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Aftermath of the world's worst chemical disaster
Journal of Loss Prevention in the Process Industries 18 (2005) 268–273 www.elsevier.com/locate/jlp
Aftermath of the world’s worst chemical disaster Bhopal, December 1984 S. Acquillaa,*, R. Bertellb, V.R. Dharac, G. Tognonid a
London Postgraduate Medical and Dental Education, London Deanery, 20 Guilford Street, London WC1N 1DZ, UK b International Institute of Concern for Public Health, Toronto, Canada c Rollins School of Public Health of Emory University, Atlanta, GA, USA d Department of Cardiovascular Research, Laboratory of Clinical Pharmacology, Istituto Mario Negri, Milano, Italy
Abstract Current practice in preventive environmental health action includes chemical analysis of land, water and air for known (controlled) toxic chemicals and comparison against standards for identification of breaches of regulatory limits. This methodology is also followed after an accident or disaster to ensure air, water and food safety. Some problems, not easily addressed by this methodology include: unidentified toxic chemicals; non-conventional uses of toxic materials, unexpected synergestic effects of toxic mixtures, and human health consequences of exposure to toxic materials with unusual and unidentified pathways of exposures. In Bhopal we were faced with a mixture of about 27 toxic substances, a variety of exposures related to activities of the persons, for example, remaining in their homes or running in the toxic cloud, and a variety of perceived injuries not all of which would have been predicted by analyzing the chemicals involved. In this paper we will present the advantages of combinations of approaches including examination of health, social and cultural environment and economic situation of the victims of the Bhopal disaster and their effect on health. This more broad analysis provides a clearer big picture of the problems in the aftermath of exposure, and also clues to effective treatment and alleviation of future problems. We will present two effective strategies for connecting health problems ten years after exposure to the original disaster, and understanding the biochemical reactions in the body when invaded by a mixture of toxic substances and how such an understanding will in turn affect public policy planning, emergency preparedness and emergency medicine. Crown Copyright q 2005 Published by Elsevier Ltd. All rights reserved.
1. Advantages of Medical Evaluation after a Chemical Disaster Whenever a toxic mixture is released on an unprepared and unsuspecting population, the effects will be modified by the characteristics of the mixture itself, including the potential interaction of the chemicals, as well as the chronological and biological ages of the victims, their activities at the time of the exposure, their basic health parameters before the accident, the medicines that they have been taking, and their state of anxiety and fear. Through the chemical engineering approach to the disaster, we can learn of the controlled aspects of the substance(s) released, their known toxicology in the workplace, and any dose-response reaction which has been researched and published, * Corresponding author. Tel.: C020 7 692 3239. E-mail address: [email protected] (S. Acquilla).
estimating the potential human health damage. While this is a necessary first step, and sets some parameters and guidelines for the medical personnel, it falls short of completely defining the disaster and its consequences. Currently there are some well-done toxicological studies, but most toxic chemicals go without professional evaluation. Toxicological testing began in about the early 1930’s, but did not become an academic discipline until about 1961 when the Society of Toxicology was formed. During the 1970’s and 1980’s, toxicology became an academic subject in the Universities. Many toxicologists have arrived at this profession through their professional experience rather than formal training, and there are clearly major disagreements in areas of toxicological concern with respect to particular chemicals. Regulation follows slowly after toxicological research, so total reliance on regulatory limits as safeguarding public health is risky. By definition, toxicology attempts to determine the
0950-4230/$ - see front matter Crown Copyright q 2005 Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jlp.2005.06.008
S. Acquilla et al. / Journal of Loss Prevention in the Process Industries 18 (2005) 268–273
effects of a given chemical on living organisms. Since our understanding of living organisms is often not precise, toxicology can be at best an educated guess. ‘In toxicology, the certainty most of us seek is that a particular chemical is safe. Unfortunately, there is no such thing as an absolutely safe chemical: all chemicals can cause toxic effects in large enough amounts. When faced with this reality, most people look for a different certainty: a ‘safe’ amount. They want to know the exact level at which a chemical changes from nontoxic to toxic. Again, this is not a scientifically realistic goal. Human individuals vary tremendously in their responses to their environment, including the chemicals in it, so what is ‘safe’ for one person may not be ‘safe’ for another’. (Ref. [1]) In addition to this problem of human variability, we have numerous potential chemical compounds and physical states for any given toxic chemical, which can alter the toxic effects. Each chemical compound needs to be evaluated separately. Gases behave differently from liquids and solids. The portal through which the toxic substance enters the body is also of concern. Those things which enter via ingestion will be sorted out by the gut wall and then subjected to further scrutiny by the liver before being excreted through the kidneys or allowed to enter the body. There are no such screening devices in our lungs for inhalation. Since we have introduced some 70,000 to 80,000 new chemicals into the human living space since 1950, the task of testing the interaction of chemicals in the many potential mixtures which occur in the environment is impossible. Faced with this dilemma, regulators have resorted to choosing particular chemicals, both for high toxicity and prevalence, for regulation. Interactions between chemicals, or between chemicals and electromagnetic energy, are ignored. The biochemical interaction of toxic chemicals within the human body, or with medicines the person may be taking, offers further complexity not even casually addressed by science.
