Bhopal Chemical Accident

The Union Carbide plant caused the accident on the 3rd of December 1984. Forty-two tonnes of meythylisocyanate (MIC) gas was released from the plant, affecting more than five-hundred-thousand people. In total, twenty-five-thousand people died and most of the rest affected left with permanent injuries. To this day, many people in Bhopal are still being affected; some babies are being born with deformities. The cause of the disaster was due to lack of safety precautions, knowledge of the chemicals used and maintenance of the plant.

The Union Carbide plant produced the pesticide carbaryl (Sevin). MIC was used in the manufacture of carbaryl; a plant was added to the site that produced MIC in 1979. MIC was used because it was a cheaper option then less toxic material. The pesticide they produced was used to increase the productivity in India’s agriculture sector to meet the food demands and cotton production of the most heavily populated areas. Their products were used internationally for the same reasons. Pesticides are used all around the world, whether it is in households or in farms. During the 1980s the demand of pesticides had fallen, but production had continued, which lead to a built-up of MIC.

Meythylisocyanate is highly toxic, therefore there are many hazards associated with it. It must be handled with proper care; it must be stored at temperatures below forty degrees Celsius; stored in only stainless steel or glass containers and kept away from water. Storing MIC avoiding these hazards can lead to unwanted reactions that can be deadly. Damage that is caused by MIC exposure at quantities of 0.4ppm includes chest pain, eye irritations, coughing, asthma, dyspnoea, nose, and skin and throat damage. High level of exposure at 21ppm can cause haemorrhages and emphysema, lung or pulmonary oedema, bronchial pneumonia and death.

The accident occurred when a large amount of water entered tank 610 of the plant, which was holding forty-two tonnes of MIC. The tanks temperature rose to over two-hundred-and-ten degrees Celsius, due to the reaction between the water and MIC. A large amount of pressure built-up in the tank, which it couldn’t withstand, forcing it to release the toxic gas through the emergency venting. The reaction was exothermic, which explains why heat was released. More than just MIC gas was released, the gas reacted with other elements in the air and the high temperatures caused elements of MIC to separate. This caused runaway decomposition reactions and mixing of incompatible chemicals. The pipelines used were not stainless steel; due to this, the reaction rate was increased because of the presence of corroding iron. The possible factors that could have caused the leakage were improper storage, poor maintenance, corroded pipelines and the shut down of safety systems to save money.