Bhopal, India

Source: Biomed.central


On December 3, 1984, at least 27 tons of methyl isocyanate gas leaked from a pesticide plant in Bhopal (23°17’ North, 77°28’ East), in the state of Madhya Pradesh, India, immediately killing at least 3,800 people and causing significant morbidity and premature death for many thousands more. The Bhopal plant was owned and operated by Union Carbide India, Limited (UCIL), an Indian company in which Union Carbide Corporation (UCC) held just over half the stock. The company involved in what became the worst industrial accident in history immediately tried to dissociate itself from legal responsibility. Eventually it reached a settlement with the Indian Government through mediation of that country's Supreme Court and accepted moral responsibility. It paid $470 million in compensation, a relatively small amount based on significant underestimations of the long-term health consequences of exposure and the number of people exposed. The disaster indicated a need for enforceable international standards for environmental safety, preventative strategies to avoid similar accidents and industrial disaster preparedness.

The accident

caption A woman looks at photographic exhibit on the Bhopal disaster. (Source: Reuters)

During the early morning hours of December 3, 1984, methyl isocyanate (MIC), a reactive and toxic gas, leaked from a Union Carbide holding tank when water was introduced into the storage tank creating a chemical reaction. MIC is used as a chemical intermediate in the production of carbamate insecticides and herbicides. This reaction generated a substantial increase in the temperature of liquid inside the tank, building pressure and giving off a large volume of toxic gas. Safety systems—such as a flare tower (for the burning of excess gas), a caustic soda scrubber (for neutralization), and a refrigeration unit—did not contain the reaction. More than 27 tons of the gas had escaped into the air, spreading approximately eight kilometers downwind, over the city of nearly 900,000.

Prevailing atmospheric conditions such as inversion and a low wind speed prevented dispersion of the gas. Eyewitnesses reported that a cloud of gas enveloped the area and moved slowly through the residential neighborhood. The MIC concentration was estimated to be about 27 parts per million (ppm), or about 1,400 times that of the U.S. Occupational Safety and Health Administration workplace standard of 0.02 ppm over an 8-hr work day.

The acute irritant effects of MIC created panic, anxiety, and disorientation, and it caused people to run out of their homes into the gas cloud, the result of which was an increased dose of the chemical. Variability in human exposure, therefore, was likely to have resulted from distance of the residence from the plant, duration of exposure, and activity during exposure.

Health effects

Of the more than 200,000 persons exposed to the gas, the death toll 1 week following the accident exceeded 2,500. In November 1989, the Department of Relief and Rehabilitation, Government of Madhya Pradesh, placed the death toll at 3,598, and by 1994 the toll was estimated at 6,000+. Some uncertainty exists regarding the number of deaths because a portion of the population left the city after the accident and never returned. Independent agencies estimate that the number of disaster-related deaths is currently between 15,000 and 20,000. Pulmonary edema was the probable cause of death in most cases, with many deaths resulting from secondary respiratory infections. Chronic inflammatory damage to the eyes and lungs appears to be the main cause of morbidity.


Immediately after the disaster, according to the author, UCC began attempts to dissociate itself from responsibility for the gas leak. Its principal tactic was to shift culpability to UCIL, stating the plant was wholly built and operated by the Indian subsidiary. Ucc also, according to the author, fabricated scenarios involving sabotage by previously unknown Sikh extremist groups and disgruntled employees but this theory was impugned by numerous independent sources.

The toxic plume had barely cleared when, on December 7, the first multi-billion dollar lawsuit was filed by an American attorney in a U.S. court. This was the beginning of years of legal machinations in which the ethical implications of the tragedy and its affect on Bhopal's people were largely ignored. In March 1985, the Indian government enacted the Bhopal Gas Leak Disaster Act as a way of ensuring that claims arising from the accident would be dealt with speedily and equitably. The Act made the government the sole representative of the victims in legal proceedings both within and outside India. Eventually all cases were taken out of the U.S. legal system under the ruling of the presiding American judge and placed entirely under Indian jurisdiction much to the detriment of the injured parties.

In a settlement mediated by the Indian Supreme Court, UCC accepted moral responsibility and agreed to pay $470 million to the Indian government to be distributed to claimants as a full and final settlement. The figure was partly based on the disputed claim that only 3,000 people died and 102,000 suffered permanent disabilities. Upon announcing this settlement, shares of UCC rose $2 per share or 7% in value. Had compensation in Bhopal been paid at the same rate that asbestosis victims where being awarded in U.S. courts by defendant including UCC – which mined asbestos from 1963 to 1985 – the liability would have been greater than the $10 billion the company was worth and insured for in 1984. By the end of October 2003, according to the Bhopal Gas Tragedy Relief and Rehabilitation Department, compensation had been awarded to 554,895 people for injuries received and 15,310 survivors of those killed. The average amount to families of the dead was $2,200.

