This refers to “Union Carbide denies role in gas leak case” (June 8). The firm had maintained that the gas leak could only have been caused by deliberate sabotage. The accident took place when a large volume of water — between 120 and 240 gallons — was “inadvertently or deliberately” pumped into one of the three tanks storing liquid methyl isocyanate. The presence of water triggered a heat-generating chemical reaction. The high temperature allowed chloroform, a solvent contaminating the methyl isocyanate, to decompose. The resulting chloride ions corroded the stainless steel tank, releasing iron, which catalysed another “runaway” reaction. At some point, the tank could no longer withstand the steadily increasing temperature and pressure, and, in the end, about 50,000 pounds of methyl isocyanate escaped.
Now consider this: The refrigeration system, which was supposed to keep methyl isocyanate cool and relatively un-reactive, had been shut down five months before the accident. A flare tower designed to burn off vented gases was not operational. An alarm meant to warn against rapid temperature rises did not go off at the time of the accident. All the safety mechanisms collectively failed to work. The company was careless and negligent, and this resulted in a major disaster.
The role of the state government was equally questionable. The Madhya Pradesh Town and Country Planning Board classified the UCIL plant as “general industry” rather than “hazardous industry”. This allowed the plant to stay in its established location rather than move to Bhopal’s new hazardous industry zone. In 1984, the Madhya Pradesh government legalised the shanty towns that had come up just outside the UCIL. The death toll would have reduced if the government had developed a green belt around the plant.
M M Gurbaxani, Bangalore