2. Regulation of Chemicals in the Environment Ordinarily the toxic effects of chemicals are first noticed in the workplace. Because of the enclosed situation of most workplaces, the ability to monitor for a particular suspected chemical, and the potential which this offers for setting a dose-response estimate needed for standard setting, most information on toxicity of chemicals is based on workplace studies. In terms of applying this information to the general public, there are drawbacks which are hard to overcome. For example, the worker is usually male, a young adult or early middle aged, in good health (able to pass a physical examination for work) and usually Caucasian, living in a country where he has at least some political voice. The
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worker is in the workplace for a limited time, usually eight hours a day, followed by a 16 h respite period, and one or two ‘free days’ a week. The workplace is contained, and the toxic chemicals to which the worker is exposed are limited in number and distribution within that space. These are all characteristics that help the toxicologist to do precise work in establishing the relative toxicity and dose-response pattern of one hazardous chemical. This is, of course, helpful for setting standards for exposure for one hazardous chemical for the typical worker in the typical workplace, but it is not helpful in trying to regulate a mixture of hazardous materials in the living place, where there is less predictability and control. In trying to transfer this learning to the living space, one faces multiple problems: the living space is not contained in a building; it houses women and children as well as adult males; some members are ill, have damaged immune systems, or are immature; children and the elderly are confined to their living space 24 h a day, seven days a week. Moreover, the chemicals in the living space are highly likely to be multiple, to be undergoing chemical reactions in the environment, and are interacting with the myriads of biological matter, bacteria, animals and plants, household cleaning agents, and medicines to create new organic and inorganic chemical compounds with unknown effects. Standards set for the workplace are likely NOT appropriate for the living space (Ref. [2]). In addition, some regulated toxic chemicals were not regulated on the basis of health studies. For example, heavy metals are often regulated on the basis of past clean-up experience at polluted industrial sites. The purpose of regulation of heavy metals is to discover recent pollution that exceeds so called ‘historic’ levels, so that prosecution of the polluters will be possible. Other substances, like ionizing radiation, are regulated by an industry committee which decides the ‘acceptable’ risk-benefit trade off, that which is most reasonable given the value of the activity. They use health related research only to contribute to the risk part of the risk-benefit equation (Ref. [3]). The International Medical Commission Bhopal (IMCB) (Ref. [4]) went to Bhopal in January 1994, at the request of the Bhopal gas survivors. We attempted to scientifically verify that survivor’s current medical problems were related to the original exposure damage, as a basis for recommending survivor’s medical care. We also attempted to identify and document chronic disability, as required for compensation. Our team consisted of thirteen physicians and scientists from eleven different countries, who had never worked together before this mission to Bhopal. We met in Delhi for a week of planning before proceeding on to Bhopal, where we worked continuously for three more weeks. All professional services were donated, and charities and unions provided us with money for travel and lodging. Although it is generally agreed that methyl isocyanate was released in the Bhopal disaster, there were other
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chemicals also released. Workers from the plant have identified the ones which they presume were released, given their experience with the work place technology. However, Union Carbide (or its new owner, Dow Chemical) has not yet (after 20 years) authored a full analysis of the toxic chemicals released, and the timing of these releases. Timing is important because of the changes in the direction of the wind during the prolonged disaster. If different gases were released at different times during the disaster, then their geographic distribution depends heavily on wind direction at time of release. This data was never available to emergency workers, or to the IMCB. There may have been multiplicative or additive effects of the toxic mixture at different times and places. The biochemical action of methyl isocyanate in the body of the victims has been disputed for the past 20 years. Some say the methyl isocyanate disassociates into cyanide in the body, while others dispute this. This dispute arose because the factory management denied this biochemical reaction. Thereafter, due to Union Carbide management assurances, pathological evidence of cyanide poisoning was rejected by the emergency physicians, who failed to apply an antidote present in the hospital pharmacy. Study only of the released chemical, and not of its biochemical reactions within the body, is inadequate for public health purposes. There is also a potential legal dispute over whether or not the polluter is responsible for all chemical compounds formed in the human or natural environment after that chemical leaves the premises. It is now clear that all hazardous materials used in the preparation of this pesticide should have been registered with the local emergency authorities, and their biochemical reactions in human tissue identified and independently confirmed before the factory was allowed to function. Emergency preparedness of first responders and of the public and medical personnel is essential if industry persists in handling toxic chemicals. However, study of the distribution of the gases could never have led to an understanding of the plight of the Bhopal emergency personnel. Many gave mouth-to-mouth resuscitation to the victims, pulling the chemical cocktail into their own lungs. Their location beyond the circle of contamination meant that they were not eligible for compensation. Hence the mobility of the toxic chemicals via the mobility of human or animal victims must also be considered. Behaviour of the victims seriously affected the health outcome of exposure. Those who ran away from the factory, in the toxic cloud, received higher doses of the toxic gases than those who stayed in their houses. This difference could have been exploited for good, had the population been alerted to the nature of the gases, namely heavy and slow moving, and the danger of running for increasing the quantity inhaled. Even the cornea of the eye was scarred by running in the toxic cloud with the eyes half open-half closed.
