In the 1950s, a strange thing started happening in a city along the western coast of Japan called Minamata. First, dead fish began to float in the bay. Then cats began to wobble and tilt in what people called "cat dancing," often falling into the sea to their death. Even birds began to drop dead from the sky.
Soon, people began to act strangely, too. They would stumble while they walked and had trouble keeping their balance. They would lose the use of their hands, so they were unable to write and had trouble fastening their buttons. In only a few years, the mysterious illness reached an epidemic. It seemed that fishermen were the most severely afflicted. These fishermen, who once were strong, were suddenly falling from their boats, and even experienced fishermen drowned. Others had convulsions and had to be tied to their beds, where they died. Sadly, fishermen's families were also stricken with the illness. Many women and children suffered, and even babies were born with mysterious problems.
Doctors began to call the illness the Minamata disease. They believed that the mysterious symptoms were caused by poisoning. They tried to find a food source that birds, cats, fish, and people had in common. Finally, they realized that it was the fish that were contaminated. It did not take long to find the source of the contamination. The city of Minamata was home to Chisso Corporation, which ran a manufacturing plant. For 20 years, the plant had been making a chemical called acetaldehyde, which is used to make plastics, drugs, and perfume. As part of its normal operations, the Chisso Corporation dumped waste products into Minamata Bay. One of the waste products of acetaldehyde production is the toxic heavy metal mercury.
When mercury is dumped into water, the bacteria in the water convert it into organic mercury. When the bacteria are eaten by small fish, which are in turn eaten by larger fish, the mercury becomes concentrated in the tissue of the fish. When cats, birds, and people in Minamata ate the fish contaminated by mercury, the toxin slowly poisoned them. The more fish they ate, the more mercury they ingested. Because mercury causes damage to the brain, doctors recognized that this exposure to small amounts of mercury over long periods of time caused the devastating neurological problems they were seeing.
At first, the leaders of the Chisso Corporation denied their responsibility for Minamata disease. After all, the industry had brought wealth and prosperity to the once poor fishing village of Minamata. Many people had made money because of the presence of the manufacturing plant. Others, however, felt betrayed by the corporation. They protested against the company and demanded that the company be held responsible for poisoning their friends and family members.
Finally, in 1968, the Chisso Corporation stopped using mercury in its manufacturing process and stopped dumping waste into the bay. Today, the corporation produces liquid crystals, preservatives, fertilizers, and other chemical products using environmentally safe technology. It has also paid more than $2 Billion to victims of Minamata disease. The city dredged the polluted bay and removed 1.5 million cubic meters of contaminated sludge from it.
Today, the water in the bay is safe for swimming and fishing. The city now maintains a park that has as its theme health and the environment. The Shinsui Greenbelt is a place for tourists and city residents to stroll along the sea and listen to the roar of the waves. The Minamata Memorial was completed in 1996. It was built as a prayer and remembrance for those who suffered and died from Minamata disease, as a pledge never to allow the repetition of such disasters and to pass on the lessons of Minamata disease to future generations. Today, the citizens of Minamata continue to rebuild their city. They believe the Minamata tragedy serves as a warning to society not to place priority on industrial and economic efficiency. Instead, they want the lessons of Minamata to help people understand how important the environment is, how difficult it is to maintain human health, and how much effort is required to protect both.