It is, writes Joshua Sokol at Digg, "one of the most famous environmental disasters in history." And the cause is now known to be fairly straightforward: From 1932 to 1968, a chemical factory in Minamata, Japan, dumped 600 tons or so of mercury into the local harbor. One of the first signs something was amiss was when the town's cats began having fatal convulsions, hence the early christening of "dancing cat disease." It became clear, though, the disease wasn't confined to felines as people began having trouble with motor skills and speech. (Worse, eating lots of seafood then was common, so they were unaware they were compounding the problem.) Then babies were born with deformities. The story traces the long search for a cause, the resistance of the company responsible, and the official 1968 finding that mercury poisoning was indeed the culprit.
Today, the ailment is known more simply as Minamata disease, and the town's trauma has ultimately led to a positive outcome. A UN treaty known as the Minamata Convention on Mercury came into legal force last month, its main goal to prevent similar disasters elsewhere. The story digs into the scientific particulars of mercury poisoning, in this case methylmercury poisoning, and talks to survivors and relatives still coping with what unfolded decades ago. One resonating detail: A researcher recalls seeing "babies with severe neurological symptoms," and yet their mothers were fine. They would discover later that methylmercury flows from pregnant mothers into their fetuses. "The mothers of children affected in this way were possessed by a haunting notion: that their babies had absorbed the toxin, sacrificing themselves to save their mothers," writes Sokol. Read the full story. (Read more mercury poisoning stories.)