen in hematological parameters in the volunteers exposed to 250 ppm compared with controls. In contrast, hematological findings were within normal limits in volunteers exposed to 500 ppm for 2 hours or <1,250 ppm acetone repeatedly for l-7.5 hours/day for as long as 6 weeks. In animals, no studies were located regarding effects on the formed elements of the blood after inhalation exposure to acetone. Musculoskeletal Effects. No studies were located regarding musculoskeletal effects in humans or animals after inhalation exposure to acetone. Hepatic Effects. No indication that acetone caused hepatic effects in humans was found in controlled studies of volunteers. Clinical chemistry parameters indicative of liver injury (e.g., serum alanine aminotransferase, aspartate aminotransferase, lactic dehydrogenase, alkaline phosphatase, ornithine carbamoyl transferase, cholesterol, triglycerides, bilirubin, lipids, etc.) were within normal limits in volunteers exposed to acetone at concentrations of 500 ppm for 2 hours or 11,250 ppm intermittently for various durations. In a health evaluation survey of 168 men and 77 women employed for at least 3 months to 23 years at a cellulose fiber production plant where acetone was used as the only solvent, all clinical blood chemistry parameters (aspartate

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aminotransferase, alanine aminotransferase, lactic dehydrogenase, alkaline phosphatase, total bilirubin, and albumin) were within normal limits. Industrial hygiene surveys found median timeweighted-average acetone concentrations of 380, 770, and 1,070 ppm, based on job categories. Fatty deposits were found in the livers upon autopsy of guinea pigs that died after exposure to high concentrations of acetone for various acute durations. In contrast, intermittent exposure of rats to a high concentration of acetone (19,000 ppm) for 2-8 weeks did not produce signs of liver toxicity, assessed by the measurement of serum aspartate aminotransferase, lactic dehydrogenase, liver weights, and histological examination of the liver. Inhalation exposure to acetone at lower concentrations does not appear to be toxic to the liver of animals; however, acetone potentiates the hepatotoxicity induced by some other chemicals. The mechanism by which acetone exerts the potentiation is through the induction or increased activity of liver microsomal monooxygenases, particularly enzymes associated with cytochrome P-450IIEl. Most of the studies showing enzyme induction have been conducted by the oral route . In acute inhalation studies in rats, acetone exposure resulted in statistically significant increases in the liver concentration of cytochrome P450, the activity of ethoxycoumarin O-deethylase (associated with P-450IIBl), and the activity of glutathione- S-transferase, and decreased the liver free glutathione content. Induction of microsomal enzymes is considered a normal physiological response to xenobiotics, rather than an adverse effect. In a developmental study, mice exposed intermittently to 6,600 ppm acetone on gestational days 6-19 had significantly increased absolute and relative liver weights compared with controls (p<0.05) (NTP 1988). Increased liver weight is considered a sign of maternal toxicity in developmental studies. The increased liver weight could have been associated with enzyme induction. Renal Effects. No indication that acetone caused renal effects in humans was found in controlled studies of volunteers. Clinical blood chemistry parameters indicative of kidney injury (e.g., blood urea nitrogen, uric acid) and urinalysis parameters were within normal limits in volunteers exposed to acetone at concentrations

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of 500 ppm for 2 hours or d”1,250 ppm intermittently for various durations. The only indication that inhalation exposure to acetone causes renal effects in animals was the consistent finding of congestion or distention of renal tubules or glomeruli in guinea pigs that died after exposure to high concentrations of acetone for various acute durations. Rats exposed intermittently to 19,000 ppm for <8 weeks had significantly decreased kidney weights (p<0.0l) after 4 weeks of exposure compared with controls, but not after 2 or 8 weeks of exposure or at 2 weeks postexposure. Blood urea nitrogen levels were not affected by acetone exposure, and no evidence of histological changes in the kidneys were found. In the absence of other evidence of renal toxicity, the sporadically reduced kidney weight cannot be considered an adverse effect. Derma/Ocular Effects. Eye irritation is a common complaint of workers exposed to acetone vapors occupationally and in volunteers exposed under controlled conditions. In a report of the experience at the Tennessee Eastman Corporation on acetone concentrations not associated with injury presented at the American Conference of Governmental Industrial Hygienists (ACGIH) Tenth Annual Meeting, it was noted that acetone is mildly irritating to the eyes at 2,000-3,000 ppm, with no irritation persisting after exposure ceases. Lacrimation has also been observed in guinea pigs exposed to acetone vapors. Other Systemic Effects. No studies were located regarding other systemic effects in humans after inhalation exposure to acetone. Other systemic effects observed in animals after inhalation exposure to acetone include body weight changes. In a developmental study, rats exposed to acetone at 11,000 ppm, but not mice exposed to 6,600 ppm, intermittently during gestation had significantly (p<0.05) reduced body weight gain from gestational day 14 onward and reduced extragestational body weight on gestational day 20 (NTP 1988). However, in a behavioral study, no effect on body weight gain was observed in female rats exposed to 16,000 ppm intermittently for 2 weeks. It is possible that the condition of pregnancy made the rats more susceptible to body weight reduction. In addition, marked congestion and hemorrhage of the spleen were observed upon autopsy of guinea pigs that died after exposure to various high concentrations of

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acetone for various acute durations. These effects could have been the consequence of death.

IMMUNOLOGICAL EFFECTS The only information regarding immunological effects in humans after inhalation exposure to acetone is the finding of statistically significant increased white blood cell counts, increased eosinophil counts, and decreased phagocytic activity of neutrophils in volunteers exposed to 500 ppm for a single 6-hour exposure or intermittently for 6 days. No significant difference in these parameters was seen in the volunteers exposed to 250 ppm compared with controls. Hematological parameters, including total white cell counts and differential white cell counts, were within normal limits in other volunteers exposed to 500 ppm for 2 hours or <1,250 ppm acetone intermittently for durations in a study with a complex protocol; however, these investigators did not examine the phagocytic activity of neutrophils. NEUROLOGICAL EFFECTS Case reports have described patients who became comatose or collapsed after hip casts were applied with acetone present in the setting fluid. In addition, a woman experienced headache, dizziness, weakness, difficulty speaking, and depression after a cast containing acetone had been applied. These patients had a strong odor of acetone in their breath, and acetone was detected in the urine and blood. These patients were exposed to acetone by inhalation during cast application and from evaporation from the casts after the applications. In addition, the possibility of contribution from dermal exposure could not be ruled out. In another case of neurological effects (drowsiness, fretfulness, irritability, restlessness, uncoordinated hand movement, nystagmus) developing after application of a cast, exposure was considered to be mainly dermal because an airblower was used continuously during the application to dissipate the fumes. However, because the patient had kept his head under a blanket, some inhalation of acetone evaporating from the cast may have occurred. Workers exposed to acetone in the past commonly experienced neurological effects. In an on-site medical appraisal of nine workers, in which the time-weighted average exposure

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concentration was 1,006 ppm, three of the workers mentioned headache and lightheadedness as subjective symptoms. In another on-site medical appraisal of four workers, in which the timeweighted average exposure concentration was 901 ppm, none of the workers complained of neurological effects. The medical examinations included the Romberg test, finger-to-nose test, and observations for nystagmus (involuntary rapid movement of the eyeball). These tests revealed no neurobehavioral effects in either study. Such symptoms as unconsciousness, dizziness, unsteadiness, confusion, and headache were experienced by seven workers exposed to >12,000 ppm acetone while cleaning out a pit containing acetone, that had escaped from nearby tanks. The degree of the symptoms varied depending on the length of time that the workers had spent in the pit (2 minutes to 4 hours). Neurological and behavioral effects have also been documented in volunteers tested under controlled laboratory conditions. These effects included general lack of energy and weakness, headache, delayed visual reaction time; subjective symptoms of tension, tiredness, complaints (not otherwise specified), and annoyance; increases in response and the percent false negatives in auditory discrimination tests and increases in anger and hostility; and increased visual evoked response. Other neurological and neurobehavioral tests (e.g., electroencephalography, choice reaction time, visual vigilance, dual task, memory scanning, postural sway, Romberg test, or heel-to-toe test) were also conducted on these volunteers, but acetone exposure had no effect on these parameters. The relationship between concentration and duration of exposure on the development of narcosis was demonstrated in volunteers exposed to acetone at 21,049-84,194 ppm for 1-8 hours. As the concentration increased, the time to observations of signs of narcosis (not otherwise described), loss of righting reflex, and loss of cornea1 reflex decreased. It should be noted that these concentrations of acetone are extremely high, and exposure to lower concentrations of acetone for shorter durations has resulted in unconsciousness in some workers, as discussed above. Based on a LOAEL of 237 ppm for 4 hours for neurobehavioral effects in humans, an acute inhalation MRL of 26 ppm was calculated

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as described in footnote “b”. Based on a LOAEL of 1,250 ppm for neurological effects in a 6-week study, intermediate and chronic inhalation MRLs of 13 ppm were calculated as described in footnote “c”. Narcotic effects have been observed in animals exposed acutely to acetone vapors. The narcotic effects observed in animals after inhalation exposure to acetone depend upon the duration and the magnitude of exposure. The narcotic effects appear to proceed through several stages: drowsiness, incoordination, loss of autonomic reflexes, unconsciousness, respiratory failure, and death as concentrations and durations increase. The acute data suggest that concentrations >8,000 ppm generally are required to elicit overt signs of narcosis, although neurobehavioral effects, when assessed by specific behavioral tests, have been observed at lower concentrations. The relationship between concentration and duration of exposure on the development of narcosis was demonstrated in rats exposed to acetone at 2,105-126,291 ppm for 5 minutes to 8 hours. While exposure to 2,105 or 4,210 ppm for 8 hours resulted in no signs of narcosis or effects on righting reflex or cornea1 reflex, these effects were observed at higher concentrations. At increasing concentrations >10,524 ppm, the time to observations of signs of narcosis, loss of righting reflex, and loss of cornea1 reflex decreased. The responses were correlated with blood acetone levels. Similar concentration- and duration-response relationships were found in mice exposed to 16,839-84,194 ppm acetone for up to 4 hours. Neurological responses included drowsiness, staggering, prostration, clonic movements of hind legs, and deep narcosis. Narcosis, evidenced by decreased respiratory and heart rates, paralysis, and coma were observed in guinea pigs exposed to 21,800 ppm continuously for periods ranging from 25 minutes to 24 hours. The degree of narcosis increased as the exposure duration increased. In a developmental study, virgin and pregnant mice experienced severe narcosis after a single 6-hour exposure to 11,000 ppm on the first day, but narcosis was no longer observed when the exposure was lowered to 6,600 ppm 6 hours/day for the rest of the study (NTP 1988). Neurobehavioral effects, indicative of narcosis, have been observed in rats, mice, and baboons acutely

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exposed to acetone vapors. These effects include central nervous system depression measured by five tests of unconditioned performance and reflex in rats, decreased operant behavior evaluated by a multiple fixed ratio-fixed interval schedule of food reinforcement in rats, inhibition of avoidance behavior and escape response in rats, decreased response to food presentation in mice, decreased duration of immobility in a behavioral despair swimming test in mice, and incoordination in a “match to sample” operant behavioral test in baboons. In these studies, the animals recovered from the neurobehavioral effects as exposure continued, indicating adaptation or tolerance, or after exposure ceased, demonstrating the reversibility of these effects. The length of the recovery period was generally related to the level of exposure. In the experiments of Geller et al. (1979a, 1979b), only four baboons and three rats were studied, precluding meaningful statistical analysis, and only two of the four baboons exhibited the effects. The rats were exposed to 150 ppm for 0.5-4 hours, and the baboons were exposed to 500 ppm continuously for 7 days. Intermediateduration intermittent exposure of rats to 19,000 ppm acetone resulted in a statistically significant decrease (p<0.02) in absolute brain weight, but no exposure-related histological lesions. Thus, based on the available data, the neurological effects of acetone are reversible and cannot be attributed to histologically observable changes in the brains of animals or to electroencephalographic changes in humans.

REPRODUCTIVE EFFECTS Information regarding reproductive effects in humans after inhalation exposure to.acetone is limited. Premature menstrual periods were reported by three of four women exposed to 1000 ppm acetone for 7.5 hours in a laboratory study of volunteers . The shortening of the menstrual cycle was considered to be possibly due to the acetone exposure. Women workers in a Russian factory where workroom levels of acetone ranged from 14 to 126 ppm were reported to have statistically significantly increased incidences of pregnancy complications, including miscarriage, toxicosis (not otherwise described), decreased hemoglobin levels and hypotension, and “weakness of labor activity,” compared with controls. However, the number of women studied, further

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description of the exposed and control groups (such as age, smoking history, use of alcohol), and description of workroom monitoring methods and statistical methods were not reported. Therefore, no conclusions can be made from this report. In a epidemiological study of the pregnancy outcome among 556 female laboratory workers, no statistically significant difference in the incidence of miscarriage was found between those exposed to a variety of solvents including acetone and those not exposed to solvents. No reproductive effects (i.e., no effects on number of implants/litter, percent live pups/litter, or mean percent resorptions/litter) were observed in rats or mice in an inhalation developmental study (NTP 1988). No studies were located regarding reproductive effects in male animals, histological effects on reproductive organs of male or female animals, or the reproductive outcomes and other indices of reproductive toxicity in animals after inhalation exposure to acetone.

DEVELOPMENTAL EFFECTS Information regarding developmental effects in humans after inhalation exposure to acetone is limited. Statistically significant increased incidences of developmental effects, such as, intrauterine asphyxia of fetuses and decreased weight and length of neonates, were reported for women workers in a Russian factory, where workroom levels of acetone ranged from 14 to 126 ppm. However, the number of women studied, further description of the exposed and control groups (such as age, smoking history, use of alcohol), and description of workroom monitoring methods and statistical methods were not reported. Therefore, no conclusions can be made from this report. In a epidemiological study of the pregnancy outcome among 556 female laboratory workers, no statistically significant differences in the incidences of miscarriage, perinatal death rate, or malformations were found between those exposed to a variety of solvents, including acetone, and those not exposed to solvents . In a development study in rats exposed intermittently to acetone during gestation, the only effect was a slight, but significant (p<0.05), decreased mean male and female fetal body weight at 11,000 ppm (NTP 1988). It should be noted that the dams exposed at this level had significantly (p<0.05) reduced body weight during gestation, reduced uterine weight, and reduced

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extragestational weight on gestational day 20. No effects were seen on sex ratio, incidence of fetal variations, reduced ossification sites, or mean fetal variations. The percent of litters with at least one fetal malformation was higher in the 11,000 ppm group than in the control group, but no statistically significant increased incidences of fetal malformations were observed. In mice similarly exposed during gestation, however, there was a slight, but significant (p<0.05) increase in percent late resorptions, decrease in mean male and female fetal weights, and increase in the incidence of reduced sternebral ossification in the 6,600 ppm group. The only evidence of maternal toxicity at this exposure level was statistically significant increased absolute and relative liver weight. No effects were found on the number of implantations per litter, percent live fetuses/litter, sex ratio, incidence of malformations or skeletal variations combined.

GENOTOXIC EFFECTS No studies were located regarding genotoxic effects in humans or animals after inhalation exposure to acetone. CANCER In a retrospective mortality study of 948 employees (697 men, 251 women) of a cellulose fiber plant where acetone was used as the only solvent, no significant excess risk of death from any cause, including malignant neoplasm, was found when compared with rates for the U.S. general population. The workers had been employed at the plant for at least 3 months to 23 years. Industrial hygiene surveys found that median time-weighted-average acetone concentrations were 380, 770, and 1,070 ppm, based on job categories. No studies were located regarding cancer in animals after inhalation exposure to acetone. ORAL EXPOSURE

DEATH The 1991 Annual Report of the American Association of Poison Control Centers National Data Collection System documented 1,137 incidents of human exposure to acetone. Of these incidents, 1,124 were due to accidental or intentional ingestion (the others

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were not clearly specified). No fatalities were reported, only three cases had a major medical problem, 364 were treated in a health care facility, 233 cases were referred to hospitals but had no effects, 367 cases suffered minor effects, and 39 suffered from moderate effects. None of the major, minor, or moderate effects were further described, and the outcomes of the remainder of the incidents were not reported. As seen in Table 2-2 and Figure 22, acute lethal dose (LD50) values were located for rats, mice, and guinea pigs. In general, the lethality of acetone decreases with the age of the rats. A higher LD50 value was found for young adult rats than for older adult rats, but the difference was not statistically significant. Higher LD50 values were found for Wistar rats and Nelson rats than for Sprague-Dawley rats. The LD50 value determined by Freeman and Hayes (1985), who also used SpragueDawley rats, is in line with values for 14-day-old and young adult Sprague-Dawley rats. An oral LD50 value of 5,250 mg/kg was found for male ddY mice, and an oral LD50 value of 3,687 mg/ kg was found for male guinea pigs. In a study to determine which doses to use in a developmental study, oral dosing of pregnant mice with acetone during gestation resulted in the death of one of four mice at 2,400 mg/kg/day, and the number of dead mice increased as the dose increased (EHRT 1987). No controls were used in the range-finding study. One of two rabbits given 7,844 mg/kg acetone by gavage died within 19 hours of dosing, two rabbits given 5,491 mglkg survived, while one rabbit given 3,922 mg/kg died in 96 hours. Oral doses of 7,500 or 8,000 mg/kg acetone were fatal to two puppies. No controls were included in these studies, and the small numbers of animals used limits the reliability of the findings. Signs of narcosis usually precede death in animals. No information was located regarding the doses of acetone that could result in increased mortality after intermediateor chronic-duration exposure.

Respiratory Effects. Oral exposure of animals to acetone has not been shown to produce adverse respiratory effects. However, microsomes from the lungs of hamsters exposed to acetone in drinking water for 7 days had a 500% increased activity of aniline hydroxylase activity, an activity associated with cytochrome P450IIEl. Furthermore, the level of cytochrome P-45011El and the activity of butanol oxidase increased 6-fold in microsomes from the nasal mucosa of rabbits exposed to acetone in drinking water for 1 week. Induction of microsomal enzymes is considered a normal physiological response to xenobiotics, rather than an adverse effect, unless accompanied by increased organ weight and histopathological or other adverse respiratory effects. Changes in respiratory rates (either increases or decreases), along with signs of narcosis, were observed in rabbits dosed with >3,922 mg/ kg acetone, and irregular respiration, along with signs of narcosis, was observed in dogs dosed with 4,000 mg/kg. In a range-finding study to determine which doses to use in a developmental study, mice that died at doses >4,800 mg/kg/day for 10 days displayed wheezing and/or rapid and labored breathing, accompanied by signs of severe narcosis, prior to death (EHRT 1987). However, the apparent respiratory effects probably reflect the severely compromised condition of these animals, rather than a toxic effect of acetone on the lungs. Gross necropsy of a dog dosed with 8,000 mg/kg acetone revealed no effects on the lungs, but the lungs were not examined histologically. Histological examination of the lungs of rats and mice exposed to acetone in drinking water for 13 weeks or of rats given acetone in water by gavage for 13 weeks revealed no treatment related lesions. Thus, acetone by itself apparently is not toxic to the lungs of animals when administered by the oral route, but the induction of lung microsomal enzymes suggests that acetone may potentiate the respiratory effects induced by other chemicals.

SYSTEMIC EFFECTS No studies were located regarding respiratory, cardiovascular, hematological, musculoskeletal, hepatic, renal, or dermal/ocular effects in humans after oral exposure to acetone. The systemic effects in humans and animals after oral exposure to acetone are discussed below.

Cardiovascular Effects. Oral exposure of animals to acetone has not resulted in adverse effects on the heart in intermediateduration studies. Histological examination of the hearts of rats and mice exposed to acetone in drinking water for 13 weeks or of rats given acetone in water by gavage for 13 weeks did not reveal treatment- related lesions. However, the heart-to-brain weight ratio was significantly increased (p<0.01) in the female rats

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treated by gavage with 2,500 mg/kg/day. In the absence of histologically observable lesions, the toxicological significance of the increased heart weight is questionable. Gastrointestinal Effects. No studies were located regarding gastrointestinal effects per se in humans after oral exposure to acetone, but a man who intentionally drank H”200 mL of pure acetone (H”2,241 mg/kg) had a red and swollen throat and erosions in the soft palate and entrance to the esophagus . Significantly increased levels of cytochrome P-450IAl in duodenal microsomes and P-450IIB2 in duodenal and jejunal microsomes from rats exposed to acetone in drinking water for 3 days were found. No increase in cytochrome P-450IIEl was found in these microsomal preparations. As discussed above for respiratory effects, induction of microsomal enzymes is considered a normal physiological response to xenobiotics rather than an adverse effect. Oral exposure of animals to acetone has not resulted in adverse effects on the gastrointestinal tract in intermediateduration studies. Histological examination of the gastrointestinal tract of rats and mice exposed to acetone in drinking water for 13 weeks or of rats given acetone in water by gavage for 13 weeks did not reveal treatment-related lesions. Hematological Effects. Exposure of rabbits to 863 mg/kg/day acetone in the drinking water for 7 days resulted in a 12.9-fold increase in the levels of cytochrome P-45011El in bone marrow microsomes. As discussed for respiratory effects, induction of microsomal enzymes is considered a normal physiological response to xenobiotics rather than an adverse effect. Hematological effects of oral exposure to acetone have been observed in rats but not in mice. Bone marrow hypoplasia was observed in five of five male rats exposed to acetone in the drinking water for 14 days at 6,942 mg/kg/day, but not at 4,312 mg/kg/day . None of the female rats had bone marrow hypoplasia. Although mice were similarly treated for 14 days in this study, the authors did not specify whether bone marrow was examined; however, in the 13-week studies, no hematological effects or histologically observable lesions in hematopoietic tissues were found in mice. In contrast, evidence of macrocytic anemia was found in male rats exposed to acetone in drinking water for 13 weeks. This evidence consisted of

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significantly (p<0.05 or p<0.01) decreased hemoglobin concentration, increased mean corpuscular hemoglobin and mean corpuscular volume, decreased erythrocyte counts, decreased reticulocyte counts and platelets, and splenic hemosiderosis. The LOAEL for these effects was 400 mg/kg/day, and the NOAEL was 200 mg/kg/day. The number of affected parameters increased as the dose increased. Based on the NOAEL of 200 mg/kg/day for macrocytic anemia, an intermediate oral MRL of 2 mg/kg/ day was calculated as described in the footnote in Table 2-2. In female rats, hematological effects consisted of statistically significant increased lymphocyte counts, increased mean corpuscular hemoglobin and mean corpuscular volume at the highest dose, and decreased platelets at the highest and next-tohighest dose levels . The biological significance of the hematological effects in female rats was not clear, but the effects were not consistent with anemia. Sex differences in the hematological effects of acetone exposure were also found in rats treated by gavage. Gavage treatment for 46-47 days significantly (p<0.01) increased hemoglobin, hematocrit, and mean cell volume in high-dose males (2,500 mg/kg/day), but not in females. With longer duration treatment (13 weeks), both high-dose males (p<0.01) and females (p<0.05) had increased hemoglobin and hematocrit, and highdose males (p<0.01) also had increased mean cell hemoglobin and mean cell volume and decreased platelets. Thus, it appears that species and sex differences exist for hematological effects of oral exposure to acetone. Musculoskeletal Effects. Histological examination of femurs of rats and mice exposed to acetone in drinking water for 13 weeks or of rats given acetone in water by gavage for 13 weeks did not reveal treatment-related lesions. Skeletal muscle was not examined histologically in the 13-week drinking water study, but histological examination of the skeletal muscle in rats in the 13-week gavage study did not reveal treatment-related lesions. Based on this limited information, it appears that acetone does not produce musculoskeletal effects. Hepatic Effects. Acetone by itself is moderately toxic to the liver of animals, but acetone potentiates the hepatotoxicity of some other chemicals by inducing microsomal enzymes that

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metabolize other chemicals to reactive intermediates. Numerous studies have investigated these mechanisms to identify the specific cytochrome P-450 isoenzymes involved. In these studies in general, rats, mice, rabbits, or hamsters were given acetone by gavage in water or in drinking water for 1 day to 2 weeks. Microsome preparations from the livers were then analyzed for cytochrome P-450 content, enzyme activities associated with specific cytochrome P-450 isoenzymes (particularly cytochrome P-450IIEl), and identification of the specific isoenzymes. Acetone has also been shown to increase the activity of glutathione S-transferase. These topics are discussed more fully in Sections 2.35 and 2.6. Induction of microsomal enzymes is considered a normal physiological response to xenobiotics rather than an adverse effect, unless it is accompanied by increased liver weight and other hepatic effects. Mice exposed to acetone in drinking water for 14 days had dose-related increased liver weights at e”965 mg/kg/day, probably associated with microsomal enzyme induction. The increased liver weight was accompanied by hepatocellular hypertrophy at 23,896 mg/kg/day. In rats treated for 14 days, increased liver weight was stated to occur at the same or lower doses as in the 13-week study, but more definitive information regarding the doses was not provided. Histological examination revealed no treatment-related hepatic effects in rats. As stated above, acetone by itself is only moderately toxic to the liver. In mice exposed to 1,900 mg/kg/day acetone in the drinking water for 10 days, histological examination of the liver revealed no hepatic lesions. Acetone did not increase the level of serum alanine aminotransferase in rats at 871 mg/kg, the levels of serum alanine aminotransferase or bilirubin at 1,177 mg/kg, or the activities of hepatic glucose-6-phosphatase, serum alanine aminotransferase, and serum ornithine carbamoyltransferase in rats given 1,961 mg/kg for 1 day or 392 mg/kg/day for 3 days. However, in an intermediate-duration study, male rats, but not female rats, treated by gavage with 2,500 mg/kg/day, but not 500 mg/kg/day, for 46-47 days and for 13 weeks had statistically significant increased levels of serum alanine amino transferase . Liver weights were

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statistically significantly increased in female rats at e”500 mg/kg/ day, but not at 100 mg/kg/day, and in male rats at 2,500 mg/ kg/day after 13 weeks, but organ weights were not measured in the rats treated for 46-47 days. In the 13-week drinking water study, liver weights were also significantly (p<0.01) increased in both sexes of rats at the same concentration (20,000 ppm, which was equivalent to 1,600 mg/kg/day for females, 1,700 mg/kg/ day for males) and in female, but not male mice, at 11,298 mg/ kg/day. However, in the mice, the increased liver weight was not associated with hepatocellular hypertrophy seen in the 14-day study, suggesting a development of tolerance. Taken together, the data indicate that acetone induces liver microsomal enzymes, increases liver weights, and may cause liver injury, as evidenced by increased serum levels of liver enzymes associated with liver injury and hepatocellular hypertrophy. Species and sex differences exist in susceptibility to acetone-induced liver effects. Renal Effects. Acetone can also induce enzymes in microsomes prepared from kidneys. In hamsters given drinking water containing acetone for 7 days or 10 days , the microsomes prepared from kidneys had increased levels of cytochrome P-450 and cytochrome b5 and/or statistically significantly increased activities of p-nitrophenol hydroxylase, aniline hydroxylase, and aminopyrine-N-demethylase. Microsomes prepared from kidneys of rats treated by gavage with acetone had increased levels of cytochrome P-450IIEl and increased activity of Nnitrosodimethylamine demethylase. Induction of microsomal enzymes is considered to represent a normal physiological response to xenobiotics rather than an adverse effect, unless accompanied by increased organ weight and other adverse renal effects. Oral exposure of rats and mice to acetone has resulted in effects on the kidney. Degeneration of the apical microvilli of renal tubules was reported in male rats after a single oral dose of acetone in corn oil, but not in corn oil treated controls. The incidence of this lesion was not reported. However, in rats treated with 1,766 mg/kg/day acetone for 2 days, no significant difference was found for kidney weight, blood urea nitrogen (BUN) levels, or organic ion accumulation compared with controls. In 14-day drinking water studies, mice had doserelated increased

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kidney weights at >6,348 mg/kg/day. In rats treated for 16days, increased kidney weight occurred at the same or lower doses as in the 13-week study, but more definitive information regarding the doses was not provided. Histological examination of the kidneys revealed no treatment-related lesions in rats or mice. In the intermediate-duration drinking water study, significantly (p<0.01) increased kidney weights were seen in female rats at 21,600 mg/kg/day and in male rats at 3,400 mg/kg/day. Conversely, male, but not female rats, given acetone in the drinking water at 21,700 mg/kg/day had increased incidence and severity of nephropathy that was not accompanied by hyaline droplet accumulation. In the 13-week gavage study, kidney weights were significantly (p<0.05 or p<0.01) increased in female rats at >500 mg/kg/day and in male rats at 2,500 mg/kg/day. In addition, renal proximal tubule degeneration and intracytoplasmic droplets of granules (hyaline droplets) in the proximal tubular epithelium were seen in both control and treated rats at similar incidence, but the severity of these lesions showed a dose-related increase in males at >500 mg/kg/day and in females at 2,500 mg/kg/day. The renal lesions seen in both the gavage study and the drinking water study may represent an enhancement by acetone of the nephropathy commonly seen in aging rats. No renal effects were observed in mice given acetone in the drinking water for 13 weeks. Thus, species differences exist in susceptibility to acetone-induced renal effects. Sex differences also exist, with kidney weight increases occurring in female rats at lower doses than in males rats, but histopathological lesions occurring in male rats at lower doses than in females. DermaVOcular Effects. No studies were located regarding dermal or ocular effects in humans after oral exposure to acetone. Histological examination of eyes and skin of rats and mice after exposure to drinking water containing acetone for 13 weeks at doses <3,400 mg/kg/day (rats) and 11,298 mg/kg/day (mice) revealed no treatment-related effects. Similarly, ophthalmoscopic examination of the eyes of rats treated by gavage with acetone at doses <2,500 mg/kg/day revealed no ocular lesions. Skin was not examined histologically in the gavage study.

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Other Systemic Effects. Acetone exposure of humans can result in diabetes-like symptoms, e.g., hyperglycemia and glycosuria. For example, a man who intentionally drank about 200 mL (about 2,241 mg/kg) of pure acetone had been treated at a hospital for acetone poisoning, but 4 weeks after the ingestion, he noticed excessive thirst and polyuria, and 2.5 months after ingestion, he was hyperglycemic. As discussed by Gitelson et al. (1966), hyperglycemia and glycosuria are commonly seen in cases of acetone poisoning. Most of the information regarding other systemic effects in animals after oral exposure to acetone relates to body weight changes. However, in an acute study conducted to determine the temporal effects of maintaining elevated plasma concentrations of acetone similar to those encountered in fasting and diabetic patients, treatment of rats by gavage with 3,214 mg/kg/day resulted in significantly reduced (p<0.01) insulin-stimulated glucose oxidation in adipose tissue. The reduction was greater in fasted rats than in fed rats. Rats treated by gavage with a lethal dose of acetone (LD50= 5,800 mg/kg) lost 15% of their body weight until 48 hours after dosing. However, treatment of rats by gavage with 1,766 mg/kg/day for 2 days or with drinking water that provided lower doses (<1,200 mg/kg/day) for up to 2 weeks did not affect body weight gain. Rats maintained on drinking water for 14 days at higher doses displayed decreased body weight gain >l0% of controls, but the decrease was associated with reduced water consumption probably due to unpalatability. In contrast, mice similarly treated had decreased water consumption at doses e”6,348 mg/kg/day, but no effects on body weight gain occurred at doses <12,725 mg/kg/day. Maternal body weight was slightly (5%) but significantly (p=0.02) reduced on day 3 postpartum in mice treated with 3,500 mg/kg/day acetone by gavage during gestation (EHRT 1987). In intermediate-duration studies, gavage or drinking water treatment of rats or mice with acetone did not result in reductions in body weight except in cases where fluid consumption was reduced.

IMMUNOLOGICAL EFFECTS No studies were located regarding immunological effects in humans or animals after oral exposure to acetone.

