Minamata Disease
Chisso Corporation was located in a small factory town Minamata on Minamata Bay of the Shiranui Sea. This corporation was once a fertilizer company, and then gradually advanced to a petrochemical producer in early 1920s through the use of a chemical called Acetaldehyde. Acetaldehyde is composed of mercury as a key ingredient. As a leading company in petrochemical industry in Japan, Chisso Corporation could generate huge income for economic recovery after World War II. The corporation adopted Noguchi’s idea that it was cheaper to pay off the Minamata fisherman in exchange for damaging their fishing environment than to invest in water pollution treatment system. From 1932 to 1968, Chisso Corporation dumped an estimated 27 tons of mercury compounds into Minamata river to the bay and spread to Kumamoto. Due to this massive amount of mercury into the bay, thousands of people whose normal diet included fish and sea weeds from the bay unexpectedly developed symptoms of mercury poisoning. The illness became known as the ‘Minamata Disease’ later.