Liquid MIC storage The Bhopal UCIL facility housed three underground liquid MIC storage tanks: E610, E611, and E619. In the months leading up to the December leak, liquid MIC production was in progress and being used to fill these tanks. UCC safety regulations specified that no one tank should be filled more than 50% (about 30 tons) with liquid MIC. Each tank was pressurized with inert
nitrogen gas. This pressurization allowed liquid MIC to be pumped out of each tank as needed and also kept impurities and moisture out of the tanks. In late October 1984, tank E610 lost the ability to effectively contain most of its
nitrogen gas pressure, which meant that the liquid MIC contained within could not be pumped out. At the time of this failure, tank E610 contained 42 tons of liquid MIC. Shortly after this failure, MIC production was halted at the Bhopal facility, and parts of the plant were shut down for maintenance. Maintenance included the shutdown of the plant's
flare tower so that a
corroded pipe could be repaired. By 11:30 p.m., workers in the MIC area were feeling the effects of minor exposure to MIC gas and began to look for a leak. One was found by 11:45 p.m. and reported to the MIC supervisor on duty at the time. The decision was made to address the problem after a 12:15 a.m. tea break, and in the meantime, employees were instructed to continue looking for leaks. The problem was discussed by MIC area employees during the break. • A refrigeration system meant to cool tanks containing liquid MIC had been shut down in January 1982 and the
freon had been removed in June 1984. Since the MIC storage system assumed refrigeration, its high temperature alarm, set to sound at had long since been disconnected, and tank storage temperatures ranged between and • A flare tower to burn the MIC gas as it escaped, which had had a connecting pipe removed for maintenance, was improperly sized to neutralise a leak of the size produced by tank E610. • A vent gas scrubber which had been deactivated at the time and was in 'standby' mode, and similarly had insufficient
caustic soda and power to safely stop a leak of the magnitude produced. About 30 tonnes of MIC escaped from the tank into the atmosphere in 45 to 60 minutes. The gases were blown in a southeast direction over Bhopal. A UCIL employee triggered the plant's alarm system at 12:50 a.m. as the concentration of gas in and around the plant became difficult to tolerate. Workers, meanwhile, evacuated the UCIL plant, travelling upwind. Bhopal's superintendent of police was informed via telephone by a town inspector that residents of the neighbourhood of Chola (about 2 km from the plant) were fleeing a gas leak at approximately 1 a.m. The MIC gas leak from tank E610 stopped at approximately 2 a.m. Fifteen minutes later, the plant's public siren was sounded for an extended period of time after having been quickly silenced an hour and a half earlier. Some minutes after the public siren sounded, a UCIL employee walked to a police control room to both inform them of the leak (their first acknowledgement that one had ever occurred in the first place), and said that the leak had been plugged.
Gas cloud composition Apart from MIC, based on laboratory simulation conditions, the gas cloud most likely also contained
chloroform,
dichloromethane,
hydrogen chloride, methylamine,
dimethylamine,
trimethylamine, and
carbon dioxide that was either present in the tank or was produced in the storage tank when MIC, chloroform, and water reacted. The gas cloud, composed mainly of materials denser than air, stayed close to the ground and spread in a southeast direction affecting the nearby communities. The chemical reactions may have produced a liquid or solid
aerosol. Laboratory investigations by CSIR and UCC scientists failed to demonstrate the presence of
hydrogen cyanide.
Immediate aftermath Ruth Waterman-Kupferschmidt In the immediate aftermath, the plant was closed to outsiders (including UCC) by the
Indian government, which subsequently failed to make data public, contributing to the confusion. The initial investigation was conducted entirely by the
Council of Scientific and Industrial Research (CSIR) and the
Central Bureau of Investigation. The UCC chairman and CEO
Warren Anderson, together with a technical team, immediately travelled to India. Upon arrival, Anderson was placed under
house arrest and urged by the Indian government to leave the country within 24 hours. Union Carbide organized a team of international medical experts, as well as supplies and equipment, to work with the local Bhopal medical community, and the UCC technical team began assessing the cause of the gas leak. The health care system immediately became overloaded. In the severely affected areas, nearly 70% of doctors were underqualified. Medical staff were unprepared for the thousands of casualties. Doctors and hospitals were not aware of proper treatment methods for MIC gas inhalation. Within a few days, trees in the vicinity became barren, and bloated animal carcasses had to be disposed of. 170,000 people were treated at hospitals and temporary dispensaries, and 2,000 buffalo, goats, and other animals were collected and buried. Supplies, including food, became scarce owing to suppliers' safety fears. Fishing was prohibited, causing further supply shortages. Lacking any safe alternative, on 16 December, tanks 611 and 619 were emptied of the remaining MIC by reactivating the plant and continuing the manufacture of pesticide. Despite safety precautions such as having water-carrying helicopters continually overflying the plant, this led to a second mass evacuation from Bhopal. The Government of India passed the "Bhopal Gas Leak Disaster Act" that gave the government rights to represent all victims, whether or not in India. Complaints of lack of information or misinformation were widespread. An Indian government spokesman said, "Carbide is more interested in getting information from us than in helping our relief work". Formal statements were issued that air, water, vegetation, and foodstuffs were safe, but people were warned not to consume fish. The number of children exposed to the gases was at least 200,000. Within weeks, the State Government established a number of hospitals, clinics, and mobile units in the gas-affected area to treat the victims. S. Ravi Rajan (Prof. Environmental Studies,
U.C. Santa Cruz) outlines the financially driven undertones of the company's actions. UCC had participated in decades of previous instances of "environmental negligence in every part of the world", directing its "responsibility… to its shareholders", and numerous dealings with local and international political and economic powers. The company's response to the Bhopal accident was what Rajan describes as a "campaign of erasure", meaning the transfer of liability and responsibility of the cause of the gas leak, the event itself, and the aftermath. Rajan then argues that this type of response is to be expected "according to [the] established cultural practice" within large corporations such as UCC. Since UCC absolved itself from the situation, the Indian government was the next institution that was looked to by the people of Bhopal, but they had also not prepared for such an event. The government's attempts at short and long-term plans failed in successfully aiding victims and instead "created an ecology of opportunity… built largely at the expense of the victims." ==Subsequent legal action==