According to this author at every turn, UCC has attempted to manipulate, obfuscate and withhold scientific data to the detriment of victims. Even to this date, the company has not stated exactly what was in the toxic cloud that enveloped the city on that December night. When MIC is exposed to 200° heat, it forms degraded MIC that contains the more deadly hydrogen cyanide (HCN). There was clear evidence that the storage tank temperature did reach this level in the disaster. The cherry-red color of blood and viscera of some victims were characteristic of acute cyanide poisoning. Moreover, many responded well to administration of sodium thiosulfate, an effective therapy for cyanide poisoning but not MIC exposure. UCC initially recommended use of sodium thiosulfate but withdrew the statement later prompting suggestions that it attempted to cover up evidence of HCN in the gas leak. The presence of HCN was vigorously denied by UCC and was a point of conjecture among researchers.

Lessons learned

The events in Bhopal revealed that expanding industrialization in developing countries without concurrent evolution in safety regulations could have catastrophic consequences. The disaster demonstrated that seemingly local problems of industrial hazards and toxic contamination are often tied to global market dynamics. UCC's Sevin production plant was built in Madhya Pradesh not to avoid environmental regulations in the U.S. but to exploit the large and growing Indian pesticide market. However the manner in which the project was executed suggests the existence of a double standard for multinational corporations operating in developing countries. Enforceable uniform international operating regulations for hazardous industries would have provided a mechanism for significantly improved in safety in Bhopal. Even without enforcement, international standards could provide norms for measuring performance of individual companies engaged in hazardous activities such as the manufacture of pesticides and other toxic chemicals in India. National governments and international agencies should focus on widely applicable techniques for corporate responsibility and accident prevention as much in the developing world context as in advanced industrial nations. Specifically, prevention should include risk reduction in plant location and design and safety legislation.

Local governments clearly cannot allow industrial facilities to be situated within urban areas, regardless of the evolution of land use over time. Industry and government need to bring proper financial support to local communities so they can provide medical and other necessary services to reduce morbidity, mortality and material loss in the case of industrial accidents.

Public health infrastructure was very weak in Bhopal in 1984. Tap water was available for only a few hours a day and was of very poor quality. With no functioning sewage system, untreated human waste was dumped into two nearby lakes, one a source of drinking water. The city had four major hospitals but there was a shortage of physicians and hospital beds. There was also no mass casualty emergency response system in place in the city. Existing public health infrastructure needs to be taken into account when hazardous industries choose sites for manufacturing plants. Future management of industrial development requires that appropriate resources be devoted to advance planning before any disaster occurs. Communities that do not possess infrastructure and technical expertise to respond adequately to such industrial accidents should not be chosen as sites for hazardous industry.

Since 1984

Following the events of December 3 1984 environmental awareness and activism in India increased significantly. The Environment Protection Act was passed in 1986, creating the Ministry of Environment and Forests (MoEF) and strengthening India's commitment to the environment. Under the new act, the MoEF was given overall responsibility for administering and enforcing environmental laws and policies. It established the importance of integrating environmental strategies into all industrial development plans for the country. However, despite greater government commitment to protect public health, forests, and wildlife, policies geared to developing the country's economy have taken precedence in the last 20 years.

India has undergone tremendous economic growth in the two decades since the Bhopal disaster. Gross domestic product (GDP) per capita has increased from $1,000 in 1984 to $2,900 in 2004 and it continues to grow at a rate of over 8% per year. Rapid industrial development has contributed greatly to economic growth but there has been significant cost in environmental degradation and increased public health risks. Since abatement efforts consume a large portion of India's GDP, MoEF faces an uphill battle as it tries to fulfill its mandate of reducing industrial pollution. Heavy reliance on coal-fired power plants and poor enforcement of vehicle emission laws have result from economic concerns taking precedence over environmental protection.

With the industrial growth since 1984, there has been an increase in small-scale industries (SSIs) that are clustered about major urban areas in India. There are generally less stringent rules for the treatment of waste produced by SSIs due to less waste generation within each individual industry. This has allowed SSIs to dispose of untreated wastewater into drainage systems that flow directly into rivers. New Delhi's Yamuna River is illustrative. Dangerously high levels of heavy metals such as lead, cobalt, cadmium, chrome, nickel and zinc have been detected in this river which is a major supply of potable water to India's capital thus posing a potential health risk to the people living there and areas downstream.