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NEUROLOGICAL EFFECTS The narcotic effects of acetone occur after oral as well as inhalation exposure. Several case reports describe patients in minimally responsive, lethargic, or comatose conditions after ingesting acetone, but most of these cases are confounded by coexposure to other possible narcotic agents. For example, a 30month-old child ingested most of a 6 ounce bottle of nail polish remover containing 65% acetone and 10% isopropyl alcohol, a known alcoholic woman ingested nail polish remover; and a man ingested 200 mL of sake prior to intentionally ingesting liquid cement containing a mixture of polyvinyl chloride, acetone, 2butanone, and cyclohexanone. The lethargic and comatose condition of these patients were, however, attributed to acetone poisoning, although one case of coma was attributed primarily to cyclohexanol, the metabolite of cyclohexanone in the liquid cement. Blood levels of acetone in some of these patients were 2.5 mg/mL and 4.45 mg/mL. In the case reported by Sakata et al. (1989), the blood level of acetone was 110 µg/L and the urine level was 123 µg/mL 5 hours after the ingestion, but the patient had been subjected to gastric lavage. A man who intentionally ingested about 200 mL of pure acetone (about 2,241 mg/kg) subsequently became deeply comatose, but responded to treatment. Six days later, he was ambulatory, but a marked disturbance of gait was observed. This condition had improved upon follow-up examination 2 months later. In acute experiments with animals, in which high oral doses of acetone resulted in death, severe neurological signs of toxicity preceded death. In a study to determine the LD50 value for acetone in rats (5,800 mg/kg), a state of prostration, usually without convulsions, preceded death. In a study to determine which doses to use in a developmental study, oral dosing of pregnant mice with acetone during gestation resulted in languid behavior with subsequent death in one of four mice at 2,400 mg/ kg/day (EHRT 1987). At higher doses, the number of mice dying increased, and they displayed a hunched appearance and became prostrate before death. No controls were used in this range-finding study. Rabbits dosed orally with 3,922, 5,491, or 7,844 acetone displayed signs of narcosis, the degree and the time to onset being

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dependent on dose. Signs of narcosis included weakness, depression, and unconsciousness. Puppies given 7,500 or 8,000 mg/kg and dogs given 4,000 mg/kg doses displayed incoordination, staggering, falling, tremors, delirium, prostration, and coma. Dogs given 1,000 mg/kg showed no adverse effects. No controls were used in these studies, and only one or two animals were treated at each dose. A significant (p<0.05) reduction in nerve conduction velocity, but no effect on balance time in the rotorod test, was observed in rats treated for 6 weeks with acetone in drinking water at a dose of 650 mg/kg/day. No reduction in nerve conduction velocity was found when tested at 3, 4, or 5 weeks of dosing. No histopathological lesions were found in tissues sampled from the cervico-medullary junction of the spinal cord; posterior tibia1 nerve proximal to the calf muscle branches; cerebellar vermis; thoracic, lumbar, and sacral spinal cord; L5 and L6 dorsal and ventral roots and spinal ganglia; and 3 levels of the sciatic nerve and the plantar nerves in the hindfeet of rats administered 732 mg/kg/day acetone in the drinking water for 12 weeks. In another intermediate duration study, rats given 2,500 mg/kg/day acetone by gavage salivated excessively beginning on the 27th day of treatment. At the terminal sacrifice after 13 weeks of treatment, absolute brain weight was decreased in the male rats, but histological examination of the brain revealed no lesions. No clinical or histological evidence of neurotoxicity was observed in the rats or mice treated with higher doses for 13 weeks in the drinking water study. The fact that clinical signs of neurotoxicity were seen in the rats treated by gavage, but not in the rats or mice given higher doses in drinking water, may reflect the intermittent nature of ad libitum dosing via drinking water, compared with the bolus nature of a gavage dose.

REPRODUCTIVE EFFECTS No studies were located regarding reproductive effects in humans after oral exposure to acetone. Reproductive effects were assessed in pregnant mice exposed by gavage to acetone during gestation (EHRT 1987). The reproductive index was significantly reduced (p=0.05) (number of females producing viable litters/ number of surviving females that were ever pregnant; 24/31 treated compared with 34/36 controls). In addition, acetone

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treatment significantly (p<0.01) increased the duration of gestation from 18.1 days in controls to 18.5 days in treated mice. No effects were observed on the fertility of male Wistar rats treated with drinking water containing acetone at 1,071 mg/kg/day for 6 weeks. The indices of fertility examined were successful matings with untreated females, number of pregnancies, number of fetuses, testicular weight, seminiferous tubule diameter, and testicular lesions. However, male Sprague-Dawley rats treated with 3,400 mg/ kg/day acetone in drinking water for 13 weeks had significantly increased (p<0.01) relative testis weight, probably because body weight was reduced, and significantly (p<0.05) decreased sperm motility, caudal weight and epididymal weight, and increased incidences of abnormal sperm. No testicular lesions were observed upon histological examination. Vaginal cytology examinations of the female rats revealed no effects. No effects on sperm morphology and vaginal cytology were observed in mice similarly treated with drinking water containing acetone at doses <4,858 mg/kg/day in males and <11,298 mg/kg/day in females.

DEVELOPMENTAL EFFECTS No studies were located regarding developmental effects in humans after oral exposure to acetone. In a reproduction study, treatment of pregnant mice during gestation with acetone significantly (<10.01) reduced postnatal pup survival (EHRT 1987). The average weight of each live pup/litter was significantly reduced (p=0.0l) on postpartum day 0, but pups from the acetone treated groups gained significantly (p<0.0l) more weight than controls from postpartum day 0 to 3. As this study was not designed as a teratology study, fetuses or pups were not examined for internal malformations or skeletal anomalies. GENOTOXIC EFFECTS No studies were located regarding genotoxic effects in humans or animals after oral exposure to acetone. CANCER No studies were located regarding cancer in humans or animals after oral exposure to acetone.

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DERMAL EXPOSURE

Death No studies were located regarding death of humans after dermal exposure to acetone. In studies to determine the dermal LD50 values for acetone in rabbits and guinea pigs, the highest doses tested did not result in death. Therefore, LD50 values are >20 mL/kg (>15,688 mg/ kg) for rabbits and >9.4 mL/kg (>7,373 mg/kg) for guinea pigs. No studies were located regarding death of animals after dermal exposure to acetone for intermediate- or chronic-durations.

SYSTEMIC EFFECTS No studies were located regarding respiratory, hematological, musculoskeletal, hepatic, or renal effects in humans after dermal exposure to acetone. Acetone has been used as a solvent or tested as a tumor promoter for other chemicals in skin painting studies in mice, and as the solvent control in these studies. An analysis of the histopathology in female SENCAR mice, used as acetone controls in a skin painting study of formaldehyde and held for up to 100 weeks of age, revealed no lesions associated with acetone exposure, that is, any lesions seen were considered spontaneous in this strain. Since all major tissues, gross lesions, and selected other (unspecified) tissues were examined histologically, it appears that no respiratory, cardiovascular, gastrointestinal, hematological, musculoskeletal, hepatic, renal, or dermal/ocular lesions were observed upon histological examination. The mice had been treated with 0.2 mL acetone on their backs twice a week for 92 weeks. The dose of 0.2 mL is recorded as a NOAEL value in mice for each systemic effect for chronic-duration exposure. No other studies were located regarding respiratory, gastrointestinal, hematological, or musculoskeletal effects in animals after dermal exposure to acetone. The cardiovascular, gastrointestinal, and dermal/ocular effects in humans and the cardiovascular, hepatic, renal, dermal/ ocular, and other systemic effects in animals after dermal exposure to acetone in other studies are discussed below. Cardiovascular Effects. As discussed high pulse rates (120160/minute) were commonly found in patients exposed to acetone by inhalation and/or dermally after application of casts for which

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acetone was used in the setting solution. Amyloidosis was observed in the hearts of mice whose lumbo-sacral regions were painted twice weekly with an unspecified quantity of acetone for 12 months.

the ACGIH Tenth Annual Meeting, it was noted that acetone is mildly irritating to the eyes at 2,000-3,000 ppm, with no irritation persisting after exposure ceases.

Gastrointestinal Effects. As discussed case reports have described vomiting of blood and gastrointestinal hemorrhage in patients who had hip casts applied with acetone in the setting fluid. In most cases, exposure was considered to be mainly by inhalation, but dermal exposure could not be ruled out. In one case, the exposure was considered to be mainly dermal.

Dermal effects have also been studied in animals after direct application of acetone to the skin. Application of 1.0 mL to the uncovered shaved skin of rabbits did not result in irritation within 24 hours. Application of 0.2 mL acetone to the shaved skin of mice increased deoxyribonucleic acid (DNA) synthesis in the skin, compared to untreated shaved controls . The increased DNA synthesis was considered a reaction to slight irritation. Moderate hyperplasia of the epidermis was observed in hairless mice treated twice weekly with 0.1 mL acetone for 18 weeks. The hyperplasia persisted for 10 weeks after the end of treatment. Application of 0.5 mL/day for 6 months to the dorsal thorax of hairless guinea pigs resulted in only mild erythema at the site of application. Amyloidosis was observed in the skin of mice whose lumbosacral regions were painted twice weekly with an unspecified quantity of acetone for 12 months. In a study in which acetonetreated mice were used as negative controls for a skin painting study of organosilanes, treatment with acetone alone 3 times/ week for 502 days resulted in cases of hyperplasia (1 of 40), dermatitis (2 of 40), and hyperkeratosis (1 of 40) at the site of application.

Hepatic Effects. Amyloidosis was observed in the livers of mice whose lumbo-sacral regions were painted twice weekly with an unspecified quantity of acetone for 12 months. Renal Effects. Amyloidosis was observed in the kidneys of mice whose lumbo-sacral regions were painted twice weekly with an unspecified quantity of acetone for 12 months. Dermal/Ocular Effects. Liquid acetone has caused dermal effects in humans exposed by direct skin contact. Application of 1.0 mL directly to the skin of the forearms of six or seven volunteers for 30 or 90 minutes resulted in histological and ultrastructural degenerative changes in the epidermis and decreased protein synthesis compared with untreated skin. The degenerative changes included a reduction and disorganization of the horny layers, intercellular edema, and vacuolization of the stratum spinosum. A laboratory technician being treated with squaric acid dibutyl ester in acetone for patchy alopecia areata on her scalp developed acute contact dermatitis after handling acetone for 2 years. Patch testing with 10% acetone in olive oil showed a strong positive reaction. Eye irritation is a common complaint of workers exposed to acetone vapors in the air at the workplace and in volunteers exposed to acetone in air under controlled laboratory conditions . This eye irritation is due to direct contact of the eyes with the vapor rather than a systemic effect of vapor inhalation. Workers whose exposures to acetone in the workroom averaged >900 ppm complained of eye irritation. In controlled situations, the volunteers had been asked to give their subjective complaints, and some of the volunteers reported eye irritation after exposure to >100 ppm . In a report of the experience at the Tennessee Eastman Corporation on acetone concentrations not associated with injury presented at

Ocular effects have been observed in animals after direct instillation of acetone into the eyes and after application of acetone to the skin. In rabbits, direct instillation of acetone into the eye has resulted in reversible cornea1 burns, edema of mucous membranes, severe eye necrosis and cornea1 burns, and uveal melanocytic hyperplasia. Application of 0.5 mL acetone directly to shaved skin of guinea pigs intermittently for 3 or 6 weeks resulted in cataract development. In contrast, rabbits did not develop cataracts after application of 1.0 mL to the shaved skin intermittently for 3 weeks . The difference in response between the guinea pigs and rabbits reflect species differences in susceptibility to the cataractogenic effects of acetone. Although the rabbits received twice as much acetone as the guinea pigs, the possibility that rabbits would have developed cataracts if an even larger quantity of acetone had been applied was not ruled out.

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However, no cataracts or lens opacities were found in hairless guinea pigs to which acetone (0.5 mL/day, 5 days/week) was applied to the skin for 6 months. Genetic variability in susceptibility between the hairless guinea pigs and the normal guinea pigs is possible, but was believed to be unlikely. Lacrimation was observed in guinea pigs exposed to acetone vapor in air at a concentration of 21,800 ppm for 25 minutes. The degree of lacrimation increased with longer exposure. Other Systemic Effects. A transient weight loss of 60 g over a 2-week period was noted in hairless guinea pigs to which acetone was applied to the skin for 6 months. Amyloidosis was observed in the adrenals and pancreas of mice whose lumbo-sacral regions were painted twice weekly with an unspecified quantity of acetone for 12 months.

IMMUNOLOGICAL EFFECTS The only information regarding immunological effects in humans after dermal exposure to acetone is a case report in which a laboratory technician being treated with squaric acid dibutyl ester in acetone for patchy alopecia areata on her scalp developed acute contact dermatitis after handling acetone for 2 years. Patch testing with 10% acetone in olive oil showed a strong positive reaction. This acetone sensitization is considered a rare complication of sensitizing therapies for alopecia areata. No studies were located regarding immunological effects in animals after dermal exposure to acetone. REPRODUCTIVE EFFECTS No studies were located regarding reproductive effects in humans after dermal exposure to acetone. Acetone has been used as a solvent or tested as a tumor promoter for other chemicals in skin painting studies in mice, and as the solvent control in these studies. An analysis of the histopathology in female SENCAR mice, used as acetone controls in a skin painting study of formaldehyde and held for up to 100 weeks of age, revealed no lesions associated with acetone exposure, that is, any lesions seen were considered spontaneous in this strain. Since all major tissues, gross lesions, and selected other (unspecified) tissues were examined histologically, it is assumed that no lesions in the female reproductive organs were observed upon histological examination.

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The mice had been treated with 0.2 mL acetone on their backs twice a week for 92 weeks. However, the dose of 0.2 mL cannot be considered a NOAEL for reproductive effects in the absence of data on male reproductive organs or reproductive studies in animals after dermal exposure to acetone.

DEVELOPMENTAL EFFECTS No studies were located regarding developmental effects in humans or animals after dermal exposure to acetone. GENOTOXIC EFFECTS No studies were located regarding genotoxic effects in humans or animals after dermal exposure to acetone. CANCER No studies were located regarding cancer in humans after dermal exposure to acetone. Acetone has been used as a solvent for other chemicals in skin painting studies in mice, and as the solvent control in these studies. An analysis of the histopathology in female SENCAR mice used as acetone controls in a skin painting study of formaldehyde and held for d”100 weeks of age, revealed no neoplastic lesions associated with acetone exposure, that is, any lesions seen were considered spontaneous in this strain. Furthermore, acetone was negative as a tumor promoter for formaldehyde. In other skin painting studies in which acetonetreated mice were used as a negative vehicle control for organosilanes or flame retardants, no evidence was found to suggest that acetone alone was a skin carcinogen. Acetone was also negative as a tumor initiator and as a tumor promoter for 7,12-dimethylbenz[a]anthracene. TOXICOKINETICS Although the focus of this profile is on the effects of exposure to acetone from exogenous sources, a full understanding of the toxicokinetics requires consideration of the metabolic fate of endogenous acetone. Acetone is one of three ketone bodies that occurs naturally throughout the body. Under normal conditions, the production of ketone bodies occurs almost entirely within the liver and to a smaller extent in the lung and kidney. The process

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is continuous, and the three products are excreted into the blood and transported to all tissues and organs of the body where they can be used as a source of energy. Two of these ketone bodies, acetoacetate and P-hydroxybutyrate, are organic acids that can cause metabolic acidosis when produced in large amounts. Acetone, in contrast, is nonionic and is derived endogenously from the spontaneous and enzymatic breakdown of acetoacetate. Endogenous acetone is eliminated from the body either by excretion into urine and exhaled air or by enzymatic metabolism. Under normal circumstances, metabolism is the predominant route of elimination and handles 70-80% of the total body burden. Levels of endogenous acetone can fluctuate greatly due to normal diurnal variations. In addition, circulating levels of endogenous acetone can fluctuate greatly depending on a person’s age, nutritional status and fasting; and degree of physical activity. These physiological states all place high energy demands upon the body which result in increased fatty acid utilization and higher than normal blood levels of acetone. Infants and young children typically have higher acetone blood levels than adults due to their higher energy expenditure. Pregnancy and lactation can also lead to higher than average blood levels of acetone. In addition to these normal physiological conditions, a number of clinical states can result in humans acetonemia and acetonuria. In each of these conditions, the ketosis can be traced to the increased mobilization and utilization of free fatty acids by the liver. The conditions include diabetes, trauma, and alcoholism. Following exposure from exogenous sources, acetone is rapidly and passively absorbed from the lungs and gastrointestinal tract. Acetone can also be absorbed from the skin. After uptake by the lungs, acetone is readily absorbed into the bloodstream. Pulmonary uptake by humans has ranged from 30% to 80%. The reason for the wide range in reported values involves the unique aqueous wash-in/wash-out effect displayed when acetone is inhaled, causing spurious results. During this phenomenon, acetone, which is highly water soluble, will dissolve in epithelial cells during inspiration (wash-in) and evaporate during expiration (wash-out). This could account for lower than expected pulmonary absorption based on the high blood-air partition coefficient. Exhaled breath

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levels of acetone rise during exposure and reach steady state within 2 hours during exposure. Breath levels of acetone are directly proportional to the exposure concentration and duration and increase with physical activity due to increased pulmonary ventilation. Blood levels of acetone rose continuously during 24 hours exposure without reaching steady state, indicating continuous absorption during exposure. About 75-80% of the inspired amount is absorbed by blood within 15 minutes, and blood levels correlate with exposure concentration. Results in humans and animals indicate that relatively little acetone is absorbed from the nasal passages. No major differences were found between humans and animals in absorption after inhalation exposure. Based on animal studies, acetone is also absorbed rapidly and extensively from the gastrointestinal tract, with at least 74-83% absorbed based on the percent of the dose excreted by the lungs as acetone and carbon dioxide. As with inhalation, plasma levels rise proportionately with oral dose. Absorption can be delayed by the presence of fat in the stomach, due to delayed gastric emptying. Dermal absorption of acetone is also fairly rapid. Acetone is highly water soluble and is widely distributed to tissues and organs throughout the body, especially to tissues with high water content. Radiolabeled unchanged acetone and total radioactivity (the percentage of total radioactivity that is not acetone represents metabolites) were detected in all tissues examined (blood, pancreas, spleen, thymus, heart, testis, vas deferens, lung, kidney, brain, liver, muscle, and adipose tissue) in male mice after inhalation exposure to radiolabeled acetone. Peak levels in these tissues occurred during the first 6 hours after exposure, and longer or repeated exposure resulted in no further accumulation except in liver and brown adipose tissue. Elimination of acetone from all tissues was complete within 24 hours, but total radioactivity, which represented metabolites, was still present in all tissues except blood and muscle. Thus acetone is not selectively distributed to any tissue and is not likely to accumulate with repeated exposure. Although information on distribution after oral and dermal exposure was not available, similar distribution is likely. Acetone can also undergo transplacental transfer to the fetus.

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The metabolic fate of acetone, whether from endogenous or exogenous sources, is similar in humans and animals, is independent of route of exposure, and involves three separate gluconeogenic pathways, with ultimate incorporation of carbon atoms into glucose and other products of intermediary metabolism, with generation of carbon dioxide and adenosine triphosphate (ATP). Metabolism takes place primarily in the liver. Some of the exogenous acetone is unmetabolized and excreted primarily in the expired air. Acetone is initially oxidized to acetol by acetone monooxygenase, the rate limiting step governing the overall accumulation and elimination of acetone from the body. Acetol is oxidized to methylglyoxal by acetol monooxygenase. Both activities are associated with P-450IIE1, and the reactions require oxygen and nicotinamide adenine dinucleotide phosphate (NADPH). Methylglyoxal is converted to glucose directly or via D-lactate. Acetol can also be converted to L-1,2-propanediol, from which the pathways branch with either formation of L-lactate to D-glucose or degradation of 1,2-propanediol to acetate and formate. The carbon atoms of acetone can also be incorporated into glycogen, amino acids, fatty acid, heme, cholesterol, choline, and urea via acetate and formate. These pathways appear to operate in rats, mice, and rabbits, with very few species differences, and hence probably in humans. The relative importance of the three pathways depends upon the dose, with the methylglyoxal and lactate pathways predominating at low doses, but shunting to the formateacetate branch of the propanediol pathway at higher doses as the methylglyoxal and lactate pathways become saturated. Physiological status, such as diabetes and fasting, and genetic status can alter the pattern of metabolism. The main route of excretion is via the lungs regardless of the route of exposure with very little excreted in the urine. Acetone is excreted both unchanged and, following metabolism, mainly as carbon dioxide. In humans exposed by inhalation, the rate and pattern of respiratory and urinary excretion of acetone is influenced by exposure concentration, duration, the level of physical activity during exposure, and gender. Respiratory excretion is complete within 20 hours after inhalation, and peak urinary excretion occurs

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between 1 and 3.5 hours after exposure. The amount expired or excreted in the urine increases with increasing exposure concentration and with increasing duration of exposure, and increases with exercise during exposure. Women expired acetone more slowly than men, but the percentages excreted were not significantly different. The time for urinary excretion to be complete increases with exposure concentration and duration. Daily intermittent exposure may result in a slight residual body burden, but elimination is generally complete in 48-72 hours after the last exposure, depending on the exposure concentration. Excretion of acetone after inhalation exposure is better characterized in humans than in animals, but appears to be similar. In rats exposed to radiolabeled acetone, 52% of the expired radioactivity was unchanged acetone and 48% was carbon dioxide. Based on animal studies, excretion of acetone and carbon dioxide after oral exposure is similar to that after inhalation exposure. Most of the toxic effects of acetone do not appear to be due to any of its metabolites. As is typical of solvents, acetone is irritating to the mucous membranes. Acetone is also narcotic, and although the mechanism by which acetone exerts is effects on the central nervous system is unknown, as a solvent, it may interfere with the composition of membranes, altering their permeability to ions. The mechanisms by which acetone produces hematological, hepatic, renal, reproductive, and developmental effects is unknown, but acetone has been found to distribute to all of these target organs, including the brain, and can undergo transplacental transfer. The renal toxicity may be due to the formation of formate and may involve á2u-globulin. One of the main effects of acetone is the induction of microsomal enzymes, particularly cytochrome P-450IIEl. Enzyme induction is probably responsible for the increased liver and kidney weights observed in animals by virtue of the increase in protein content. Acetone also potentiates the toxicity of numerous other chemicals primarily by increasing their metabolism to toxic intermediates by the induction of cytochrome P-450IIE1, or otherwise interfering with their metabolism and elimination.

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ABSORPTION

Inhalation Exposure Due to its high blood-air partition coefficient (167-330), acetone is rapidly and passively taken up by the respiratory tract and absorbed into the bloodstream during inhalation exposure. Experiments in humans exposed to 23-4,607 ppm for up to 4 hours have measured pulmonary uptakes ranging from H”30% to 80%. The reason for the wide range in reported values involves the unique aqueous wash-in/wash-out effect when acetone in inhaled, which can lead to spurious results. During this phenomenon, acetone, which is highly water soluble, will dissolve in epithelial cells during inspiration (wash-in) and evaporate during expiration (wash-out). This could account for the lower than expected pulmonary absorption based on the high blood/air partition coefficient. Exhaled breath levels of acetone in humans rose during exposure and reached steady-state within H”2 hours during exposure. Uptake was directly proportional to exposure concentration and duration. Uptake also increased as the level of physical activity increased, i.e., during exercise, due to increased pulmonary ventilation. Lungs (including the mouth and trachea) retained a greater percentage of inspired acetone (55%) than the nasal cavity (18%) in humans, indicating that the nasal cavity absorbs acetone less readily than the rest of the respiratory system. Blood levels of acetone rose rapidly during exposure for up to 4 hours with no indication that steady-state was reached, suggesting that during exposure, the rate of absorption exceeded the rate of distribution and elimination. In humans exposed to 100 or 500 ppm acetone for 2 or 4 hours, 75-80% of the amount of acetone inspired was absorbed by blood after 15 minutes of exposure, and 20-25% remained in the dead space volume. Higher inspired amounts resulted in higher blood levels. A correlation between blood level at the end of exposure and exposure concentration was found in humans exposed to 23-208 ppm for 2-4 hours. No significant difference in uptake or retention was found between men and women. Animals also absorb acetone rapidly during inhalation exposure. Measurement of blood acetone levels in rats after 4-6 hours of exposure to various concentrations shows that blood

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levels correlate well with exposure concentrations and are highest immediately after exposure. In rats exposed to 1.50 ppm for 0.54 hours, measurement of blood acetone concentrations during exposure revealed that blood levels increased steadily for 2 hours and then remained constant for the next 2 hours of exposure. Blood acetone levels also correlated well with exposure concentration in dogs exposed for 2 hours. Blood levels were 4, 12, and 25 mg/L after exposures to 100, 500, and 1,000 ppm, respectively. Comparison of uptakes in dogs and humans revealed that humans absorbed a greater absolute quantity under comparable exposure conditions, but when expressed in terms of kg body weight, dogs absorbed 5 times more than humans. In anesthetized dogs allowed to inhale concentrated vapors of acetone spontaneously from a respirator at various ventilation rates, uptake by the respiratory tract was 52% at flow rates of 518 L/minute and 42% at ventilation rates of 21-44 L/minute. Retention in the lower respiratory tract was 48% at 5-18 L/minute and 37.5% at 2140 L/minute. Retention by the upper respiratory tract was 57% at 4-18 L/minute. The effect of exposure concentration on total uptake was studied at a range of ventilation rates equated with exposure concentrations. Percent uptakes were 52.1% at a mean concentration of 212 ppm, 52.9% at 283 ppm, and 58.7% at 654 ppm. These results indicate the respiratory uptake of acetone by dogs is similar to human uptake values reported by Landahl and Herrmann (1950). The retention in the upper respiratory tract was higher than in the lower respiratory tract of dogs. Exposure concentration had little effect on retention. The absorption of acetone by the nasal walls of anesthetized dogs, in which the nasal passage was isolated, increased when the airflow rate was increased. This suggests that increased airflow decreases the amount of acetone that reaches the lungs. In rats exposed continuously to 2,210 ppm for 9 days, peak acetone blood levels of H” 1,020-l ,050 mg/L were reached in 34 days and remained at this level for the duration of exposure. In rats exposed to 4,294 ppm for 12 days, acetone blood levels plateaued at 2,420-2,500 mg/L in 4 days. Blood levels in rats exposed to these concentrations for 8 hours/day were about half of those reached during continuous exposure. The amount of

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acetone absorbed in the first 8 hours exceeded the amount eliminated in the next 16 hours of exposure to fresh air, leading to a small accumulation. However, the accumulation during intermittent exposure did not reach the levels achieved during continuous exposure. In other experiments of rats exposed to 2,105-126,291 ppm, the time to peak blood level decreased as the exposure concentration increased. As was found in humans and dogs, disposition of acetone in the upper respiratory tract of rats, mice, guinea pigs, and hamsters indicates that relatively little acetone is absorbed from the upper respiratory tract. The deposition efficiency was greater in Sprague-Dawley rats than in Fischer-344 rats. Deposition was similar in B6C3Fl mice and Fischer-344 rats, and greater than in Hartley guinea pigs and Syrian golden hamster. No difference was found between male and female Sprague-Dawley rats. The differences among strains and species could not be attributed to differences in metabolism because acetone is not significantly metabolized in the upper respiratory tract of these species. Rather, the difference was attributed to differences in perfusion rates.

ORAL EXPOSURE In a series of experiments conducted in male volunteers given acetone orally at 40-80 mg/kg, an estimated 65-93% of the administered dose was eliminated via metabolism, with the remainder excreted in the urine and expired air in about 2 hours, indicating rapid and extensive gastrointestinal absorption. In a human who ingested 137 mg/kg acetone on an empty stomach, the blood level of acetone rose sharply to a peak 10 minutes after dosing. In other experiments, the subject ingested the same dose 10 or 12 minutes after eating porridge. The blood acetone level rose slowly over 48-59 minutes to levels of about one-half to twothirds that achieved after taking acetone on an empty stomach. Thus, the presence of food in the gastrointestinal tract lead to a slower rate of absorption. Measurement of acetone in blood and urine of patients who accidentally or intentionally ingested acetone indicated that acetone was absorbed, but the percentage absorbed cannot be determined from the data. In one case, a man ingested liquid cement that

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provided a dose of acetone of H”231 mg/kg. His plasma acetone level was about 110 µg/mL and his urinary level was 123 µg/mL 5 hours after ingestion, but he had been subjected to gastric lavage. In a another case, a woman who had ingested nail polish remover had a blood acetone level of 0.25 g/100 mL (2.5 mg/mL) upon admission to the hospital. The authors estimated that her body burden was 150 g acetone at the time of admission. The serum acetone level of a 30-month-old child was 445 mg/l00 mL (4.45 mg/rnL) 1 hour after ingestion of a 6ounce bottle of nail polish remover (65% acetone). Experiments in rats indicated that acetone is rapidly and almost completely absorbed from the gastrointestinal tract after oral exposure. A rat given 14C-acetone at a dose of 1.16 mg/kg expired 47.4% of the dose as 14C-carbon dioxide over the 13.5hour collection period. Another rat given about 7.11 mg/kg 14Cacetone by gavage once a day for 7 days expired 67-76% of the administered radioactivity as 14C-carbon dioxide and 7% as 14Cacetone over a 24-hour period after the last dose. From these data, absorption of least 74-83% of the administered dose can be inferred. A rat dosed with 6.19 mg/kg 14C-acetone expired 4.24% of the radiolabel as unchanged 14C-acetone over 5.5 hours, indicating rapid absorption. In rats given a single gavage dose of 1,177 mg/ kg acetone, the maximum blood level of 850 µg/mL was reached in 1 hour and declined gradually to about 10 µg /mL over 30 hours. In another experiment, peak blood levels and the time to peak blood levels were compared after various gavage doses to rats. After a dose of 78.44 mg/kg, the maximum blood level of acetone of about 200 µg/mL was reached in 3 hours and declined to 10 µg/mL at 12 hours, where it remained for the next 12 hours. After a dose of 196.1 mg/kg, the peak blood level was 400 µg/mL at 6 hours and declined biphasically to 50 µg/mL at 12 hours and to 30 µg/mL at 18 hours where it remained for the next 6 hours. After a dose of 784.4 mg/kg, the peak level was 900 µg/mL at 1 hour and declined to 300 µg /mL at 12 hours, 110 µg/mL at 18 hours, and 50 µg/mL at 24 hours. After a dose of 1,961 mg/ kg, the peak level was 1,900 µg /mL at 3 hours and declined slowly to 400 µg /mL at 24 hours. In other studies where rats were

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given similar or higher doses of acetone, plasma acetone levels rose proportionately with dose in rats given acetone as single doses by gavage or in the drinking water for 7 days. In a study comparing the blood levels of acetone achieved after fasting with those after oral dosing, peak blood levels of acetone of about 35 and 110 µg /mL were reached within about 3 hours after dosing of rats with 78 and 196 mg/kg acetone, respectively. The levels declined to near background levels within the next 16 hours. At an acetone dose of 20 mg/kg, the blood level increased to about 5 µg /mL over 19 hours, when the rats were sacrificed. In rats fasted for 48 hours, blood acetone levels increased continuously to about 13 µg /mL. While the maximal blood concentrations of the treated rats differed considerably from that of the fasting group, the areas under the curve for the 78 and 196 mg/kg groups were comparable to the fasting groups. Conflicting data were located regarding the effect of vehicle on the gastrointestinal absorption of acetone. In one study, maximum blood levels were higher and achieved earlier in rats given acetone by gavage in water than in rats given acetone by gavage in corn oil. The slower absorption of acetone in corn oil may have resulted from a delayed gastric emptying due to the presence of corn oil (fat) in the stomach. In a later study, however, very little difference in blood and liver levels of acetone were found in rats given the same dose of acetone in water or in corn oil. No studies were located regarding absorption of acetone in other animal species after oral exposure to acetone.

DERMAL EXPOSURE Dermal absorption of acetone has been demonstrated in humans. Application of cotton soaked in acetone to a 12.5 cm2 uncovered area of skin of volunteers for 2 hours/day for 4 days resulted in blood levels of acetone of 5-12 µg /mL, alveolar air levels of 5-12 ppm, and urinary concentrations of 8-14 µg /mL on each day. Higher blood, alveolar air, and urinary levels were obtained when the daily exposure increased to 4 hour/day: 2644 µg /mL in blood, 25-34 ppm in alveolar air, and 29-41 µg / mL in urine. The absorption was fairly rapid, with peak blood levels appearing at the end of each daily application. Although

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precautions were taken to limit inhalation of acetone vapors, the authors noted that it was not possible to completely prevent inhalation, and the acetone concentration in the breathing zone of one subject was found to be 0.4-0.6 ppm. From the alveolar air and urine concentrations, it was estimated that a 2-hour dermal exposure was equivalent to a 2-hour inhalation exposure to 50150 ppm, and a 4-hour dermal exposure was equivalent to a 2hour inhalation exposure to 250-500 ppm acetone. No studies were located regarding the absorption of acetone in animals after dermal exposure. The findings of cataract formation in guinea pigs exposed dermally however, indicated that acetone was absorbed from the skin of the guinea pigs.

DISTRIBUTION Of eight samples of breast milk from lactating women from four urban areas, all were found to contain acetone. Whether the source of acetone was endogenous or exogenous could not be determined. Nevertheless, the data indicate that acetone is distributed to mother’s milk, and represents a source of excretion from the mother and exposure for infants. Acetone was identified in maternal and cord blood collected at the time of delivery, indicating transplacental transfer. INHALATION EXPOSURE No studies were located regarding distribution of acetone or its metabolites in humans after inhalation exposure to acetone. However, acetone is well absorbed into the blood from the respiratory tract of humans and is highly water soluble. Therefore, widespread distribution, especially to tissues with high water content, is expected. The distribution of acetone has been studied in mice exposed to acetone by inhalation. Mice were exposed to 500 ppm 14Cacetone for 1, 3, 6, 12, and 24 hours or for 6 hours/day for 1, 3, or 5 consecutive days, after which they were immediately killed. Radioactive unmetabolized acetone and total radioactivity were found in blood, pancreas, spleen, thymus, heart, testis, vas deferens, lung, kidney, brain, liver, muscle, brown adipose tissue, subcutaneous adipose tissue, and intraperitoneal adipose tissue.

