Risk Assessment: Tools, Techniques, and Their Applications

4.4 Minimata Methylmercury

The Chisso Corporation first opened a chemical factory in Minamata, Japan, in 1908. Initially producing fertilizers, the factory followed the nationwide expansion of Japan's chemical industry, branching out into production of acetylene, acetaldehyde, acetic acid, vinyl chloride, and other chemicals. The Minamata factory became the most advanced chemical company in Japan in the 1930s and 1940s. The waste products resulting from the manufacture of these chemicals were released right into Minamata Bay. As with any chemical put into the environment, these pollutants had an impact. Owing to the chemicals in the environment, the fisheries were damaged. The Chisso company negotiated two separate compensation agreements with the fishery cooperative in the years of 1926 and 1943 (13).

The Chisso Minamata factory was very successful and it had a very positive effect on the local economy (14). The area lacked other industry and Chisso had great influence in Minamata. Over half of the tax revenue of Minamata City authority came from Chisso and its employees. Also, the company and its subsidiaries were responsible for creating a quarter of all jobs in Minamata.

The Chisso Minamata factory first started acetaldehyde production in 1932. In the first year, they produced 210 tons. Acetaldehyde is used as a chemical intermediary in the production of numerous products, for instance, vinyl. By 1951, production had jumped to 6000 tons/year and reached a peak of 45,245 tons ...