Karen Wetterhahn

In August 1997, Dr Karen Wetterhahn of Dartmouth College,New Hampshire, in the north-eastern United States, died of mercury poisoning. Tests showed that she had eighty times the lethal dose of mercury in her body.

Karen Wetterhahn was poisoned in her laboratory in August 1996. She was doing an experiment with a very rare kind of mercury, a thick liquid called dimethyl mercury. When she was pouring some of the mercury from one container to another, a few drops fell onto her rubber glove near her thumb. Because she knew the mercury was poisonous, she quickly wiped it off. She was sure that none of the mercury had got into her body.

She didn’t think about the accident any more until five months later when she suddenly found she couldn’t walk properly or speak clearly. She recognized the symptoms of mercury poisoning, but by then it was too late to do anything about it. As time passed, the poison affected her brain more and more. Her field of vision narrowed until it was as thin as a pencil, and finally she became completely blind. She also lost her hearing. Before she died, she had been in a coma for a long time.

It has been known for many years that mercury is a powerful poison that harms animals and human beings when it gets into the environment through industrial waste that is not treated properly, or because people have carelessly thrown away old batteries. And scientists also knew that dimethyl mercury was much more poisonous than ordinary mercury.

Before the accident, however, no one knew that dimethyl mercury was so soluble that it could instantly penetrate rubber gloves. Even so, after Karen died, the government of New Hampshire fined Dartmouth College for not telling Dr Wetterhahn that rubber gloves were not enough protection against chemicals like dimethyl mercury. And the company that supplied the mercury now sends a warning to buyers that even a short exposure can be lethal. They tell them that anyone handling the chemical must wear two pairs of gloves, a highly resistant rubber glove with many layers underneath, and, on top, a heavy glove that it is also very resistant to chemicals.

The head of the Chemistry Department at Dartmouth said Karen’s death was noble. He pointed out that because of what happened to her no one in the future will have to die in a similar way. He also said that there is no way of preventing accidents caused by ignorance of the dangers of some chemicals. He said there are fourteen million known chemical substances and that every day chemists are creating new ones. So we have to learn from experience.

- information from: The New York Times (97.10.03)