Union Carbide's Bhopal plant leaked toxic gas — thousands died in their sleep

On the night of December 2-3, 1984, a Union Carbide pesticide plant in Bhopal, India, leaked approximately 40 tons of methyl isocyanate (MIC) gas into the surrounding neighborhoods. The gas, used in the production of the pesticide Sevin, was stored in large tanks, and a combination of equipment failures, safety system shutdowns and inadequate maintenance led to the release.

The immediate death toll was estimated at 3,000-8,000 people, with thousands more dying in the following weeks and months from exposure-related illnesses. Over 500,000 people were exposed. The plant's safety systems — a flare tower, a vent gas scrubber and a water curtain — were either malfunctioning or turned off to save costs.

Union Carbide paid $470 million in a 1989 settlement with the Indian government, a sum widely criticized as inadequate. The site remains contaminated, and Dow Chemical, which acquired Union Carbide in 2001, has refused to accept liability. The Bhopal disaster remains the world's worst industrial accident and a landmark case in corporate accountability, industrial safety and the ethics of multinational operations in developing countries.