Engineering studies of dispersal, wind patterns, time lapse, and environmental deposition could not predict the various reactions of the victims which either lessened or heightened their exposure. Long-term environmental effects of the disaster could also not be measured with an engineering approach. There is little or no research on the subsequent sensitivity to exposure of people who have passed through a disaster. The compromised lung tissue became susceptible to environmental pollutants which a healthy subject would not find harmful. Household pollution, such as the cooking stoves, became a major source of further health damage. Toxic waste long buried on the Union Carbide property leached into the water supply, re-exposing the same people who suffered the brunt of the disaster. Epidemiology studies well populations exposed to some environmental or workplace chemical, not persons who are already disabled from previous exposures. What was originally an acute toxic exposure, became for many victims a chronic exposure. Also the original damage to human organs came, in time, to affect the functioning and health of other organs. For example, lung damage causes breathing difficulties which can interfere with sleep. This sleep deprivation in turn causes neurological problems. The disaster experience, even for those who were not physically harmed, can cause post traumatic stress syndrome. One of the Bhopal victims recalls fainting, and when he awoke he was lying with a pile of dead bodies. The subsequent memories of such experiences can seriously disturb normal living patterns. Many victims found themselves unable to do the work they had done before the disaster, or they were limited in productivity. Many women cared for the sick while trying to earn a meager living with their own impaired health. The wage earner in the family was often killed or seriously injured, cutting off family income. The survivors were vulnerable to TB and other infectious diseases. In general, the effects of toxic exposure far exceed the dose-response estimates found in Toxicology Textbooks! While in natural disasters such as earthquakes or volcanoes, time appears to heal the damage done to humans, animals and the natural environment, man-made disasters appear to become worse with time. This is partially due to the compromised immune systems of the victims, which invites further sickness and disability under the normal stress on living, but it is also due to the effect of toxic materials on the reproductive organs, the embryo and fetus, resulting in diseased or disabled offspring. This places further burdens on survivor families, and on society. Lack of stable and adequate income adds to these burdens over time.
3. Epidemiological survey An epidemiological survey of a representative sample of randomly selected gas-exposed inhabitants of Bhopal was
S. Acquilla et al. / Journal of Loss Prevention in the Process Industries 18 (2005) 268–273
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Table 1 Exposure indices, formula number and description of the index [8] Index
Units
Description
Time Exposed Overall Sum of Duration Time Exposed Overall Weighted for Distance Sum of Duration Weighted for Distance Total Exposure Total Exposure Weighted for Distance
Minutes Minutes Min/km Min/km Liters Liters/km
Single estimate of total time each victim was exposed Sum of duration of physical activity periods during exposure Time Exposed Overall *1/Distance Sum of duration *1/Distance Sum of (duration*vent rate) for physical activity periods Total Exposure *1/Distance
Exposure-response relationships were examined, to determine whether these indices were useful in predicting health outcomes.
conducted in four, two km. concentric zones south of the factory, nine years after the accident in January 1994. For a reference group of unexposed persons in the same city, residents of similar area outside the exposed area were surveyed. Questionnaires regarding health and exposure were administered to 474 persons. A systematic sample comprising every fifth of the surveyed population (nZ76) was subjected to clinical examination including pulmonary function and neurological testing. Responses to the questionnaire and the results of clinical testing were analyzed according to a measure of individual gas exposure, with distance from the factory as the surrogate measure of exposure. The result showed that a large number of subjects reported general health problems (exposed v. unexposed; 94% v. 52%) and episodes of fever (7.5/year v. 2.5/year); adverse outcome of pregnancy (e.g. still-births, 9% v. 4%) and respiratory symptoms (81% v. 38%), with a strong gradient by exposure category. This was not accounted for by differences in smoking, and was consistent with the results of spirometric lung function testing. Subjects reported neurological and psychiatric symptoms more frequently, in the higher exposure categories. The results of neurological examination and testing tended to confirm this finding. Ophthalmic symptoms demonstrated a similar pattern. Although a number of other symptoms were reported (with the possible exception of musculo-skeletal and gastrointestinal disease), there was no clear evidence of
other organ system damage attributable to gas exposure. We concluded that the gradient of reported symptoms and clinical test results with estimates of exposure among these survivors of the gas leak, suggests that a proportion of their current respiratory and neurological disease was due to gas exposure (Refs. [5,6]). The randomized epidemiological method used by IMCB, provided a valid estimate of respiratory damage and exposure-response for the total exposed population in Bhopal (Ref. [7]). In the original investigation, we used as a study design and analysis: stratification of the study population, random selection of subjects, blinding of investigators to exposure status, and use of personal measures to increase the accuracy of exposure estimation. In the first two papers published by the IMCB, discussed above, distance of residence from the Union Carbide factory was significantly, inversely associated with respiratory and other symptoms, as was pulmonary function. In the third study (Ref. [8]), data was collected on selfreported activity patterns of the survivors, and it was determined that most individuals left home after encountering the gas cloud. About half of the subjects in the sample ran, walked, or left home by transport, and slightly less than a fourth remained at home. Some subjects gave responses such as ‘left home/went away/protected’ which were subject to varying interpretation and were therefore classified as ‘other’. Based on these self-reported activity patterns,
Table 2 Summary of associations between health outcomes and exposure indices [8] Exposure Index
Time Exp Overall Time Exp Overall Wgtd. For Distance Sum of Duration Sum of Duration Wgtd. for Distance Total Exposure Total Exposure wgtd. for Distance Distance
Respiratory Symptoms
Pulmonary Function
Cough 3 months
Asthma
Phlegm
Shortness of Breath
# #
# #
#
#
#
#
# #
# #
# #
#
#
#
#
#
#
#
#
Full Sample FEF25–75
Case Series FEF25–75
Case Series FVC
Case Series FEV1
# #
#
# #
‘#’: the exposure index and health outcome were associated in these data, based: on ratio of mean exposures in those with and without symptom, or slope of regression line for pulmonary function parameter; as well as on p-value from test that the mean difference or slope was zero.
