Today is the 20th anniversary of the world's worst ever industrial accident, at Bhopal in India. Thousands - we don't know exactly how many - of people were gassed when a huge tank of methyl isocyanate leaked at Union Carbide's plant there. Multiple layers of safety should have been present but were not. The victims died in horrific pain, shitting themselves and eventually drowning in their own blood and lung fluids. Those who survived are mostly still suffering twenty years later.
Union Carbide abandoned the site after the accident. The plant and tons of chemicals are still in situ and the water supply is contaminated. Neither UC nor their new owners, Dow Chemical, have even bothered to say exactly what (as well as the MIC) escaped on the night. They originally claimed the stuff was no more deadly than teargas but eventually admitted that 3,800 people died. The Indian government estimates between 10,000 and 12,000 people. Organisations in Bhopal itself reckon some 20,000.
Nobody has ever admitted responsibility.
If you want more detail, try here.