Just after midnight, corroded safety systems failed at the Union Carbide India plant, releasing a cloud of methyl isocyanate gas over densely packed neighborhoods. Official death tolls list around 3,800 immediate deaths, but Indian government estimates and survivor groups put the true toll—including long-term deaths from exposure—at 15,000 to 20,000 or higher, with over half a million people injured. Union Carbide's settlement and the plant's abandoned site remain contentious decades later.
Residents near the plant woke to burning eyes, choking coughs, and a smell like burnt chili peppers as the gas cloud settled into low-lying slum areas, where it was heaviest, in the middle of the night. People fled blindly through the dark streets, trampling each other, vomiting, collapsing; hospitals were overwhelmed within hours by tens of thousands of patients and had no idea what chemical they were treating for, since Union Carbide had not shared full safety data with local authorities.
Investigations later found the plant's refrigeration unit for the chemical had been shut off to save money, safety alarms were disconnected, and staffing had been slashed. Union Carbide paid a $470 million settlement in 1989—criticized by victims' groups as a fraction of the actual damage—and its former chairman, Warren Anderson, was charged with culpable homicide in India but the U.S. never extradited him. Contaminated soil and groundwater around the derelict factory site continue to cause birth defects and illness in the surrounding population, a slow-motion continuation of the disaster more than four decades later.