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Bhopal gas tragedy

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Bhopal Gas Tragedy BIBINDUDept. of Pharma sciencesMDU Rohtak

THE BHOPAL DISASTER Around 1 a.m. on Monday, the 3rd of December, 1984, In the city of Bhopal, Central India, a poisonous vapour burst from the tall stacks of the Union Carbide pesticide plant. This vapour was a highly toxic cloud of methyl isocyanate. 2,000 died immediately300,000 were injured 7,000 animals were injured, of which about one thousand were killed.

Company involvedUnion Carbide CorporationStarted in 1969 in bhopalPhosgene, Monomethlyamine, Methyl Isocyanate (MIC) and the pesticide Carbaryl, also known as Sevin.Taken over by DOW Chemicals in 2001.DOW refused Union Carbides Liabilities in Bhopal, India.

Technical View

Affected Area

The Possible CauseA tank containing methyl isocyanate (MIC) leaked.MIC is an extremely reactive chemical and is used in production of the insecticide carbaryl. The scientific reason for the accident was that water entered the tank where about 40 cubic meters of MIC was stored. When water and MIC mixed, an exothermic chemical reaction started, producing a lot of heat. As a result, the safety valve of the tank burst because of the increase in pressure. It is presumed that between 20 and 30 tonnes of MIC were released during the hour that the leak took place.The gas leaked from a 30 m high chimney and this height was not enough to reduce the effects of the discharge.

Weather conditionThe high moisture content (aerosol) in the discharge when evaporating, gave rise to a heavy gas which rapidly sank to the ground. A weak wind which frequently changed direction, which in turn helped the gas to cover more area in a shorter period of time (about one hour). The weak wind and the weak vertical turbulence caused a slow dilution of gas and thus allowed the poisonous gas to spread over considerable distances.

Plant conditionThe pesticide factory was built in midst of highly dense populated area.The work force was brought down by half from 1980 to 1984.The size of work crew was cut in half from 12 to 6 workers.The maintenance supervisor had been eliminated.The period of safety training to workers was brought down from 6 month to 15 days.

Plant condition cont.UCIL chose to store MIC( permitted exposure is 0.02 ppm in USA and BRITAIN)MIC was filled to 87% of its capacity.Vital gauges and indicator in MIC tank were defective.Refrigeration and cooling system had been shut down 5 months before disaster.

Gas vent scrubber stacks

Flare tower


According to this story, an MIC operator was told to wash a section of a subheader of the relief valve vent header ("RVVH") in the MIC manufacturing unit.Because he failed to insert a slip-blind, the water supposedly backed up into the header and eventually found its way into the tank.Because he failed to insert a slip-blind, as called for by plant standard operating procedures, the water supposedly backed up into the header and eventually found its way into the tank and flowed 400 feet to the tank Conclusive reports indicated that 2000 lbs of water entered the tank.

THE DIRECT-ENTRY THEORYDuring the shift change -- that a disgruntled operator entered the storage area and hooked up one of the readily available rubber water hoses to Tank with the intention of contaminating and spoiling the tank's contents.He unscrewed the local pressure indicator, which can be easily accomplished by hand, and connected the hose to the tank. The entire operation could be completed within five minutes.

UCIL BEFORE THE DISASTER1980-Plant had cause death and injury to many.1981-plant operator was killed by phosgene gas leak.1982-three american engineers reported that surrounding was not according to the standards.

Political decisionIn dec.1982 issue of danger posed by the pesticide plant to Bhopal was raised in assembly in Madhya Pradesh.T.S. Viyogi , labour minister allayed all fear saying , a sum of Rs.250 million has been invested in this unit. The factory is not a small stone , which can be shifted elsewhere.There is no danger to Bhopal , nor will there be


OFFENCE TAKEN BY UCCFollowing the accident ,GOI filed a compensation lawsuit against the UCC for an estimated US$3 billion in 1986 UCC filed a countersuit against GOI and state of Madhya PradeshThey said GOI was also responsible for same because they knew the toxicity of MIC but failed to take adequate precaution to prevent disaster.

Documentary proof ?Under two section first step at control and contingency planning and experience helpA task force was set by Warren Anderson and a medical and technical team were dispatched to the site with in 24 hours. BUT UCC does not have any kind of emergency plan in at its Indian subsidiry.

Documentary proof?UCC tried to defend its position by saying that it had only 50.9% stake in UCIL.The said that all the employee in the company were Indian and thatthe last American employee at the site had left 2 year before.UCC argued that day- to day working of UCIL was independent of parent company.

THE SETTLEMENTGOI- legal representative of victim for legal dealing(in ordinance)Then replaced by Bhopal Leak (Process of Claim)Act,1985Then GOI filed suit in United State District Court for the Southern District of New YorkJudge J. F. Keenan asked UCC as a matter of fundamental decency to provide an interim relief payment $ 5-10 million

Litigation in indiaDec. 17 ,1987-Bhopal district court Judge passed order directing UCC to pay Rs.3.5 billion as interim relief UCC challenged this order in MP high court On April 4th , Justice S.K. Seth of high court reduced the interim compensation to Rs. 2.5 billion .Then UCC appealed in SCOn 14th feb. 1989 SC directed UCC to pay up US$ 470 million in full and final settlement .

Litigation in india cont. in 1991,Bhopal court summoned Warren Anderson to appear on a charge of homicide in a criminal case. However , he did not turn up.On September 9, 1993 UCC sold its entire 50.9% stake in UCIL to the Calcutta based Mc Leod Russel India Ltd.In August 1999, Dow chemical purchased UCC for US$ 9.3 billion

ConclusionThe Bhopal gas tragedy could have been averted.There were lapses on part of the government and UCC.The actual reason for the tragedy is contrary to popular belief.An alternate way to produce carbaryl was suggested.Design of Inherently safer process was required.