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A common feature was an increase in tissue concentration of acetone and total radioactivity during the first 6 hours after exposure. These levels generally peaked from about 2.5 to 3.5 µmol/g tissue except in adipose tissues for total radioactivity. Peak levels of unmetabolized acetone were generally l, whereas the ratios in the kidneys and liver were >1 after 6 hours. Only the muscle and subcutaneous and intraperitoneal adipose tissue rose continuously. Elimination of acetone was fastest in blood, kidneys, lungs, brain, and muscles with half-times of about 2-3 hours during the first 6 hours after exposure. The slowest elimination was in subcutaneous adipose tissue with a half-time of >5 hours. Elimination of acetone was complete in all tissues by 24 hours after exposure, but total radioactivity, indicative of metabolites, was still present in all tissues except blood and muscle. These data indicate that acetone is not selectively distributed to any tissues but is more evenly distributed in body water. Acetone is not likely to accumulate with repeated exposure. The continued accumulation of radioactivity in the liver and brown adipose tissue could be the result of high metabolic turnover in these tissues.

ORAL EXPOSURE No studies were located regarding the distribution of acetone or its metabolites in humans or animals after oral exposure except that acetone was found in the liver of rats after oral exposure.

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However, acetone is well absorbed from the gastrointestinal tract and is highly water soluble. Therefore, widespread distribution, especially to tissues with high water content, is expected.

DERMAL EXPOSURE No studies were located regarding distribution of acetone or its metabolites in humans or animals after dermal exposure. The findings of cataract formation in guinea pigs exposed dermally, however, indicated that acetone was absorbed from the skin of the guinea pigs and distributed to the eyes. OTHER ROUTES OF EXPOSURE The finding of acetone and its metabolites in fetuses from rats injected intravenously with 100 mg/kg acetone on gestational day 19 indicates transplacental transfer. METABOLISM The metabolic fate of acetone is independent of route of administration and involves three separate gluconeogenic pathways, with ultimate incorporation of carbon atoms into glucose and other products and substrates of intermediary metabolism with generation of carbon dioxide. The metabolic pathways appear to be similar in humans and animals. The primary (major) pathway involves hepatic metabolism of acetone to acetol and hepatic metabolism of acetol to methylglyoxal, while two secondary (minor) pathways are partially extrahepatic, involving the extrahepatic reduction of acetol to L-1,2-propanediol. Some of exogenous acetone is unmetabolized and is excreted primarily in the expired air with little acetone excreted in urine. The only studies located regarding the metabolism of acetone in humans were conducted in normal fasted, obese fasted, and diabetic patients. The involvement of gluconeogenesis was demonstrated in normal patients fasted for 3 days, obese patients fasted for 3 days, and obese patients fasted for 21 days before intravenous injection of 2-[14C]-acetone. The percentages of 14C-glucose in plasma derived from 14C-acetone were 4.2%, 3.1%, and 11.0% in the three respective groups, suggesting the involvement of gluconeogenesis. Cumulative 14C-carbon dioxide excretion by the lungs during the a 6-hour collection period accounted for

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17.4%, 21.5%, and 4.9% in the three respective groups. Radioactivity was also incorporated into plasma lipids and plasma proteins. Unmetabolized acetone in the expired air accounted for 14.7%, 5.3%, and 25.2%, urinary excretion of acetone accounted for 1.4%, 0.6%, and 1.3%, respectively, and in vivo metabolism accounted for 83.%, 94.1%, and 73.%, respectively, of the radioactivity. Intravenous infusion of 2-[14C]-acetone into patients with diabetic ketoacidosis resulted in a mean plasma acetone turnover rate of 6.45 µmol /kg/minute. Analysis of glucose in urine revealed a labeling pattern in five of the six patients consistent with the involvement of pyruvate in the gluconeogenic pathway. A different pathway may have operated in the other patient. Acetol and 1,2propanediol were also detected in the plasma and the concentrations of these metabolites were directly related to the plasma level of acetone. The results demonstrated high plasma acetone levels in decompensated diabetic patients. The suggested pathway of acetone metabolism in these patients was acetone to acetol to 1,2-propanediol to pyruvate and ultimately to glucose, but other pathways may exist between subclasses of diabetic patients. The metabolism of acetone has been studied extensively in animals, primarily in rats, and three separate pathways of gluconeogenesis have been elucidated. These pathways are consistent with the metabolic fate of acetone in humans, discussed above. The elucidation of these pathways has been performed in experiments in which rats, mice, or rabbits were exposed by inhalation, by gavage, via drinking water, or by intravenous, subcutaneous, or intraperitoneal injection of nonradiolabeled acetone or to acetone labeled with 14C in the methyl groups, number 2 carbon atom, or all three carbon atoms. In these experiments, identification of metabolites in liver, plasma, or urine, the labeling patterns of 14C incorporation into metabolites from 14C-acetone in plasma or in liver, or the results of enzyme reactions using microsomes from acetone treated animals have led to the pathways illustrated. In the first step, acetone is oxidized (hydroxylation of a methyl group) to acetol by acetone monooxygenase (also called acetone hydroxylase), an activity associated the cytochrome P-450IIE1,

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and requires oxygen and NADPH. Cytochrome P-45011El can be induced by fasting, experimental diabetes, or exposure to ethanol or acetone. When the rate of acetone oxidation was evaluated in microsomes with acetone added to the incubation system, microsomes from rats and mice pretreated with acetone had a 78 times greater rate than microsomes from control rats or mice. Thus, acetone induces its own metabolism. The formation of acetol is common to all three pathways. Subsequent conversion of acetol to methylglyoxal in microsomes is catalyzed by acetol monooxygenase (also called acetol hydroxylase), an activity also associated with cytochrome P450IIE1, and also requires oxygen and NADPH. Methylglyoxal can then be converted to D-glucose by an unidentified pathway, and/or possibly by catalysis by glyoxalase I and II and glutathione to D-lactate, which is converted to D-glucose. The conversion of methylglyoxal to D-lactate by the actions of glyoxalase I and II is well established, but may represent a minor pathway in the metabolism of acetone. The unidentified pathway by which methylglyoxal is converted to D-glucose may involve conversion of methylglyoxal to pyruvate by 2-oxoaldehyde dehydrogenase, an activity identified using aqueous extracts of sheep liver acetone powders. In the second and third pathways, acetol is converted to L1,2-propanediol by an extrahepatic mechanism that has not been characterized. The two pathways then diverge from the point of production of 1,2-propanediol. In the second pathway, 1,2propanediol formed extra-hepatically returns to the liver where it is converted to L-lactaldehyde via nicotinamide adenine dinucleotide (NADH)-dependent alcohol dehydrogenase, and Llactaldehyde, in turn, is converted to L-lactate via NADHdependent aldehyde dehydrogenase. L-lactate can then be converted to D-glucose. In the third pathway, the L-1,2-propanediol formed extra-hepatically returns to the liver where it is degraded by an uncharacterized mechanism to acetate and formate. Several studies have traced the labeling patterns of 14C from 2-[14C]-acetone or 1,3-[14C]-acetone to gluconeogenic precursors and formate to incorporation of 14C into glycogen, glycogenic amino acids, fatty acids, heme, cholesterol, choline, and urea. The

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pattern of labeling suggested the involvement of the “acetate and formate” pathway. The ultimate fate of glucose is entry into glycolysis or into the tricarboxylic acid cycle, via pyruvate and acetyl coenzyme A (CoA) with the liberation of carbon dioxide, and subsequent electron transport and oxidative phosphorylation with the production of ATP. Fatty acids, amino acids, and glycogen may also enter stages of intermediary metabolism. The relative importance of the three pathways in the metabolism of acetone may depend upon the amount of acetone administered. When a trace amount of 2-[14C]-acetone was administered intravenously to rats, the pattern of incorporation of 14C into glucose was consistent with the production of glucose via the methylglyoxal/ lactate pathway. When a higher dose of 2-[14C]-acetone (325 mg/ kg) was injected, the pattern of incorporation was more consistent with the 1,2-propanediol pathway. These results suggest that at low doses of acetone or endogenous acetone, the methylglyoxal and lactate pathways predominate, but at higher doses, these pathways become saturated and metabolism is shunted to the formate-acetate branch of the 1,2-propanediol pathway. In addition to the pathways 2,3-butanediol and isopropyl alcohol were detected in the blood of rats after oral dosing with acetone, but their position in the metabolic scheme is not clear. That acetone is extensively metabolized has been demonstrated by the finding of high percentages of 14C-carbon dioxide in the expired air of animals exposed to 14C-acetone. Although the liver is the primary site of acetone metabolism, radioactive unmetabolized acetone and total radioactivity were found in blood, pancreas, spleen, thymus, heart, testis, vas deferens, lung, kidney, brain, liver, muscle, brown adipose tissue, subcutaneous adipose tissue, and intraperitoneal adipose tissue of mice after inhalation exposure to 14C-acetone. The fraction of total radioactivity that was not unchanged acetone represented metabolites. Elimination of acetone was complete in all tissues by 24 hours after exposure, but total radioactivity, indicative of metabolites, was still present in all tissues except blood and muscle. Whether these tissues (other than the liver) were capable of metabolizing acetone or whether the metabolites themselves were distributed to the tissues was not clear. However, microsomes from the lungs of hamsters

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exposed to acetone in drinking water for 7 days had a 500% increased activity of aniline hydroxylase activity, an enzyme associated with cytochrome P-450IIEl (Ueng et al. 1991). Furthermore, the level of cytochrome P-450IIEl increased 6-fold in microsomes from the nasal mucosa of rabbits exposed to acetone in drinking water for 1 week. In hamsters given drinking water containing acetone for 7 days or 10 days, the microsome prepared from kidneys had increased levels of cytochrome P-450 and cytochrome b,. These results suggest that acetone metabolism, which involves cytochrome P-450IIE1, may occur in the lungs and kidneys of hamsters and the nasal mucosa of rabbits. Incubation of acetone with homogenates of nasal mucosa from mice indicated that acetone was metabolized via a NADPH-dependent pathway in vitro, but no evidence of in vivo metabolism of acetone by the upper respiratory tract was found in mice, rats, guinea pigs, or hamsters. Injection of pregnant rats with acetone on gestational day 19 resulted in high levels of 1,2-propanediol and acetol in the fetuses. Whether these findings reflect transfer of the metabolites from the dams or metabolism of transferred or endogenous acetone by the fetuses was not resolved. Very few differences have been found among species in the metabolism of acetone. The pathways illustrated in Figure 2-3 appear to operate in rats, mice, and rabbits. In microsomes from rabbits exposed to acetone via drinking water, it was found that the oxidation of acetol could be catalyzed by cytochromes P-4503b (IIC3), 2 (IIB6), and 4(IA2), as well as by cytochrome P-4503a (P450IIEl). Only cytochrome P-450IIEl could catalyze the oxidation of acetone to acetol. No studies were located regarding the ability of other isoenzymes of P-450 to catalyze these reactions in other species. Physiological or genetic status may alter the metabolism of acetone. When nondiabetic and diabetic rats were treated by gavage with acetone at doses of 1,000, 2,000, or 4,000 mg/kg, isopropyl alcohol was detected in the blood. The levels of isopropyl alcohol and acetone increased with increasing dose in the diabetic rats, although with plateaus for both acetone and isopropyl alcohol at 1,000 and 2,000 mg/kg doses, but leveled off in the nondiabetic rats, indicating either saturation of the metabolic pathway from

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acetone to isopropyl alcohol or a reversibility of the conversion at high doses. It was suggested that in the diabetic rats, acetone and NADH, both needed for isopropyl alcohol production from acetone, presumably via alcohol dehydrogenase, may be diverted to gluconeogenic pathways to meet the diabetic rat’s need for glucose, resulting in the short plateau. The subsequent rises of both compounds at the high dose of acetone in the diabetic rats could be accounted for by greater generation of NADH from fatty acid oxidation in the diabetic rat, which reduces acetone to isopropyl alcohol, accounting for the rising level of isopropyl alcohol. Liver homogenates from mice heterozygous for the obesity gene treated with acetone were more effective in converting acetone to lactate than liver homogenates from normal homozygous mice treated with acetone. The more effective conversion by heterozygous mice may account for their prolonged survival on the starvation regimen, compared with normal mice. In pregnant and virgin rats (either fed or fasted) injected intravenously with acetone, plasma acetol levels were not significantly different between fasted and nonfasted rats, but pregnant rats had significantly lower levels than virgin rats. Liver levels of acetol were also significantly lower in pregnant rats than in virgin rats. Methylglyoxal levels were very high in the livers and plasma of nonfasted rats (pregnant or virgin), but fasting resulted in much lower levels. In contrast, no major differences were found in the expiration of carbon dioxide between fasted and diabetic rats injected intraperitoneally with acetone or in the labeling pattern of 14C derived from 14C-acetone into glucose among nonfasted diabetic, fasted diabetic, normal nonfasted, and normal fasted rats injected intravenously with 14C-acetone.

EXCRETION

Inhalation Exposure The main route of excretion of acetone is via the lungs regardless of the route of exposure. Acetone is excreted both unchanged and, following metabolism, mainly as carbon dioxide. Studies have been conducted in humans exposed by inhalation, but these studies have followed the elimination only of unchanged

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acetone from blood and the excretion of unchanged acetone in the expired air and urine. In humans exposed to acetone <1,250 ppm for <7.5 hours/day in a complex protocol for 16 weeks, the concentration of acetone in venous blood was directly related to the vapor concentration and duration of exposure, and inversely related to the time elapsed following exposure. The rate of elimination of acetone from blood was constant regardless of blood acetone concentration. Half-times for blood elimination of 3-3.9 hours have been estimated in humans exposed to 100-500 ppm for 2-4 hours. Elimination half-times of 3.9 hours and 6.2 hours have been estimated for arterial and venous blood, respectively. No differences in elimination half-times were found between men and women. The elimination from blood was found to be complete in 24 hours after a 6-hour exposure in subjects exposed to 250 ppm, in 32 hours in subjects exposed to 500 ppm, and in 48 hours in subjects exposed to 1,000 ppm. When humans were exposed for 6 hours/day for 6 days, the blood levels of acetone rose each day and declined to background levels by the following morning each day when the exposure concentration was 250 ppm. At an exposure concentration of 500-ppm, however, the blood levels declined each day, but not to background levels. At the end of the 6-day exposure, blood acetone levels declined to background within 2 days for the 250 ppm group and within 3 days for the 500 ppm group. From the half-time and the data on time for decline to background levels, it appears that at higher concentrations, acetone may accumulate slightly in the blood during daily intermittent exposure, as would be experienced by workers. The rate and pattern of respiratory excretion of acetone is influenced by exposure concentration, duration, the level of physical activity during exposure, and gender. In humans exposed to acetone <1,250 ppm for <7.5 hours/day in a complex protocol for <6 weeks, the rate of respiratory excretion was a function of the duration, and the concentration of acetone in breath after exposure was directly related to the time-average concentration during exposure, with constant duration. The length of time after exposure in which acetone could be detected in the expired air was related to the magnitude of

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exposure, with acetone still readily detectable 16 hours after exposure to 1,000 or 1,250 ppm for 7.5 hours. Excretion of acetone by the lungs was complete within 20 hours postexposure in humans exposed to 237 ppm for 4 hours. During exposure for 2 hours, the acetone concentration in expired air rose to 20 ppm in humans exposed to 100 ppm and to 90-100 ppm in those exposed to 500 ppm. After exposure to 100 ppm, the expired air concentration of acetone declined biphasically over the next 7 hours to 5 ppm. However, after exposure to 500 ppm, the expired air concentration dropped sharply to 2 ppm and declined to 1 ppm over the next 7 hours. Prolonging the exposure duration to 4 hours resulted in less than a 2-fold increase in acetone levels in postexposure expired air, which may reflect a greater loss of acetone through metabolism and urinary excretion. Exercise during the exposure period increased the elimination almost 2-fold. In humans exposed to acetone at rest, during exercise at a constant workload, or during exercise with step-wise increments in workload, expiration of acetone via the lungs amounted to 70, 80, and 200 mg, respectively, at 4 hours postexposure and to 50, 80, and 200 mg, respectively, over the next 4-20 hours . Excretion of acetone from the lungs and kidneys (combined) amounted to 16, 20, and 27% of the amount absorbed in the three respective groups of subjects. Urinary excretion amounted to only 1% of the total uptake. Women expired acetone more slowly than men after a 4-hour exposure to 127-131 ppm, but the percentages excreted by the lungs were not statistically significantly different between men and women (17.6% for men, 15.0% for women). Very little unchanged acetone is excreted in the urine. Urinary excretion is biphasic. Peak urinary excretion occurred between 1 and 3.5 hours after exposure. In male volunteers exposed to 497 or 990 ppm acetone for 4 hours, cumulative acetone excretion in urine at 18 hours after cessation of exposure was 89.5 mg, suggesting slow excretion of acetone in the urine . The amount of acetone excreted in the urine is influenced by the exposure concentration, the duration of exposure, and the level of physical activity during exposure. The acetone concentration in the urine ranged from 0-17.5 mg/L at the end of the 8-hour workshift in

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45 workers exposed to 0-70 ppm acetone (background urinary concentration in 343 nonexposed subjects averaged 1.5 mg/L). Acetone levels in the preshift urine samples were significantly higher than background levels when acetone exposure on the previous day was above 15 ppm. There was no significant difference between background urine levels and preshift urine levels when the previous day’s exposure was <15 ppm. In humans exposed for 6 hours, peak urinary levels were found within the first hour after exposure and were 5.2 mg/ dL in subjects exposed to 1,000 ppm, 2.9 mg/dL in subjects exposed to 500 ppm, and 1.8 mg/dL in subjects exposed to 250 ppm. The decline in urinary acetone to background levels occurred within 48 hours for the 1,000 ppm group, within 32 hours for the 500 ppm group, and within 24 hours in the 250 ppm group. When human subjects were exposed for 6 hours/day for 6 days, urinary levels of acetone rose each day and declined to background levels by the following morning each day when the exposure concentration was 250 ppm. At an exposure level of 500 ppm, however, urinary levels declined each day, but not to background levels. At the end of the 6-day exposure period, urinary acetone levels declined to background within 2 days for the 250 ppm group and within 3 days for the 500 ppm group. Therefore, excretion was more complete after exposure to lower concentrations, and at higher concentrations, acetone may accumulate somewhat during daily intermittent exposure, as would be experienced occupationally. Total 24-hour urine content of acetone was 1.25 mg in subjects exposed to 100 ppm for 2 hours and 3.51 mg in subjects exposed to 500 ppm for 2 hours . Prolonging the duration to 4 hours in 100 ppm group resulted in a total of 1.99 mg acetone in the urine. A slight increase in the urinary content of acetone (1.39 mg) was found when humans exposed to 100 ppm for 2 hours exercised during the exposure. The nature of physical activity during exposure also influenced the urinary excretion. At 3-3.5 hours after exposure, 8.5, 8.5, and 13.4 mg were excreted by the kidney in subjects exposed at rest, during exercise at a constant workload, and during exercise with step-wise increments in workload, respectively. Urinary excretion

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amounted to only 1% of the total uptake. As in humans, acetone is excreted mainly by the lungs of animals. Studies in animals have followed the elimination of acetone from blood and tissues, excretion of acetone and carbon dioxide in expired air, and the urinary excretion of formic acid.

linear manner. The breath levels were directly related to the magnitude of exposure. Breath levels declined from 1.6 ppm at 30 minutes after exposure to 0.3 ppm at 300 minutes in the l00ppm group, from 6.8 to 1.5 ppm in the 500-ppm group, and from 15 to 4 ppm in the l,000-ppm group.

Blood levels of acetone were highest immediately after a 4hour exposure of rats to acetone. In rats exposed to 10,000 ppm, the blood level dropped from 2,114 to 5 µg /mL in 25 hours. In rats exposed to 15,000 ppm, the blood level dropped from 3,263 µg/mL to 50 µg /rnL after 25 hours. Elimination from blood was biphasic in rats exposed to 10,000 and 15,000 ppm, perhaps indicating saturation. Elimination from blood was triphasic in rats exposed to 1,000, 2,500, or 5,000 ppm and was complete within 17-25 hours. In dogs exposed to 100, 500, or 1,000 ppm acetone for 2 hours, blood levels declined in a log-linear manner with a half-time of 3 hours, similar to that observed in humans. Blood levels declined from 25 mg/L immediately after exposure to 10 mg/L at 5 hours postexposure for the 1,000 ppm group, from 12 to 3 mg/L for the 500 ppm group, and from 4 to 1.5 mg/L for the 100 ppm group. Elimination of radioactivity and 14C-acetone was fastest from blood, kidney, lungs, brain, and muscle tissues of mice exposed to 500 ppm 14C-acetone for 6 hours, with halftimes of 2-3 hours during 6 hours postexposure. Elimination of acetone was complete in 24 hours in all tissues, but radioactivity (indicative of metabolites) was still present in all tissues except blood and muscle. When rats were exposed for 5 days, acetone tended to accumulate in adipose tissue.

Urinary excretion of formic acid was followed for 7 days in rats exposed to 62,000 ppm acetone for 2 days. The rate of formic acid excretion was 344 µg/hour compared with 144 µg /hour in controls .

Excretion of acetone in air followed pseudo-first-order kinetics in rats exposed to <20 ppm acetone for l-7 days, while at higher concentrations, saturation kinetics were observed. In rats exposed to 500 ppm 14C-acetone for 6 hours, 42 µmol of radioactive acetone and 37 µmol 14C-carbon dioxide were excreted in the expired air during a 12-hour postexposure period, with 95% and 85%, respectively, recovered in the first 6 hours postexposure. Radioactive acetone accounted for 52% and radioactive carbon dioxide accounted for 48% of the expired radioactivity. The concentration of acetone in the expired breath of dogs exposed to 100, 500, or 1,000 ppm acetone for 2 hours declined in a log-

Oral Exposure In volunteers who ingested 40-60 mg/kg acetone, the elimination of acetone in expired air and urine was determined 2 hours later, and a rate of metabolism of 1.82 mg/kg/hour along with the excretion data was used to calculate that 3.54-7.38 mg/ kg had been excreted and metabolized. The authors estimated that 65-93% of the administered dose was eliminated via metabolism, with the remainder excreted in the urine and expired air. The only other information regarding excretion of acetone in humans after oral exposure is from case reports of accidental or intentional ingestion of materials containing acetone plus other components that may have influenced the elimination of acetone. In a man who ingested liquid cement containing 18% acetone (231 mg/kg), 28% 2-butanone, and 29% cyclohexanone and 720 mL sake, the plasma level of acetone was H”1,120 µg /mL 5 hours after ingestion and declined to 65 µg /mL at 18 hours, 60 µg / mL at 24 hours, and <5 µg /mL at 48 hours. A first-order plasma elimination rate constant of 0.038/hour and a half-time of 18.2 hours were calculated. The urinary level of acetone decreased gradually from about 123 µg /mL at 5 hours after ingestion to about 61 yg/mL at 19 hours. In a case of a known alcoholic who had ingested nail polish remover and whose blood acetone level was 0.25 g/dL (2.5 mg/mL) upon admission to the hospital, the blood level of acetone declined in a log-linear manner to about 0.06 g/dL (0.6 mg/mL) about 86 hours after admission, with a half-life of 31 hours. The calculated clearance of acetone from the lungs was 29 ml/minute or 0.39 ml/minute/kg. A half-time of

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25 hours for lung clearance was calculated, which is in agreement with the observed plasma elimination half-time of 31 hours. The serum acetone level of a 30-month-old child was 445 mg/100 mL (4.45 mg/mL) 1 hour after ingestion of a 6-ounce bottle of nail polish remover (65% acetone) and declined to 2.65 mg/mL at 117 hours, to 0.42 mg/mL at 48 hours, and to 0.04 mg/mL at 72 hours. The halftime of acetone in this patient was 19 hours in the severe early stage and 13 hours in later stages of intoxication, which suggested to the authors greater metabolism and/or excretion in children, compared with adults. For animals, information regarding the excretion of acetone after oral exposure is available only for rats. As is the case after inhalation exposure, acetone, mainly as carbon dioxide, is excreted primarily by the lungs. In a rat given 1.16 mg/kg 14C-acetone by gavage in water, expiration of 14C-carbon dioxide totaled 47.4% of the administered radioactivity over the 13.5-hour collection period. In another experiment, a rat was given 7.11 mg/kg radioactive acetone. A small amount of radioactive acetone (10%) was found in the expired air. Radioactive carbon dioxide and acetate were also detected. In a rat made diabetic by alloxan and given 6.15 mg/kg 14C-acetone, a total of 7.29% of the administered radioactivity was expired as acetone and 51.78% as carbon dioxide. Radioactive acetate was detected in the urine. These data indicate that very little acetone (<10%) was excreted by the lungs after small doses of acetone. A major fraction was oxidized to carbon dioxide and some of the derived carbon was used for acetylation. The diabetic rat was also able to oxidize acetone, but only to H”70% of that in the normal rat. The dose of acetone influences the elimination of acetone from blood. At a dose of 78.44 mg/kg, the maximum blood level of 200 µg /mL at 3 hours declined to 10 µg /mL at 12 hours, where it remained for the next 12 hours (data inadequate to calculate total body clearance). At a dose of 196.1 mg/kg, the maximum blood level of 400 µg /mL at 6 hours declined biphasically to 50 µg /mL at 12 hours and to 30 µg /mL at 18 hours where it remained at 24 hours (total body clearance-64 ml/hour). At a dose of 784.4 mg/kg, the maximum blood level of 900 µg /mL at 1 hour declined to 300 µg /mL at 12 hours, to 110 µg /mL at 18 hours,

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and to 50 µg /mL at 24 hours (total body clearance-86 ml/hour). At a dose of 1,961 mg/kg, the maximum blood level of 1,900 µg /mL at 3 hours declined slowly to 400 µg /mL at 24 hours (total body clearance- 75 ml/hour). Thus total body clearance was independent of dose, but the half-time for elimination increased from 2.4 hours for 196.1 mg/kg, to 4.9 hours for 784.4 mg/kg, and 7.2 hours for 1,96 1 mg/kg. The vehicle (corn oil or water) in which acetone is administered has little influence on the elimination of acetone from blood (Charbonneau et al. 1986a). After gavage treatment of rats with 78, 196, 392, 784, or 1,177 mg/kg acetone in corn oil or water, elimination was biphasic for the two higher doses and triphasic for the lower doses. Acetone elimination from blood declined to <5 to
Dermal Exposure Information regarding excretion of acetone after dermal exposure of humans is limited, but the main route of excretion is via the lungs, with little excreted in the urine. Application of an unspecified quantity of acetone to a 12.5 cm2 area of skin of volunteers for 2 hours/day for 4 days resulted alveolar air levels of 5-12 ppm and urinary concentrations of 8-14 µg /mL on each day. These levels declined to background levels by the next day after each exposure. Higher alveolar air and urinary levels were obtained when the daily exposure increased to 4 hour/day: 2534 ppm in alveolar air, and 29-41 µg /mL in urine, but these levels also returned to background each day. No studies were located regarding excretion of acetone by animals after dermal exposure.

Other Routes of Exposure As determined in humans, physiological status may influence the disposition of endogenous and exogenous acetone. In groups of nonobese patients fasted for 3 days, obese patients fasted for 3 days, and obese patients fasted for 21 days and injected

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intravenously with 14C-acetone, 8-29% of the urinary acetone was derived from plasma radioactive acetone. The concentrations of urinary acetone were 1.2, 0.4, and 2.6 µmol/mL in 3-day-fasted nonobese, 3-dayfasted obese, and 21-day-fasted obese patients, respectively. The rates of urinary acetone excretion were 1.2, 0.4, and 1.7 µmol/minute, respectively, suggesting marked renal reabsorption or backdiffusion. The percentages of measured acetone production that could be accounted for by excretion via the lungs were 14.7, 5.3, and 25.2%, respectively. The percentages that could be accounted for by urinary excretion were 1.4, 0.6, and 1.3%, respectively. Cumulative excretion of 14C-carbon dioxide during the 6-hour turnover study periods accounted for 17.4, 21.5, and 4.9%, respectively. Thus, nonobese subjects fasted for 3 days excreted more acetone at higher rates than did obese subjects fasted for 3 days. However, excretion by the obese patients fasted for 21 days exceeded that by both 3-day-fasted groups. These differences are probably related to the effect that the degree of starvation ketosis has on the metabolism and overall disposition of acetone.

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Fasted pregnant rats had an enhanced capacity for acetone elimination compared with fasted or fed virgin rats or fed pregnant rats, after intravenous dosing with 100 mg/kg. While the elimination of acetone from plasma was biphasic in all groups, the fasted pregnant rats eliminated acetone at a faster rate than the other groups.

Mechanism of Action As discussed in the preceding sections, acetone is readily and passively absorbed from the lungs and gastrointestinal tract and probably from the skin. Since acetone is highly water soluble, it is readily taken up by the blood and widely distributed to body tissues.

In contrast, no major differences were observed among normal rats, fasted rats, and diabetic rats in the excretion of 14C-carbon dioxide from the lungs after intraperitoneal injections of 14Cacetone. However, the dose level influenced the pattern of metabolism and, hence, the excretion of carbon dioxide. Rats that received 9.3-22.7 mg/kg radioactive acetone rapidly metabolized acetone, as evidenced by exhalation of 24-43% of the administered radioactivity as 14C-carbon dioxide within the first 3 hours after dosing.

Other than gastric lavage in the case of ingestion, there is no known way to interfere with the absorption of acetone. Within the liver, acetone is metabolized by three separate gluconeogenic pathways through several intermediates, but most of its intermediate or final metabolites are not considered toxic. Unmetabolized acetone does not appear to accumulate in any tissue, but is excreted mainly in the expired breath. Acetone is irritating to mucous membranes, possibly due to its lipid solvent properties, resulting in eye, nose, throat, and lung irritation upon exposure to the vapors, and skin irritation upon dermal contact. The mechanism of the narcotic effects of acetone is not known, but as a solvent, acetone may interfere with the composition of the membranes, altering their permeability to ions. Systemically, acetone is moderately toxic to the liver and produces hematological effects.

Rats that received 258-460 mg/kg radioactive acetone exhaled only 2.1-5.7% of the radiolabel as carbon dioxide in the first 3 hours, 2.8-7.8% in the next 3-6 hours, and 16-29% in the next 624 hours. Rats injected subcutaneously with 14C-acetone also excreted the derived radioactive carbon mainly as carbon dioxide. In rats fasted for 24 hours and given 170 mg/kg radioactive acetone, 27% of the radiolabel was excreted as carbon dioxide in 4 hours. Rats fasted for 48 hours before the subcutaneous dose of 174 mg/kg radioactive acetone excreted 53% of the radiolabel as carbon dioxide over a 14-hour collection period.

The mechanism by which acetone produces these effects is unknown. The renal toxicity may be due to the metabolite, formate, which is known to be nephrotoxic (NTP 1991) and is excreted by the kidneys. Furthermore, the renal toxicity, which appears to be specific for male rats, may involve á2µ-globulin syndrome, as hyaline droplet formation was associated with the nephropathy observed in male rats in the American Biogenics Corp. (1986) study. Acetone also causes increases in liver and kidney weight, probably through the induction of microsomal enzymes, which would increase the weight of the organs by virtue of the increased

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Public Health Statement for Acetone

protein content. Acetone also causes reproductive effects in male rats and is fetotoxic. Although the exact mechanism for many of the effects of acetone is not known, distribution studies in mice indicate that acetone and metabolites are found in all of the target organs. Acetone and some of its metabolites were also transferred to rat fetuses after the dams were exposed to acetone.

RELEVANCE TO PUBLIC HEALTH

One of the major effects of acetone is the potentiation of the toxicity of other chemicals. Pretreatment with acetone has been shown to potentiate the hepatotoxicity and nephrotoxicity of carbon tetrachloride and chloroform by inducing particular forms of cytochrome P-450, especially cytochrome P-45OIIE1, and associated enzyme activities. The induction of these enzymes leads to the enhanced metabolism of carbon tetrachloride and chloroform to reactive intermediates capable of causing liver and kidney injury. Acetone enhances the formation of carboxyhemoglobin by dichloromethane via induction of cytochrome P-450IIE1, leading to enhanced metabolism of dichloromethane to carbon monoxide. Acetone also potentiates the hepatotoxicity of acetaminophen, Nnitrosodimethylamine and N-nitrosodiethylamine, thiobenzamide, oxygen , and chromate (Cr[VI]); the genotoxicity of Nnitrosodimethylamine; the hematotoxicity of benzene; and the lethality of acetonitrile by inducing cytochrome P-450IIEl. The hepatotoxic and nephrotoxic effects of dibromochloromethane and bromodichloromethane and the hepatotoxic effects of 1,l ,Ztrichloroethane, 1, 1-dichloroethene, and dichlorobenzene are also enhanced by acetone. The exact mechanisms for these interactions are not clear, but the involvement of mixed function oxidases has been implicated. The renal toxicity of N-(3,5-dichlorophenyl) succinimide (a fungicide) is potentiated by acetone by the induction of cytochrome P-450IIEl. In other interactions, acetone enhances the neurotoxicity of ethanol by a proposed mechanism whereby acetone inhibits the activity of alcohol dehydrogenase, a reaction responsible for 90% of the elimination of ethanol. Acetone also potentiates the neurotoxicity and reproductive toxicity of 2,5-hexanedione. The exact mechanism for these interactions is not clear but appears to involve decreased body clearance of 2,5-hexanedione by acetone.

