Severe Mercury Poisoning from Local Industry Kills Hundreds in 1950s Japan

Talk about a tragedy! Imagine this. You're growing up in 1950s Japan. The war which completely obliterated your country is finally fading into distant memory as the economy recovers and all of a sudden, you kid sister is suddenly unable to walk properly or button her buttons, or even speak. She sometimes even suffers from convulsions. Soon, all of the kids in the neighborhood are suffering from similar diseases. Then birds start falling out of the sky and fish start floating the the surface. To top it all off, your sister, and a bunch of your neighbors slip into comas and promptly die. That, in a nutshell, is what happened in Minamata, Japan in the 1950s. I would have been scared out of my wits. Lucky for the world, it wasn't some new and deadly plague. Unlucky for the poor people of Minamata, it seems that the local acetaldehyde factory was dumping tons and tons of mercury into the nearby ocean. This event became one of the great man-made environmental disasters of the 20th century (and gave severe mercury poisoning a more exotic name - Minamata Disease)

Areas Affected by Minamata Disease

The terrible symptoms of Minamata Disease include numbness, muscle weakness, imparement of vision, hearing and speech, and in the more severe cases coma and death. Among the first batch of people diagnosed with the disease in 1956, over 30% died. As researchers initially thought the disease was caused by a pathogen due to its localized nature (it seemed to occur in clusters of families and neighborhoods) people were terrified. A contagious disease with a 30% mortality rate could cause some serious problems. This led to the initial patients being quarantined and as a result ostrasized by their communities. Unsurprisingly, the spreading reach of the disease brough panic to the local community. It took three years for the full scale of mercury pollution and poisoning to be revealed to the public.

In fact, as researchers sampled the water, they were astounded by the amount of mercury they found in the water there. It turned out that there was about 2kg of mercury per ton of sediment. Just to give you an indication, this mercury level was so high that the company later went back to mine the mercury from the sediment! Unbelievable. After testing the hair of local people, it was conclusively determined that they had been exposed to massive doses of mercury through the fish and shellfish that they consumed from the local water. While people living outside of Minamata registered a mercury level of just 4 parts per million (PPM) asymptomatic residents of Minamata often had levels of about 190PPM and levels as high as 705PPM were recorded in some of the sick. That's almost 200 times the normal level!

In a response worthy of a stereotypical evil corporation (as depicted by Hollywood), as evidence mounted against it Chisso (the company dumping the mercury) stopped dumping its pollutants directly into the ocean. Instead they decided to be good neighbors and started dumping it into the nearby Minamoto river, causing a whole new set of people to suffer. Good move guys. Way to be responsible.

Unfortunately, in this case knowledge was not power for many many years. It took 12 years before any serious action was taken by anyone to halt this disease. While there was no way to repay the people for their suffering, at least they got a little bit of monetary compensation. Not ideal but better than nothing. In the end 2265 have been offically recognized as suffering from Minamata disease and over 10000 people have not been offically recognized but have recieved compensation for their suffering. Depressingly, though, the only reason that the pollution stopped was that the production process which caused the production of waste mercury became outdate and was replaced.

This is a true tragedy that hopefully prevented many environmental disasters in the future (although a second outbreak of the disease in the mid 1960s in a separate part of Japan proved that not everyone had learned a lesson). Lawsuits from surviving sufferers and their families are still ongoing today.