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Minamata Disease

Thousands poisoned, disabled, and killed

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Updated October 23, 2004

In the mid 1950s the people of Minamata, Japan, on the coast of the Shiranui Sea, began to notice something wrong with the cats in their town. The cats appeared to be going insane, and were falling into the sea. The people thought the cats were committing suicide.

Soon the people in the town were also contracting a strange illness. Individuals began to have numbness in their limbs and lips. Some had difficulty hearing or seeing. Others developed shaking (tremors) in their arms and legs, difficulty walking, even brain damage. Others seemed to be going crazy, shouting uncontrollably.

Unknown syndrome called Minamata disease
In 1956, researchers worked to find the source of the illness, which they termed Minamata disease. Something was affecting the nervous systems of the people. One thing people in this fishing town had in common was that they all ate fish, so scientists suspected that the fish in Minamata Bay were being poisoned.

Chisso Corporation source of environmental pollution
A large petrochemical plant in Minamata run by Chisso Corporation was immediately suspect. Chisso denied the allegations and continued its manufacturing with no changes to the method of production. Finally, in July 1959 researchers from Kumamoto University found that organic mercury was the cause of Minamata disease.

Chisso continued to refute the information and any link of its mercury waste to the illness. It was later discovered that Chisso Corporation had dumped an estimated 27 tons of mercury compounds into Minamata Bay.

People severely affected
As the mercury dumping continued, babies were born to poisoned mothers. The children were born with severe deformities, including gnarled limbs, mental retardation, deafness, and blindness. A photographer, W. Eugene Smith, traveled to Minamata in the 1970s, and his series of photographs of the suffering of the people there were published and seen around the world.

The people fight back
The fishermen of Minamata began protesting against Chisso Corporation in 1959. They demanded compensation, and that Chisso quit dumping toxic waste. Chisso in turn tried to make deals with people affected by mercury poisoning using legal documents that stated it would compensate individuals for their illnesses, but would accept no present or future liability. Many people felt this was their only chance at receiving any compensation, and signed the papers.

A poisoning epidemic
Chisso finally quit poisoning the waters in Minamata in 1968. According to Japanese government figures, 2,955 people contracted Minamata disease, and 1,784 people have since died. Researchers believe, however, that the criteria the government uses to diagnose Minamata disease is too strict, and that anyone who showed any impairment in his/her senses should be certified as a victim. A group of these yet-to-be-recognized victims plans to file a compensation suit against the government.

Government also held liable
In October 1982, 40 plaintiffs filed suit against the Japanese government, saying it had failed to stop Chisso from polluting the environment, and had actually looked the other way while Chisso violated pollution laws. In April 2001 the Osaka High Court determined that the government's Health and Welfare Ministry should have begun taking regulatory action to stop the poisoning at the end of 1959, after it concluded that Minamata disease was caused by mercury poisoning. The court also ordered Chisso to pay $2.18 million in damages to the plaintiffs.

Supreme Court orders payment of damages
On October 16, 2004, the Supreme Court of Japan ordered the government to pay 71.5 million yen ($703,000) in damages to the Minamata disease victims. The Environment Minister bowed in apology to the plaintiffs. After 22 years, the plaintiffs achieved their goal of making those responsible for Japan's worst case of industrial pollution pay for their negligence. No amount of money, though, can ever make up for the lives needlessly lost to Minamata disease.

Information for this article was taken from:
- American University, The School of International Service. Minamata disaster.
- Kyodo News. Unrecognized Minamata disease patients to sue government. Japan Today, October 17, 2004.
- Mizoguchi, K. Court orders damages paid to Japan poisoning victims. The Boston Globe, October 16, 2004.
- Olson, D. A. (2002). Mercury. eMedicine, accessed at http://www.emedicine.com/neuro/topic617.htm
- Tanaka, F. Negligence clear in Minamata case. The Daily Yomiuri, October 17, 2004.

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