Union Carbide plant incident

The design of chemical plants to be more nearly inherently safe has received a great deal of attention in recent years. This is due in part to the worldwide attention to safety issues in the chemical industry brought on by the gas release at the Union Carbide plant in Bhopal, India, in December 1984. This and the fairly frequent occurrence of other chemical plant incidents has raised the issue of chemical plant safety to a very high level of visibility and concern. The major factors that should be considered in the planning, design, and operation of chemical plants are described below. The reader is referred to the list of recommended supplementary reading at the end of the chapter for more detailed information. 

It was this incident that led to the Emergency Planning and Community Right-To-Know Act of 1986 (EPCRA). This same chemical has been released on several occasions from the Union Carbide plant in Institnte, West Virginia, shortly after Bhopal and as recently as 1996. Fortnnately, these releases did not affect the surrounding community. 

On December 3, 1984, a toxic gas release from a pesticide plant in India killed nearly 3000 people and injured at least 100,000 others. The chemical that leaked was methyl isocyanate, a chemical intermediate that was supposed to be stored in a cooled bunker near the plant s outer boundary. The vapor is highly toxic and causes cellular asphyxiation and rapid death. Despite engineering and procedural provisions to prevent its release, a total system breakdown resulted in the release of 40 tons of the deadly material into the densely populated community of Bhopal. Because of this incident, the plant was dismantled and ultimately the parent corporation. Union Carbide, was forced to make a number of organizational changes. The occurrence is considered by many to have been the most tragic chemical accident in history. 

A number of chemicals, fortunately a limited number, become dangerous either when they are used wrongly, or when they are accidentally set free. Thalidomide, put on the market in 1957 by the German company Chemie Gruenenthal, was indeed a powerful sedative. But it took three years to perceive that when prescribed to pregnant women, it dramatically crippled the newborn children. The synthetic intermediate for insecticides, methyl isocyanate, which Union Carbide has used for years without incident in its West Virginia Institute plant, caused over 2,000 deaths when it escaped in 1984 from a storage tank in Union Carbide s Bhopal plant in India. 

The Wall Street Journal reported that several weeks before the Bhopal disaster, Union Carbide changed procedures at its Institute West VA plant, on which the Bhopal plant design was based, to prevent a similar incident. Rep. Henry Waxman (D. CA.) disclosed that a Union Carbide safety team in September had warned of a potential runaway reaction of methyl isocyanate at Institute and the EPA had reported that there were 28 small leaks of the chemical in 1980 at the facility (Winslow, 1985). 

In 1984, one of the most notable process incidents occurred in Bhopal, India, at a plant owned by Union Carbide. On December 3, 1984, methyl isocyanate (MIC) was vented to the atmosphere from a vent gas scrubber after a run away reaction overwhelmed the scrubber. It is reported that more than 2500 people died and 20,000 people were injured as a result of exposure to MIC. The subsequent investigation showed that the run away reaction occurred in the MIC tanks after water was reportedly intentionally added to the tank. The safety systems, a pressure relief valve, a vent gas scrubber, and a flare were reportedly poorly maintained. The relief valve worked to vent the pressure, but the scrubber was overwhelmed, and the flare was down for maintenance. This incident highlighted several loss prevention areas that needed improvement. The first was mechanical integrity. No strong preventive maintenance effort appeared to be in place. The second was emergency preparedness and response. It appears that while the plant was built 1.5 miles away from the community, zoning problems allowed the community to expand to the plant limits. It does not appear that much effort was made to work with the community on commimication/notification or evacuation needs. ... 

Natural zeolites have played important roles as in clean-up from nuclear accidents. After the Three Mile Island incident, the SDS (Submerged Dcmineraliser System) made use of a 60/40 mixture by volume of IE-96 and LTA zeolite (A-51) from the then Union Carbide Corporation to immobilise 340,000 Ci of fission products from >1.5 million gallons of water [128], Phillipsite tuff, from Pine Valley Nevada, clinoptilolite, A-51, and IE-96 have all been used at pilot plant scale to deal with high salt, high activity, aqueous wastes at West Valley, New York- site of the PUREX plant used for reprocessing nuclear fuels from 1966 to 1972. 

The incident had both acute and long-term consequences. The company operating the plant. Union Carbide, established a hospital in Bhopal to care for the victims which is still treating long-term respiratory disease almost 30 years after the event... 

The Bhopal incident was caused when a U.S.-based Union Carbide Corporation pesticide plant accidentally released approximately 40 metric tons of methyl isocyanate (MIC) into the atmosphere. The incident was a catastrophe for Bhopal, with an estimated 2,000 deaths, 100,000 injuries, and significant damage to livestock and crops. The long-term health effects from such an incident are difficult to evaluate the International Medical Commission on Bhopal estimated that as of 1994 more than 50,000 people remained partially or totally disabled (House of Representatives 1984). 

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