Bhopal gas disaster

In the night of December 2 and 3, 1984, a cloud of methyl isocyanate (MIC) and other gases escaped from a pesticide plant run by Union Carbide India Limited in Bhopal, the capital of Madhya Pradesh in central India. The gas, heavier than air, drifted across crowded neighborhoods, including shanty settlements next to the plant, as people slept. The Madhya Pradesh government's count of immediate deaths was about 3,800, other estimates run to several thousand more in the following days, and more than half a million people were exposed. It remains the worst industrial accident in history.¹⁴⁶

The plant, opened in 1969, made the insecticide carbaryl, sold as Sevin, for the farmers of India's Green Revolution. In the late 1970s it began making the key ingredient, MIC, on site. By the 1980s sales had fallen, the plant was losing money, and staff and maintenance had been cut. On the night of the accident, water entered a tank holding about 42 tons of MIC, starting a reaction that built heat and pressure. Safety systems failed or were out of service: the refrigeration unit meant to keep the tank cool was off, the scrubber to neutralize escaping gas was not working, and the flare tower was disconnected. Gas escaped for roughly an hour or two.¹³⁴

Union Carbide's chief executive, Warren Anderson, was arrested in Bhopal, released on bail, and never returned to India. In 1989 the company agreed to pay $470 million to the Indian government in a settlement. An Indian court in 2010 convicted seven former plant managers of negligence and sentenced them to two years. Survivors suffered lung damage, blindness and other illness, and the abandoned site remained contaminated for decades. The disaster led to new laws on chemical plant safety and public right-to-know, including the US Emergency Planning and Community Right-to-Know Act of 1986.¹²⁵