Professor Fiona Macleod, Professor of Process Safety at the University of 91ֱ, has co-written a comprehensive overview of the Bhopal disaster, plus a detailed analysis of the root cause, which both feature in the latest IChemE (pages 3 and 6). They centre around The Union Carbide India Ltd (UCIL) plant in Bhopal, India which started production in 1969, producing carbaryl insecticides.
The plant initially used imported Methyl Isocyanate (MIC) which was used as an intermediate in the production process and later built facilities which allowed the factory to produce their own. The reports suggest that a design decision to store huge quantities of a highly reactive and toxic intermediate (MIC) in a densely populated town led to the disaster. Warnings about the deterioration of equipment and bypassing of safety controls were ignored. . The plant was uneconomic and due to close on 31 December 1984.
Just after midnight on 2 December 1984, 28 tonnes of toxic gas were released into the community from a pesticide factory in Bhopal, India. Water entered a tank of MIC, an intermediate in the manufacture of pesticides, leading to a runaway chemical reaction and the release of a cocktail of highly toxic gases.
Because it was a cold night and the gas was released from a lower point in the vent, the gas cooled quickly and descended to ground level outside the factory walls and spread towards the centre of town. Thousands died as a result of exposure to the gas and hundreds of thousands were injured.
A key theme of the two articles is how we can learn from past disasters and not make the same mistakes in the future. Professor Macleod writes “Few — if any — major accidents are caused by a single act. Few — if any — industrial disasters appear out of the blue. If you have eyes to see and ears to listen, then there are always early warning signs that, with proper investigation and action, will prevent more serious events. The Bhopal accident is no exception…The original tragedy of Bhopal is that so many early warning signs were ignored. With only 27 days to go before permanent closure, acting on any one of those warning signs might have prevented the catastrophe.”