Minamata Disease – 1932-1968

Doctors first noticed something strange in the Japanese coastal town of Minimata towards the end of April 1956. Patients were presenting with unusual symptoms – loss of balance, shambolic gait, impaired speech, tingling in fingers and toes and, in more serious cases, convulsions, coma and even death. In his official report of May 1, Dr. Hajime Hosokawa concluded that Minimata had been hit by an ‘epidemic of an unknown disease of the central nervous system’.

As the weird new disease spread, an atmosphere of panic and suspicion pervaded the whole town. Anyone walking oddly was ostracized for fear of contagion, houses were disinfected, people reported seeing ‘dancing cats’, dogs running in frenzied circles, birds dropping out of the sky, and dead fish floating in the waters of Minimata Bay. At first Dr. Hosokawa and his fellow researchers were baffled, but eventually it dawned on them that the illness must be caused by some sort of poisoning: all the symptoms pointed to ingestion of heavy metal.

For centuries the inhabitants of Minimata had scraped a livelihood from fishing. Then in 1908 the Chisso chemical plant was established, providing much-needed employment. For years the factory had been pumping out waste water into Minimata Bay without ill-effect. But investigations revealed that in recent years the waste had been tainted with mercury that had got into the food chain: it was being ingested by fish which were in turn eaten by humans and animals.

The tragedy of Minimata was that Chisso had been a major benefactor to the community – everyone had wanted the factory built, benefited from the employment opportunities and enjoyed the rise in living standards that accompanied the industry. Nobody could possibly have foreseen that the town’s enduring legacy would be incurable illness and congenital birth defects.

When was the Minamata Disease: 1932-1968

Where was the Minamata Disease: Minamata Bay, Kumamoto, Japan

What was the Minamata Disease death toll: Over the years 2,265 people have been officially certified as permanently disabled, of whom 1,784 have died; but compensation payments of more than $610 million to another 10,000 people have been wrung out of the Chisso Corporation and the Japanese government, and at least another 20,000 victims are thought to have been affected.

You should know: After the event, which was itself a tragic mishap, neither the Chisso Corporation nor the Japanese government behaved well. Every possible attempt was made to cover up the true extent of the poisoning. Although it paid ‘sympathy money’ to some of the most affected victims and their families, for years Chisso refused to accept liability and used strong-arm tactics to stop people speaking out.