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Acetone is a highly volatile, highly water-soluble aliphatic ketone. Acetone is readily absorbed by the lungs and gastrointestinal tract, taken up the blood, and widely distributed to organs and tissues of the body. Acetone can also be absorbed dermally. Acetone is metabolized mainly in the liver by three separate gluconeogenic pathways, leading to the production of glucose with subsequent liberation of carbon dioxide. With the possible exception of formate, none of the intermediate metabolites appear to be toxic. Acetone and acetone-derived carbon dioxide are excreted mainly in the expired breath, with very little acetone excreted in the urine. Elimination of acetone is generally complete within l-3 days, depending on the dose and duration of exposure, and has little tendency to accumulate. Acetone is also produced endogenously in the body during lipid metabolism, which increases with fasting. Normal levels of acetone in breath, blood, and urine can vary widely depending on a number of factors, such as infancy, pregnancy, lactation, diabetes, physical exercise, dieting, physical trauma, and alcohol consumption. As a solvent, acetone is irritating to mucous membranes, and exposure to the vapors can irritate the respiratory system and eyes. Acetone has anesthetic properties and causes headaches, lightheadedness, confusion, dizziness, and can lead to unconsciousness and coma in humans at high enough exposure levels. Neurobehavioral effects have been observed in humans exposed acutely by inhalation either in the workplace or in laboratory experiments. Hematological effects, which might indicate immunological effects, have been observed in humans exposed acutely to acetone in laboratory experiments. Acute inhalation of acetone may shorten the menstrual cycle. Exposure to acetone vapor can also lead to increased pulse rates, gastrointestinal irritation, nausea, vomiting, and hemorrhage. However, the odor threshold of acetone (l00-140 ppm) and the feelings of irritancy are excellent warning properties that generally preclude serious inhalation over-exposure. Accidental or intentional ingestion of acetone can cause erosions in the mouth, coma, and diabetes-like symptoms. Acute dermal exposure of humans to liquid acetone resulted in degenerative

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changes in the epidermis, and a case of contact dermatitis was reported. Acetone is also irritating to the respiratory system of animals and produces narcosis, coma, and behavioral effects upon acute inhalation exposure. Hematological effects have also been observed in animals. Acute inhalation exposure of animals during gestation has resulted in decreased fetal body weight and increased incidences of late resorption and reduced ossification. Acute oral exposure of animals resulted in enzyme induction in the respiratory system, bone marrow, gastrointestinal tract, kidney, and liver, increased liver weight and bone marrow hypoplasia, degeneration of apical microvilli in renal tubules, and reduced insulin-stimulated glucose oxidation in adipose tissue. Acute oral exposure of animals also resulted in neurological effects, such as languid behavior, prostration before death, reproductive effects (reduced reproduction index and increased duration of gestation), and developmental effects (reduced postnatal pup survival and reduced fetal weight). Intermediate-duration oral studies in animals have found liver effects, hematological effects, nephropathy, and effects on male reproductive organs. Ocular exposure to undiluted or concentrated acetone has produced severe cornea1 burns and necrosis, and dermal exposure of animals to acetone has resulted in reports of cataracts in one species and only a single report of amyloidosis. These observations have not been made by other investigators or in other species, despite many experiments involving dermal exposure of test animals to acetone. The relevance of the liver, reproductive, and developmental effects to humans is not known, since these end points have not been sufficiently examined in humans. However, few species differences exist in the toxicokinetics of acetone, suggesting that these effects might be of concern for humans. The renal effects may be specific for male rats, and the cataract formation may be specific for guinea pigs, The relevance of amyloidosis in completely unknown. Acetone appears to have no delayed toxic effects. Acetone may be weakly genotoxic, but the majority of genotoxicity assays were negative. Acetone has not been studied for carcinogenicity by the inhalation or oral route, but it was not tumorigenic when tested alone, when tested as a tumor initiator,

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or when tested as a tumor promoter in skin painting studies. One of the most studied effects of acetone is the induction of microsomal enzymes, particularly of cytochrome P-450IIEl. Acetone induces its own metabolism by this induction, and potentiates the toxicity of numerous other chemicals by enhancing the metabolism, which depends on cytochrome P-450IIE1, to reactive intermediates. The induction of cytochrome P-45011El by acetone has been documented in many species, and therefore poses a concern for humans exposed to acetone and the chemicals whose toxicity is potentiated by acetone. Based on results of animal studies, which indicate that male animals are more susceptible than female animals, men may be more susceptible than women to the hematological, hepatic, and renal effects, and effects on reproductive organs. Furthermore, acetone may exacerbate preexisting hematological, liver, kidney, or reproductive disorders in humans. The very young and the elderly may be more susceptible. Fasting and diabetes increases endogenous levels of acetone in humans, suggesting that dieters and diabetics may have a higher body burden, and additional exposure to acetone may make them more susceptible to any effects. Results in animals suggest that the rate of acetone metabolism is slower in pregnancy, making pregnant animals more susceptible, and this susceptibility might apply to humans. The general population can be exposed to acetone in the air, in contaminated water and soil, and by ingestion of food containing acetone. As discussed in chapter 5, acetone is emitted into the air from plants and trees, volcanic eruptions, forest fires, automobile exhaust, chemical manufacturing, tobacco smoke, wood burning and pulp, refuse in polyethylene combustion, petroleum storage facilities, landfill sites, and solvent use. Acetone is also found in nail polish remover, paint remover, glue, and cleaning agents. Acetone is released into water by chemical manufacturing industries and energy-related industries. Acetone can be released to soil from municipal and industrial landfills, from atmospheric deposition, from disposed agricultural, food and animals wastes, and from household septic tanks. The half-life of acetone in air due to reactions with hydroxyl radical and photolysis is 22 days. The relatively long half-life permits transport to areas remote

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from the source. Because of its high water solubility, precipitation can remove acetone from the air to surface water and soil. In water and soil acetone undergoes microbial degradation but can also evaporate back into the atmosphere, depending on the moisture content of soil. Adsorption to soil and sediment is inconsequential. Acetone does not accumulate in fish or other aquatic or terrestrial organisms. Ambient air levels of acetone average
INHALATION MRLS An MRL of 26 ppm has been derived for acute-duration inhalation exposure (14 days or less) to acetone. The MRL was based on a LOAEL of 237 ppm for 4 hours for neurobehavioral effects in an experimental study in humans . In this study, groups of 11 men and 11 women were exposed for 4 hours to acetone at a concentration of 237 ppm. Statistically significant changes in performance from controls were seen in two measures of auditory tone discrimination (increased response time and increased false alarms) and in anger and hostility. Neurological and behavioral effects have also been observed in humans exposed to 250 ppm acetone for 6 hours or repeatedly for 6 hours/day for 6 days. Effects included lack of energy, general weakness, delayed visual reaction time, and headache. Although irritation of the nose, throat, and trachea was reported in humans exposed to 100 ppm for 6 hours, other studies in humans report respiratory irritation only at higher levels (>250 ppm) for longer

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durations. Furthermore, the reporting of these irritating effects was subjective, and only six volunteers were exposed to 100 ppm. An MRL of 13 ppm has been derived for intermediate-duration inhalation exposure (15-364 days) to acetone. The MRL was based on a LOAEL of 1,250 ppm for neurological effects in volunteers in a 6-week study. There was a statistically significant increase in amplitude of the visual evoked response in subjects tested following exposure to 1,250 ppm. Neurological and behavioral effects (lack of energy, general weakness, delayed visual reaction time, and headache) have also been observed in humans exposed to 250 ppm acetone for 5.25 hours or repeatedly for 6 hours/day for 6 days. Increased anger and hostility, as well as increased response time and rate of false negatives in a test of auditory tone discrimination, were reported in volunteers exposed to 237 ppm for 4 hours. No other effects were detected in humans or animals exposed to acetone for intermediate durations. An MRL of 13 ppm has been derived for chronic-duration inhalation exposure (365 days or more) to acetone. The MRL was based on a LOAEL of 1,250 ppm for neurological effects in volunteers in a 6-week study. There was a statistically significant increase in amplitude of the visual evoked response in subjects tested following exposure to 1,250 ppm. Neurological and behavioral effects (lack of energy, general weakness, delayed visual reaction time, and headache) have also been observed in humans exposed to 250 ppm acetone for 5.25 hours or repeatedly for 6 hours/day for 6 days. Increased anger and hostility, as well as increased response time and rate of false negatives in a test of auditory tone discrimination, were reported in volunteers exposed to 237 ppm for 4 hours. A health survey of workers exposed to acetone between 3 months and 23 years revealed no systemic effects.

ORAL MRLS An MRL of 2 mg/kg/day has been derived for intermediateduration oral exposure (15-364 days) to acetone. The MRL was based on a NOAEL of 200 mg/kg/day for macrocytic anemia in rats treated with acetone in the drinking water for 13 weeks. The LOAEL was 400 mg/kg/day.

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Hematological effects have been observed in humans exposed by inhalation to acetone, in rats exposed to 6,942 mg/kg/day in the drinking water for 14 days, and in rats treated by gavage with 2,500 mg/kg/day for 93-95 days. Male rats treated with 900 mg/ kg/day in the drinking water also had increased incidence of agerelated nephropathy, which increased in severity as the dose increased. These renal lesions were not seen in female rats or in male or female mice similarly treated. In male rats treated by gavage with >500 mg/kg/day, but not 100 mg/kg/day, an enhancement of age-related nephropathy, accompanied by hyaline droplet accumulation, was observed. Female rats had enhanced age-related nephropathy only at the highest dose (2,500 mg/kg/ day), but no evidence of hyaline droplet accumulation was found. Because the mechanism for acetone-induced renal toxicity has not been elucidated, but may be specific for male rats, renal end points have not been considered for the derivation of MRLs for acetone. An MRL has not been derived for acute-duration oral exposure (14 days or less) to acetone because a suitable NOAEL or LOAEL for a sensitive end point has not been sufficiently characterized, Such effects as bone marrow hypoplasia, reduced insulinstimulated glucose oxidation, and hepatocellular hypertrophy were observed in rats or mice exposed to acetone in the drinking water for acute durations, but the NOAEL and LOAEL values for these effects are close to or fall within the range of LD50 values for rats administered acetone by gavage. Degeneration of apical microvilli in renal tubules was observed in male rats treated once by gavage with 871 mg/kg, but incidences were not reported. Furthermore, as discussed above, acetone-induced renal lesions may be specific for male rats and may not represent a suitable end point to consider for MRL derivation for acetone. An MRL was not derived for chronic-duration oral exposure (365 days or more) to acetone because no chronic-duration studies were located. Death. No studies were located regarding death of humans after dermal exposure to acetone. A retrospective mortality study of workers exposed to time-weighted-average acetone concentrations of 380-1,070 ppm at a cellulose fiber plant where

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acetone was used as the only solvent found no significant excess risk of death from any cause compared with rates for the U.S. general population. Furthermore, in the 1991 Annual Report of the American Association of Poison Control Centers National Data Collection System, no fatalities were reported among 1,124 cases of accidental or intentional ingestion of acetone. However, inhalation of saturated atmospheres of acetone or accidental or intentional ingestion of acetone can lead to unconsciousness if doses are sufficiently high, and death could ensue if the subjects do not receive medical intervention. Two workers became unconscious after a single accidental exposure to acetone at high concentrations (>1,200 ppm) (Ross 1973). Coma developed in patients who had hip casts applied with acetone present in the setting fluid. These patients were exposed to acetone by inhalation during the application and from evaporation of acetone from the casts after application, but dermal exposure also could have occurred. In most cases of accidental or intentional ingestion, the quantity of acetone consumed is not known. In one case, a man became comatose after ingesting 100 mL of liquid cement containing 15% polyvinyl chloride, 18% acetone, 28% 2-butanone, and 39% cyclohexanone, along with 750 mL sake. The dose of acetone ingested would be approximately 231 mg/kg, but the other components in the cement and the sake could have contributed to his condition. In another case, a man became comatose after ingesting 200 mL of pure acetone (2,241 mg/kg). Since the patients received medical treatment, none died. High concentrations of acetone in air are required to produce death in animals. An 8-hour LC50 value of 21,091 ppm and a 4hour LC50 value of 31,944 ppm were found for female rats. Death of animals has occurred after acute inhalation exposure to l0,00050,000 ppm. No information was located regarding levels of acetone that would result in death of animals after inhalation exposure for longer durations. Acute oral LD50 values in rats have ranged from 1,726 to 9,833 mg/kg, depending on age and strain. In general, newborn rats are the most sensitive, followed by 14-dayold rats, older adult rats, and younger adult rats, and SpragueDawley rats appeared to be more sensitive than Wistar rats or Nelson rats. Acute oral LD50 values of 5,250 mg/kg for male mice

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and 3,687 mg/kg for guinea pigs have been reported. Doses of 3,922-7,844 mg/kg and 7,500-8,000 mg/kg have been reported to be fatal to rabbits and puppies, respectively. An acute oral dose of 2,400 mg/kg was fatal to one of four pregnant mice, and more pregnant mice died at higher doses (EHRT 1987), but no effect on mortality was found in nonpregnant mice exposed to acetone in drinking water at doses < 1,298 mg/kg/day for 13 weeks (NTP 1991). Therefore, pregnant mice may be more susceptible than nonpregnant mice. Likewise, in intermediate-duration studies, no effects on mortality were found in rats exposed to acetone by gavage or in drinking water (NTP 1991) at doses <3,400 mg/kg/ day. In studies attempting to determine dermal LD50 values for animals, the highest doses used did not result in death. Therefore, the LD50 values for dermal exposure were >9.4 mL/kg for guinea pigs and >20 mL/kg for rabbits. The lethality of acetone is related to its narcotic properties, since prostration and unconsciousness usually precede death. It is unlikely that humans would die after exposure to acetone at ambient air, soil, or water levels, or at levels present at hazardous waste sites. Accidental occupational exposure and accidental or intentional ingestion of acetone could conceivably lead to death if the victims do not receive medical attention. In the case of the worker who became unconscious at an acetone level of 900 ppm, the OSHA standard of 750 ppm (OSHA 1989) was exceeded.

SYSTEMIC EFFECTS Respiratory Effects. Acetone does not appear to produce respiratory effects in humans or animals after oral or dermal exposure. As is common with solvent exposure, the respiratory effects of acetone observed in humans exposed by inhalation are related to the irritating properties of acetone. Experimental subjects experienced irritation of the nose, throat, and trachea at acute inhalation concentrations e”100 ppm for 6 hours, but this appears to be related to the duration of exposure, as people exposed to 200 ppm for 3-5 minutes experienced no irritation and estimated that they could tolerate this concentration for 8 hours. Workers exposed to higher concentrations also complained of nose, throat, and lung irritation. Individual sensitivity to acetone-induced respiratory irritation appears to be highly variable. Pulmonary function testing

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of volunteers exposed to <1,250 ppm acetone intermittently for various durations in a complex protocol revealed no abnormalities caused by the exposure. Acetone is also irritating to the respiratory system of animals after acute inhalation exposure. Guinea pigs that died after exposure to high concentrations of acetone had pulmonary congestion and edema due to the irritating properties of acetone, and hemorrhage of the lung, probably as a consequence of death. An RC50 of 77,516 ppm was found for mice. The decrease in respiratory rate is due to sensory irritation and is typical of sensory irritants, No intermediate-duration inhalation studies examined animals for respiratory effects, and no chronicduration inhalation studies in animals were located. Changes in respiratory rates or irregular respiration were observed in rabbits dosed orally with >3,922 mg/kg and dogs dosed orally with 4,000 mg/kg, but were accompanied by signs of narcosis. Acute oral exposure of rabbits to 863 mg/kg/day resulted in the induction of microsomal enzymes in the nasal mucosa, but induction of microsomal enzymes is a normal physiological response to xenobiotics and is not adverse. However, acetone potentiates the toxicity of chemicals by enzyme induction. While it is conceivable that acetone might potentiate the toxicity of chemicals toxic to the respiratory system, no such interactions were located. It is unlikely that people would experience respiratory irritation after exposure to acetone at ambient air, soil, or water levels, or at levels present at hazardous waste sites. Occupational exposure to acetone can cause respiratory irritation, but other respiratory effects are unlikely. The OSHA timeweighted average standard to protect against irritation is 750 ppm, and the short-term exposure limit is 1,000 ppm (OSHA 1989), which is higher than the exposure levels producing irritation in laboratory subjects. Cardiovascular Effects. No studies of workers located reported cardiovascular effects of acetone unrelated to narcosis. A retrospective mortality study of workers exposed to time-weightedaverage acetone concentrations of 380-1,070 ppm at a cellulose fiber plant where acetone was used as the only solvent found no significant excess risk of death from circulatory system disease or ischemic heart disease compared with rates for the U.S. general

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population. Electrocardiography of volunteers exposed to <1,250 ppm acetone intermittently for various durations in a complex protocol revealed no abnormalities caused by the exposure. Patients exposed to acetone by inhalation and/or dermally after application of casts for which acetone was used in the setting solution commonly had high pulse rates (120-l60/minute). No gross heart lesions were found in guinea pigs exposed acutely by inhalation to lethal concentrations, and no histopathological heart lesions were found in rats exposed by inhalation to acetone for 2-8 weeks or in rats or mice exposed orally in intermediate-duration studies. However, amyloidosis was observed in the hearts of mice whose lumbo-sacral regions were painted twice weekly with an unspecified quantity of acetone for 12 months. The significance of the amyloidogenic effect of acetone to humans is unknown since no clinical data regarding amyloidosis in humans who come in frequent dermal contact with acetone, such as manicurists, are available. The effects of acetone on the perfused isolated hearts of rabbits (Raje 1980) and the isolated right atrium of rats (Chentanez et al. 1987) have been investigated in vitro. Acetone at concentrations of 0.5 and 1.0% (v/v) in the perfusate inhibited the force of cardiac contractions and increased the heart rate of rabbits in a doserelated manner (Raje 1980). Acetone also increased the coronary flow, but not in a dose-related manner. The author stated, however, that the concentrations of acetone were physiologically unrealistic. Acetone at concentrations of l0-210 mM in the bathing solution increased the atria1 contraction rate of the isolated rat atrium in a dose-dependent manner. At concentrations >210 mM, the atria1 contraction rate gradually decreased to the normal control value. At concentrations of l0-750 mM, acetone resulted in a dosedependent increase in the release of norepinephrine from the right atrium. The dose-response curves for atria1 contraction and peak norepinephrine release were parallel at acetone concentrations of l0-210 mM, but norepinephrine release still increased at concentrations <500 mM, while the atria1 contraction rate decreased at >210 mM. The results indicated that the increase in atria1 contraction rate may be due in part to an increase in norepinephrine release from the atria1 sympathetic nerve terminals at the lower concentrations, but the higher concentrations may

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have been too toxic for norepinephrine to exert a further effect on atria1 contraction. These in vitro studies were conducted to investigate the mechanism of tachycardia in glue-sniffers to determine whether acetone, one of the components of glue, was the component responsible for the tachycardia. Other components of glue, however, could also cause tachycardia. These in vitro experiments suggest that acetone may cause tachycardia in vivo, but tachycardia was not demonstrated by electrocardiography in the subjects exposed to <1,250 ppm in the experiments by Stewart et al. (1975), and rapid heart rates were not reported as one of the subjective symptoms in workers or experimental subjects. The weight of evidence for cardiovascular effects in humans and animals exposed to acetone in vivo suggest that it is unlikely that people would experience cardiovascular effects after exposure to acetone at ambient air, soil, or water levels, or at levels present at hazardous waste sites. Gastrointestinal Effects. Nausea and vomiting of blood have been observed in patients who had hip casts applied with acetone present in the setting fluid. The vomitus contained blood several hours after the onset of vomiting; therefore, the gastrointestinal hemorrhage may have been due to trauma of repeated vomiting. These patients were exposed to acetone by inhalation during the application and from evaporation of acetone from the casts after application, but dermal exposure also could have occurred. None of the workers examined in on-site medical evaluations or experimental subjects exposed to <1,250 ppm complained of nausea or vomiting. However, complaints of nausea and intermittent vomiting were reported by workers with accidental exposure to acetone (>12,000 ppm) (Ross 1973). It is possible that nausea and vomiting are secondary to central nervous system toxicity. Effects on the stomach or intestines were not reported in case reports of people who ingested acetone intentionally or accidentally, but a man who intentionally drank H”200 mL of pure acetone (H”2,241 mg/kg) had a red and swollen throat and erosions in the soft palate and entrance to the esophagus. No gross stomach lesions were found in guinea pigs exposed acutely by inhalation to lethal concentrations, and no histopathological stomach or intestinal lesions were found in rats

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or mice exposed orally in intermediate-duration studies. Although cytochrome P-450 enzyme levels were significantly elevated in duodenal and jejunal microsomes from rats exposed to acetone in drinking water for 3 days, induction of microsomal enzymes is not considered an adverse effect. People exposed to acetone at work could experience nausea and vomiting, but levels of acetone in ambient air, soil, or water at hazardous waste sites are not likely to be high enough to cause nausea and vomiting. Hematological Effects. Acetone exposure has caused hematological effects in both humans and animals. In men exposed experimentally to >500 ppm acetone for 6 hours or for 6 hours/ day for 6 days, significantly increased white blood cell counts, increased eosinophil counts, and decreased phagocytic activity of neutrophils were observed, compared with controls . No women were included in these studies. However, experimental studies that examined hematological indices did not find any abnormalities in men (women not included in study) at exposure levels of 500 ppm for 2 hours or in men or women at exposure levels <1,250 ppm acetone for <7.5 hours for various durations. The reasons for these different results are not known. In a health evaluation survey of 245 workers exposed to timeweighted- average acetone concentrations of 380-1,070 ppm at a cellulose fiber production plant where acetone was used as the only solvent, all hematological parameters were within normal limits. Oral exposure of rats to acetone was found to significantly increase the level of cytochrome P-45IIE1 in bone marrow microsomes. While microsomal enzyme induction is not generally considered an adverse effect, the hemotoxicity of benzene depends upon its activation by cytochrome P-450IIEl; therefore, acetone may potentiate the hemotoxicity of benzene by this mechanism. Hematological effects observed in animals consisted of bone marrow hypoplasia in male rats, but not female rats, exposed to acetone in the drinking water for 14 days at 6,942 mg/kg/day (NTP 1991); evidence of macrocytic anemia in male rats at e”400 mg/kg/day and nonspecific hematological effects not indicative of anemia in female rats at 3,100 mg/kg/day via drinking water for 13 weeks (NTP 1991); increased hemoglobin, hematocrit, and mean cell volume in male rats, but not female rats, treated by

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gavage at 2,500 mg/kg/day for 46 days, and in both males and females at this dose for 13 weeks. In mice treated at <12,725 mg/ kg/day for 14 days, it was not clear whether bone marrow was examined, but in the 13-week study, no hematological effects or histologically observable lesions in hematopoietic tissues were found in mice (NTP 1991). Thus, sex differences exist in the hematological effects of acetone in animals, and species differences exist in the hematological effects of acetone among animals and between animals and humans. The weight of evidence indicates that acetone exposure might produce hematological effects in humans. Based on animals studies, men might be more susceptible than women. Whether levels of acetone in ambient air, soil, or water, or levels present at hazardous waste sites are high enough to cause hematological effects is not known, but occupational exposure levels may be high enough, as the OSHA time-weighted average standard is 750 ppm and the short-term exposure limit is 1,000 ppm (OSHA 1989). Musculoskeletal Effects. No studies were located regarding musculoskeletal effects in humans after inhalation, oral, or dermal exposure in humans or animals after inhalation or dermal exposure to acetone. Histological examination of rats and mice in intermediate-duration drinking water or gavage studies did not find any evidence of musculoskeletal effects. In appears unlikely that exposure of humans to acetone in any setting would result in musculoskeletal effects. Hepatic Effects. No indication that acetone caused hepatic effects in humans was found in controlled studies of volunteers based on analysis of clinical chemistry parameters. Furthermore, none of the located studies of workers or case reports documented hepatic effects. In a health evaluation survey of 245 workers exposed to time-weighted-average acetone concentrations of 3801,070 ppm at a cellulose fiber production plant where acetone was used as the only solvent, all clinical blood chemistry parameters (aspartate aminotransferase, alanine aminotransferase, lactic dehydrogenase, alkaline phosphatase, total bilirubin, and albumin) were within normal limits. Inhalation and oral studies in animals have found only mild to moderate hepatic effects. Guinea pigs acutely exposed by

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inhalation to lethal concentrations had fatty deposits in the liver, which were considered toxicologically insignificant. Mice exposed intermittently to 6,600 ppm acetone during gestation had significantly increased absolute and relative liver weights, indicative of maternal toxicity (NTP 1988). The increased liver weight could have been associated with enzyme induction. No increases in serum levels of hepatic enzymes indicative of liver injury were found in acute oral studies in rats, and no histopathological liver lesions were found in an acute oral study in mice. Liver effects observed in animals orally exposed to acetone consisted of dose-related increased liver weight in mice exposed to acetone in drinking water at >965 mg/kg/day and hepatocellular hypertrophy at >3,896 mg/kg/day for 14 days, probably associated with microsomal enzyme induction (NTP 1991); significantly increased levels of serum alanine aminotransferase in male rats, but not female rats, at a gavage dose of 2,500 mg/kg/day for 46 days or 13 weeks, and significantly increased liver weights in female rats at >500 mg/kg/day and in male rats at 2,500 mg/kg/day for 13 weeks; and significantly increased liver weights in both sexes of rats at the same drinking water concentration (1,600 mg/kg/day for females, 1,700 mg/ kg/day for males) and in female mice, but not male mice, at 11,298 mg/kg/day for 13 weeks (NTP 1991). Histological examination of the liver of rats and mice in the 13-week studies revealed no evidence of liver pathology. The increased liver weight in mice in the 13-week study was not associated with hepatocellular hypertrophy as was seen in the 14-day study, suggesting a development of tolerance (NTP 1991). In the absence of histologically observable liver lesions in rats in the 13-week gavage study, the toxicological significance of the increased serum level of alanine aminotransferase in the same study is questionable. Amyloidosis was observed in the livers of mice whose lumbosacral regions were painted twice weekly with an unspecified quantity of acetone for 12 months. The significance of the amyloidogenic effect of acetone to humans is unknown, since no clinical data regarding amyloidosis in humans who come in frequent dermal contact with acetone, such as manicurists, are available.

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As mentioned above, increased liver weight was probably associated with hepatic microsomal enzyme induction. Numerous acute oral and inhalation studies have demonstrated that acetone induces hepatic microsomal monooxygenase activities, particularly activities associated with cytochrome P-450IIEl. Acetone potentiates the hepatotoxicity of carbon tetrachloride and chloroform and other chemicals by inducing microsomal enzymes that metabolize these chemicals to reactive intermediates. Therefore, it is likely that people would develop no or only minimal liver effects by exposure to acetone alone at ambient air, soil, or water levels, at levels present at hazardous waste sites, or in occupational settings. However, exposure to acetone alone is extremely unlikely in these scenarios, since many other chemicals are also present in air, soil, and water and at hazardous waste sites, and workers are commonly exposed to other solvents and chemicals that produce hepatotoxic effects potentiated by acetone. Such coexposure might make people more susceptible to the hepatotoxicity of these chemicals. Renal Effects. No indication that acetone caused renal effects in humans was found in controlled studies of volunteers based on analysis of clinical chemistry parameters (blood urea nitrogen, uric acid) and urinalysis. Furthermore, none of the located studies of workers or case reports documented renal effects. The only indication that inhalation exposure to acetone causes renal effects in animals was the consistent finding of congestion or distention of renal tubules or glomeruli in guinea pigs exposed acutely to lethal levels of acetone. Rats exposed intermittently to 19,000 ppm for 18 weeks had no clinical or histological evidence of kidney damage. Amyloidosis was observed in the kidneys of mice whose lumbo-sacral regions were painted twice weekly with an unspecified quantity of acetone for 12 months. The significance of the amyloidogenic effect of acetone to humans is unknown, since no clinical data regarding amyloidosis in humans who come in frequent dermal contact with acetone, such as manicurists, are available. No significant differences in kidney weight, BUN levels, or organic ion accumulation by renal slices were found in rats given 1,766 mg/kg/day acetone for 2 days compared with controls.

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Oral exposure of animals to acetone in other studies, however, has resulted in adverse renal effects, including degeneration of the apical microvilli of renal tubules in rats given a single oral dose of 871 mg/kg; dose-related increased kidney weight in mice at >6,348 mg/kg/day in drinking water for 14 days (NTP 1991); increased kidney weight in female rats at >1,600 mg/kg/day and in male rats at 3,400 mg/kg/day, and a dose-related increased incidence and/or severity of nephropathy at >900 mg/kg/day in male rats, but not female rats, in drinking water for 13 weeks (NTP 1991); and increased kidney weight in female rats at 2500 mg/ kg/day and in male rats at 2,500 mg/kg/day by gavage for 13 weeks. In addition, increased severity of renal proximal tubule degeneration and intracytoplasmic droplets of granules (hyaline droplets) in the proximal tubular epithelium showed a dose-related increase in males at >500 mg/kg/day and in females at 2,500 mg/ kg/day. The kidney lesions seen in both the drinking water study and the gavage study may indicate that acetone enhanced the agerelated nephropathy in rats. No kidney effects were observed in mice given acetone in the drinking water for 13 weeks (NTP 1991). Formate, one of the metabolites of acetone, may be responsible for the nephrotoxicity of acetone (NTP 1991). Thus, species differences exist in susceptibility to acetoneinduced kidney effects. Sex difference also exist; kidney weight increases in female rats at lower doses than in male rats, while histopathological lesions occur in male rats at lower doses than in females. As in the liver, acetone also induced enzymes in microsomes prepared from kidneys of rats and hamsters treated orally with acetone. The increased kidney weights observed in rats and mice might also be associated with an increased amount of protein as a result of enzyme induction. Furthermore, acetone might potentiate the nephrotoxicity of other chemicals, such as chloroform, by increasing the rate of metabolism to reactive intermediate via enzyme induction. Since there is no indication that acetone causes kidney effects in humans or animals exposed by inhalation to nonlethal concentrations, exposure of people to acetone alone in ambient air, in air near hazardous waste sites, or at work sites probably

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poses little risk for the development of nephropathy. Whether levels in water or soil are high enough to increase kidney weight or cause other kidney effects is not known. The relevance of the acetone-enhanced age-related nephropathy seen in male rats treated orally with acetone to humans is not clear. The kidney lesions were seen in male rats, but not female rats or mice of either sex, in the NTP (1991) study. In the American Biogenics Corp. (1986) study, an increased severity of renal lesions was seen in female rats at the highest dose, but the increased severity was dose-related in male rats at lower doses and was associated with hyaline droplet formation. Hyaline droplet formation was not observed in the NTP (1991) study. The presence of hyaline droplets suggests that the renal effects observed in male rats may be associated with á2µ-globulin syndrome, which appears to be specific for male rats, as this protein has not been found in female rats, mice, or humans (EPA 1991a). This low molecular weight protein has been implicated in the mechanism of chemicallyinduced renal toxicity and renal tumor formation in male rats for a number of chemicals. Thus, the renal pathology induced in male rats by acetone exposure may have no relevance to human health. The ability of acetone to induce microsomal enzymes may also pose a concern. Exposure to acetone alone is extremely unlikely in these scenarios, since many other chemicals are also present in air, soil, and water and at hazardous waste sites, and workers could be exposed to other chemicals with nephrotoxic effects that are potentiated by acetone. Such coexposure could make people more susceptible to the nephrotoxicity of these chemicals. Dermal/Ocular Effects. Like many solvents, acetone is irritating to the skin and eyes. Dermal contact with vapors of acetone in air has not been reported to cause dermal effects in humans or animals. No studies were located regarding dermal or ocular effects in humans after oral exposure to acetone. Exposure of humans by direct contact of the skin with liquid acetone for 30 or 90 minutes has resulted in histological and ultrastructural degenerative changes in the epidermis, and frequent dermal contact may cause contact dermatitis in sensitized humans. Oral exposure of animals to acetone in intermediate-duration studies did not cause any histological changes in the skin (NTP

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1991), but dermal exposure of mice resulted in increased DNA synthesis, indicative of irritation, moderate hyperplasia of the epidermis, hyperplasia, dermatitis, and hyperkeratosis; and amyloidosis in the skin. Hairless guinea pigs developed only mild erythema after direct application of acetone to the dorsal thorax.

with soil containing high concentrations of acetone could possibly cause some dermal irritation, but acetone in water would probably be too dilute to irritate the buccal cavity. The relevance of the observed cataract formation and amyloidosis in animals after dermal exposure to acetone to human health is not known.