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exposure indices were developed to reconstruct pulmonary dose. These indices incorporated surrogates of exposure, such as duration, activity, and distance of residence, either individually or in various combinations. Exposure-response relationships were examined, and it was determined whether these indices were useful in predicting health outcomes Tables 1 and 2. The results showed that an index incorporating distance of residence, duration, and activity was associated with both respiratory and non-respiratory symptoms, as well as pulmonary function. It was concluded that, despite the time elapsed since the accident and the potential for recall bias, it might be possible to estimate the individual exposure in the survivors with some degree of accuracy, perhaps because of the dramatic nature of the accident.
4. Effectiveness of the International Medical Commission Bhopal The International Medical Commission Bhopal’s humanitarian visit to Bhopal and research of these problems, gave a clearer picture of the long term health effects, and helped to set some directions toward appropriate political and medical response, which would be relevant and proportional to the long term effects of the disaster. While government response was slight, private initiatives like the Sambhavna Clinic, Bhopal Gas Peedith Mahila Udyog Saghatana (Bhopal was affected Womens Group), and Swabhiman Kendra (Self-Respect Centre) were established with the aim of meeting some of the most urgent needs of the Bhopal Survivors. A reliable and thorough medical-epidemiological investigation of the events and consequences has yet to be made; given the time elapsed since the disaster occurred; it is likely never to become avilable. This fact does not come as a surprise: too many conflicting interests prevented any coordinated medical investigation into the disaster. Other factors include the non-accountability for lives lost in natural and man-made disasters, which occur in economically developing nations. It is all too well known that the planned absence of knowledge is a key (and most of the time very effective) mechanism of impunity. The IMCB could obviously not (nor pretended to) fill the gap: the length and the extent of its involvement were too limited in terms of resources to allow an impact going much beyond a contribution to a broader awareness of some of the incapacity of the so called ‘scientific community’ in playing a decisive role in the defense of the rights of the victims. The following points try to summarize some of the findings which integrate and give more sense to the very limited (almost symbolic) data which have been collected and are briefly recalled in this contribution. (1) The IMCB. Created so long after the event-documents
first of all the dramatic absence of the medical, toxicological, epidemiological disciplines from the areas where they were most needed. It is enough to compare the degree of mobilization of resources and action which (though far from ideal) occurred only eight years before in the far less dramatic event in Seveso, whose follow-up continues to produce data on the consequences of the exposure of the population to the toxic substances released into the environment from the ICMESA reactor (dioxin was the main and most dangerous component). The difference is the measure of the incapacity (impotence? impossibility? incompetence? unwillingness? their combination?) of the present organization of life-science professionals to assure equal opportunities of knowledge, even before solutions, to peoples with similar rights. (2) The concrete, but clearly symbolic activity of the IMCB produced urgent recommendations on the priority of establishing a model health care system in the area, where primary care had to be the protagonist (via a good integration of traditional and western approaches and competences), with the support of specialized services. The experiences of the previously mentioned private initiatives (based on ‘traditional’ tools and using voluntary funds) highlight the critical importance of services which are relevant to the daily needs of the population. They also reveal the failure of the ‘orthodox’ (national and international) sciences to provide effective, medium and long-term support, and relief, in terms of knowledge and care. (3) The absence of first hand knowledge and care for the medical outcomes of the Bhopal disaster is one of the aspects of the overall re-victimization process of the victims of Bhopal. A comprehensive, critical recompilation of all the fragments of information on the toxicological, epidemiological, clinical consequences of the worst industrial disaster would certainly be needed, though it would be much time consuming, and most likely hardly feasible. Though, it should be a ‘must’ for the responsibility of the international scientific community. In its absence, it would be good to make the history of the ‘absences’ and of the ‘missing information’ on Bhopal victims a mandatory component of the curricula of all those who are trained in environmental toxicology and epidemiology as well as in public and clinical health.
References [1] Chemical toxicity: A matter of massive miscalculation, By: Jay H. Lehr, Ph.D., Managing Editor; Published In: Environment News, March 1, 2001. Publisher: The Heartland Institute. [2] ‘Investigating Environmental Health Hazards’ by James Melius, M.D., Dr. P.H., in OCCUPATIONAL MEDICINE, Second Edition, Editor Carl Zenz, The Yearbook Medical Publishers, 1988, p 99.
S. Acquilla et al. / Journal of Loss Prevention in the Process Industries 18 (2005) 268–273 [3] The Fundamental aim of Radiological Protection was set out as follows in the 1990 Recommendations of ICRP: ‘The primary aim of radiological protection is to provide an appropriate standard of protection for man without unduly limiting the beneficial actions giving rise to radiation exposure..All those concerned with radiological protection have to make judgements about the relative importance of different kinds of risk and about balancing of risks and benefits.’. [4] ‘International Medical Commission Bhopal: a model for the future’, by R. Bertell and G. Tognoni. Nat. Med. J. India: 9(2): 86-91, 1996.
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[5] Acquilla SD, Cullinan P, Dhara VR, ‘Long-term morbidity in survivors of the 1984 Bhopal gas leak’. Natl Med J India. 1996; 9:5-10. [6] ‘Respiratory morbidity 10 years after the Union Carbide gas leak in Bhopal’ by Cullinan P (1997). Acquilla SD, Dhara VR. BMJ. 314: 338–342. [7] ‘An exposure-response method for assessing the long-term health effects of the Bhopal disaster’ by Dhara VR, Kriebel D. Disasters. 1993;17(4):281-90. [8] ‘Personal exposure and long-term health effects in survivors of the Union Carbide disaster in Bhopal’ by Dhara VR (2002). Dhara R, Acquilla SD, Cullinan P. Environ Health Prespectives. 110(5):487–500.