Land pollution due to uncontrolled disposal of industrial solid and hazardous waste is also a problem throughout India. With rapid industrialization, the generation of industrial solid and hazardous waste has increased appreciably and the environmental impact is significant.

UCC has shrunk to one sixth of its size since the Bhopal disaster in an effort to restructure and divest itself. By doing so, the company avoided a hostile takeover, placed a significant portion of UCC's assets out of legal reach of the victims and gave its shareholder and top executives bountiful profits. The company still operates under the ownership of Dow Chemicals and still states on its website that the Bhopal disaster was "caused by deliberate sabotage".

Some positive changes were seen following the Bhopal disaster. The British chemical company, ICI, whose Indian subsidiary manufactured pesticides, increased attention to health, safety and environmental issues following the events of December 1984. The subsidiary now spends 30–40% of their capital expenditures on environmental-related projects. However, they still do not adhere to standards as strict as their parent company in the UK.


The tragedy of Bhopal continues to be a warning sign at once ignored and heeded. Bhopal and its aftermath were a warning that the path to industrialization, for developing countries in general and India in particular, is fraught with human, environmental and economic perils. Some moves by the Indian government, including the formation of the MoEF, have served to offer some protection of the public's health from the harmful practices of local and multinational heavy industry and grassroots organizations that have also played a part in opposing rampant development. The Indian economy is growing at a tremendous rate but at significant cost in environmental health and public safety as large and small companies throughout the subcontinent continue to pollute. Far more remains to be done for public health in the context of industrialization to show that the lessons of the countless thousands dead in Bhopal have truly been heeded.

Editor's Note

This article is derived largely from Edward Broughton, The Bhopal disaster and its aftermath: a review, Environmental Health: A Global Access Science Source 2005, 4:6, doi:10.1186/1476-069X-4-6. Topic editors and authors for the Encyclopedia of Earth have edited its content or added new information. That article is used here under the terms of its Creative Commons Attribution License. The use of information from the original article should not be construed as support for or endorsement by its author for any new information added by EoE personnel, or for any editing of the original content.

Further Reading

  • International Campaign for Justice in Bhopal
  • Students for Bhopal
  • The Bhopal Medical Appeal and Sambhavna Trust
  • U.S. Environmental Protection Agency
  • Union Carbide Bhopal site
  • Carlsten, C., 2003. The Bhopal disaster: prevention should have priority now. International Journal of Occupational and Environmental Health, 9:93–94. [PubMed]
  • Castleman, B., PP., 1985. Appendix: the Bhopal disaster as a case study in double standards. In: Ives J., editor. The export of hazard: transnational corporations and environmental control issues. Routledge and Kegan Paul, London. pp. 213–222. ISBN: 0710200722
  • Chander, J., 2001. Water contamination: a legacy of the union carbide disaster in Bhopal, India. International Journal of Occupational and Environmental Health, 7:72–73. [PubMed]
  • Dhara, V.R., Dhara, R., 2002. The Union Carbide disaster in Bhopal: a review of health effects. Archives of Environmental Health, 57:391–404. [PubMed]
  • Ingrid Eckerman, 2005. The Bhopal Saga: Causes and Consequences of the World's Largest Industrial Disaster, Orient Blackswan,
    ISBN 8173715157, 9788173715150, 283 pages
  • Fortun, K., 2001. Advocacy after Bhopal. University of Chicago Press, Chicago. p. 259. ISBN: 0226257207
  • Hazardous Installations Directorate. Health and Safety Executive, 2004. Accident Summary, Union Carbide India Ltd., Bhopal, India: December 3, 1984.
  • MacKenzie D., 2002. Fresh evidence on Bhopal disaster. New Scientist, 19.
  • Sharma, D.C., 2005. Bhopal: 20 Years On. Lancet, 365:111–112. doi: 10.1016/S0140-6736(05)17722-8. [PubMed]
  • Shrivastava, P., 1987. Bhopal: Anatomy of a Crisis. Ballinger Publishing, Cambridge, MA. p. 184. ISBN: 0887300847
  • Shrivastava, P., 1987. Managing Industrial Crisis. Vision Books, New Delhi. p. 196.
  • Tyagi, Y.K., Rosencranz, A., 1988. Some international law aspects of the Bhopal disaster. Social Science & Medicine, 27:1105–1112. doi: 10.1016/0277-9536(88)90305-X. [PubMed]



(2008). Bhopal, India. Retrieved from


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