Like many solvents, acetone is irritating to the eyes. Humans exposed to acetone vapors in the air, either occupationally or in experimental studies, frequently complained of eye irritation. Concentrations of acetone in the air >100 ppm have been reported as irritating to the eyes of humans. Eye irritation has also been observed in animals exposed to acetone vapors, and direct instillation of acetone into the eyes of rabbits has caused reversible cornea1 burns, edema of mucous membranes, severe eye necrosis, and uveal melanocytic hyperplasia. Ocular effects have been observed in animals even after dermal exposure. Application of acetone to shaved skin of guinea pigs, but not rabbits for 3 or 6 weeks resulted in the development of cataracts. Cataracts also occurred in guinea pigs after subcutaneous injection of acetone (3.8 mg/kg) 3 days/week for 3 weeks. The difference in response between the guinea pigs and rabbits reflect species differences in susceptibility to the cataractogenic effects of acetone, as twice as much acetone was applied to rabbits than to guinea pigs. However, no cataracts or lens opacities were found in hairless guinea pigs to which acetone was applied to the skin for 6 months. Genetic differences in susceptibility between hairless and normal guinea pigs was suggested to account for the different results, but was considered to be unlikely. Acetone produced a dose-related increased incidence of opacity in bovine cornea1 preparations in vitro. No cases of cataract formation in humans exposed to acetone by any route were located; therefore, the relevance of these findings to public health is not known. Histological and/or ophthalmoscopic examination of eyes of rats and mice did not reveal any ocular effects in intermediate-duration oral studies.

Other Systemic Effects. No studies were located regarding other systemic effects in humans after inhalation or dermal exposure to acetone, but a case report of man who intentionally drank 200 mL pure acetone (2,241 mg/kg) described the subsequent development of diabetes-like symptoms, such as excessive thirst, polyuria, and hyperglycemia . In an acute study, treatment of fasted or fed rats by gavage with 3,214 mg/kg/day significantly reduced insulin-stimulated glucose oxidation in adipose tissue. The reduction was greater in fasted rats than in fed rats. Acetone is a ketone so exposure can result in ketosis, and fasting can result in further ketosis through the production of ketone bodies in response to low fat intake. Diabetics with ketoacidosis produce more acetone endogenously than nondiabetic people; therefore, the fact that exogenous acetone mimics some aspects of a diabeticlike condition is not surprising.

Eye irritation is a concern for people exposed to acetone vapors occupationally, and splashing of liquid acetone into the eyes may cause cornea1 burns or necrosis, but concentrations of acetone in air in the general environment or near hazardous waste sites are probably not high enough to produce eye irritation. Dermal contact

Most of the information regarding other systemic effects in animals after inhalation and oral exposure relates to body weight changes. Pregnant rats that were exposed to acetone by inhalation at 11,000 ppm during gestation had reduced body weights (NTP, 1988), but no effect on body weight of nonpregnant female rats exposed to 16,000 ppm for 2 weeks was found in another study. Furthermore, maternal body weights of mice were statistically significantly reduced on day 3 postpartum after treatment with 3,500 mg/kg/day acetone by gavage during gestation (EHRT 1987). It is possible that the condition of pregnancy made the rats and mice more susceptible to body weight reduction. Although body weight loss was observed in rats treated by gavage with lethal doses of acetone, no indication of decreased body weight gain unrelated to decreased water consumption was found in animals exposed to acetone in drinking water. The only information on other systemic effects in animals exposed dermally to acetone was the finding of amyloidosis in the adrenals and pancreas of mice and a transient weight loss of 60 g over a 2-week period in

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hairless guinea pigs to which acetone was applied to the skin for 6 months. The relevance of these findings to human health is not known. Exposure to acetone orally or by inhalation may result in ketosis, but whether concentrations of acetone in air, water, or soil in the general environment or at hazardous waste sites would result in appreciable ketosis is not known. Occupational levels could be high enough to produce ketosis. Based on results of animal studies, pregnant women may be susceptible to body weight reduction if exposed to acetone, but it is unlikely that exposure levels in the environment or near hazardous waste sites would be high enough to cause body weight loss. Immunological Effects. Information regarding immunological effects in humans after exposure to acetone is limited. Significantly increased white blood cell counts, increased eosinophil counts, and decreased phagocytic activity of neutrophils were found in volunteers exposed to 500 ppm for a single 6-hour exposure or intermittently for 6 days. A case report of a laboratory technician described the development of acute contact dermatitis from handling acetone 2 years after being treated with squaric acid dibutyl ester in acetone for patchy alopecia areata on her scalp. This acetone sensitization is considered a rare complication of sensitizing therapies for alopecia areata. No studies were located regarding immunological effects in humans after oral exposure or in animals after inhalation, oral, or dermal exposure to acetone. While hematological findings in humans may represent immunological effects, they have not been corroborated. Furthermore, other inhalation studies in humans that examined hematological end points did not find any abnormalities. The development of contact dermatitis in the laboratory technician appears to be an isolated incident, but it is possible that acetone could produce dermatitis in sensitized humans who come in frequent dermal contact with acetone, such as laboratory workers. Neurological Effects. No studies were located regarding neurological effects in animals after dermal exposure to acetone, but acetone exposure by the inhalation and oral routes has resulted in neurological effects, related to the narcotic effects of acetone, in both humans and animals. Patients who were exposed to acetone, mainly by inhalation, during and after the application of hip casts

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with acetone present in the setting fluid became comatose or collapsed. Some dermal exposure could have contributed to the total exposure. Headache, dizziness, weakness, difficulty speaking, and depression were experienced by a woman after an acetonecontaining cast was applied. In addition, drowsiness, fretfulness, irritability, restlessness, uncoordinated hand movement, and nystagmus developed in patients after application of cast where exposure was considered to be mainly dermal. Neurological effects were commonly experienced by workers exposed to acetone in the past. These include headache, lightheadedness, dizziness, unsteadiness, confusion, and unconsciousness, and have been observed at concentrations of acetone >901 ppm in the workplace. Neurobehavioral tests conducted in some of these workers did not reveal any effects of acetone on the parameters examined. Neurological and behavioral effects, such as, lack of energy and weakness, headache, delayed visual reaction time at 250 ppm for 6 hours or 6 hours/day for 6 days; subjective symptoms of tension, tiredness, and annoyance; increases in response and the percent false negatives in auditory discrimination tests and increases in anger and hostility at 237 ppm for 4 hours; and increased visual evoked response at 1,250 ppm intermittently in complex protocol have been documented in volunteers tested under controlled laboratory conditions. Electroencephalography revealed no abnormalities. In volunteers exposed to 21,049-84,194 ppm acetone for l-8 hours, the time to observation of signs of narcosis, loss of righting reflex, and loss of cornea1 reflex decreased as the exposure concentration increased. It should be noted that these concentrations are higher than those resulting in unconsciousness in workers exposed for shorter durations. Several case reports have described patients in unresponsive, lethargic, or comatose conditions after ingesting acetone , but most of these cases are confounded by coexposure to other possible narcotic agents. The lethargic and comatose conditions of these patients was, however, generally attributed to acetone poisoning. Deep coma developed in a man who intentionally ingested about 200 mL of pure acetone (about 2,241 mg/kg). Six days after medical treatment, he was ambulatory but had a marked disturbance of

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gait, which had improved upon follow-up examination 2 months later. Narcotic effects have been observed in animals acutely exposed to acetone vapors. Signs of narcosis, loss of righting reflex, and loss of cornea1 reflex were observed in rats exposed to concentrations of acetone e”10,524 ppm . Drowsiness, staggering, prostration, clonic movements of hind legs, and deep narcosis were observed in mice exposed to 16,839-84,194 ppm. The time to observations of these signs decreased as the concentration of acetone increased. Narcosis as evidenced by decreased respiratory and heart rates, paralysis, and coma were observed in guinea pigs exposed to a lethal concentration (21,800 ppm) continuously for periods of 25 minutes <24 hours. The degree of narcosis increased as the exposure duration increased. Severe narcosis was also observed in mice after a single 6hour exposure to 11,000 ppm (NTP 1988). Neurobehavioral effects, indicative of narcosis, have been observed in rats, mice, and baboons acutely exposed to acetone vapors at exposure levels >150 ppm for baboons. A statistically significant decrease in absolute brain weight was observed, but no histopathological brain lesions, in rats exposed intermittently to 19,000 ppm in an intermediate-duration study. Acetone is also neurotoxic in animals after oral exposure. Death in mice and rats exposed acutely was preceded by prostration. Weakness, depression, and unconsciousness were observed in rabbits dosed orally with 3,922-7,844 mg/kg, with the degree and time to onset dependent on dose. Incoordination, staggering, falling, tremors, delirium, prostration, and coma were observed in dogs and puppies at oral doses of 4,000-8,000 mg/ kg. In intermediate-duration oral studies, reduction in the nerve conduction velocity of rats exposed via drinking water at 650 mg/ kg/day and excessive salivation in rats exposed by gavage at 2,500 mg/kg/day >27 days were found. Absolute brain weight was lower in the gavaged rats at the 13-week sacrifice, but no histopathological lesions were found. No histopathological lesions were found in any of numerous central and peripheral nervous system tissues of rats given 732 mg/kg/day acetone in drinking water for 12 weeks. However, no clinical or histopathological evidence was observed in rats or mice treated with higher doses

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for 13 weeks in the drinking water study, suggesting that the intermittent nature of ad libitum dosing via drinking water did not provide high enough doses, compared with the bolus nature of a gavage dose. The mechanism by which acetone exerts its narcotic effects is not known, but based on the available data, it cannot be attributed to histologically observable changes in the brains of animals or to electroencephalographic changes in humans. As a solvent, however, acetone may interfere with the composition of membranes, altering their permeability to ions . That acetone distributes to the brain was demonstrated in mice. The narcotic effects of acetone are generally reversible. The narcotic effects of acetone represent a concern for public health, particularly in workers exposed occupationally, as occupational exposure in the case above exceeded the timeweighted average standard of 750 ppm, but not the short-term exposure limit of 1,000 ppm (OSHA 1989). Narcotic effects are also of particular concern for accidental ingestion of acetone-containing household products, such as nail polish remover and liquid cement. Levels of acetone in ambient air, soil, or water, or levels present at hazardous waste sites are probably not high enough to cause narcosis or coma, but more subtle neurological and neurobehavioral effects may be of concern. Furthermore, acetone potentiates the neurotoxicity of 2,5-hexanedione by an unknown mechanism. Thus, coexposure to these neurotoxic ketones is of greater concern than exposure to either alone. Reproductive Effects. No studies were located regarding reproductive effects in humans after oral or dermal exposure to acetone. Information regarding reproductive effects in humans after inhalation exposure is limited to reports of premature menstrual periods by 3 of 4 women exposed to 1,000 ppm acetone for 7.5 hours, the lack of a statistically significant increased incidence of miscarriage in female laboratory workers exposed to a variety of solvents, including acetone, and an unreliable report of pregnancy complications in women factory workers exposed to acetone in Russia. Information regarding reproductive effects in animals after inhalation exposure is also limited. In an inhalation developmental

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study in rats and mice, no effects were found on the number of implants/litter, percent live pups/litter, or mean percent resorptions/litter (NTP 1988). No studies were located regarding reproductive effects in male animals, histological effects on reproductive organs of male or female animals, or the reproductive outcomes and other indices of reproductive toxicity in animals after inhalation exposure to acetone. Reproductive effects (reduced reproductive index and increased duration of gestation) were found in pregnant mice exposed orally to 3,500 mg/kg/day during gestation (EHRT 1987). Intermediateduration oral studies have shown that acetone produces reproductive effects in male Sprague-Dawley rats, but not male Wistar rats or male mice. Exposure of male Wistar rats to 1,071 mg/kg/day acetone in drinking water for 6 weeks did not affect successful mating to untreated females, number of pregnancies, number of fetuses, testicular weight, seminiferous tubule diameter, and testicular lesions. However, statistically significantly increased relative testis weight (possibly due to decreased body weight), decreased sperm motility, caudal weight and epididymal weight, and increased incidences of abnormal sperm, but no histopathological testicular lesions, were found in male Sprague-Dawley rats treated with 3,400 mg/kg/day acetone in drinking water for 13 weeks (NTP 1991). As discussed by NTP (1991), these effects on spermatogenesis are similar to those seen in alcoholics, and could be associated with the similarities in metabolism of acetone and ethanol. Vaginal cytology examinations of the female rats revealed no effects, and similar evaluation of male and female mice revealed no effects. While differences in susceptibility might account for the different results in Wistar and Sprague-Dawley rats, the Wistar rats were treated with a lower dose for a shorter duration. However, sex differences in rats, and species differences between male rats and male mice appear to exist. No indication that dermal exposure of female mice results in histopathological effects in reproductive organs was found in an analysis of female SENCAR mice used as acetone controls in a skin painting study of formaldehyde.

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The available data are too limited to predict whether exposure of humans to acetone under any conditions would result in reproductive effects. The finding of shortened menstrual cycles in women has not been corroborated. Developmental Effects. No studies were located regarding developmental effects in humans after oral or dermal exposure to acetone. Information regarding developmental effects in humans after inhalation exposure is limited to a report that found no statistically significant increased incidence of miscarriage, perinatal death rate, or malformations of offspring in female laboratory workers exposed to a variety of solvents including acetone and to an unreliable report of fetal death and low birth weight and length of neonates in female factory workers exposed to acetone in Russia (Nizyaeva 1982). Developmental effects have been found in animals after inhalation and oral exposure. In rats exposed by inhalation to acetone during gestation, the only effect was a statistically significantly decreased mean male and female fetal body weight at 11,000 ppm, the same concentration at which dams displayed reduced body weight during gestation, reduced uterine weight, and reduced extragestational weight (NTP 1988). Mice similarly exposed were more susceptible than rats; at 6,600 ppm, statistically significantly increased incidence of late resorption, decreased fetal weight, and significantly increased incidence of reduced stemebral ossification were observed, along with increased absolute and relative liver weight of dams. Thus acetone produced fetotoxicity in rats and mice at concentrations that were maternally toxic. Developmental toxicity was also found in mice after oral treatment of the dams with 3,500 mg/kg/day during gestation, such as reduced postnatal pup survival and reduced average weight of each live pup/litter on postpartum day 0 (EHRT 1987). Some of the dams treated at this dose displayed neurological signs of toxicity and died. Fetuses or pups were not examined for internal malformations or skeletal anomalies. No studies were located regarding developmental effects in animals after dermal exposure to acetone. Acetone has been tested in attempts to develop in vitro methods for assessing developmental toxicity. Acetone at a concentration

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range of 0.l-1.0% (v/v) in the incubation medium had no effects on growth or malformations of 9.5 day postimplantation rat embryos or on growth and vascularization of the yolk sac (Schmid 1985). Negative results were also obtained for growth of 11 day mouse embryo limb buds at acetone concentrations of 10-100 mg/ mL. However, 10.5 day whole rat embryo cultures failed to grow and differentiate and eventually died at an acetone concentration of 2.5% (v/v). A concentration of 0.5% acetone reduced yolk sac diameter and significantly increased the percentage of abnormal embryos (enlarged pericardium). At 0.1% acetone, abnormal brain development and edematous mandibular arches were also observed. Although results of studies conducted in vitro are difficult to extrapolate to in vivo exposure, acetone and its metabolites were found in fetuses from rats injected intravenously with 100 mg/ kg acetone on gestational day 19, indicating transplacental transfer. Thus, acetone appears to be toxic to rat and mouse fetuses at maternally toxic inhalation concentrations and to developing neonatal mice at maternally toxic oral doses. Mice appear to be more susceptible than rats in in vivo studies. From limited information, acetone does not appear to be teratogenic in animals in in vivo experiments. Whether acetone would cause developmental toxicity in humans under any exposure conditions is not known, but concentrations and doses used in the animal studies were much higher than are likely to be experienced by humans. Genotoxic Effects. No studies were located regarding the genotoxicity of acetone in humans or animals after inhalation, oral, or dermal exposure. The results of in vivo studies conducted by intraperitoneal injection are summarized in Table 2-4. Negative results were obtained in the micronucleus test in Chinese hamsters (Basler 1986) and for cell transformation in fetal cells from pregnant hamsters. In addition, tests for gene mutation in silk worms exposed by an unspecified route were negative. Acetone has been tested for genotoxicity in numerous assays in vitro, and results of representative studies are summarized in Table 2-5. Results were negative for reverse mutation in all tested strains of Salmonella typhimurium, in the ret assay in Bacillus subtilis with and without metabolic activation, and for prophage induction and DNA

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binding in Escherichia coli. However, with enzyme-generated triplet acetone or photo-generated triplet acetone, results were positive for DNA damage in E. coli lambda prophage and DNA chain breaks and thymidine dimers in E. coli. Triplet acetone, which is electronically excited in one of the methyl groups, can be generated by endogenous enzymatic reactions or by photochemical reactions. Thus, the relevance of the DNA damage induced by triplet acetone to human exposure scenarios to acetone is questionable. Results were mixed in fungi, and results for gene mutation were negative in Arubidopsis thaliana seeds. Results have usually been negative in assays for cell transformation, chromosomal aberrations, sister chromatid exchange, colony formation inhibition, and gene mutation in cultured animal cells, and for sister chromatid exchange and unscheduled DNA synthesis in cultured human fibroblasts and skin epithelial cells. However, some positive results were obtained for chromosomal aberrations in Chinese hamster fibroblasts and hamster lung fibroblasts. Acetone also inhibited metabolic cooperation (intracellular communication) in Chinese hamster V79 cells and produced chromosome malsegregation in porcine brain tubulin. The overwhelming evidence is that acetone is, at best, weakly genotoxic. Genotoxicity assay conditions vary widely, and probably account for different results in similar cell systems. Because of its solvent properties and mostly lack of genotoxic effects, acetone is often used as a solvent for testing the genotoxicity of other chemicals and as the solvent control in these assays. Acetone was used as the solvent control to study the promoting activity of 12-O-tetradecanoylphorbol 13-acetate in a 2-stage cell transformation assay in the BALB/3T3 cell line. No indication that acetone promoted the transforming activity of nine known genotoxic and carcinogenic chemicals was found. The weight of evidence for the genotoxicity indicates that acetone poses little threat for genotoxic effects in humans exposed to acetone under any conditions. Cancer. No studies were located regarding cancer in humans after oral or dermal exposure. A retrospective mortality study of workers exposed to time-weighted-average acetone concentrations of 380-1,070 ppm at a cellulose fiber plant where acetone was used

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as the only solvent found no significant excess risk of death from any cause, including malignant neoplasm, compared with rates for the U.S. general population. No studies were located regarding cancer in animals after inhalation or oral exposure to acetone. In an analysis of the histopathology in female SENCAR mice used as acetone controls in a skin painting study of formaldehyde, no neoplastic lesions associated with acetone exposure were found. Furthermore, acetone was negative as a tumor promoter for formaldehyde. In addition, no evidence was found that acetone was a skin carcinogen when used as a negative control for organosilanes or flame retardants in skin painting studies in mice. Acetone was also negative as a tumor initiator and as a tumor promoter for 7,12dimethylbenz[a]anthracene. EPA has classified acetone in Group D, that is, not classifiable as to human carcinogenicity due to the lack of data concerning carcinogenicity in humans and animals (IRIS 1992). Acetone has not been classified by the National Toxicology Program (NTP) or the International Agency for Research on Cancer (IARC). BIOMARKERS OF EXPOSURE AND EFFECT Biomarkers are broadly defined as indicators signaling events in biologic systems or samples. They have been classified as markers of exposure, markers of effect, and markers of susceptibility (NASLNRC 1989). A biomarker of exposure is a xenobiotic substance or its metabolite(s), or the product of an interaction between a xenobiotic agent and some target molecule(s) or cell(s) that is measured within a compartment of an organism (NAS/NRC 1989). The preferred biomarkers of exposure are generally the substance itself or substance-specific metabolites in readily obtainable body fluid(s) or excreta. However, several factors can confound the use and interpretation of biomarkers of exposure. The body burden of a substance may be the result of exposures from more than one source. The substance being measured may be a metabolite of another xenobiotic substance (e.g., high urinary levels of phenol can result from exposure to several different aromatic compounds). Depending on the properties of the substance (e.g., biologic half-

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life) and environmental conditions (e.g., duration and route of exposure), the substance and all of its metabolites may have left the body by the time samples can be taken. It may be difficult to identify individuals exposed to hazardous substances that are commonly found in body tissues and fluids (e.g., essential mineral nutrients such as copper, zinc, and selenium). Biomarkers of exposure to acetone are discussed in Section 2.5.1. Biomarkers of effect are defined as any measurable biochemical, physiologic, or other alteration within an organism that, depending on magnitude, can be recognized as an established or potential health impairment or disease (NAS/NRC 1989). This definition encompasses biochemical or cellular signals of tissue dysfunction (e.g., increased liver enzyme activity or pathologic changes in female genital epithelial cells), as well as physiologic signs of dysfunction such as increased blood pressure or decreased lung capacity. Note that these markers are not often substance specific. They also may not be directly adverse, but can indicate potential health impairment (e.g., DNA adducts). Biomarkers of effects caused by acetone are discussed in Section 2.5.2. A biomarker of susceptibility is an indicator of an inherent or acquired limitation of an organism’s ability to respond to the challenge of exposure to a specific xenobiotic substance. It can be an intrinsic genetic or other characteristic or a preexisting disease that results in an increase in absorbed dose, a decrease in the biologically effective dose, or a target tissue response. If biomarkers of susceptibility exist, they are discussed in Section 2.7, “Populations That Are Unusually Susceptible.”

BIOMARKERS USED TO IDENTIFY OR QUANTIFY EXPOSURE TO ACETONE Acetone concentrations in expired air, blood, and urine have been monitored in a number of studies of humans exposed to acetone in the workplace as well as in controlled laboratory situations, and correlations with exposure levels have been found. However, acetone is cleared from breath, urine, and blood within 1-3 days, so these methods are useful for monitoring only for recent exposure to acetone. In addition, these methods can be used to detect or confirm relatively high exposure to acetone, such as what might occur in the workplace or from accidental ingestion, but they cannot be used to detect exposure in the general population

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at levels reasonably likely to occur outside the workplace. The detection of acetone odor in the breath can alert a physician that a nondiabetic patient has been exposed to acetone. It should be noted that exposure to other chemicals that are metabolized to acetone, such as isopropyl alcohol, could also lead to elevated blood, expired air, or urinary levels of acetone. Levels of endogenous acetone can fluctuate greatly due to normal diurnal variations (Wildenhoff 1972). In addition, physical exercise; nutritional status and fasting; trauma; and pregnancy and lactation place high energy demands upon the body, resulting in increased fatty acid utilization and higher than average blood levels of acetone. Diabetes and alcohol use may result in high levels of endogenous acetone. Infants and young children typically have higher acetone in their blood than adults due to their higher energy expenditure (Peden 1964). These factors and physiological states can complicate measuring acetone levels in blood, breath, and urine for biomonitoring purposes. In a group of 115 workers, alveolar air samples obtained during the workshift were collected at the same time as breathing zone acetone concentrations. The mean ratio of alveolar air acetone and breathing zone acetone was 0.288. Correlations were high between alveolar air concentrations and breathing zone concentrations. Because the alveolar air samples and breathing zone concentrations were collected at the same time, and since the equilibration of alveolar air with environmental air requires some time, the alveolar samples might not necessarily reflect the environmental concentration. Similar results were obtained in a group of 20 workers in a shoe factory in which the mean environmental air concentrations ranged from 10 to 12 ppm at four sampling times. The mean alveolar concentrations ranged from 2.75 to 3.75 ppm at three sampling times during the workshift. The correlation was good between workroom air concentration and alveolar air concentration, indicating that alveolar air concentrations of acetone are useful for monitoring concurrent occupational exposure to acetone. In a group of 110 male workers exposed to acetone for an average of 14.9 years, alveolar air samples were collected before work and at the end of work on 2 consecutive days. The breathing zone concentrations of acetone were measured for each individual with personal monitors and ranged from 0 to

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about 1,200 ppm, with most concentrations between 100 and 500 ppm. The average concentration of acetone in alveolar air before exposure on the first day was 2.95 ppm. Alveolar air concentrations at the end of the workday (range of about 20 to 300 ppm, average not reported) correlated strongly with exposure concentrations (r=0.65). It was estimated that the alveolar air concentrations corresponding to the ACGIH threshold limit value (TLV) of 750 ppm and to the Japan Association of Industrial Health acceptable concentration of 200 ppm were 177 and 56.2 ppm, respectively. Expired air concentrations of acetone have also been studied in volunteers exposed to acetone in controlled laboratory situations. In 11 men and 11 women exposed to 237 ppm acetone for 2 or 4 hours, alveolar breath samples collected immediately after exposure contained mean levels of acetone of 21.5 ppm in those exposed for 2 hours and 25.8 ppm in those exposed for 4 hours. The alveolar air concentrations of acetone dropped to 12.8 ppm by 90 minutes after the 4-hour exposure and to background levels of 0.6 ppm by 20 hours postexposure. In humans exposed to acetone at <1,250 ppm for <7.5 hours/day in a complex protocol for <6 weeks, the rate of respiratory excretion was a function of the duration, and the concentration of acetone in breath after exposure was directly related to the time-average concentration during exposure, with constant duration. The length of time after exposure in which acetone could be detected in breath was related to the magnitude of exposure; acetone was still readily detectable 16 hours after exposure to 1,000 or 1,250 ppm for 7.5 hours. Therefore, breath analysis can be used as a rapid method to estimate the magnitude of recent acetone exposure, but has limited usefulness for more remote exposure because elimination in expired air is generally complete within 1 day. As discussed in Section 2.3.4.1, the level and nature of physical activity, the exposure concentration, the duration of exposure, and gender can influence the rate and amount of acetone elimination in the breath. In general more acetone is expired faster following exposure to high concentrations than to low concentrations. Doubling the duration of exposure almost doubles the total amount of acetone expired. Exercise during exposure eliminates nearly twice the amount in expired air compared with

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exposure to the same concentration at rest, due to increased uptake from increased pulmonary ventilation. Furthermore, exercising at stepwise increments in workload during exposure results in greater respiratory elimination than exercising at a constant workload. Women appeared to expire acetone more slowly than men, but the total expired by women was not statistically significantly different than the total expired by men. Acetone is mainly excreted in the expired air after oral exposure as well as after inhalation exposure. Since urinary clearance of acetone is minimal, the calculated clearance of acetone from the lungs was 29 ml/minute or 0.39 ml/minute/kg for a patient who ingested nail polish remover using an average minute ventilation of 9.65 L/minute based on the patient’s age, weight, and sex. With a volume of distribution of 0.82 L/kg, the calculated half-life was 25 hours. Monitoring of expired air for acetone exposure should take into consideration background levels of acetone, since acetone is produced endogenously in the body, especially during fasting and in diabetics. In addition, the ingestion of ethanol can influence the breath levels of acetone. Endogenous levels of acetone in normal humans averaged 0.56 ppm. Endogenous levels of acetone in alveolar air in a group of volunteers in an experimental study averaged 0.108 ppm. In healthy men who had fasted for 12 hours, the breath acetone levels ranged from 0.96 to 1.7 ppm (Jones 1987). Fasting for 36 hours resulted in average acetone breath levels of 14-66 ppm. However, in fasting men who ingested 0.25 g/kg of ethanol, the breath acetone levels decreased by 40% after a 12hour fast and by 18% after a 36-hour fast (Jones 1988). Acetone is metabolized to carbon dioxide, which is eliminated in expired air. However, since carbon dioxide is the main constituent of normal respired air, expired carbon dioxide has not been monitored to determine acetone exposure. Although unchanged acetone is excreted mainly by the lungs, urinary levels are sufficiently high for monitoring purposes. In a group of 104 workers employed at factories in which breathing zone levels of acetone ranged from <242 to <1,452 ppm, urine was collected before the workshift and 4 hours later. A close correlation was found between the time-weighted average workroom

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concentration and the urinary concentration of acetone. The equation obtained was: urinary concentration (µmol/L) = 0.033x time-weighted average environmental concentration (umol/m3) = 0.005 (r=0.94, n=104). In another study of 28 workers, personal breathing zone monitoring revealed wide variation depending on the type of job and ranged from <1 to 30 ppm. Results of stationary monitoring revealed workroom concentrations ranging from 1.4 to 16.2 ppm. Urine was collected at the end of the workshift, and acetone was detected in the urine of all the workers. The concentration of acetone in urine was linearly correlated with the breathing zone concentration as follows: acetone in urine (mg/L) = 0.10 + 0.40 x breathing zone concentration (ppm) (r=0.90, p15 ppm, but there was no significant difference between background urine levels and preshift urine levels when acetone exposure on the previous day was <15 ppm. In a group of 110 males workers exposed to acetone for an average of 14.9 years, urine samples were collected before work and at the end of work for 2 consecutive days. The breathing zone concentrations of acetone were measured for each individual with personal monitors and ranged from 0 to about 1,200 ppm, with most concentrations between 100 and 500 ppm. The average urinary concentration before exposure on the first day was 2.44 mg/L. Urinary levels at the end of the workshift (range of about 5 to 150 ppm, average not reported) correlated strongly with exposure concentration (r=0.71). It was estimated that the urinary concentrations corresponding to the ACGIH TLV of 750 ppm and to the Japan Association of Industrial Health acceptable concentration of 200 ppm were 76.6 and 21.6 mg/L, respectively. Acetone has also been detected in the urine of 15 subjects exposed to acetone under controlled laboratory conditions. In volunteers exposed to 23-208 ppm for 2-4 hours, the urinary concentrations of acetone immediately after exposure ranged from

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18.8 to 155.2 µmol/L and displayed statistically significant linear relationships with the exposure concentrations. The regression equation for subjects exposed for 2 hours at rest was: acetone in urine (µmol/L) = 0.0125 x environmental concentration (µmol/m3) + 5.87 (r=0.98, n=5). For subjects exposed for 4 hours at rest the equation was: acetone in urine (µmol/L) = environmental concentration (µmol/m3) + 6.97 (r=0.96, n=5). For the subjects exposed for 2 hours with exercise, the equation was: acetone in urine (pmol/L) = environmental concentration (µmol/m3) - 4.52 (r=0.99, n=5). At 4 hours after exposure, the urine concentration increased to 120% of that measured immediately after exposure, then fell to 65% at 7 hours, 45% at 9 hours, 35% at 12 hours, and 15% at 20 hours. Urinary acetone was completely cleared within 20 hours from subjects exposed to 242 or 542 ppm for 2 hours, regardless of whether or not they had exercised during exposure. In a group of subjects exposed to acetone vapors for about 6 hours, urinary levels of acetone peaked within the first hour after exposure to 1.8 mg/dL at 250 ppm, 2.9 mg/dL at 500 ppm, and 5.3 mg/dL at 1,000 ppm and declined rapidly after exposure to control levels within 24, 32, and 48 hours, respectively . In subjects exposed to 250 ppm for 6 hours/ day for 6 days either at rest or during exercise, the urinary levels declined to normal by the next morning each day and within 48 hours after the last exposure day, regardless of whether or not they had exercised. However, in subjects exposed to 500 ppm 6 hours/day for 6 days, the level of acetone in the urine fell each day, but not to background levels. After the last day of exposure, urinary levels declined to background levels within 3 days. Background urinary levels of acetone in these subjects were about 0.1 mg/dL. Therefore, the rate of urinary clearance is dependent on the magnitude of exposure. Acetone can also be detected in urine after oral exposure. In a patient who was admitted to the hospital in a comatose condition after ingesting sake and liquid cement containing 18% acetone (231 mg/kg), urinary clearance of acetone was followed, but after he had been subjected to gastric lavage. Urine levels of acetone decreased gradually from 123 µg/mL at 5 hours after ingestion to about 61 µg/mL at 19 hours. Acetone then disappeared more

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rapidly from the urine. Formic acid was detected in the urine of rats collected for 7 days after exposure to 62,000 ppm acetone in air, and was excreted at a rate of 344 µg formic acid/hour, compared with controls that excreted formic acid at a rate of 144 µg/hour . The authors concluded that the low rate of formic acid excretion by rats suggests that 24 hours is an insufficient period of time for following formic acid excretion in order to biomonitor acetone exposure in humans. Blood levels of acetone can also be useful for exposure monitoring, but blood sampling is less desirable because it is invasive. In a group of 110 males workers exposed to acetone for an average of 14.9 years, blood samples were collected before work on the first day and at the end of work on the second day. The breathing zone concentrations of acetone were measured for each individual with personal monitors and ranged from 0 to about 1,200 ppm, with most concentrations between 100 and 500 ppm. The average blood concentration before exposure on the first day was 3.80 mg/L. Blood levels at the end of the workshift (range of about 2 to 225 mg/L, average not reported) correlated strongly with exposure concentration (r=0.65). It was estimated that the blood concentrations corresponding to the ACGIH TLV of 750 ppm and to the Japan Association of Industrial Health acceptable concentration of 200 ppm were 118 and 41.4 mg/L, respectively. Subjects exposed to 100 or 500 ppm for 2 or 4 hours had a blood acetone clearance half-life of 3 hours. The rate of blood elimination was constant regardless of blood acetone concentration. In volunteers exposed to 237 ppm acetone, blood levels of acetone averaged 2.0 µg/mL preexposure, 9.0 µg/ mL after 2 hours of exposure, 15.3 µg/mL after 4 hours of exposure, 11.9 µg/mL at 90 minutes postexposure, and 1.5 µg/mL at 20 hours postexposure. Therefore, elimination of acetone from blood was complete 20 hours after exposure. Results were similar for subjects exposed to acetone vapors for =6 hours. Maximum blood levels of acetone achieved and blood clearance of acetone were exposure concentration-related, but not in direct proportion. At an exposure level of 250 ppm, the maximum blood level was 2 mg/dL and declined to background level within 24 hours. At an exposure level of 500 ppm, the maximum blood level was 4.7 mg/

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dL and declined to background level within 32 hours. At an exposure level of 1,000 ppm, the maximum blood level of 6.0 mg/ dL declined to background level within 48 hours. In subjects exposed 6 hours/day for 6 days, maximum blood levels on each day were similar to those seen in the subject exposed only 1 day. Blood levels declined to background levels on the morning after exposure on each day when the exposure concentration was 250 ppm. With an exposure concentration of 500 ppm, however, the blood levels declined each day, but not to background levels. As with urinary clearance, blood clearance of acetone at the end of the 6-day exposure period declined to background within 2 days at 250 ppm and within 3 days at 500 ppm. Background blood levels of acetone in these subjects were about 0.1 mg/dL. In subjects exposed to 242 or 542 ppm for 2 hours, the arterial blood concentration 1 hour after exposure plotted as a function of total uptake gave a linear relationship, indicating that an arterialized capillary sample during or after exposure may be useful for exposure monitoring. In humans exposed to acetone <1,250 ppm for <7.5 hours/day in a complex protocol for <6 weeks, the concentration of acetone in venous blood was directly related to the vapor concentration and duration of exposure and inversely related to the time elapsed following exposure. Using a physiologically-based pharmacological model, Leung and Paustenbach (1988) calculated a biological exposure index of 35 mg acetone/L blood for occupational exposure. The authors reported a background acetone blood level of 2 mg/L. This value is in agreement with normal background levels determined in other studies: 0.016 mM (0.93 mgn) (Gavin0 et al. 1986); 0.03 mmol/L (1.74 mg/L); 2100 ppb (2.1 mg/L). Similar rates of blood acetone clearance occur after oral exposure. In a patient admitted to the hospital in a comatose condition after ingesting liquid cement containing 18% acetone (231 mg/kg), the plasma level of acetone was 110 µg/rnL at 5 hours after ingestion and declined to 65 µg/rnL at 18 hours, to 60 µg/mL at 20 hours, and to <5 µg/mL at 48 hours. The gastric contents of a patient were analyzed using infrared spectrophotometry and found to contain 1 mL acetone/100 mL. This analytical method was developed to detect volatile solvents

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in gastric contents due to accidental ingestion of these solvents. Acetone has been identified in breast milk of lactating women. According to the authors, mother’s milk is an attractive medium for biomonitoring purposes because sample collection is reasonably straight-forward, milk contains a high amount of fat, so that fatsoluble pollutants may be found at higher concentrations in milk than in blood or urine, large volumes are easily collected, and the population of nursing mothers is relatively large. A disadvantage is the fact that only young to middle-age females are nursing, making extrapolation to the general population difficult.