Aftermath of the world’s worst chemical disaster Bhopal, December 1984 S. Acquillaa,*, R. Bertellb, V.R. Dharac, G. Tognonid a
London Postgraduate Medical and Dental Education, London Deanery, 20 Guilford Street, London WC1N 1DZ, UK b International Institute of Concern for Public Health, Toronto, Canada c Rollins School of Public Health of Emory University, Atlanta, GA, USA d Department of Cardiovascular Research, Laboratory of Clinical Pharmacology, Istituto Mario Negri, Milano, Italy
Abstract Current practice in preventive environmental health action includes chemical analysis of land, water and air for known (controlled) toxic chemicals and comparison against standards for identification of breaches of regulatory limits. This methodology is also followed after an accident or disaster to ensure air, water and food safety. Some problems, not easily addressed by this methodology include: unidentified toxic chemicals; non-conventional uses of toxic materials, unexpected synergestic effects of toxic mixtures, and human health consequences of exposure to toxic materials with unusual and unidentified pathways of exposures. In Bhopal we were faced with a mixture of about 27 toxic substances, a variety of exposures related to activities of the persons, for example, remaining in their homes or running in the toxic cloud, and a variety of perceived injuries not all of which would have been predicted by analyzing the chemicals involved. In this paper we will present the advantages of combinations of approaches including examination of health, social and cultural environment and economic situation of the victims of the Bhopal disaster and their effect on health. This more broad analysis provides a clearer big picture of the problems in the aftermath of exposure, and also clues to effective treatment and alleviation of future problems. We will present two effective strategies for connecting health problems ten years after exposure to the original disaster, and understanding the biochemical reactions in the body when invaded by a mixture of toxic substances and how such an understanding will in turn affect public policy planning, emergency preparedness and emergency medicine. Crown Copyright q 2005 Published by Elsevier Ltd. All rights reserved.
1. Advantages of Medical Evaluation after a Chemical Disaster Whenever a toxic mixture is released on an unprepared and unsuspecting population, the effects will be modified by the characteristics of the mixture itself, including the potential interaction of the chemicals, as well as the chronological and biological ages of the victims, their activities at the time of the exposure, their basic health parameters before the accident, the medicines that they have been taking, and their state of anxiety and fear. Through the chemical engineering approach to the disaster, we can learn of the controlled aspects of the substance(s) released, their known toxicology in the workplace, and any dose-response reaction which has been researched and published, * Corresponding author. Tel.: C020 7 692 3239. E-mail address: [email protected] (S. Acquilla).
estimating the potential human health damage. While this is a necessary first step, and sets some parameters and guidelines for the medical personnel, it falls short of completely defining the disaster and its consequences. Currently there are some well-done toxicological studies, but most toxic chemicals go without professional evaluation. Toxicological testing began in about the early 1930’s, but did not become an academic discipline until about 1961 when the Society of Toxicology was formed. During the 1970’s and 1980’s, toxicology became an academic subject in the Universities. Many toxicologists have arrived at this profession through their professional experience rather than formal training, and there are clearly major disagreements in areas of toxicological concern with respect to particular chemicals. Regulation follows slowly after toxicological research, so total reliance on regulatory limits as safeguarding public health is risky. By definition, toxicology attempts to determine the
0950-4230/$ - see front matter Crown Copyright q 2005 Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jlp.2005.06.008
S. Acquilla et al. / Journal of Loss Prevention in the Process Industries 18 (2005) 268–273
effects of a given chemical on living organisms. Since our understanding of living organisms is often not precise, toxicology can be at best an educated guess. ‘In toxicology, the certainty most of us seek is that a particular chemical is safe. Unfortunately, there is no such thing as an absolutely safe chemical: all chemicals can cause toxic effects in large enough amounts. When faced with this reality, most people look for a different certainty: a ‘safe’ amount. They want to know the exact level at which a chemical changes from nontoxic to toxic. Again, this is not a scientifically realistic goal. Human individuals vary tremendously in their responses to their environment, including the chemicals in it, so what is ‘safe’ for one person may not be ‘safe’ for another’. (Ref. [1]) In addition to this problem of human variability, we have numerous potential chemical compounds and physical states for any given toxic chemical, which can alter the toxic effects. Each chemical compound needs to be evaluated separately. Gases behave differently from liquids and solids. The portal through which the toxic substance enters the body is also of concern. Those things which enter via ingestion will be sorted out by the gut wall and then subjected to further scrutiny by the liver before being excreted through the kidneys or allowed to enter the body. There are no such screening devices in our lungs for inhalation. Since we have introduced some 70,000 to 80,000 new chemicals into the human living space since 1950, the task of testing the interaction of chemicals in the many potential mixtures which occur in the environment is impossible. Faced with this dilemma, regulators have resorted to choosing particular chemicals, both for high toxicity and prevalence, for regulation. Interactions between chemicals, or between chemicals and electromagnetic energy, are ignored. The biochemical interaction of toxic chemicals within the human body, or with medicines the person may be taking, offers further complexity not even casually addressed by science.
