The Bhopal disaster was an industrial catastrophe that occurred at a pesticide plant owned and operated by Union Carbide (UCIL) in Bhopal, Madhya Pradesh, India. Around midnight on the intervening night of December 2–3, 1984, the plant released methyl isocyanate (MIC) gas and other toxins, resulting in the exposure of over 500,000 people. Estimates vary on the death toll. The official immediate death toll was 2,259 and the government of Madhya Pradesh has confirmed a total of 3,787 deaths related to the gas release.[1] Other government agencies estimate 15,000 deaths.[2] Others estimate that 8,000 died within the first weeks and that another 8,000 have since died from gas-related diseases.[3][4]

Some 25 years after the gas leak, 390 tons of toxic chemicals abandoned at the UCIL plant continue to leak and pollute the groundwater in the region and affect thousands of Bhopal residents who depend on it,[5][6][7] though there is some dispute as to whether the chemicals still stored at the site pose any continuing health hazard.[2] There are currently civil and criminal cases related to the disaster ongoing in the United States District Court, Manhattan and the District Court of Bhopal, India against Union Carbide,[8] now owned by Dow Chemical Company, with an Indian arrest warrant pending against Warren Anderson, CEO of Union Carbide at the time of the disaster.[9][10] No one has yet been prosecuted.

Summary of background and causes

The UCIL factory was established in 1969 near Bhopal. 50.9% was owned by Union Carbide Corporation (UCC) and 49.1 % by various Indian investors, including public sector financial institutions.^[3][4] It produced the pesticide carbaryl (trademark Sevin). In 1979 a methyl isocyanate (MIC) production plant was added to the site. MIC, an intermediate in carbaryl manufacture, was used instead of less hazardous but more expensive materials. UCC understood the properties of MIC and its handling requirements.^[11][12][13]

During the night of December 2–3, 1984, large amounts of water entered tank 610, containing 42 tonnes of methyl isocyanate. The resulting exothermic reaction increased the temperature inside the tank to over 200 °C (392 °F), raising the pressure to a level the tank was not designed to withstand. This forced the emergency venting of pressure from the MIC holding tank, releasing a large volume of toxic gases into the atmosphere. The reaction sped up because of the presence of iron in corroding non-stainless steel pipelines. However, laboratory experiments conducted by CSIR (Dec. 1985 Report) and UCC scientists do not support the effect of iron as having any effect in speeding up the reaction. A mixture of poisonous gases flooded the city of Bhopal, causing great panic as people woke up with a burning sensation in their lungs. Thousands died immediately from the effects of the gas and many were trampled in the panic.

Theories of how the water entered the tank differ. At the time, workers were cleaning out pipes with water, and some claim that owing to bad maintenance and leaking valves, it was possible for the water to leak into tank 610.^[14] In December 1985 The New York Times reported that according to UCIL plant managers the hypothesis of this route of entry of water was tested in the presence of the Central Bureau Investigators and was found to be negative.^[15] UCC also maintains that this route was not possible, and that it was an act of sabotage by a "disgruntled worker" who introduced water directly into the tank.^[16] However, the company's investigation team found no evidence of the necessary connection.^[17] The Trade Union Report failed to mention that the investigation was totally controlled by the government investigators denying UCC investigators any access to inspecting the ill-fated tank.

The 1985 reports^[17][18][19] give a picture of what led to the disaster and how it developed, although they differ in details.

Factors leading to the gas leak include:

• The use of hazardous chemicals (MIC) instead of less dangerous ones
• Storing these chemicals in large tanks instead of over 200 steel drums.
• Possible corroding material in pipelines
• Poor maintenance after the plant ceased production in the early 1980s
• Failure of several safety systems (due to poor maintenance and regulations).
• Safety systems being switched off to save money—including the MIC tank refrigeration system which alone would have prevented the disaster.

The problem was made worse by the plant's location near a densely populated area, non-existent catastrophe plans and shortcomings in health care and socio-economic rehabilitation. Analysis shows that the parties responsible for the magnitude of the disaster are the two owners, Union Carbide Corporation and the Government of India, and to some extent, the Government of Madhya Pradesh.^[3][4][20]

Health effects

Short term health effects

• Apart from MIC, the gas cloud may have contained phosgene, hydrogen cyanide, carbon monoxide, hydrogen chloride, oxides of nitrogen, monomethyl amine (MMA) and carbon dioxide, either produced in the storage tank or in the atmosphere.^[4]

• The gas cloud composed mainly of materials denser than the surrounding air, stayed close to the ground and spread outwards through the surrounding community. The initial effects of exposure were coughing, vomiting, severe eye irritation and a feeling of suffocation. People awakened by these symptoms fled away from the plant. Those who ran inhaled more than those who had a vehicle to ride. Owing to their height, children and other people of shorter stature inhaled higher concentrations. Many people were trampled trying to escape.^[4]