BIOMARKERS USED TO CHARACTERIZE EFFECTS CAUSED BY ACETONE The most consistently observed effect of acetone exposure in animals is the induction of microsomal enzymes, particularly of cytochrome P-450IIEl. The enzyme induction has been associated with increased liver weights and hepatocellular hypertrophy due to the increased protein content (NTP 1991). Acetone itself is only moderately toxic to the liver of animals, as most studies have found no clinical or histological evidence of liver damage. However, increased levels of serum alanine aminotransferase, which constitutes clinical evidence of liver damage, have been found in rats in one study. Cytochrome P-450IIEl is associated with the metabolism of acetone itself, but acetone is not metabolized to toxic intermediates . However, the induction of this enzyme by acetone is the mechanism by which acetone potentiates the hepatotoxicity, nephrotoxicity, genotoxicity, and perhaps the reproductive and hematological toxicity of other chemicals. Cytochrome P-450IIEl can be induced by a variety of other factors, such as exposure to ethanol, fasting, and experimental diabetes ; therefore, the induction is not specific to acetone. Moreover, the detection of enzyme induction might require invasive methods, such as liver biopsy. As discussed an in vivo probe is being developed to identify human populations with elevated levels of cytochrome P-45011El. These persons are thought to be at greater risk for developing the carcinogenicities and cytotoxicities related to P-45011El activity. Exposure of animals to acetone has resulted in degeneration of apical microvilli in renal tubules and enhancement of

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nephropathy commonly seen in aging rats (NTP 1991), but these effects have not been associated with increased levels of blood urea nitrogen. As is typical of many organic solvents, acetone is irritating to respiratory mucosa, the skin, and eyes. Acetone exposure can also result in such nonspecific narcotic effects as headache, dizziness, lightheadedness, confusion, unconsciousness, some neurobehavioral and hematological effects, and perhaps menstrual disorders. In addition, patients who had hip casts applied with acetone as the setting fluid became nauseous, vomited blood, and had a strong odor of acetone in the breath. These symptoms were associated with the subsequent development of unconsciousness. The detection of a strong acetone odor on the breath and nausea could alert physicians to the development of more serious sequelae, such as gastrointestinal hemorrhage and narcosis. Since acetone is a ketone, acetone exposure can lead to ketosis and other diabeteslike symptoms in humans and to reduced insulin-stimulated glucose oxidation in animals. Again the detection of a strong odor of acetone on the breath, or high levels of acetone in blood or urine can alert physicians to these effects.

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systems (immune, renal, hepatic) can be found in ATSDR/CDC (1990) and on neurological effects in OTA (1990). INTERACTIONS WITH OTHER SUBSTANCES While acetone by itself is only moderately toxic, it potentiates the toxicity of a variety of chemicals, including halogenated alkanes and alkenes, benzene, dichlorobenzene, ethanol, 2,5-hexanedione, nitrosamines, acetonitrile, and acetaminophen. By far, the most extensively studied interactions are those with carbon tetrachloride and chloroform. In most of the interactions discussed below, acetone exerts its potentiating effect by inducing microsomal mixed function oxidases, in particular cytochrome P-45OIIEl and P450IIEl-dependent enzyme activities, that bioactivate the other chemicals to reactive metabolites.

In male rats, acetone exposure resulted in anemia as detected by hematological parameters, and in increased testis weight, decreased sperm motility, caudal and epididymal weight, and increased incidences of abnormal sperm (NTP 1991). Hematological tests and tests for sperm motility and abnormalities could be used to screen humans for possible hematological and fertility effects. Dermal exposure of humans to acetone irritated the skin, which when examined by light and electron microscopy, showed signs of degenerative changes in the epidermis. Decreased protein synthesis was also found. Overt signs of skin irritation could alert physicians to possible degenerative changes. Allergic reactions to acetone can be detected by patch testing.

Halogenated Alkanes and Alkenes. No studies were located regarding the effects of coexposure of humans to acetone and carbon tetrachloride. However, acetone, a metabolite of isopropyl alcohol, was implicated in a study of workers in a isopropyl alcohol packaging plant who became ill after accidental exposure to carbon tetrachloride. Fourteen workers became ill (nausea, vomiting, headache, and weakness or abdominal pain, dizziness, diarrhea, and blurred vision). Workers in closer proximity to isopropyl alcohol were especially affected. Renal failure and hepatitis developed in 4 of the workers with closer proximity to isopropyl alcohol. Expired air samples taken subsequently from workers during isopropyl alcohol bottling revealed strikingly elevated levels of acetone (mean = 19 ppm in workers on the bottling line and 7.5 ppm in more remote workers). The blood acetone levels were 3-30 times higher than the normal range. Thus it appeared that isopropyl alcohol, by way of acetone, predisposed the workers to the hepatotoxicity and renal toxicity induced by carbon tetrachloride.

As most of the effects of acetone are not specific to acetone, there is no reliable biomarker of effect that can be used to detect or screen for possible effects from exposure to acetone at levels reasonably likely to occur outside the workplace or from accidental ingestion. For more detailed discussion of the effects caused by acetone. Further information on biomarkers for specific organ

The potentiation of carbon tetrachloride-induced hepatotoxicity and renal toxicity by acetone has been well documented in rats. Pretreatment of rats by gavage with acetone enhanced the hepatotoxicity of carbon tetrachloride, as evidenced by the statistically significantly increased relative liver weights, increased severity of histopathological lesions (necrosis,

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hepatocellular swelling, lipid droplets), activities of serum alanine aminotransferase and ornithine carbamoyltransferase, the serum concentration of bilirubin, and/or the liver concentration of triglycerides compared with the liver toxicity induced by carbon tetrachloride alone in several studies. Acetone treatment alone had no effect on these parameters. The potentiation increased in a doserelated manner at single doses of acetone >0.25 mL/kg (>196 mg/kg); doses of <0.10 mL/kg (<78 mg/kg) are ineffective. In rats given the minimal effective dose of acetone (196 mg/kg) twice daily for 3 days (total dose 1,177 mg/kg), carbon tetrachloride-induced liver toxicity was further enhanced over that of a single dose of 196 mg/kg acetone. However, the repetitive dose of acetone (6x196 mg/kg = 1,177 mg/kg) potentiated the liver toxicity of carbon tetrachloride to a lesser extent than a single dose of 1,177 mg/kg. Administration of the noneffective dose (78 mg/kg) twice a day for 3 days (total dose 468 mg/kg) did not affect the liver toxicity of carbon tetrachloride, even though the cumulative dose of 468 mg/kg, if given as a single dose, would have been high enough to cause significant potentiation. When a dose of acetone of 1.5 mL/kg (1,177 mg/kg) was given once, divided into 6 doses of 0.25 mL/kg (196 mg/kg) over 3 days (cumulative dose 1,177 mg/kg) or into 12 doses of 0.125 mL/kg (98 mg/kg) over 3 days (cumulative dose 1,177 mg/kg), or infused intravenously over 3 days, before challenge with carbon tetrachloride, the most severe potentiation occurred with the single dose, followed by 6 divided doses, and, then by 12 divided doses. The intravenous infusion did not enhance the toxicity of carbon tetrachloride. The maximum blood levels calculated from pharmacokinetic parameters for the different acetone treatment regimens showed a direct relationship with the degree of potentiation. The results indicate that threshold blood, and hence liver, concentrations must be exceeded before potentiation occurs. Acetone pretreatment also prolonged the liver toxicity induced by carbon tetrachloride and decreased the recovery time. With carbon tetrachloride alone, the severity of liver toxicity increased temporally in rats sacrificed 24 and 48 hours after dosing, but liver toxicity was no longer observed at 96 hours.

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Following pretreatment with acetone, the liver toxicity induced by carbon tetrachloride was enhanced and increased in severity at all sacrifice times, even at 96 hours. Gavage pretreatment of rats with 1,452 mg/kg/day acetone in corn oil twice weekly for <12 weeks, followed by carbon tetrachloride challenge, resulted in decreased body weight gain and 35% mortality, compared with no effect on body weight gain and 5% mortality in rats given corn oil and challenged with carbon tetrachloride. The acetone plus carbon tetrachloride treated rats also had statistically significantly decreased relative liver weights and statistically significantly increased kidney weights at all four sacrifice times, compared with corn oil plus carbon tetrachloride rats. Bilirubin concentrations and collagen content were also enhanced. Histological examination revealed fully developed cirrhosis in the acetone plus carbon tetrachloride rats, compared with less severe cirrhosis in the corn oil plus carbon tetrachloride rats. Renal toxicity was also enhanced, as evidenced by statistically significantly elevated blood urea nitrogen levels in the acetone pretreated rats, compared with corn oil pretreated rats. It should be noted that acetone displays a greater degree of potentiation when it is administered in corn oil than in water, and it appears that corn oil alone can be toxic to the liver. Inhalation exposure of rats to acetone vapors also displays a threshold effect. In rats exposed to 1,000, 2,500, 5,000, 10,000, or 15,000 ppm acetone for four hours, and challenged 18 hours later with carbon tetrachloride, the liver toxicity of carbon tetrachloride was enhanced in a concentration-related manner at >2,500 ppm acetone. The noneffective concentration was 1,000 ppm. No cumulative effect of repetitive inhalation exposure to acetone on the carbon tetrachloride-induced liver toxicity was found, but maximum blood levels of acetone correlated with the degree of potentiation. When rats were challenged with a mixture of trichloroethylene and carbon tetrachloride, the minimal effective dose of acetone required to enhance the liver toxicity of carbon tetrachloride decreased at least five-fold, indicating that mixtures of haloalkanes can cause severe liver injury, and prior exposure to acetone can markedly affect the response produced by the mixtures. The

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mechanism of acetone potentiation of carbon tetrachloride-induced liver toxicity involves the induction of mixed function oxidase microsomal enzymes. In microsomes prepared from rats treated by gavage with acetone at 2.5 mL/kg (1,961 mg/kg) and incubated with 14C-carbon tetrachloride, covalent binding of radioactivity to microsomal protein increased 3-4 times that of control microsomes. The time course followed the increased activity of N-nitrosodimethylamine N-demethylase, indicating enzyme induction. Furthermore, aminothiazole, an inhibitor of cytochrome P-450 and mixed function oxidase induction, reduced the potentiation by acetone of carbon tetrachloride-induced liver toxicity. More recent studies have indicated that the effects of acetone on the toxicity of carbon tetrachloride are caused by induction of cytochrome P-450 forms belonging to at least two gene subfamilies, i.e., P-45011B and P-45011E. Complementary DNA and protein sequencing analyses have shown that these P450 gene subfamilies are similar in rats and humans. Acetone treatment caused a nine-fold increase in cytochrome P-450IIEl accompanied by a similar increase in the rate of nicotinamide adenine dinucleotide phosphate (NADPH)-dependent metabolism of carbon tetrachloride. Acetone treatment also increased the amount of messenger ribonucleic acid (mRNA) and apoprotein of P-450IIBl l0- to 30fold, suggesting regulation of cytochrome P-450IIBl at the transcriptional level. mRNA coding for P-45OIIEl was increased by a combination of fasting and acetone treatment, but not by treatment with acetone alone. The results suggested an enhanced rate of P-45OIIEl gene transcription, P-450IIEl mRNA stabilization, or other posttranscriptional mechanisms. The exact mechanism by which acetone increases the P-450 subfamilies is a subject of recent and on-going investigations. The findings that pretreatment of rats or rabbits with acetone results in increases in cytochrome P-45OIIEl and associated enzyme activities, but has no effect on the level of P-450IIEl mRNA suggests that regulation of acetoneinduced P-450IIEl occurs at the posttranscriptional level. In microsomal and ribosomal preparations from rats administered acetone intraperitoneally, the polyribosomal distribution of cytochrome P-45OIIEl mRNA shifted, compared with controls,

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suggesting that the induction of P-45OIIEl by acetone involved enhanced translation efficiency through increased loading of ribosomes of P-45OIIEl mRNA. However, in another study, incorporation of 3H-leucine into P-45OIIEl in microsomes from rats treated with acetone was lower than that in control microsomes, but the rate of translation of the P-450IIEl mRNA was about the same in both sets of microsomes, indicating that P-45OIIEl is not induced by an increase in the rate of translation of its mRNA. Furthermore, incorporation of NaH14C03 was three-fold less in acetone induced P-450IIEl protein than in controls. The rate of disappearance of radiolabel from P45OIIEl in controls was biphasic, with half-lives of 7 and 37 hours for the fast and slow phase, respectively. However, in acetonetreated rats, the fast phase was absent, with a monophasic halflife of 37 hours. These results demonstrated that the induction of P-450IIEl by acetone is due primarily to protein stabilization. In microsomes and lysosomes from rats treated with acetone, cytochromes P-45OIIEl and P-450IIBl increased, but the increase was greater in microsomes. Quantification of the proteins in lysosomes indicated that P-450IIEl and P-450IIBl are degraded via an autophagosomal/autolysosomal pathway. The authors speculated that P-450IIEl is catalytically inactivated in microsomes prior to degradation in lysosomes and that acetone may interfere with the inactivation. Thus, the induction P-450IIBl appears to occur at the transcriptional level, while the induction of P-450IIEl by acetone appears to occur through stabilization of the apoprotein. In contrast, pretreatment of mice with carbon tetrachloride enhanced the toxicity of acetone. In mice intraperitoneally pretreated with olive oil, the oral LD50 of acetone was 5,250 mg/ kg, while in mice pretreated with a 20% solution of carbon tetrachloride in olive oil reduced the LD50 of acetone to 4,260 mg/ kg. The dose of carbon tetrachloride alone did not result in any death. The authors suggested that carbon tetrachloride inactivated the microsomal monooxygenase system, thereby inhibiting the inactivation of acetone. Acetone also potentiates the hepato- and nephrotoxicity of chloroform. Pretreating rats with 15 mmol/kg (871 mg/kg) acetone in corn oil by gavage 18 hours prior to a challenge dose of 0.5 mL/

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kg chloroform in corn oil statistically significantly increased the relative kidney weight, inhibited lactate stimulated accumulation of p-aminohippurate and the accumulation of tetraethylammonium ion in kidney slices, and resulted in vacuolar degeneration in the tubular epithelium, but not necrosis, compared with corn oil controls. No effects on these parameters were observed with acetone alone or in rats pretreated with corn oil and challenged with chloroform. Acetone pretreatment also statistically significantly increased the plasma activities of alanine aminotransferase (32-fold) and ornithine carbamoyltransferase (134-fold), compared with corn oil pretreated controls challenged with chloroform, and caused balloon cells with pyknotic nuclei in the centrilobular region of the liver. Acetone alone and chloroform alone did not cause liver lesions. In rats treated by gavage with acetone in corn oil at 58, 290, 436, 581, 726, or 871 mg/kg and challenged with 0.5 mL/kg chloroform in corn oil, acetone showed a dose-dependent decrease in p-aminohippurate uptake and an increase in plasma creatinine levels, with maximum effects seen at doses between 290 and 581 mg/kg acetone. Renal necrosis, hyaline bodies, and/or tubular casts were seen in 3/6 rats at 58 mg/kg acetone and in 4/6-5/ 6 rats at higher doses. Acetone pretreatment also statistically significantly increased plasma activities of alanine aminotransferase at >290 mg/kg. Balloon cells and necrosis were observed in 216 rats pretreated with 58 mg/kg and in most of the rats pretreated with >290 mg/kg. The effects of acetone pretreatment and chloroform challenge were greater than the effects of corn oil pretreatment and chloroform challenge. Pretreating rats by gavage with 0.5 mL/kg acetone (871 mg/kg) in corn oil prior to a challenge dose of chloroform (0.5 mL/kg) in corn oil statistically significantly increased the plasma activities of alanine aminotransferase and ornithine carbamoyltransferase above that seen in rats pretreated with corn oil and challenged with chloroform, and the potentiation was maximal at 18 hours. Microsomes from the acetone treated rats showed increased activities of ethoxycoumarin O-deethylase and NADPH-dependent cytochrome c reductase and statistically significantly increased rates of covalent binding of radioactivity

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from 14C-chloroform in the reaction medium, compared with control microsomes. Results were similar with microsomes prepared from rats treated by gavage with 2.5 mL/kg (1,961 mg/kg) acetone in corn oil. Acetone enhanced the covalent binding of radioactivity of 14C-chloroform two-fold compared with control microsomes and increased the activity of N-nitrosodimethylamine N-demethylase, an activity associated with cytochrome P-450IIEl. Thus, acetone increased the biotransformation of chloroform. The involvement of cytochrome P-450IIEl was confirmed with microsomes from rats given a gavage dose of acetone (871 mg/ kg) in corn oil. Acetone statistically significantly increased the cytochrome P-450 content, the activity of N-nitrosodimethylamine N-demethylase, and the content of cytochrome P-450IIE1, but not P-450IIB1, compared with control microsomes. Furthermore, no effect was seen on the activity of benzphetamine demethylase, an activity associated with P-45011B 1. The acetone-induced microsomes also showed a three-fold enhancement of P-450IIEldependent chloroform metabolism, but the activity required the presence of cytochrome b5 No increased P-45011B l-dependent metabolism was seen. The involvement of P-450IIEl was further demonstrated by inhibition of the reaction with a monoclonal antibody to P-450IIEl and by alternate substrates for P-450IIE1, such as, pyrazole, benzene, nitrosodimethylamine, and diallyl sulfate. Acetone also potentiates the toxicity of other halogenated alkanes. In rats injected intraperitoneally with acetone in saline at doses of 581, 1,162, 1,742, or 2,323 mg/kg 48 hours prior to a gavage dose of dichloromethane (0.4 mL/kg), statistically significantly increased blood levels of carboxyhemoglobin were observed at 21,742 mg/kg acetone, compared with controls challenged with dichloromethane. The results indicated that acetone increased the metabolism of dichloromethane to carbon monoxide. Results obtained with fasting rats or rats pretreated with isoniazid, which also induces cytochrome P-450IIE1, produced similar potentiation of dichloromethane-induced carboxyhemoglobinemia, thus implicating induction of cytochrome P-450IIEl as the mechanism whereby acetone increased the metabolism of dichloromethane to carbon monoxide.

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While neither bromodichloromethane or dibromochloromethane were hepatotoxic (assessed by relative liver weight and plasma activities of alanine aminotransferase and ornithine carbamoyltransferase) in rats at the sublethal doses used, acetone pretreatment at 871 mg/kg by gavage in water resulted in liver toxicity at lower challenge doses of these compounds compared to the doses that produced toxicity when these compounds were administered without acetone pretreatment. Neither bromodichloromethane or dibromochloromethane alone displayed appreciable toxicity to the kidney (assessed by relative kidney weight, accumulation of p-aminohippurate and tetraethylammonium ion in kidney slices, and blood urea nitrogen). However, pretreatment with acetone resulted in statistically significantly increased kidney weight, inhibition of paminohippurate uptake, and increased levels of blood urea nitrogen after challenge with bromodichloromethane. With a challenge dose of dibromochloromethane, only blood urea nitrogen was significantly increased by acetone pretreatment. Acetone pretreatment of rats by gavage at doses of 196 and 392 mg/kg, prior to challenge with 1,1,2-trichloroethane, potentiated 1,1,2trichloroethane-induced increased activity of plasma alanine aminotransferase. However, higher pretreatment doses of acetone did not potentiate the toxicity and may have decreased the severity. Pretreatment of rats with acetone (392 mg/kg) followed by a challenge dose of 14C-1,1,2-trichloroethane did not increase covalent binding of radioactivity to microsomal proteins but resulted in a greater decline in the content of reduced glutathione. When 14C-trichloroethane was added in vitro, covalent binding of the radiolabel statistically significantly increased in microsomes from rats treated with acetone, compared with control microsomes. The in vitro covalent binding was inhibited 80% by the addition of reduced glutathione. It was suggested that acetone alters the bioactivation and the detoxication of 1,1,2-trichloroethane, but the exact mechanism is unclear. Acetone also potentiated the hepatotoxicity of chlorinated alkenes. Inhalation exposure of rats to 10,000 ppm acetone vapor for 2 hours prior to or during concomitant inhalation exposure to

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2,000 ppm 1,l -dichloroethene resulted in statistically significant increased activity of serum alphaketoglutarate transaminase, compared with that induced by l,l-dichloroethene alone. A biphasic pattern of potentiation of the liver toxicity induced by l,ldichloroethene was observed in rats pretreated orally with acetone at several dose levels. At doses of 290 and 581 mg/kg acetone prior to challenge with 1,l-dichloroethene, statistically significantly increased activities of plasma alanine aminotransferase and ornithine carbamoyltransferase were observed, compared with water pretreated rats challenged with 1,l-dichloroethene. At higher pretreatment doses of acetone (>871 mg/kg), the effect on these parameters diminished and acetone appeared to have a protective effect. Treatment of rats with l,l-dichloroethene did not result in any evidence of nephrotoxicity, but acetone pretreatment statistically significantly reduced the accumulation of tetraethylammonium ion in kidney slices. The biphasic pattern of potentiation/protection may be related to alterations in the rate and/or pattern of l,l-dichloroethene bioactivation, such as, bioactivation to reactive intermediates or decreased detoxication by decreasing hepatic glutathione levels at the potentiating doses of acetone. Benzene. Although potentiation of benzene toxicity by acetone has not been specifically tested, microsomes from rats treated with acetone (3,922 mg/kg) for 1 or 2-days produced a <9-fold increase in the rate of NADPH-dependent oxidation of benzene and induced cytochrome P-450, in particular cytochrome P-450j (cytochrome P-450IIEl). Addition of inhibitors of P-450IIEl inhibited the oxidation of benzene in microsomes from acetone treated rats, providing further evidence that this form of cytochrome P-450 is involved. In addition, antibodies to rabbit cytochrome P-450LMeb (IIEl) and rat cytochrome P-450j (IIEl) inhibited the oxidation of benzene by 80-100% in microsomes prepared from rabbits and rats treated with acetone. In hepatocytes from rabbits given acetone (863 mg/kg/day) in drinking water for 7 days, immunoblot analysis identified three distinct cytochromes: P-450IIE1, P-450IA1, and P-450IA2. In bone marrow cells from the treated rabbits, P450IIEl and P-450IAl were identified. Quantitative analysis revealed that acetone treatment

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resulted in a 7.3-fold induction of P-450IIEl in liver and a 12.9fold induction of P-450IIEl in bone marrow cells. Acetone slightly decreased the concentration of cytochrome P-450 reductase in bone marrow, and increased the ratio of P-450IIEl to reductase by 16.4 times and the ratio of P-450IAl to reductase by 2 times. Hepatic microsomes from acetone-treated rabbits were 4.8 times more active than control microsomes in benzene hydroxylation, an activity of P-450IIEl. Acetone-induced marrow microsomes were 9.4 times more active in benzene hydroxylation. Thus, the stimulation of benzene metabolism by acetone occurs by a mechanism similar to that of the stimulation of carbon tetrachloride metabolism by acetone. The results suggest that acetone may potentiate the toxicity of benzene, since bioactivation is required for the expression of hematotoxicity of benzene . It should be noted that commercial acetone contains 30 ppm benzene (Union Carbide 1992). Dichlorobenzene. Inhalation exposure of rats to acetone vapors at 4,785, 10,670, or 14,790 ppm for 4 hours increased the cytochrome P-450 contents and the activity of glutathione-Stransferase, with the greatest increases occurring at the 4,785 ppm level. When the rats were challenged 18 hours later by inhalation exposure to 1,2-dichlorobenzene, the level of P-450 and the activity of glutathione-S-transferase was no different from that seen with acetone alone. However, acetone preexposure potentiated the liver toxicity of 1,2-dichlorobenzene at the lowest exposure, reduced it at 10,670 ppm, and suppressed it at 14,790 ppm. In mice exposed to 6,747, 8,910, or 14,345 ppm acetone for 4 hours, followed by a challenge by l,2-dichlorobenzene, acetone preexposure caused an interactive glucose-6-phosphatase response in the mediolobular area of the liver. It was suggested that, at low concentrations, acetone induces the microsomal enzymes that convert 1,2dichlorobenzene to toxic intermediates. However, since the glutathione-S-transferase activity did not increase in rats preexposed to acetone and challenged with 1,2dichlorobenzene, the diminished liver toxicity induced by 1,2dichlorobenzene after preexposure to the higher concentrations cannot be explained by detoxification via enhanced glutathione conjugation. Instead, two microsomal enzymes may be involved,

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in which, at low concentrations of acetone, one (activating) enzyme is induced, but at higher concentrations concomitant induction of the second enzyme system could result in protection. Ethanol. Acetone potentiated the central nervous system toxicity of ethanol in mice. Mice were pretreated with an intraperitoneal injection of acetone in corn oil at 581, 1,162, or 2,323 mg/kg, and 30 minutes later injected with 4,000 mg/kg ethanol. At 1,162 and 2,323 mg/kg, acetone statistically significantly prolonged the duration of the loss of righting reflex induced by ethanol. In mice given 2,323 mg/kg acetone prior to 2,000 mg/ kg ethanol, the blood level of ethanol was statistically significantly higher at all time intervals measured, and acetone pretreatment significantly decreased the mean elimination rate of ethanol. In vitro, acetone inhibited the activity of liver alcohol dehydrogenase, a reaction responsible for 90% of ethanol elimination. It was suggested that acetone produced a prolongation of the central nervous system toxicity of ethanol by reducing its elimination. Other Ketones. The neurological and reproductive effects of coexposure to acetone and 2,5-hexanedione has been studied in animals. In rats exposed to 0.5% 2,5-hexanedione, 0.5% acetone (650 mg/kg/day), or to a combination of 0.5% 2,5-hexanedione and 0.5% acetone in drinking water for 6 weeks, peripheral motor nerve conduction velocity was measured weekly from the third week of dosing. Acetone alone reduced the nerve conduction velocity compared with controls only at 6 weeks, while 2,5hexanedione alone significantly reduced it from the third week on. The combination treatment resulted in a statistically significantly greater reduction than seen with 2,5-hexanedione alone on the fourth and sixth week. Acetone alone had no effect on balance time in the rotorod test, but balance time was statistically significantly reduced from the second week with the combination treatment, and the reduction was greater than that with 2,5hexanedione alone from the fourth week on. In a similar dosing regimen for 7 weeks, coexposure to 2,5-hexanedione and acetone statistically significantly inhibited acquisition, but not performance of spatial learning, (assessed in the radial arm maze) above that seen with 2,5-hexanedione alone. Brain weights of rats exposed

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to 2,5-hexanedione alone or to the combination were significantly reduced, with greater reduction in the coexposed group. Both treatments reduced synaptosomal 5-hydroxytryptamine uptake rate, but the combination treatment did not reduce the uptake below that seen with 2,5-hexanedione alone. In a companion report of these treatment groups, there was no significant difference on the number and size of neurons in the cerebral cortex between rats treated with 2,5-hexanedione alone or rats coexposed to 2,5hexanedione and acetone. Acetone alone had no effect on indices of fertility in male rats but potentiated the reproductive toxicity of 2,5-hexanedione when coadministered, compared with that seen with 2,5-hexanedione alone. The rats were exposed to drinking water containing 0.13%, 0.25%, or 0.5% 2,5-hexanedione or in combination with 0.5% acetone for 6 weeks. Fertility was assessed by mating the exposed males with nonexposed females. 2,5-Hexanedione alone or the combination had no effects on the number of matings. 2,5Hexanedione alone at 0.5% statistically significantly decreased the number of pregnancies, the number of fetuses, and the testicular weight. The combination treatments further reduced all indices, and at 0.5% 2,5-hexanedione plus 0.5% acetone, complete infertility occurred. Morphological assessment of the testes revealed mild to moderate vacuolization, chromatin margination, epithelial disruption, multinucleated giant cells, and/or atrophy in rats exposed to 2,5-hexanedione alone after 6 weeks of treatment, and the combination increased the severity of these lesions. When assessed 10 weeks after the end of treatment, the lesions were still present. The mechanism by which acetone potentiates or adds to the toxicity of 2,5-hexanedione in rats is not known, but coexposure of rabbits to 2,5-hexanedione and acetone altered the pharmacokinetic parameters of 2,5-hexanedione. The combined treatment decreased the body clearance of 2,5hexanedione, compared to the clearance of 2,5-hexanedione alone. In a neurobehavioral study in volunteers, 11 men and 11 women exposed to 237 ppm acetone, 12 men and 13 women exposed to 200 ppm 2-butanone (methyl ethyl ketone), and 8 men and 13 women exposed simultaneously to acetone (125 ppm) and 2butanone (100 ppm) for 4 hours were subjected to psychomotor

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tests (choice reaction time, visual vigilance, dual task, memory scanning), sensimotor tests (postural sway), and psychological tests (profile of mood states). Acetone exposure alone produced small, but statistically significant changes in performances from controls in two measures of auditory tone discrimination (increase response time and increase false alarm) and hostility in men only. Neither 2-butanone alone or the combination of acetone and 2butanone produced any statistically significant changes. Furthermore, no interactions between acetone and 2-butanone on the uptake or elimination of acetone or 2-butanone were found in the same human subjects. From this limited information, it appears that acetone and 2-butanone do not interact to produce neurological effects. Styrene. Although no studies were located regarding interactions between acetone and styrene in the expression of toxic effects in animals, several studies have reported that coexposure to acetone and styrene produce different changes in the content or activity of biotransformation enzymes in the liver and lungs, compared with the changes seen with styrene alone. However, in humans subjects exposed for 2 hours to 293 mg/m3 styrene alone or to a mixture of 301 mg/m3 styrene and 1,240 mg/ m3 (517 ppm) acetone, there was no indication that acetone alters the uptake, distribution, metabolism, or elimination of styrene. Nitrusamines. Acetone potentiated the hepatotoxicity of Nnitrosodimethylamine in rats pretreated by gavage with 2.5 mL/ kg (1,961 mg/kg) acetone in water 24 hours prior to a challenge intraperitoneal dose of 75 mg/kg N-nitrosodimethylamine (Lorr et al. 1984). The acetone pretreatment doubled the plasma activity of alanine aminotransferase (p<0.005) and increased the extent and severity of liver necrosis and hemorrhage, compared with that seen with N-nitrosodimethylamine alone. Microsomes prepared from rats treated with N-nitrosodimethylamine had diminished N-nitrosodimethylamine- N-demethylase activity, compared with microsomes from untreated mice. The results indicate that N-nitrosodimethylamine N-demethylase, an activity associated with cytochrome P-450IIE1, is responsible for the activation of N-nitrosodimethylamine to a toxic intermediate, and that the induction of this enzyme by acetone potentiates the