2. Regulation of Chemicals in the Environment Ordinarily the toxic effects of chemicals are first noticed in the workplace. Because of the enclosed situation of most workplaces, the ability to monitor for a particular suspected chemical, and the potential which this offers for setting a dose-response estimate needed for standard setting, most information on toxicity of chemicals is based on workplace studies. In terms of applying this information to the general public, there are drawbacks which are hard to overcome. For example, the worker is usually male, a young adult or early middle aged, in good health (able to pass a physical examination for work) and usually Caucasian, living in a country where he has at least some political voice. The
269
worker is in the workplace for a limited time, usually eight hours a day, followed by a 16 h respite period, and one or two ‘free days’ a week. The workplace is contained, and the toxic chemicals to which the worker is exposed are limited in number and distribution within that space. These are all characteristics that help the toxicologist to do precise work in establishing the relative toxicity and dose-response pattern of one hazardous chemical. This is, of course, helpful for setting standards for exposure for one hazardous chemical for the typical worker in the typical workplace, but it is not helpful in trying to regulate a mixture of hazardous materials in the living place, where there is less predictability and control. In trying to transfer this learning to the living space, one faces multiple problems: the living space is not contained in a building; it houses women and children as well as adult males; some members are ill, have damaged immune systems, or are immature; children and the elderly are confined to their living space 24 h a day, seven days a week. Moreover, the chemicals in the living space are highly likely to be multiple, to be undergoing chemical reactions in the environment, and are interacting with the myriads of biological matter, bacteria, animals and plants, household cleaning agents, and medicines to create new organic and inorganic chemical compounds with unknown effects. Standards set for the workplace are likely NOT appropriate for the living space (Ref. [2]). In addition, some regulated toxic chemicals were not regulated on the basis of health studies. For example, heavy metals are often regulated on the basis of past clean-up experience at polluted industrial sites. The purpose of regulation of heavy metals is to discover recent pollution that exceeds so called ‘historic’ levels, so that prosecution of the polluters will be possible. Other substances, like ionizing radiation, are regulated by an industry committee which decides the ‘acceptable’ risk-benefit trade off, that which is most reasonable given the value of the activity. They use health related research only to contribute to the risk part of the risk-benefit equation (Ref. [3]). The International Medical Commission Bhopal (IMCB) (Ref. [4]) went to Bhopal in January 1994, at the request of the Bhopal gas survivors. We attempted to scientifically verify that survivor’s current medical problems were related to the original exposure damage, as a basis for recommending survivor’s medical care. We also attempted to identify and document chronic disability, as required for compensation. Our team consisted of thirteen physicians and scientists from eleven different countries, who had never worked together before this mission to Bhopal. We met in Delhi for a week of planning before proceeding on to Bhopal, where we worked continuously for three more weeks. All professional services were donated, and charities and unions provided us with money for travel and lodging. Although it is generally agreed that methyl isocyanate was released in the Bhopal disaster, there were other
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chemicals also released. Workers from the plant have identified the ones which they presume were released, given their experience with the work place technology. However, Union Carbide (or its new owner, Dow Chemical) has not yet (after 20 years) authored a full analysis of the toxic chemicals released, and the timing of these releases. Timing is important because of the changes in the direction of the wind during the prolonged disaster. If different gases were released at different times during the disaster, then their geographic distribution depends heavily on wind direction at time of release. This data was never available to emergency workers, or to the IMCB. There may have been multiplicative or additive effects of the toxic mixture at different times and places. The biochemical action of methyl isocyanate in the body of the victims has been disputed for the past 20 years. Some say the methyl isocyanate disassociates into cyanide in the body, while others dispute this. This dispute arose because the factory management denied this biochemical reaction. Thereafter, due to Union Carbide management assurances, pathological evidence of cyanide poisoning was rejected by the emergency physicians, who failed to apply an antidote present in the hospital pharmacy. Study only of the released chemical, and not of its biochemical reactions within the body, is inadequate for public health purposes. There is also a potential legal dispute over whether or not the polluter is responsible for all chemical compounds formed in the human or natural environment after that chemical leaves the premises. It is now clear that all hazardous materials used in the preparation of this pesticide should have been registered with the local emergency authorities, and their biochemical reactions in human tissue identified and independently confirmed before the factory was allowed to function. Emergency preparedness of first responders and of the public and medical personnel is essential if industry persists in handling toxic chemicals. However, study of the distribution of the gases could never have led to an understanding of the plight of the Bhopal emergency personnel. Many gave mouth-to-mouth resuscitation to the victims, pulling the chemical cocktail into their own lungs. Their location beyond the circle of contamination meant that they were not eligible for compensation. Hence the mobility of the toxic chemicals via the mobility of human or animal victims must also be considered. Behaviour of the victims seriously affected the health outcome of exposure. Those who ran away from the factory, in the toxic cloud, received higher doses of the toxic gases than those who stayed in their houses. This difference could have been exploited for good, had the population been alerted to the nature of the gases, namely heavy and slow moving, and the danger of running for increasing the quantity inhaled. Even the cornea of the eye was scarred by running in the toxic cloud with the eyes half open-half closed.
