This incident occurred in 1984 at the Union Carbide chemical plant in Bhopal, India. 27 tons of methyl isocynate were leaked into the surrounding area causing an estimated 20,000 deaths to date. The accident site has still not been properly treated and the victims have not been compensated for Union carbide's negligence.
http://www.bhopal.org/whathappened.html
http://www.bhopal.com/