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hepatotoxicity. Microsomes from mice given 2,614 mg/kg acetone increased the covalent binding of radioactivity from [14C]-Nnitrosodimethylamine to microsomal DNA, RNA, and protein. Microsomes from rats pretreated with acetone had a four-fold increased activity of N-nitrosodimethylamine demethylase and a six-fold increase in DNA methylation compared with control microsomes. Several studies have shown that acetone given to rats or mice enhances the microsomal activity of Nnitrosodimethylamine N-demethylase in a dose-related manner, and this activity is associated with cytochrome P-450, in particular cytochrome P-45OIIEl . Acetone pretreatment of rats also enhanced the denitrosation of N-nitroso-dimethylamine in microsomes, and antibodies against cytochrome P-450IIEl inhibited this activity. Similar results were obtained with N-nitrosodiethylamine deethylation and denitrosation. The rates of both types of reactions depended upon the concentration of the nitrosamine in the reaction mixture, leading to the conclusion that P-45OIIEl has a role in the metabolism of low concentrations of these nitrosamines, and that this form of the enzyme is important in the carcinogen activation. In Ames assays, addition of acetone to the S-9 mix inhibited the mutagenicities of N-nitrosodimethylamine, Nnitrosodiethylamine, 6 derivative of N-nitrosopropylamine, and N-nitroso- 2,6-dimethylmorpholine in S. typhimurium Tal00 at a concentration of <5.2 mg/0.l mL (52,000 mg/L) nitrosamines. Acetone also inhibited the metabolism of N-nitrosodimethylamine, N-nitrosomethyl (2-hydroxypropyl)amine, and N-nitrosomethyl (2-0xopropyl)amine in vitro. In contrast, another study found that the S-9 mix prepared from mice treated with acetone strongly enhanced the mutagenicity of N-nitrosodimethylamine in the Ames assay in S. typhimurium TA92, which was more sensitive to N-nitrosodimethylamine than TAl00. This assay used concentrations of the nitrosamine at <20 mM (1,491 mg/L). However, acetone did not enhance the mutagenicity in the host-mediated assay. The authors explained that in vitro, the activity of the dilute metabolizing system is limiting for the activity of Nnitrosodimethylamine, such that induction increases mutagenicity, whereas in vivo, N-nitrosodimethylamine is completely metabolized in both induced and noninduced animals. The reason

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for the different effects of acetone on the mutagenicity of nitrosamines in the studies by Mori et al. (1985) and Glatt et al. (1981) could be related to differences in the assay system (e.g., acetone added to medium versus acetone-induced S-9), to the difference in concentration of the nitrosamines, or to the different strains of S. typhimurium. Microsomes from rats pretreated with acetone increased the activity of N-nitrosodimethylamine demethylase and increased the mutagenicity of Nnitrosodimethylamine in Chinese hamster lung V79 cell cultures at low substrate concentrations (0.1 and 4 mM or 5.8 and 232 mg/ L) compared with untreated microsomes. However, a slight decrease in mutagenic activity was found at a Nnitrosodimethylamine concentration of 200 mM (11,616 mg/L). Acetone induced microsomes also enhanced the mutagenic activity of N-nitrosomethylethylamine, N-nitrosodiethylamine, and Nnitrosomethylbutylamine, but not N-nitrosomethylbenzylamine or N-nitrosomethylaniline. The findings that lower concentrations enhanced the mutagenicity of N-nitrosodimethylamine are consistent with the conclusions of Yoo et al. (1990) that cytochrome P-450IIEl is important in the activation of the carcinogen at low concentrations. Acetonitrile. Acetone also potentiates the toxicity of acetonitrile. When rats were given a 1:l mixture of acetone plus acetonitrile by gavage, the acute LD50 was 3-4 times lower than the predicted LD50 for additive toxicity. The LD50 values of these chemicals alone were 5,800 mg/kg for acetone and 4,050 mg/kg for acetonitrile, while the LD50 for the mixture was 1,160 mg/kg, compared with the predicted value of 4,770 mg/kg. However, deaths occurred later with the mixture than with either acetone or acetonitrile alone. Blood cyanide (a toxic metabolite of acetonitrile) levels were higher, but peaked at a later time, in the rats given the mixture than in those given acetonitrile alone. Administration of a second dose of acetone 30 hours after administration of the mixture protected the rats from lethality to a degree similar to that seen with a dose of sodium thiosulfate (an antidote used for cyanide poisoning). It was suggested that, initially, acetone competitively inhibits the metabolism of acetonitrile to cyanide but later induces an isoenzyme of

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cytochrome P-450 that catalyzes the metabolism of acetonitrile to cyanide, hence explaining the greater toxicity of the mixture seen at a later time. To test this hypothesis, the metabolism of acetonitrile by microsomes from rats treated with acetone at the same dose that potentiated the toxicity was compared with that by noninduced microsomes. The metabolism of acetonitrile required oxygen and NADPH and was inhibited by known inhibitors of cytochrome P-450. Microsomes from acetone pretreated rats increased the Vmax, while acetone added to the reaction mixture in vitro competitively inhibited the conversion of acetonitrile to cyanide. The in vitro metabolism of acetonitrile was competitively inhibited by ethanol, which also induces cytochrome P-450IIE1, by dimethyl sulfoxide, which inhibits cytochrome P-450IIEl-dependent metabolism of ethanol, and by aniline, a substrate for P-45011El. Thus, the mechanism for the potentiation of the toxicity of acetonitrile by acetone also appears to involve cytochrome P-450IIEl. A case report describes a woman who was asymptomatic for 24 hours after ingesting an overdose of acetonitrile and acetone, but subsequently developed cardiovascular collapse, and profound acidosis, and eventually died. It was suggested that acetone delayed the onset of symptoms by initially inhibiting the metabolism of acetonitrile to cyanide, which is consistent with the mechanism proposed by Freeman and Hayes (1988). Acetaminophen. Acetone has been reported to increase the hepatotoxicity of acetaminophen in vitro and in vivo. The addition of acetone to phenobarbital-induced rat liver hepatocytes caused a three-fold increase in acetaminophen-glutathione conjugation due to enhanced cytochrome P-450-dependent activation of acetaminophen to a toxic metabolite. The addition of acetone to the reaction system also caused loss of hepatocyte viability, which was not seen when acetone or acetaminophen were excluded from the system. According to the suggested mechanism, acetone enhanced a cytochrome P-450-dependent activation of acetaminophen to a metabolite that conjugates with glutathione, thereby depleting hepatic glutathione stores, leading to accumulation of the reactive metabolite. In contrast, pretreatment of rats with 813 or 1,975 mg/kg acetone 18 hours and 1 hour prior

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to administration of acetaminophen resulted in an increased blood half-life of acetaminophen, a decreased rate constant for acetaminophen mercapturate formation, decreased acetaminophen sulfate formation, and decreased renal elimination of acetaminophen. Acetone also decreased the incidence and severity of liver necrosis induced by acetaminophen. The authors suggested that acetone decreased the formation of an acetaminophen reactive metabolite. However, in mice pretreated orally with acetone at 1,900 mg/kg/day for 10 days and then given 600 mg/kg acetaminophen intraperitoneally 6 hours before sacrifice, a greater portion of the liver lobules with necrosis and hemorrhage was observed than when acetaminophen was administered alone. Acetone pretreatment followed by saline injection resulted in no hepatic lesions. When dimethylsulfoxide (DMSO), an inhibitor of cytochrome P-450IIE1, was incubated with microsomes prepared from the acetone-pretreated, acetaminophen-treated mice, a 91% inhibition of acetaminophen-glutathione conjugation was found compared to when DMSO was excluded from the incubation mixture. Presumably, the inhibition of glutathione conjugation by DMSO was due to inhibition of cytochrome P-45011El to form the active metabolite of acetaminophen. Activation of acetaminophen to a reactive metabolite, N-acetyl-p-benzoquinone imine, which can bind to tissue macromolecules leading to necrosis at high doses of acetaminophen, is known to be dependent on cytochrome P-450IIEl. N-acetyl-p-benzoquinone imine can also be detoxified via conjugation with glutathione. The addition of acetone to the reaction system enhances the formation of the glutathione conjugate in rat liver microsomes. These results support a mechanism whereby acetone enhances the cytochrome P-450IIEl-dependent conversion of acetaminophen to N-acetyl-p-benzoquinone imine, which in turn conjugates with glutathione to deactivate it. Thus, acetone could decrease the toxicity of acetaminophen. However, if the dose of acetaminophen is high, leading to more N-acetyl-pbenzoquinone imine than can be handled by glutathione detoxification, glutathione is depleted and N-acetyl-p-benzoquinone imine accumulates. Thus, the induction of cytochrome P-45OIIEl by acetone to produce enough

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N-acetyl-p-benzoquinone imine from acetaminophen to deplete glutathione would result in an enhancement of acetaminopheninduced toxicity. Miscellaneous Chemicals. 9,10-Dimethyl-1,2-benzanthracene (DMBA) in acetone was more effective as a carcinogen than DMBA in mineral oil when applied to the tongues of hamsters (Marefat and Shklar 1977). A dose of 581 mg/kg acetone prior to administration of N-(3,5-dichlorophenyl)succinimide (NDPS), a fungicide, enhanced the NDPS-induced increase in blood urea nitrogen and kidney weight, but had no effect on NDPS-induced changes in urine volume or content, organic ion uptake by kidney slices, or renal pathology. Lower doses of acetone were ineffective. Since NDPS requires bioactivation by cytochrome P-450-dependent microsomal enzymes in the liver before renal toxicity occurs, it appears that acetone potentiated the renal toxicity of NDPS by inducing a cytochrome P-450 capable of the bioactivation. Pretreatment of rats with acetone prior to administration of thiobenzamide enhanced the degree of liver necrosis and serum activity of alanine aminotransferase, while coadministration of acetone and thiobenzamide reduced the extent of liver damage. In addition, liver microsomes from acetone treated rats statistically significantly increased the rate of thiobenzamide-Soxidation, which was dependent on a cytochrome P-450 enzyme. Thiobenzamide competitively inhibited acetone monooxygenase activity, which is highly specific for P-45011El. The results indicated that pretreatment of rats with acetone induces P-450IIE1, leading to enhanced bioactivation of thiobenzamide to a reactive metabolite and enhanced thiobenzamide-induced liver damage. However, when acetone and thiobenzamide were administered together, competition for the enzyme may have led to less bioactivation of thiobenzamide, thereby affording the protective effect of acetone. Acetone appears to afford protection against other toxic effects of other chemicals. Pretreatment of rats with acetone produced complete protection against clonic tonic convulsions induced by isonicotinic acid and electroshockinduced convulsion (Kohli et al. 1967). Since the protective action of acetone was nonspecific, a biochemical mechanism did not seem likely.

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Acetone also increased the toxicity of oxygen and chromate (Cr[VI]). Pretreatment of rats with acetone prior to oxygen exposure potentiated the NADPH-dependent microsomal lipid peroxidation in the liver and lung and decreased the survival of the rats. Oxygen also induced cytochrome P-450IIE1, indicating a role for cytochrome P-450IIEl in oxygen-mediated tissue toxicity. Coexposure of rats to acetone and sodium chromate (Cr[VI]) resulted in some macroscopic alterations in the liver (not otherwise described), whereas no liver toxicity was noted with chromate or acetone alone. Cytochrome P-450IIEl exhibited high chromate reductase activity, and biochemical studies indicated that acetone caused the induction of microsomal Cr(V1) metabolism. While the interactions discussed above involve the potentiation of the toxicity of other chemicals by acetone, acetone has been found to antagonize the toxicity of semicarbizide. In mice injected intraperitoneally with 168 mg/kg semicarbizide, 93% had convulsions and 91% died. Pretreatment with 4,000 mg/kg acetone orally reduced the percentage of the semicarbizide-induced convulsions and mortality to 0%. A dose of 1,800 mg/kg acetone reduced the percentage of mice convulsing to 31%, delayed the onset of convulsions by 286%, reduced the percentage that exhibited unmodified seizure from 98% to 40%, reduced the mortality to 12.5%, and delayed the time to death by 125%. The authors attributed the protective effect of acetone to the presence of the keto group. POPULATIONS THAT ARE UNUSUALLY SUSCEPTIBLE A susceptible population will exhibit a different or enhanced response to acetone than will most persons exposed to the same level of acetone in the environment. Reasons include genetic makeup, developmental stage, age, health and nutritional status (including dietary habits that may increase susceptibility, such as inconsistent diets or nutritional deficiencies), and substance exposure history (including smoking). These parameters result in decreased function of the detoxification and excretory processes (mainly hepatic, renal, and respiratory) or the preexisting compromised function of target organs (including effects or clearance rates and any resulting end-product metabolites). For

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these reasons we expect the elderly with declining organ function and the youngest of the population with immature and developing organs will generally be more vulnerable to toxic substances than healthy adults. Populations who are at greater risk due to their unusually high exposure are discussed in Section 5.6, “Populations With Potentially High Exposure.” Several lines of evidence from studies in animals indicate that sex differences exist in the susceptibility to effects caused by acetone. Male rats were more susceptible than female rats to acetone’s hematological, hepatic, and renal effects, and effects on reproductive organs. While results in animals cannot always be extrapolated to humans, it is possible that men may be more susceptible than women to the hematological, hepatic, renal, and reproductive effects of acetone. Furthermore, acetone may exacerbate preexisting hematological, liver, kidney, or reproductive disorders in humans. In a lethality study among newborn rats, 14day-old rats, and adult rats, susceptibility to the lethal effects of acetone generally decreased with increasing maturity. Humans may have the same order of susceptibility. Pregnant rats exposed to acetone by inhalation during gestation had reduced body weights (NTP 1991), while nonpregnant rats exposed to a higher concentration for a longer duration did not show any effects on body weight. Pregnant rats also had lower plasma and liver levels of acetol, the first intermediate in the overall metabolism of acetone, than virgin rats (Peinado et al. 1986), suggesting differences in the rate of acetone metabolism. It is possible that the condition of pregnancy made these rats more susceptible to body weight changes, and this susceptibility might apply to humans. The role of acetone in fasting and diabetes is complicated and not well understood. Acetone is produced endogenously and, as demonstrated in humans, more acetone is produced endogenously by fasting, which can result in ketosis. This implies that people on diets exposed to exogenous acetone will have a higher body burden of acetone than nondieters exposed to the same amount of exogenous acetone, perhaps making them more susceptible to any possible adverse effects. Acetone exposure of rats resulted in a reduced insulin-stimulated glucose oxidation rate, and the

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reduction was greater in fasted rats than in fed rats, indicating that the insulin resistance indigenous to fasting may be attributed in part to metabolic influences of acetone. This implies that people on diets may have a diminished capacity to utilize glucose, and exposure to acetone may reduce the capacity further. Diabetics may also be more susceptible to the effects of acetone. Acetone-induced insulin resistance might also result in greater hyperglycemia in diabetics. Patients with diabetic ketoacidosis have higher plasma levels of endogenous acetone, and exposure to exogenous acetone may increase the levels further. Similar results were found in rats. Diabetic rats had higher plasma acetone levels than nondiabetic rats after treatment with the same doses of acetone, due to the higher endogenous level of acetone in the diabetic rats and differences in the metabolism of acetone to isopropyl alcohol. Diabetic rats were also less able to oxidize acetone than nondiabetic rats. METHODS FOR REDUCING TOXIC EFFECTS This section will describe clinical practice and research concerning methods for reducing toxic effects of exposure to acetone. However, because some of the treatments discussed may be experimental and unproven, this section should not be used as a guide for treatment of exposures to acetone. When specific exposures have occurred, poison control centers and medical toxicologists should be consulted for medical advice.

REDUCING PEAK ABSORPTION FOLLOWING EXPOSURE Since acetone is irritating to mucous membranes of the respiratory system and eyes, people exposed occupationally wear protective clothing, goggles, and respirators. If exposure has occurred and symptoms of narcosis are present, the victim is removed from the contaminated area, clothing is removed and isolated, the skin is washed with soapy water, oxygen is administered, and eyes are thoroughly flushed with water. In the case of ingestion of acetone, activated charcoal is given. Although induction of emesis by administration of syrup of ipecac is sometimes recommended in the case of ketones in general, this may be contraindicated in the case of acetone ingestion because

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of the possibility of pulmonary aspiration, which increases for substances with high volatility and low viscosity. Gastric lavage has been used to treat a patient who ingested acetone, but the possibility of aspiration also exists for this method.

REDUCING BODY BURDEN Following inhalation or oral exposure, acetone is eliminated within about l-3 days in humans. Acetone does not accumulate in any tissue and its metabolites do not appear to be toxic or retained. To reduce the body burden of acetone, a cathartic, such as magnesium sulfate in water, is administered. In a case of isopropyl alcohol poisoning (acetone is a major metabolite of isopropyl alcohol), hemodialysis has been used successfully to enhance elimination of both isopropyl alcohol and acetone (Rosansky 1982). INTERFERING WITH THE MECHANISM OF ACTION FOR TOXIC EFFECTS The mechanism of the narcotic effects of acetone is not known, but as a solvent, acetone may interfere with the composition of the membranes, altering their permeability to ions. Systemically, acetone is moderately toxic to the liver, and produces hematological effects. The mechanism by which acetone produces these effects is unknown. The renal toxicity may be due to the metabolite, formate, which is known to be nephrotoxic (NTP 1991), and is excreted by the kidneys . Furthermore, the renal toxicity, which appears to be specific for male rats, may involve á2µ-globulin syndrome, as hyaline droplet formation was associated with the nephropathy observed in male rats in the American Biogenics Corp. (1986) study. Acetone also causes reproductive effects in male rats, and is fetotoxic. Although the exact mechanism for many of the effects of acetone is not known, distribution studies in mice indicate that acetone and metabolites are found in all of the target organs. Acetone and some of its metabolites were also transferred to rat fetuses after the dams were exposed to acetone. The metabolites of acetone are gluconeogenic precursors and most do not appear to be the toxic. Therefore, acetone itself appears to be a toxic agent, and increasing the metabolism of acetone would appear to be the best method for interfering with the mechanism of action. However,

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acetone induces its own metabolism by inducing cytochrome P450IIEl. The first and second steps of the metabolism of acetone are dependent on cytochrome P-45OIIEl. Since ethanol also induces this particular form of P-450IIEl, the metabolism of acetone might be increased by administering ethanol, although this may competitively slow acetone metabolism, at first, and induce cytochrome P-450IIEl only after a lag of several hours. In healthy men who fasted for 12 hours, the breath acetone levels ranged from 0.96 to 1.7 ppm (Jones 1987). Fasting for 36 hours resulted in average acetone breath levels of 14-66 ppm. In fasting men who ingested 0.25 g/kg of ethanol, the breath acetone levels decreased by 40% after a 12-hour fast and by 18% after a 36-hour fast (Jones 1988). However, since acetone potentiates the toxicity of other chemicals by inducing cytochrome P-45OIIE1, which enhances the metabolism of the chemicals to reactive intermediates, further increasing the cytochrome P-450IIEl levels might be counterproductive in cases of exposure to acetone followed by exposure to the other chemicals. Furthermore, acetone potentiates the central nervous system toxicity of ethanol by reducing the activity of alcohol dehydrogenase, which is responsible for 90% of ethanol elimination. ADEQUACY OF THE DATABASE Section 104(i)(5) of CERCLA, as amended, directs the Administrator of ATSDR (in consultation with the Administrator of EPA and agencies and programs of the Public Health Service) to assess whether adequate information on the health effects of acetone is available. Where adequate information is not available, ATSDR, in conjunction with the National Toxicology Program (NTP), is required to assure the initiation of a program of research designed to determine the health effects (and techniques for developing methods to determine such health effects) of acetone. The following categories of possible data needs have been identified by a joint team of scientists from ATSDR, NTP, and EPA. They are defined as substance-specific informational needs that if met would reduce the uncertainties of human health assessment. This definition should not be interpreted to mean that all data needs discussed in this section must be filled. In the

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future, the identified data needs will be evaluated and prioritized, and a substance-specific research agenda will be proposed.

EXISTING INFORMATION ON HEALTH EFFECTS OF ACETONE The existing data on health effects of inhalation, oral, and dermal exposure of humans and animals to acetone are summarized in Figure 2-4. The purpose of this figure is to illustrate the existing information concerning the health effects of acetone. Each dot in the figure indicates that one or more studies provide information associated with that particular effect. The dot does not imply anything about the quality of the study or studies. Gaps in this figure should not be interpreted as “data needs.” A data need, as defined in ATSDR’s Decision Guide for Identifying Substance-Specific Data Needs Related to Toxicological Profiles (ATSDR 1989), is substance-specific information necessary to conduct comprehensive public health assessments. Generally, ATSDR defines a data gap more broadly as any substance-specific information missing from the scientific literature. Data exist for inhalation exposure of humans for death, for systemic effects of acute- and intermediate-duration exposure, and for immunological, neurological, developmental, and reproductive effects. The data for systemic, neurological, immunological, and neurological effects were derived from medical evaluations of workers after a single day exposure, from case reports, and from experimental studies of humans exposed for acute- and intermediate-durations. The systemic effects include respiratory irritation, cardiovascular effects, gastrointestinal effects, and hematological effects, with no indications of hepatic or renal effects. Possible immunological effects consisted of increased white blood cell counts and decreased phagocytic activity of neutrophils. Neurological effects consisted of subjective symptoms, coma, and some behavioral effects. Reproductive and development effects consisted of shortened menstrual periods of women in an experimental study. An epidemiological study of pregnancy outcome among female laboratory workers who handle solvents found no effects, but an unreliable study of pregnancy complications in Russian women factory workers reported

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reproductive and developmental effects. Information in humans after oral exposure was derived from case reports of intentional or accidental ingestion. Effects included erosions in the buccal cavity, development of diabetes-like symptoms, and coma, and other neurological effects. Effects of dermal/ocular exposure of humans consisted of eye irritation, degenerative changes in the epidermis, and the development of contact dermatitis in a sensitized woman. In addition, patients exposed by inhalation and/or dermally from applications of casts using acetone as a setting agent developed increased pulse rate, vomiting and nausea, and neurological effects, including coma. For animals exposed by inhalation, data exist for death, systemic effects of acute- and intermediateduration exposure, and neurological, developmental, and reproductive effects. Systemic effects consisted of respiratory irritation, hepatic effects, renal effects, and body weight changes. Neurological effects consisted of narcosis, coma, and behavioral effects. Fetotoxicity, but no reproductive effects, were found in a developmental study. For oral exposure, data in animals were available for death (acute), systemic effects of acute- and intermediate-duration exposure, and neurological, reproductive, and developmental effects. Systemic effects included respiratory (enzyme induction), hematological, hepatic, and renal effects, and reduced insulin-stimulated glucose oxidation and body weight changes. No cardiovascular, gastrointestinal (other than enzyme induction), musculoskeletal, or dermal/ocular effects were found. Neurological effects consisted of narcotic effects and reduced nerve conduction velocity. Reproductive effects were found in male rats, and fetotoxicity was found in a developmental study. Effects of dermal/ocular exposure consisted of amyloidosis in the heart, liver, kidney, pancreas, and adrenals of mice exposed dermally, eye irritation and cornea1 burns and necrosis, skin irritation, and cataract development due to dermal exposure. Mice used as acetone solvent controls in skin painting studies did not develop any acetonerelated neoplastic or nonneoplastic lesions after comprehensive histological examination. Acetone was negative as a tumor initiator or promotor in skin painting studies.

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IDENTIFICATION OF DATA NEEDS Acute-Duration Exposure. Acute inhalation studies in volunteers and on-site medical evaluations of workers on a single work day have found that acetone is irritating to the nose, throat, trachea, lungs, and eyes. Acute experimental studies in humans also found hematological effects, which might also indicate immunological effects and neurological and neurobehavioral effects. Case reports of patients exposed to acetone vapors by inhalation and/or dermally during and after application of hip casts have found cardiovascular effects (increased pulse rates), gastrointestinal effects (vomiting of blood, hemorrhage), and neurological effects (lethargy, headache, listlessness, mystagmus, dizziness, coma, collapse). No indication that the liver and kidney were target organs, based on clinical chemistry parameters, was found in humans exposed under laboratory conditions. Information on effects of acute oral exposure in humans was derived from case reports of accidental or intentional ingestion of acetone and indicate that ingestion causes coma , erosions in the buccal cavity, and possible diabetes-like symptoms. Direct application of acetone to the skin of humans resulted in skin irritation and degenerative changes in the epidermis, and a case of contact dermatitis was reported. Acute inhalation studies in animals have provided LC50 val, liver in mice, guinea pigs, and rats, and kidney in guinea pigs as possible target organs. The heart and stomach did not appear to be target organs, and the kidney effects in guinea pigs were found at lethal concentrations. For acute oral exposure in animals, LD50 values are available for rats, for mice, and guinea pigs. Oral doses associated with death were also available for rabbits and dogs. The systemic effects of acute oral exposure found in animals were enzyme induction in the respiratory system of hamsters and rabbits in the duodenum and jejunum of rats, in the bone marrow of rabbits, in the liver of rats, mice, rabbits, guinea pigs, and hamsters, and in the kidneys of hamsters and rats, increased liver weight in mice and bone marrow hypoplasia in rats kidney effects in rats, and reduced insulin-stimulated glucose oxidation in adipose tissue in rats. Acute dermal exposure of animals produced increased DNA synthesis in the skin, indicative of irritation, in mice, and

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ocular exposure caused cornea1 bums and necrosis in rabbits and guinea pigs. Acetone does not appear to be very toxic by the dermal route, as attempts to determine LD50 values for rabbits and guinea pigs found no deaths at the highest dermally applied concentrations. The acute inhalation study of Specht et al. (1939) was conducted at lethal concentrations. An acute inhalation MRL of 26 ppm was derived based on neurobehavioral effects in humans. Most of the acute inhalation and oral studies in animals were designed to study enzyme induction. Comprehensive histological examination was performed in the high dose and control animals in the 14day drinking water study in rats and mice exposed at several dose levels. An acute oral MRL was not derived because NOAEL and LOAEL values in rats or mice in the acute-duration drinking water studies were close to or fell within the range of LD50 values for rats exposed by gavage. Acute-duration inhalation and oral studies conducted at several exposure levels in rats and mice that perform clinical tests and comprehensive histological examination of all dose groups would provide valuable information on doseresponse relationships and better characterize target organs, which might serve as bases for the development of MRLs. This information is important because there are populations surrounding hazardous waste sites that might be exposed to acetone for brief periods. Intermediate-Duration Exposure. The only information located regarding systemic effects in humans after intermediate-duration inhalation exposure was an experimental study in volunteers exposed intermittently to acetone at concentrations <1,250 ppm for <7.5 hours and <5 or 6 weeks in a complex protocol (Stewart 1975). Throat irritation was reported, but pulmonary function testing, electrocardiography, clinical chemistry and urinalysis determinations for liver and kidney damage, and hematology did not reveal any abnormalities. No studies were located regarding effects in humans after intermediate-duration oral or dermal exposure to acetone. An intermediate-duration inhalation study in rats found no histological or clinical evidence of effects on lungs, hearts, kidneys, or livers, but histological examination was not comprehensive. An intermediate inhalation MRL of 13 ppm

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was derived based on neurological effects in humans. An intermediateduration drinking water study found increased liver weight in mice and hematological effects (macrocytic anemia), increased liver weight, and kidney effects (nephropathy) in rats. An intermediate-duration gavage study in rats found clinical evidence of liver effects, hematological effects, and nephropathy. The renal effects seen in these studies appeared to be specific for male rats and may be related to á2µ-globulin syndrome, since hyaline droplet formation was observed in the American Biogenics Corp. (1986) study, but not the NTP (1991) study. No other systemic target organs were identified by comprehensive histological examination. An intermediate-duration oral MRL of 2 mg/kg/ day was derived based on the NOAEL for macrocytic anemia in rats in the 13-week drinking water study. Intermediate-duration dermal exposure of animals resulted in moderate hyperplasia of the epidermis of mice (Iversen et al. 1981), mild erythema and transient weight loss in guinea pigs, cataracts in the eyes of guinea pigs, and amyloidosis in the heart, liver, kidney, skin, pancreas, and adrenals of mice. Intermediate-duration ocular exposure of rabbits resulted in uveal melanocytic hyperplasia. An intermediateduration inhalation study in rats and mice that is designed to establish dose-response data for noncancer end points would also provide dose-response relationships and identify target organs useful for MRL derivation and fill this data gap. An intermediateduration drinking water study in rats conducted at lower exposure levels than those used in the NTP (1991) study might provide information on the threshold for anemia and nephropathy. Furthermore, a study designed to confirm whether the acetoneinduced nephrotoxicity is related to á2µ-globulin syndrome would aid in the assessment of the relevance of the renal effects to human health. Examination of workers who handle liquid acetone might provide information on the relevance to humans of the cataract formation and amyloidosis seen in animals. This information is important because there are populations surrounding hazardous waste sites that might be exposed to acetone for similar durations. Chronic-Duration Exposure and Cancer. A retrospective mortality study of workers exposed to acetone found no significant excess risk of death from any cause (all causes, malignant neoplasm,

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circulatory system disease, ischemic heart disease). Furthermore, a health evaluation survey of active employees found no evidence of hematological or liver effects. No studies were located regarding systemic effects in humans after oral or dermal exposure to acetone or in animals after inhalation or oral exposure for chronic durations. The only information regarding systemic effects in animals after chronic-duration exposure to acetone is that female mice used as acetone solvent controls in skin painting studies did not develop any acetonerelated nonneoplastic lesions after comprehensive histological examination and that chronic dermal of exposure of mice resulted in low incidences of hyperplasia, dermatitis, and hyperkeratosis. A chronic inhalation MRL of 13 ppm was derived based on meurological effects in humans in an intermediateduration study. The lack of data regarding systemic effects after oral exposure precludes the derivation of an oral MRL. The conduct of chronic studies by these routes in rats and mice would provide information on the dose-response relationships and identify target organs of chronic inhalation and oral exposure to acetone. This information is important because there are populations surrounding hazardous waste sites that might be exposed to acetone for long periods of time. A retrospective mortality study of workers exposed to acetone found no significant excess risk of death from any cause, including malignant neoplasm. No studies were located regarding cancer in humans after oral or dermal exposure to acetone, or in animals after inhalation or oral exposure. Mice used as acetone solvent controls in skin painting studies did not develop any acetone-related neoplastic lesions after comprehensive histological examination or skin tumors. Acetone was negative as a tumor initiator and as a tumor promoter for 7,12-dimethylbenz[a]anthracene . Following dermal absorption, acetone is probably widely distributed throughout the body, as occurs after pulmonary absorption. However, it is not possible to predict that acetone would not be carcinogenic after inhalation or oral exposure, because quantitative data regarding dermal absorption were not located. Genotoxicity studies indicate that acetone may be weakly genotoxic. Chronic inhalation and oral studies in rats and mice designed to establish dose-response data

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for noncancer end points would also provide information on the potential for acetone to cause cancer. Genotoxicity. No studies were located regarding genotoxicity in humans or animals after inhalation, oral, or dermal exposure. In vivo genotoxicity studies were conducted by the intraperitoneal route for micronuclei formation in Chinese hamsters (Basler 1986) and for cell transformation in fetal cells from pregnant hamsters with negative results. In addition, tests for gene mutation in silk worms by an unspecified route were negative. Numerous studies were conducted in vitro. Mostly negative results were obtained in bacterial and yeast assays and in plant seeds with or without metabolic activation, but some results were positive in E. coli when acetone was in the triplet state and in yeast for aneuploidy and for mitotic chromosome malsegregation (Albertini 1991) without metabolic activation. Mostly negative results were obtained in assays for cell transformation, chromosomal aberrations, sister chromatid exchange, colony formation inhibition, and gene mutation in cultured animal cells, and for sister chromatid exchange and unscheduled DNA synthesis in cultured human fibroblasts and skin epithelial cells. However, some positive results were obtained for chromosomal aberrations in Chinese hamster fibroblasts and hamster lung fibroblasts, for inhibition of metabolic cooperation in Chinese hamster cells, and for chromosome malsegregation in porcine brain tubulin. Acetone did not promote the transforming activity initiated by nine known genotoxic and carcinogenic chemicals. The mostly negative results in bacteria and cultured animal cells and the negative results in human fibroblasts and skin epithelial cells indicate that acetone poses little threat for genotoxicity in humans. However, peripheral lymphocytes, fibroblasts, and skin epithelial cells from workers exposed to acetone could be examined for chromosomal aberrations to confirm this hypothesis. Reproductive Toxicity. Information regarding reproductive effects in humans after inhalation exposure is limited to the report of premature menstrual periods by 3 of 4 women exposed to 1,000 ppm acetone for 7.5 hours, the lack of a statistically significant increased incidence of miscarriage in female laboratory workers exposed to a variety of solvents, including acetone and an unreliable

