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The Begininng of The Problem
In 1908 Chisso Corporation begins producing chemical fertilizers in Minamata village, Japan -
Period: to
Timeline of Minamata
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The start of the pollution
By 1932 Chisso had begun manufacturing acetaldehyde, a raw material of plastic. When this is produced, highly toxic methyl mercury is generated. The methyl mercury flowed into the sea with discharged water, and sludge containing a large amount of mercury accumulated at the bottom of the sea -
Dying Fish
In 1950 shellfish started to die as well as fish with their bellies up, and seaweed stopped growing -
Animals go mad
From 1954, many cats died and birds fell out of the sky. At homes in which fish was mixed with the feed and given to chickens and pigs, domestic animals went mad and died -
Official discovery of Minamata disease
The director of SNC Hospital reports to the Minamata Public Health Center on an influx of patients with similar nervous system damage symptoms. -
Discovery Begins
The Kumamoto University Study Group makes its public official report concerning the causes of Minamata disease: "... causative agents of Minamata disease are methyl mercury compound extracted from shellfish caught in the bay and taken from sludge from the SNC plant. However, the extracted substances are slightly different in structure." -
Minamata Disease Finally Recognized by Government
In 1968, Minamata disease was finally recognized by the government as a pollution disease caused by methylmercury discharged from the Chisso Minamata Factory -
Chisso Corporation Stops Discharging Mercury
In 1968, Chisso Corporation finally stopped discharging mercury -
Construction of Landfill Begins
In 1977, Kumamoto Prefecture began construction of a landfill for the sludge containing mercury and sealed it off. -
Declaration of Safety for Minamata Bay
In 1997, Kumamoto Prefecture issued a declaration of safety for Minamata Bay. As a result, currently Minamata Bay is one of the cleanest seas with high water clarity and low degree of contamination.
