Bhopal Disaster

In 1977 Union Carbide India Limited (UCIL) set up a manufacturing facility in Bhopal, a city of some 900,000 inhabitants in Madhya Pradesh, India. It was licensed by the Madhya Pradesh Government to manufacture phosgene, monomethylamine (MMA), methylisocyanate (MIC), and the pesticide carba-ryl, also known as Sevin. The plant was located in an urban area in the center of the city, despite the existence of an industrial area that had been set aside for such hazardous undertakings. The site was near a lake that provided an essential water source.

On the night of December 2, 1984, one of the world's worst industrial disasters occurred at the plant. Water inadvertently entered the MIC storage tank. Safety systems could not contain the gases that formed as a result of the heat generated by the chemical reaction. The leak was first detected at 11:30 p.m. by workers whose eyes had begun to burn. The supervisor was informed, but action was not taken immediately. About 40 tons of MIC escaped into the densely populated surrounding area over a period of two hours.

There was no warning because the emergency alarm designed to warn of the rising temperature in the MIC tank had been switched off. Indeed, the temperature and pressure gauges were so unreliable that workers often ignored potential warning signs. The impact on people living in the shanty settlements adjacent to the plant was devastating. Many died in their beds, others choked and vomited in the streets, and many more died later in hospitals. The main cause of death was respiratory failure. The immediate aftermath saw 8,000 people killed.

Following the disaster it was discovered that the plant had been suffering from a number of other technical problems. The freon gas refrigeration unit designed to store MIC had been disconnected and the gas was being used elsewhere on site. The vent gas scrubber designed to neutralize escaping gas had been shut down for maintenance, though it would have been unable to cope with the gas in any event. The flare tower, designed to burn off the gas that escaped the vent gas scrubber, was also turned off, because a piece of corroded pipe needed replacing. The pressure on the water spray system, designed to reach points from which any gas was escaping, was too low and therefore ineffective. Union Carbide's operational procedures also required the MIC tanks to be filled only to 50 percent of capacity. The Bhopal tank was filled to between 75 percent and 87 percent capacity. Another storage tank used to hold excess MIC was already full.

Ironically, a study conducted by a team from Union Carbide in 1982 noted that there was a serious potential for the release of toxic chemicals. Workers may also have been ill equipped to deal with the scale of the problem. Between 1980 and 1984, the crew for the MIC unit had been cut by 50 percent (from 12 to six) and the maintenance crew was cut 66 percent (from six to two). Many workers in key safety positions were not properly trained and the operating manuals were all in English.

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