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1949
Minamata Village becomes Minamata City -
Period: to
minimata
Minamata disease is a neurological syndrome caused by severe mercury poisoning. Minamata disease was first discovered in Minamata City, Japan in 1956. It was caused by the release of methyl mercury into the industrial wastewater from the Chisso Corporation chemical factory, which continued from 1932 to 1968. -
1956
The disease is discovered when the director of SNC Hospital reports an influx of patients with similar nervous system damage symptoms. The disease is initially thought to be infectious, and the administration disinfects the patients' homes. The symptoms include diffuse numbness, slurred speech, and tunnel vision. -
1957
Kumamoto University and the Minamata Public Health Center conduct experiments on cats, and one develops Minamata disease after eating fish from Minamata Bay. Kumamoto Prefecture advises people not to eat fish or shellfish from the bay. -
1965
The Chisso Corporation, formerly known as Shin Nichitsu, dumps an estimated 27 tons of mercury compounds into Minamata Bay between 1932 and 1968. On June 12, a second outbreak of Minamata disease is made public in Niigata Prefecture. -
1968
In March, patients in Niigata file a lawsuit against Showa Denko. On September 26, the national government officially concludes that the disease is caused by eating fish and shellfish contaminated by methylmercury from the chemical plant. -
1975
Kumamoto Prefecture, Minamata City, and Minamata Fisheries Co-op voluntarily restrict fishing in Minamata Bay.