• Thousands of people had succumbed by the morning hours. There were mass funerals and mass cremations as well as disposal of bodies in the Narmada river. 170,000 people were treated at hospitals and temporary dispensaries. 2,000 buffalo, goats, and other animals were collected and buried. Within a few days, leaves on trees yellowed and fell off. Supplies, including food, became scarce owing to suppliers' safety fears. Fishing was prohibited as well, which caused further supply shortages.^[4]

• A total of 36 wards were marked by the authorities as being "gas affected", affecting a population of 520,000. Of these, 200,000 were below 15 years of age, and 3,000 were pregnant women. In 1991, 3,928 deaths had been certified. Independent organizations recorded 8,000 dead in the first days. Other estimations vary between 10,000 and 30,000. Another 100,000 to 200,000 people are estimated to have permanent injuries of different degrees.^[4]

• The acute symptoms were burning in the respiratory tract and eyes, blepharospasm, breathlessness, stomach pains and vomiting. The causes of deaths were choking, reflexogenic circulatory collapse and pulmonary oedema. Findings during autopsies revealed changes not only in the lungs but also cerebral oedema, tubular necrosis of the kidneys, fatty degeneration of the liver and necrotising enteritis.^[30] The stillbirth rate increased by up to 300% and neonatal mortality rate by 200 %.^[4]

Long term health effects

• It is estimated that 20,000 have died since the accident from gas-related diseases. Another 100,000 to 200,000 people are estimated to have permanent injuries.^[4]

• The quality of the epidemiological and clinical research varies. Reported and studied symptoms are eye problems, respiratory difficulties, immune and neurological disorders, cardiac failure secondary to lung injury, female reproductive difficulties and birth defects among children born to affected women. Other symptoms and diseases are often ascribed to the gas exposure, but there is no good research supporting this.^[4]

• There is a clinic established by a group of survivors and activists known as Sambhavna. Sambhavna is the only clinic that will treat anybody affected by the gas, or the subsequent water poisoning, and treats the condition with a combination of Western and traditional Indian medicines, and has performed extensive research.^[36]

• Union Carbide as well as the Indian Government long denied permanent injuries by MIC and the other gases. In January, 1994, the International Medical Commission on Bhopal (IMCB) visited Bhopal to investigate the health status among the survivors as well as the health care system and the socio-economic rehabilitation.

• The reports from Indian Council of Medical Research^[21] were not completely released until around 2003.

• For a review of the research on the health effects of the Bhopal disaster, see Dhara & Dhara (2002).^[37]

Compensation from Union Carbide

• The Government of India passed the Bhopal Gas Leak Disaster Act that gave the government rights to represent all victims in or outside India.^[4]
• UCC offered US$ 350 million, the insurance sum.^[4] The Government of India claimed US$ 3.3 billion from UCC.^[4] In 1999, a settlement was reached under which UCC agreed to pay US$470 million (the insurance sum, plus interest) in a full and final settlement of its civil and criminal liability.^[4]
• When UCC wanted to sell its shares in UCIL, it was directed by the Supreme Court to finance a 500-bed hospital for the medical care of the survivors. Bhopal Memorial Hospital and Research Centre (BMHRC) was inaugurated in 1998. It was obliged to give free care for survivors for eight years.^[4]

Economic rehabilitation

• After the accident, no one under the age of 18 was registered. The number of children exposed to the gases was at least 200,000.^[4]
• Immediate relief was decided two days after the tragedy.^[4]
• Relief measures commenced in 1985 when food was distributed for a short period and ration cards were distributed.^[4]
• Widow pension of the rate of Rs 200/per month (later Rs 750) was provided.^[4]
• One-time ex-gratia payment of Rs 1,500 to families with monthly income Rs 500 or less was decided.^[4]
• Each claimant was to be categorised by a doctor. In court, the claimants were expected to prove "beyond reasonable doubt" that death or injury in each case was attributable to exposure. In 1992, 44 percent of the claimants still had to be medically examined.^[4]
• From 1990 interim relief of Rs 200 was paid to everyone in the family who was born before the disaster.^[4]
• The final compensation (including interim relief) for personal injury was for the majority Rs 25,000 (US$ 830). For death claim, the average sum paid out was Rs 62,000.^[4]
• Effects of interim relief were more children sent to school, more money spent on treatment, more money spent on food, improvement of housing conditions.^[4]
• The management of registration and distribution of relief showed many shortcomings.^[38]
• In 2007, 1,029,517 cases were registered and decided. Number of awarded cases were 574,304 and number of rejected cases 455,213. Total compensation awarded was Rs.1,546.47 crores.^[39]
• Because of the smallness of the sums paid and the denial of interest to the claimants, a sum as large as Rs 10 billion is expected to be left over after all claims have been settled.^[4]