Engineering studies of dispersal, wind patterns, time lapse, and environmental deposition could not predict the various reactions of the victims which either lessened or heightened their exposure. Long-term environmental effects of the disaster could also not be measured with an engineering approach. There is little or no research on the subsequent sensitivity to exposure of people who have passed through a disaster. The compromised lung tissue became susceptible to environmental pollutants which a healthy subject would not find harmful. Household pollution, such as the cooking stoves, became a major source of further health damage. Toxic waste long buried on the Union Carbide property leached into the water supply, re-exposing the same people who suffered the brunt of the disaster. Epidemiology studies well populations exposed to some environmental or workplace chemical, not persons who are already disabled from previous exposures. What was originally an acute toxic exposure, became for many victims a chronic exposure. Also the original damage to human organs came, in time, to affect the functioning and health of other organs. For example, lung damage causes breathing difficulties which can interfere with sleep. This sleep deprivation in turn causes neurological problems. The disaster experience, even for those who were not physically harmed, can cause post traumatic stress syndrome. One of the Bhopal victims recalls fainting, and when he awoke he was lying with a pile of dead bodies. The subsequent memories of such experiences can seriously disturb normal living patterns. Many victims found themselves unable to do the work they had done before the disaster, or they were limited in productivity. Many women cared for the sick while trying to earn a meager living with their own impaired health. The wage earner in the family was often killed or seriously injured, cutting off family income. The survivors were vulnerable to TB and other infectious diseases. In general, the effects of toxic exposure far exceed the dose-response estimates found in Toxicology Textbooks! While in natural disasters such as earthquakes or volcanoes, time appears to heal the damage done to humans, animals and the natural environment, man-made disasters appear to become worse with time. This is partially due to the compromised immune systems of the victims, which invites further sickness and disability under the normal stress on living, but it is also due to the effect of toxic materials on the reproductive organs, the embryo and fetus, resulting in diseased or disabled offspring. This places further burdens on survivor families, and on society. Lack of stable and adequate income adds to these burdens over time.
3. Epidemiological survey An epidemiological survey of a representative sample of randomly selected gas-exposed inhabitants of Bhopal was
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Table 1 Exposure indices, formula number and description of the index [8] Index
Units
Description
Time Exposed Overall Sum of Duration Time Exposed Overall Weighted for Distance Sum of Duration Weighted for Distance Total Exposure Total Exposure Weighted for Distance
Minutes Minutes Min/km Min/km Liters Liters/km
Single estimate of total time each victim was exposed Sum of duration of physical activity periods during exposure Time Exposed Overall *1/Distance Sum of duration *1/Distance Sum of (duration*vent rate) for physical activity periods Total Exposure *1/Distance
Exposure-response relationships were examined, to determine whether these indices were useful in predicting health outcomes.
conducted in four, two km. concentric zones south of the factory, nine years after the accident in January 1994. For a reference group of unexposed persons in the same city, residents of similar area outside the exposed area were surveyed. Questionnaires regarding health and exposure were administered to 474 persons. A systematic sample comprising every fifth of the surveyed population (nZ76) was subjected to clinical examination including pulmonary function and neurological testing. Responses to the questionnaire and the results of clinical testing were analyzed according to a measure of individual gas exposure, with distance from the factory as the surrogate measure of exposure. The result showed that a large number of subjects reported general health problems (exposed v. unexposed; 94% v. 52%) and episodes of fever (7.5/year v. 2.5/year); adverse outcome of pregnancy (e.g. still-births, 9% v. 4%) and respiratory symptoms (81% v. 38%), with a strong gradient by exposure category. This was not accounted for by differences in smoking, and was consistent with the results of spirometric lung function testing. Subjects reported neurological and psychiatric symptoms more frequently, in the higher exposure categories. The results of neurological examination and testing tended to confirm this finding. Ophthalmic symptoms demonstrated a similar pattern. Although a number of other symptoms were reported (with the possible exception of musculo-skeletal and gastrointestinal disease), there was no clear evidence of
other organ system damage attributable to gas exposure. We concluded that the gradient of reported symptoms and clinical test results with estimates of exposure among these survivors of the gas leak, suggests that a proportion of their current respiratory and neurological disease was due to gas exposure (Refs. [5,6]). The randomized epidemiological method used by IMCB, provided a valid estimate of respiratory damage and exposure-response for the total exposed population in Bhopal (Ref. [7]). In the original investigation, we used as a study design and analysis: stratification of the study population, random selection of subjects, blinding of investigators to exposure status, and use of personal measures to increase the accuracy of exposure estimation. In the first two papers published by the IMCB, discussed above, distance of residence from the Union Carbide factory was significantly, inversely associated with respiratory and other symptoms, as was pulmonary function. In the third study (Ref. [8]), data was collected on selfreported activity patterns of the survivors, and it was determined that most individuals left home after encountering the gas cloud. About half of the subjects in the sample ran, walked, or left home by transport, and slightly less than a fourth remained at home. Some subjects gave responses such as ‘left home/went away/protected’ which were subject to varying interpretation and were therefore classified as ‘other’. Based on these self-reported activity patterns,
Table 2 Summary of associations between health outcomes and exposure indices [8] Exposure Index
Time Exp Overall Time Exp Overall Wgtd. For Distance Sum of Duration Sum of Duration Wgtd. for Distance Total Exposure Total Exposure wgtd. for Distance Distance
Respiratory Symptoms
Pulmonary Function
Cough 3 months
Asthma
Phlegm
Shortness of Breath
# #
# #
#
#
#
#
# #
# #
# #
#
#
#
#
#
#
#
#
Full Sample FEF25–75
Case Series FEF25–75
Case Series FVC
Case Series FEV1
# #
#
# #
‘#’: the exposure index and health outcome were associated in these data, based: on ratio of mean exposures in those with and without symptom, or slope of regression line for pulmonary function parameter; as well as on p-value from test that the mean difference or slope was zero.