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report of pregnancy complications of Russian women factory workers (Nizyaeva 1982). No studies were located regarding reproductive effects in humans after oral or dermal exposure to acetone. Information regarding reproductive effects in animals after inhalation exposure is also limited. In an inhalation developmental study in rats and mice, no effects were found on the number of implants/litter, percent live pups/litter, or mean percent resorptions/litter (NTP 1988). No studies were located regarding reproductive effects in male animals, histological effects on reproductive organs of male or female animals, or the reproductive outcomes and other indices of reproductive toxicity in animals after inhalation exposure to acetone. Reproductive effects (reduced reproductive index and increased duration of gestation) were found in pregnant mice exposed orally to 3,500 mg/kg/day during gestation (EHRT 1987). In a 6-week drinking water study in male Wistar rats, no effects were found on successful mating to untreated females, number of pregnancies, number of fetuses, testicular weight, seminiferous tubule diameter, and testicular lesions. However, male Sprague-Dawley rats had statistically significantly decreased sperm motility, caudal weight and epididymal weight, and increased incidences of abnormal sperm, but no histopathological testicular lesions in a 13-week drinking water study (NTP 1991). Vaginal cytology examinations of the female rats revealed no effects, and similar evaluations of male and female mice revealed no effects. No indication that dermal exposure of female mice results in histopathological effects in reproductive organs was found in an analysis of female SENCAR mice used as acetone controls in a skin painting study of formaldehyde. An inhalation distribution study in male mice showed that acetone is distributed to the testes and vas deferens, and the 13-week oral study showed effects on the male rat reproduction organs. Acetone is widely distributed throughout the body regardless of route of exposure and species. Therefore, it is reasonable that male rats (and perhaps male mice) exposed to acetone by inhalation for 13 weeks might have effects on reproductive organs, but the concentration of acetone that would cause such effects cannot be predicted. Therefore, reproductive

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organ pathology should be examined in the suggested intermediate-duration inhalation study. The reproductive organs of female rats and mice could also be examined in the intermediateduration inhalation study to confirm the lack of effects in the existing oral study. A multi-generation study conducted by the oral route would clarify whether the reproductive effects observed in male rats in the existing 13-week drinking water study would affect reproductive outcomes and other indices of reproduction. If the proposed intermediate-duration inhalation study showed reproductive organ pathology, a similar multigeneration study by the inhalation route might be warranted. Developmental Toxicity. Information regarding developmental effects in humans after inhalation exposure is limited to a report that found no statistically significant increased incidence of miscarriage, perinatal death rate, or malformations of offspring in female laboratory workers exposed to a variety of solvents, including acetone and an unreliable report of fetal death and reduced birth weight and length of neonates in Russian women factory workers exposed to acetone (Nizyaeva 1982). No studies were located regarding developmental effects in humans after oral or dermal exposure to acetone. Developmental effects have been found in animals after inhalation and oral exposure. Decreased mean fetal body weight occurred at maternally toxic doses in rats exposed by inhalation during gestation (NTP 1988). Significantly increased incidence of late resorption, decreased fetal weight, and significantly increased incidence of reduced sternebral ossification occurred at maternally toxic doses in mice exposed by inhalation during gestation (NTP 1988). In mice exposed orally during gestation, reduced postnatal pup survival and reduced average weight of each live pup/litter on postpartum day 0 occurred at maternally toxic doses (EHRT 1987). Fetuses or pups were not examined for internal malformations or skeletal anomalies. Therefore, a more conventional oral developmental toxicity study in mice would help to determine whether acetone causes fetal malformations or skeletal anomalies. Developmental studies were not conducted in rats by the oral route, but while it is reasonable to expect that fetotoxicity would occur, it is not possible to predict the dose that

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would cause fetotoxicity in rats. An oral developmental study in rats would provide this information. No studies were located regarding developmental effects in animals after dermal exposure to acetone. Acetone can undergo transplacental transfer. While it appears that acetone is absorbed after dermal exposure, quantitative data were not available. If enough acetone is absorbed dermally, then fetotoxicity by this route would also be expected. A dermal developmental study might confirm or refute this possibility. Acetone has been tested in attempts to develop in vitro methods for assessing developmental toxicity in postimplantation rat embryos and in mouse embryo limb buds with inconclusive results. Further in vitro studies could be conducted to resolve the inconsistencies, but such studies would be useful only for preliminary screening purposes and would not substitute for developmental studies in animals administered acetone by environmentally relevant routes. Immunotoxicity. Information regarding immunological effects in humans after exposure to acetone is limited. Significantly increased white blood cell counts, increased eosinophil counts, and decreased phagocytic activity of neutrophils were found in volunteers exposed by inhalation, but a battery of immune function tests has not been performed. A case report of a laboratory technician described the development of acute contact dermatitis from handling acetone 2 years after being treated with squaric acid dibutyl ester in acetone for patchy alopecia areata on her scalp. This acetone sensitization is considered a rare complication of sensitizing therapies for alopecia areata. No studies were located regarding immunological effects in humans after oral exposure or in animals after inhalation, oral, or dermal exposure to acetone. A study performing a battery of immune function tests would clarify whether acetone is an immunotoxicant. Neurotoxicity. Exposure to acetone by the inhalation and oral routes has resulted in neurological effects, related to the narcotic effects of acetone, in both humans and animals. Acetone can cause coma and other neurological effects in humans after inhalation and/or dermal exposure or oral exposure if exposure levels or doses are high enough. Neurological effects were commonly experienced by workers and volunteers exposed by inhalation to

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acetone and include headache, lightheadedness, dizziness, unsteadiness, and confusion. Neurobehavioral tests conducted in some of these workers were negative. Neurological and behavioral effects have also been observed in volunteers exposed by inhalation. Neurobehavioral effects, indicative of narcosis, have been observed in rats, mice, and baboons exposed by inhalation. Acetone was also neurotoxic in rats after oral exposure, producing prostration, reduction in nerve conduction velocity, and excessive salivation. Oral exposure to acetone caused prostration in mice, weakness, depression, and unconsciousness in rabbits, and incoordination, staggering, falling, tremors, delirium, prostration, and coma in dogs (Albertoni 1884). No studies were located regarding neurological effects in animals after dermal exposure to acetone. There is no reason to suspect that the effects are route- or species-specific. Acetone is widely distributed throughout the body after absorption, and its presence in the brain of mice after inhalation exposure has been demonstrated. If enough acetone is absorbed dermally, neurological effects could occur; however, no studies that applied acetone to the skin of animals described any neurological signs of toxicity. Epidemiological and Human Dosimetry Studies. A retrospective mortality study of workers exposed to acetone found no significant excess risk of death from any cause (all causes, malignant neoplasm, circulatory system disease, ischemic heart disease). Furthermore, a health evaluation survey of active employees found no evidence of hematological or liver effects. Other epidemiological studies are limited to studies of pregnancy outcome among female laboratory workers exposed to a variety of solvents, including acetone and among female factory workers exposed to acetone in Russia (Nizyaeva 1982). No statistically significant increased incidence of miscarriage, perinatal death rate, or malformations of offspring was found in the laboratory workers. Miscarriages and neonates with reduced body weights and length were reported for the factory workers (Nizyaeva 1982), but this study was considered unreliable because of reporting limitations. Acute inhalation studies in volunteers and on-site medical evaluations of workers on a single workday have found that acetone is irritating to the nose, throat, trachea, lungs, and

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eyes and may cause unconsciousness if exposure levels are high enough. Acute experimental studies in humans also found hematological effects, which might also indicate immunological effects and neurobehavioral effects. Case reports of patients exposed to acetone vapors by inhalation and/or dermally during and after application of hip casts have found cardiovascular effects (increased pulse rates), gastrointestinal effects (vomiting of blood, hemorrhage), and neurological effects (headache, dizziness, listlessness, mystagmus, difficulty speaking, coma, collapse). No indication that the liver and kidney were target organs, based on clinical chemistry parameters, was found in humans exposed under laboratory conditions. Information on effects of acute oral exposure of humans was derived from case reports of accidental or intentional ingestion of acetone and indicate that ingestion causes coma, erosions in the buccal cavity, and possible diabetes-like symptoms. Some of these cases were confounded by coexposure to other narcotic chemicals, such as alcohol and liquid cement. Direct application of acetone to the skin of humans resulted in skin irritation and degenerative changes in the epidermis, and a case of contact dermatitis was reported. Populations likely to be exposed to acetone include workers in industries that process and use acetone, such as, paint, plastic, artificial fibers, and shoe factories. Professional painters and commercial cleaners, laboratory workers, and manicurists, if they still use acetone-containing nail polish remover, can also have greater exposure than the general population. Inhalation and dermal exposure are the most likely routes of exposure for workers. Cigarette smokers, people living near landfill sites that contain acetone, near highways (automobile exhaust), or incinerators will also have greater exposure primarily by inhalation than the general population. Any epidemiological studies designed for these populations should look for neurological, immunological, hematological, hepatic, renal, reproductive, developmental, and genotoxic effects and cancer. This information would be useful for establishing cause/effect relationships and for future monitoring of individuals living near hazardous waste sites.

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BIOMARKERS OF EXPOSURE AND EFFECT Exposure. Acetone has been identified in breast milk of lactating women, but nursing mothers represent only a fraction of the general population. Acetone concentrations in expired air, blood, and urine have been monitored in a number of studies of humans exposed to acetone in the workplace as well as by inhalation in controlled laboratory situations, and correlations with exposure levels have been found. Acetone levels in expired air, blood, and urine have also been used to determine whether patients admitted to the hospital in comatose conditions had ingested acetone. Gastric contents can also be analyzed for determining whether acetone was ingested. In addition, the detection of the odor of acetone in the breath can alert a physician that a patient might have been exposed to acetone. Carbon dioxide is the main end metabolite of acetone, but has not been used to monitor for exposure, probably because much unchanged acetone is expired and monitoring directly for acetone is more specific. However, acetone is cleared from breath, urine, and blood of humans within l-3 days and shows little tendency to accumulate, so these methods are useful for monitoring only for recent occupational exposure or from accidental or intentional ingestion. Carbon dioxide derived from acetone is also cleared rapidly. This implies that monitoring for more remote exposure is not possible. Other metabolites of acetone enter gluconeogenic pathways, so their origin from exogenous acetone would be masked. Furthermore, because acetone is a metabolite of isopropyl alcohol, it would be difficult to distinguish whether a person was exposed to isopropyl alcohol or acetone. Furthermore, endogenous levels of acetone vary widely due to a variety of factors. As discussed in Section 2.9.3, an abstract indicated that acetone increased the levels of DNA adducts in rats exposed via drinking water. Effect. The consistently observed effect of acetone exposure in animals is the induction of microsomal enzymes, particularly cytochrome P-450IIE1, which can be detected by immunochemical methods using antibodies to it. The enzyme induction has been associated with increased liver weights and hepatocellular hypertrophy due to the increased protein content (NTP 1991). Cytochrome P-450IIEl is associated with the metabolism of acetone

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itself, but acetone is not metabolized to toxic intermediates. However the induction of this enzyme is the mechanism by which acetone potentiates the toxicity of many other chemicals. Cytochrome P-450IIEl can be induced by a variety of other factors, such as ethanol, fasting, and experimental diabetes; therefore, the induction is not specific to acetone, and the detection of the enzyme would require liver biopsy and would probably be indicative only of recent exposure. However, an in vivo probe to detect elevated levels of cytochrome P-450IIEl in human populations is being developed. Exposure of rats to acetone has resulted in degeneration of apical microvilli in the kidney and nephropathy (NTP 1991), but these effects have not been associated with increased levels of blood urea nitrogen. A strong odor of acetone on the breath and nausea, or high levels of acetone in blood or urine in patients can alert physicians to the possibility of more serious sequelae such as gastrointestinal hemorrhage and narcosis or to metabolic acidosis. In rats, acetone exposure resulted in anemia as detected by hematological parameters and increased testis weight, decreased sperm motility, caudal weight and epididymal weight, and increased incidences of abnormal sperm (NTP 1991). These effects were seen after intermediate-duration exposure. Hematological tests and tests for sperm motility and abnormalities could be used to screen humans for possible hematological effects and effects on fertility. Overt signs of skin irritation could alert physicians to possible degenerative changes, which can be detected by microscopic examination of the epidermis. Allergic reactions can be detected by patch testing. There does not appear to be a need for additional biomarkers. Absorption, Distribution, Metabolism, and Excretion. A substantial database exists regarding absorption and excretion of acetone by humans and animals after acute inhalation and oral exposure to acetone and the information is sufficient to assess relative rates and extent of absorption and excretion. Uptake and excretion are directly proportional to dose and duration of exposure but can be influenced by exercise during exposure and fasting. Acetone does not appear to accumulate to any great extent after

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repeated exposure, so information on absorption and excretion after intermediate- and chronic-duration exposure does not appear to be necessary. An inhalation study in mice examined the distribution of acetone, which is widespread regardless of route of uptake. The metabolic pathways of acetone are relatively well understood based on animals studies. There is some indication that at low doses, the pathways, via methylglyoxal and lactate, predominate, but at higher doses that saturate this pathway, metabolism is shunted to the formateacetate branch of the propanediol pathway. Although acetone is absorbed dermally, quantitative data are limited to a study in which an unspecified amount of acetone was applied to the skin of volunteers and levels of acetone were measured in blood, alveolar air, and urine. While the dermal absorption was stated to be fairly rapid, the net amount absorbed and rate of absorption were not determined. Furthermore, inhalation of acetone could not be completely prevented. Additional studies in humans or animals, designed to measure the rate and extent of dermal absorption, would help to fill this gap in understanding the toxicokinetics of acetone. Other than this gap in the database, there appears to be little need for additional information on absorption, distribution, metabolism, and excretion. Comparative Toxicokinetics. Acetone appears to have similar target organs in animal and humans, such as, the hematological system and the central nervous system. Toxicokinetic studies have been conducted in both humans and animals, especially in humans exposed by inhalation. There appear to be very few differences between animal species, and the dog appears to be a good model for extrapolating absorption results to humans. Metabolic pathways have been elucidated primarily in rats, but mice and rabbits have also been studied. Metabolism involves three different pathways of gluconeogenesis. The first step in the metabolism of acetone is dependent on cytochrome P-450IIEl , which acetone induces, and this induction has been demonstrated in rats, mice, hamsters, and rabbits. It

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appears that the metabolic pathways operate in all species. The distribution of acetone has been studied only in mice exposed by inhalation. Acetone was widely distributed to organs and tissues throughout the body. This is expected to be true for all species by virtue of its high water solubility, facilitating distribution through the water compartment of the body. There appears to be little need for additional comparative toxicokinetic studies. Methods for Reducing Toxic Effects. Acetone is readily and passively absorbed from the lungs and gastrointestinal tract into the blood stream and widely to distributed throughout the water compartment. The only known methods for reducing absorption from the gastrointestinal tract are administration of syrup of ipecac and gastric lavage. Established methods for reducing body burden are administration of a cathartic, such as magnesium sulfate and hemodialysis (Rosansky 1982). The mechanism of the narcotic effects of acetone is not known, but as a solvent, acetone may interfere with the composition of the membranes, altering their permeability to ions. Developing a method to block this interference might prevent acetone induced coma. Since the metabolites are gluconeogenic precursors, they are probably not toxic. Therefore, acetone itself is probably the toxic agent, and enhancing its metabolism may block its toxic action. However, acetone induces its own metabolism by inducing cytochrome P450IIEl. Since ethanol also induces this particular form of P-450IIEl, the metabolism of acetone might be increased by administering ethanol. Ethanol has been shown to decrease the breath levels of acetone (Jones 1988). However, since acetone potentiates the toxicity of other chemicals by inducing cytochrome P-450IIE1, which enhances the metabolism of the chemicals to reactive intermediates, further increasing the cytochrome P-450IIEl levels might be counterproductive in cases of exposure to acetone followed by exposure to the other chemicals. Furthermore, acetone potentiates the central nervous system toxicity of ethanol by inhibiting alcohol dehydrogenase, which is

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responsible for 90% of ethanol elimination. Development of other means of enhancing acetone’s metabolism might solve this dilemma. The established method for mitigating acute acetone poisoning is the administration of a cathartic, and administration of diazepam to alleviate seizures, or phenobarbital if diazepam is ineffective. No methods were located to mitigate more subtle effects.

direct measurement of hepatic P-450IIEl levels in normal and isoniazid-treated populations.

ON-GOING STUDIES Dr. C.S. Yang of Rutgers University is conducting on-going studies sponsored by the National Institute of Environmental Health Sciences (NIEHS) on the molecular mechanism of the regulation of cytochrome P-450IIEl (CRISP 1993). The specific aims of the project are to examine the role of acetone, other ketone bodies, and hormones in the induction of this enzyme in rat liver; to characterize the molecular events in the regulation of P-45011El by measuring transcriptional and translational activities and the stabilities of mRNA and proteins; to investigate sex-related differences and hormonal regulation of P-450IIEl in the mouse kidney at the physiological, biochemical, and molecular biological levels; and to understand the active site dynamics and catalytic function of P-450IIEl by examining the structural characteristics of its substrates, by deriving structural information from the amino acid sequence, by modifying specific amino acid residues in the active site with a site-directed mutagenesis approach, and by studying the metabolism and toxicity of environmental chemicals. Dr. K.E. Thummel of the University of Washington is conducting on-going studies sponsored by the National Institute of General Medical Sciences on whether humans exposed to acetone and other inducers of cytochrome P-450IIE1, or with altered metabolic states, will have elevated levels of this enzyme that can be identified by an in vivo probe (CRISP 1993). The utility of the probe candidates will be validated by determining the in vitro catalytic specificity of the probe toward human liver P-450IIEl; identifying an in vivo metabolic clearance parameter that reflects intrinsic P-450IIEl catalytic activity; and determining whether the in vivo clearance parameter predicts

Fed pregnant rats on gestational day 20 had slightly higher endogenous serum acetone levels compared with nonpregnant controls, and acetone monooxygenase activity was significantly lower in the pregnant rats than in the nonpregnant rats (Casazza et al. 1990).

A number of recent abstracts of studies yet to be published were located covering topics related to toxicokinetics and enzyme induction, These studies are described below. In rats treated intraperitoneally with acetone, the concentration of acetone in expired air was 40% and the half-life was 4 hours.

Administration of acetone in the drinking water for 5 days increased the acetone monooxygenase activity, but the activity was lower than in acetone treated nonpregnant rats. Immunoblot analysis showed that cytochrome P-45OIIEl decreased progressively during pregnancy and rapidly returned to normal after parturition. The decrease in P-45011El was accompanied by a gradual decrease in P-450IIEl mRNA. The results indicated that liver P45011El is suppressed in the pregnant rat, while the levels still respond to acetone induction. A pretranslational mechanism was suggested for P-450IIEl suppression. Serum levels of endogenous acetone were 26 µmol/mL in 20day pregnant rats and 14 µmol/mL in the pooled blood from litters of fetal siblings. No increase in maternal blood acetone was seen on day postpartum day 1, but the levels in pups were markedly increased. Measurable levels of serum acetol and 1,2-propanediol were also found in the 2- to 3-day-old pups. Injection of acetol into the pups resulted in a nine-fold increase in 1,2-propanediol levels. The results demonstrate the acetone is normally present in newborn rats, and that the pups are able to metabolize acetone to 1,Zpropanediol soon after birth. Acetone added to the culture system increased the incorporation of methionine into cytochrome P-450IIEl in rabbit hepatocytes, indicating that the acute phase of acetone induction of this enzyme partly involves an increased rate of P-450IIEl

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protein synthesis. Xenobiotic metabolizing activities associated with cytochrome P-45011El were elevated in liver microsomes from acetone treated rats. Coadministration of phorbol myristate acetate, an activator of protein kinase c, with acetone suppressed P-450IIEl content and the activities of the associated oxidases, indicating that the induction of P-450IIEl by acetone involves inhibition of protein kinase c. Acetone inhibited the tumor promoting activity of phorbol myristate acetate following initiation with dimethylbenz[a]anthracene on mouse skin. Nnitrosodimethylamine demethylase activity in rat hepatoma was increased by treating the rats with acetone. The levels of hepatic N7-methylguanine and O6-methylguanine DNA adducts were significantly increased by treatment of rats with 10% acetone in drinking water for 10 days.

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Worster, Donald : Dust Bowl: The Southern Plains in the 1930s, New York, Oxford University Press, 1979.

McPhee, John : The Control of Nature, New York, Farrar, Straus, Giroux, 1989. Norris, Debra Hess : Disaster Recovery: Salvaging Photograph Collections, Philadelphia, PA, 1998. Odum, Howard T. : Environment, Power and Society, New York, Wiley-Interscience, 1971. Peter Woodrow : Rising From the Ashes, Developing Strategies in Times of Disaster, Boulder, Colorado, Westview Press, 1989. Quarantelli, E.L. : What is a Disaster—Perspectives on the Question, New York, Routledge, 1998.

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C

INDEX A Acetone, 136, 137, 138, 140, 141, 142, 143, 145, 147, 148, 149, 150, 151, 153, 154, 155, 156, 157, 159, 160, 161, 162, 163, 165, 166, 167, 168, 169, 171, 172, 173, 174, 175, 177, 178, 179, 180, 181, 183, 184, 185, 186, 187, 189, 190, 191, 192, 193, 195, 196, 197, 198, 199, 201, 202, 203, 204, 205, 207, 208, 209, 210, 211, 213, 214, 215, 216, 217, 219, 220, 221, 222, 223, 225, 226, 227, 228, 229, 231, 232, 233, 234, 235, 237, 238, 239, 240, 241, 243, 244, 245, 246, 247, 249, 250, 251, 252, 253, 255, 256, 257, 258, 259, 261, 262, 263, 264, 265, 267, 268, 269, 270, 271, 273, 274, 275, 276, 277, 279, 280. Administration, 27, 70, 143, 185, 240, 253, 255, 259, 277, 278, 279. Agency, 39, 114, 125, 136, 144, 228. AIDS, 106.

139, 146, 152, 158, 164, 170, 176, 182, 188, 194, 200, 206, 212, 218, 224, 230, 236, 242, 248, 254, 260, 266, 272, 278, 131, 256, 142,

Anthrax, 17, 25, 27, 28, 32, 35, 36, 37, 39, 40, 41, 42, 43, 92, 93, 95, 101, 102, 103, 104, 105, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 126, 128, 130, 131, 132, 133. Antibiotic, 32, 42, 45, 49, 73. Authority, 113.

B Bacteria, 34, 39, 41, 43, 46, 47, 48, 51, 99, 107, 268. Biological Agents, 14, 15, 27, 34, 35, 36, 37, 38, 39, 92, 95, 96, 99, 104, 126. Biological Phenomena, 4. Biological Warfare, 14, 20, 34, 35, 37, 38, 39, 43, 44, 47, 49, 51, 52, 59, 61, 62, 79, 85, 92, 95. Bioterrorism, 14, 15, 16, 17, 20, 21, 25, 26, 27, 28, 32, 33, 34, 36, 42. Bioterrorist, 14, 16, 17, 19, 21, 28, 29, 31, 32, 33. Blood Chemicals, 75. Botulinum Toxin, 35, 36, 39, 60, 61, 99, 101. Brucellosis, 49, 50.

Carbon, 76, 97, 139, 175, 176, 177, 181, 185, 186, 188, 190, 194, 196, 198, 200, 201, 215, 232, 239, 240, 241, 242, 243, 245, 248, 274. Chemical Terrorism, 74. Chemical Warfare, 5, 64, 68, 134, 135. Chemical Weapon, 65, 66, 71. Chlorine, 24, 65, 66, 75, 77, 78, 95, 97. Cholera, 35, 46, 47. Committee, 87. Communication, 12, 15, 30, 227. Community, 1, 3, 9, 12, 14, 15, 21, 22, 23, 24, 25, 26, 29, 31, 32, 33, 86, 87, 88, 91. Company, 110, 113, 126. Conditions, 4, 9, 22, 24, 31, 32, 51, 68, 95, 140, 147, 151, 153, 166, 170, 173, 174, 179, 221, 225, 226, 227, 229, 233, 264, 273, 274. Constitution, 124. Conventional Warfare, 5. Cyanide, 65, 68, 71, 75, 95, 99, 103, 104, 106, 108, 111, 113, 122, 128, 133, 134, 253, 254. Cyanogen Chloride, 75.

D Department, 8, 9, 25, 38, 68, 80, 110, 112, 142. Derangements, 16. Destruction, 2, 3, 21, 26, 32, 45, 79, 93, 98, 124.

Development, 1, 12, 45, 64, 74, 81, 100, 101, 125, 152, 163, 171, 174, 180, 194, 237, 239, 240, 241, 242, 243, 248, 261, 280. Diagnosis, 15, 17, 20, 21, 26, 27, 38, 41, 42, 44, 46, 48, 50, 52, 53, 54, 56, 57, 58, 59, 61, 62, 63, 70, 72, 82, 83. Diagnostic, 15, 16, 20, 42, 82, 83. Disaster Classification, 4. Disaster Management, 1, 2, 3, 6, 7, 11, 12, 13, 88, 89, 90, 95. Disaster Preparedness, 7, 12, 13, 87, 88. Diseases, 4, 16, 17, 19, 20, 23, 24. Distribution, 19, 53, 54, 87, 92, 102, 175, 178, 183, 184, 185, 200, 232, 242, 251, 260, 269, 275, 276, 277. Droughts, 4, 90, 91. Drugs, 11, 42, 58, 61, 73, 132, 137.

E Earthquakes, 1, 2, 4, 5, 89, 90, 91. Emergency, 3, 7, 8, 9, 10, 13, 14, 16, 18, 20, 21, 25, 30, 67, 68, 72, 73, 76, 77, 82, 86, 91, 92, 94, 96, 97, 98, 103, 108, 129. Employees, 110, 113, 120, 146, 157, 267, 272. Energy, 89, 139, 140, 153, 174, 203, 204, 205, 221, 230.

286

Index

Environment, 8, 34, 38, 45, 51, 67, 79, 90, 95, 136, 137, 142, 218, 220, 257. Evidence, 15, 20, 30, 32, 62, 90, 100, 147, 148, 151, 157, 160, 167, 173, 189, 206, 211, 212, 213, 214, 215, 222, 227, 228, 237, 247, 258, 265, 266, 267, 272.

Injection, 49, 56, 57, 60, 79, 82, 83, 84, 185, 189, 218, 226, 249, 255, Investigations, 15, 18, 85, 242. Involvement, 52, 72, 96, 129, 185, 186, 188, 200,

70, 186, 279. 143, 97, 245.

L

Hierarchy, 22. HIV, 55, 103, 106, 108, 121, 127. Hydrogen, 75, 95.

Laboratory, 16, 20, 37, 41, 42, 44, 48, 49, 50, 51, 56, 58, 59, 62, 63, 72, 80, 81, 147, 148, 149, 153, 155, 156, 170, 172, 201, 209, 220, 221, 223, 225, 229, 231, 233, 262, 264, 268, 270, 271, 272, 273, 274. Law Enforcement, 10, 15, 16, 22, 32, 100. Leaders, 11. Legislation, 7, 8. Lewisite, 66, 74. Liberation, 108, 129, 188, 201. Literature, 32, 34, 98, 262.

I

M

Industry, 1, 2, 65, 129. Infection, 23, 24, 27, 30, 39, 40, 42, 43, 44, 47, 48, 49, 50, 51, 53, 54, 62, 67, 73, 84, 95, 96. Information, 9, 15, 16, 18, 19, 20, 23, 24, 70, 87, 88, 93, 94, 95, 100, 101, 111, 136, 140, 144, 145, 148, 152, 155, 156, 158, 161, 162, 164, 165, 172, 175, 195, 196, 197, 207, 219, 220, 223, 225, 226, 238, 251, 261, 262, 263, 264, 265, 266, 267, 268, 269, 270, 271, 273, 275, 276, 278.

Management, 1, 2, 3, 6, 7, 8, 11, 12, 13, 14, 22, 30, 67, 77, 86, 88, 89, 90, 92, 94, 95, 96, 97, 98. Mass Fatality Management, 29. Medical Management, 22, 67, 96. Medical System, 29. Medicine, 8. Metabolism, 174, 176, 177, 180, 185, 186, 187, 188, 189, 190, 192, 195, 196, 198, 200, 201, 203, 216, 224, 237, 242, 245, 248, 251, 252, 253, 254, 257, 258, 259, 260, 261, 275, 276, 277, 278.

F Floods, 1, 2, 4, 6, 90, 91.

G Government, 33, 36, 37, 80, 97, 100, 110, 124, 128, 135, 140, 143.

H

Index

287

Meteorological Conditions, 95. Microsomes, 159, 160, 163, 186, 187, 188, 189, 212, 216, 242, 243, 244, 245, 246, 247, 248, 251, 252, 253, 254, 255, 256, 280. Mitigation, 8, 12, 13, 87, 89. Monkeypox, 54, 55. Mustard Gas, 72, 74, 125. Mycotoxins, 27, 62, 63, 64.

N Natural Disaster Reduction, 1, 91. Natural Disasters, 2, 21, 23, 87, 91. Network, 15, 17, 19. Nitrogen, 71, 74, 75, 150, 151, 163, 215, 238, 241, 246, 256, 275. Nuclear, 1, 2, 5, 88, 93, 98, 99, 103, 106, 119, 123, 127, 129. Nuclear Power, 2, 123. Nuclear Weapons, 93, 106, 119.

O Operations, 11, 22, 31, 32, 134. Organisms, 17, 34, 43, 44, 45, 46, 50, 51, 93, 99,

28, 29, 30, 36, 39, 40, 47, 48, 49, 204.

P Pathogens, 14, 16, 17, 18, 19, 24, 27, 30, 32. Patients, 8, 9, 10, 14, 15, 16, 17, 18, 19, 22, 24, 25, 26, 27, 28, 29, 30, 96, 127, 140, 148, 152, 165, 166, 169, 170, 180, 185, 186, 197, 198, 207,

210, 211, 220, 221, 238, 259, 263, 264, 273, 274, 275. Phenomenon, 4, 101, 174, 178. Phenothiazines, 75. Plague, 5, 17, 18, 23, 25, 28, 32, 35, 37, 39, 43, 44, 45, 46, 48. Policy, 88. Powers, 31. Pregnancy, 143, 151, 155, 156, 174, 201, 203, 219, 223, 230, 258, 262, 269, 272, 279. Prevention, 2, 6, 7, 11, 13, 17, 43, 45, 47, 49, 50, 52, 54, 56, 59, 60, 61, 62, 64, 74, 84, 89, 91. Production, 15, 66, 69, 72, 81, 89, 97, 149, 173, 187, 188, 190, 198, 201, 212, 213, 219. Property, 1, 2, 13, 31. Protection, 12, 14, 26, 27, 39, 47, 56, 76, 94, 96, 121, 125, 136, 247, 249, 256. Public Health, 3, 14, 20, 21, 22, 23, 38, 97, 136, 143, 144, 145, 218, 223, 262.

R Red Phosphorous, 75. Rehabilitation, 7, 11, 13, 86, 87, 91. Ricin, 37, 39, 60, 61, 79, 80, 81, 82, 83, 84, 85, 99, 103, 104, 105, 131. Risk Redution, 88.

S Smallpox, 16, 23, 25, 35, 39, 52, 53, 54, 55. Society, 98.

288

Index

Surgery, 27, 28, 73, 84. Symptoms, 15, 16, 18, 19, 27, 28, 38, 40, 41, 43, 44, 45, 46, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 67, 68, 69, 70, 71, 72, 73, 77, 78, 81, 82, 83, 84, 95, 141, 147, 153, 165, 201, 211, 219, 221, 238, 254, 259, 262, 263, 264, 273.

T Tear Gas, 102, 104, 105, 113, 118, 121, 122, 123, 125, 126, 127, 128, 129, 131, 132, 133, 134. Technology, 98, 101. Terrorism, 1, 20, 23, 24, 74, 98, 99, 100, 101, 104. Toxicokinetics, 173, 202, 279.

107, 124, 130,

37, 102, 276,

Toxins, 14, 19, 27, 34, 39, 40, 59, 60, 61, 63, 93, 95, 99. Treatment, 3, 8, 9, 10, 11, 14, 15, 17, 20, 21, 24, 25, 26, 27, 28, 32, 38, 39, 40, 42, 45, 47, 49, 50, 51, 52, 54, 56, 58, 59, 61, 62, 63, 67, 70, 73, 77, 79, 84, 93, 125, 129, 131, 148, 159, 160, 161, 162, 164, 165, 166, 167, 168, 171, 197, 207, 219, 221, 225, 240, 242, 247, 249, 250, 259, 280. Tularemia, 25, 39, 47, 48, 49.

V Virus, 16, 32, 52, 53, 54, 55, 57, 58, 59, 121, 128. Volcanoes, 1, 90, 91.

W Wind Storms, 4. ‡‡‡

Biological and Disaster Management

289