Industrial Disasters

Bhopal: The World’s Worst Industrial Tragedy

Thirty three years ago, on the night of 2 December 1984, an accident at the Union Carbide pesticide plant in Bhopal, India, released at least 30 T of a highly toxic gas called methyl isocyanate (MIC), as well as a number of other poisonous gases. The pesticide plant was surrounded by shanty towns, leading to more than 600 000 people being exposed to the deadly gas cloud that night. The gases stayed low to the ground, causing victims’ throats and eyes to burn, inducing nausea, and many deaths. Estimates of the death toll vary from as few as 3 800 to as many as 16 000, but government figures now refer to an estimate of 15 000 killed over the years. Toxic material remains, and 30 years later, many of those who were exposed to the gas have given birth to physically and mentally disabled children. For decades, survivors have been fighting to have the site cleaned up, but they say the efforts were slowed when Michigan‐based Dow Chemical took over Union Carbide in 2001. Human rights groups say that thousands of tons of hazardous waste remain buried underground, and the government has conceded the area is contaminated. There has, however, been no long‐term epidemiological research which conclusively proves that birth defects are directly related to the drinking of the contaminated water.

What Happened that Evening!

Due to lack of environmental regulations, enforcement and compliance, maintenance and operation safety, the plant in Bhopal where the disaster happened started to produce “Carbaryl” in 1977. Carbaryl is mainly used as an insecticide. At first, the production was 2500 T/Y. This was no problem, as the plant had been designed for an output of 5000 T. At the beginning of the 1980s, Carbaryl did not sell very well. For this reason, the owners of the plant started to cut costs. This included employing fewer people, doing maintenance less frequently, and using parts that were made of lower‐grade steel. Closing the plant was being considered as well. When the disaster happened, there was no production at the plant because there was a surplus on the market.

The disaster happened because water entered a tank containing MIC. This caused a chemical reaction which resulted in the buildup of much carbon dioxide, among other things. The resulting reaction increased the temperature inside the tank to reach over 200 °C (392 °F). The pressure was more than the tank was built to withstand. The tank had valves to control the pressure. These were triggered in an emergency, which reduced the pressure. As a result, large amounts of toxic gases were released into the environment. The pipes were rusty. The rust in the iron pipes made the reaction faster. All the contents of the tank were released within a period of about two hours. The water had entered the tank because of a sequence of events. The tank had been maintained badly. When cleaning work was done, water could enter the tank. The leakage of MIC gas from Union Carbide Corporation, Bhopal, gave impetus to the development of environmental law and principles of quantum of compensation (Union Carbide v. Union of India 1989).

Taj Mahal Acid Rain Attack

Yellowing of a historical monument, the Taj Mahal at Agra, was attacked by acid gases due to emissions of oxides of sulfur (SO_x) from foundries, coal‐fired power plants, chemical and hazardous industries, and oil refinery. The sulfur dioxide emitted from these industries, combined with atmospheric oxygen in presence of moisture and sun, formed sulfuric acid called “acid rain” affecting the marble of the Taj Mahal (Mehta 1987).