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exposure indices were developed to reconstruct pulmonary dose. These indices incorporated surrogates of exposure, such as duration, activity, and distance of residence, either individually or in various combinations. Exposure-response relationships were examined, and it was determined whether these indices were useful in predicting health outcomes Tables 1 and 2. The results showed that an index incorporating distance of residence, duration, and activity was associated with both respiratory and non-respiratory symptoms, as well as pulmonary function. It was concluded that, despite the time elapsed since the accident and the potential for recall bias, it might be possible to estimate the individual exposure in the survivors with some degree of accuracy, perhaps because of the dramatic nature of the accident.
4. Effectiveness of the International Medical Commission Bhopal The International Medical Commission Bhopal’s humanitarian visit to Bhopal and research of these problems, gave a clearer picture of the long term health effects, and helped to set some directions toward appropriate political and medical response, which would be relevant and proportional to the long term effects of the disaster. While government response was slight, private initiatives like the Sambhavna Clinic, Bhopal Gas Peedith Mahila Udyog Saghatana (Bhopal was affected Womens Group), and Swabhiman Kendra (Self-Respect Centre) were established with the aim of meeting some of the most urgent needs of the Bhopal Survivors. A reliable and thorough medical-epidemiological investigation of the events and consequences has yet to be made; given the time elapsed since the disaster occurred; it is likely never to become avilable. This fact does not come as a surprise: too many conflicting interests prevented any coordinated medical investigation into the disaster. Other factors include the non-accountability for lives lost in natural and man-made disasters, which occur in economically developing nations. It is all too well known that the planned absence of knowledge is a key (and most of the time very effective) mechanism of impunity. The IMCB could obviously not (nor pretended to) fill the gap: the length and the extent of its involvement were too limited in terms of resources to allow an impact going much beyond a contribution to a broader awareness of some of the incapacity of the so called ‘scientific community’ in playing a decisive role in the defense of the rights of the victims. The following points try to summarize some of the findings which integrate and give more sense to the very limited (almost symbolic) data which have been collected and are briefly recalled in this contribution. (1) The IMCB. Created so long after the event-documents
first of all the dramatic absence of the medical, toxicological, epidemiological disciplines from the areas where they were most needed. It is enough to compare the degree of mobilization of resources and action which (though far from ideal) occurred only eight years before in the far less dramatic event in Seveso, whose follow-up continues to produce data on the consequences of the exposure of the population to the toxic substances released into the environment from the ICMESA reactor (dioxin was the main and most dangerous component). The difference is the measure of the incapacity (impotence? impossibility? incompetence? unwillingness? their combination?) of the present organization of life-science professionals to assure equal opportunities of knowledge, even before solutions, to peoples with similar rights. (2) The concrete, but clearly symbolic activity of the IMCB produced urgent recommendations on the priority of establishing a model health care system in the area, where primary care had to be the protagonist (via a good integration of traditional and western approaches and competences), with the support of specialized services. The experiences of the previously mentioned private initiatives (based on ‘traditional’ tools and using voluntary funds) highlight the critical importance of services which are relevant to the daily needs of the population. They also reveal the failure of the ‘orthodox’ (national and international) sciences to provide effective, medium and long-term support, and relief, in terms of knowledge and care. (3) The absence of first hand knowledge and care for the medical outcomes of the Bhopal disaster is one of the aspects of the overall re-victimization process of the victims of Bhopal. A comprehensive, critical recompilation of all the fragments of information on the toxicological, epidemiological, clinical consequences of the worst industrial disaster would certainly be needed, though it would be much time consuming, and most likely hardly feasible. Though, it should be a ‘must’ for the responsibility of the international scientific community. In its absence, it would be good to make the history of the ‘absences’ and of the ‘missing information’ on Bhopal victims a mandatory component of the curricula of all those who are trained in environmental toxicology and epidemiology as well as in public and clinical health.
References [1] Chemical toxicity: A matter of massive miscalculation, By: Jay H. Lehr, Ph.D., Managing Editor; Published In: Environment News, March 1, 2001. Publisher: The Heartland Institute. [2] ‘Investigating Environmental Health Hazards’ by James Melius, M.D., Dr. P.H., in OCCUPATIONAL MEDICINE, Second Edition, Editor Carl Zenz, The Yearbook Medical Publishers, 1988, p 99.
S. Acquilla et al. / Journal of Loss Prevention in the Process Industries 18 (2005) 268–273 [3] The Fundamental aim of Radiological Protection was set out as follows in the 1990 Recommendations of ICRP: ‘The primary aim of radiological protection is to provide an appropriate standard of protection for man without unduly limiting the beneficial actions giving rise to radiation exposure..All those concerned with radiological protection have to make judgements about the relative importance of different kinds of risk and about balancing of risks and benefits.’. [4] ‘International Medical Commission Bhopal: a model for the future’, by R. Bertell and G. Tognoni. Nat. Med. J. India: 9(2): 86-91, 1996.
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[5] Acquilla SD, Cullinan P, Dhara VR, ‘Long-term morbidity in survivors of the 1984 Bhopal gas leak’. Natl Med J India. 1996; 9:5-10. [6] ‘Respiratory morbidity 10 years after the Union Carbide gas leak in Bhopal’ by Cullinan P (1997). Acquilla SD, Dhara VR. BMJ. 314: 338–342. [7] ‘An exposure-response method for assessing the long-term health effects of the Bhopal disaster’ by Dhara VR, Kriebel D. Disasters. 1993;17(4):281-90. [8] ‘Personal exposure and long-term health effects in survivors of the Union Carbide disaster in Bhopal’ by Dhara VR (2002). Dhara R, Acquilla SD, Cullinan P. Environ Health Prespectives. 110(5):487–500.