When her pipette spilled one or two droplets onto her left-hand glove, chemistry professor Karen Wetterhahn was not especially concerned. After all, she had adhered to the safety regulations involving dimethylmercury. She was wearing a lab coat, along with goggles and disposable latex gloves. And, as the substance poses a risk through inhalation, she undertook the transfer beneath a fume hood.
The minuscule spill of this clear liquid had caused her no pain or any other sensation, and she had no reason to think the incident was serious. Besides, her work was too important to spend much time indulging any fears: Wetterhahn, the first female chemistry professor at Dartmouth College, US, had obtained the largest research grant in her school’s history to study and elucidate how heavy metals impact human health.1 Tragically, they would soon impact her own.
On 14 August 1996, Wetterhahn had been preparing mercury samples for NMR spectroscopy. ‘The dimethylmercury was the standard of choice for mercury NMR since it is a pure “neat” liquid, so you did not have to worry about concentration or pH effects that may give spurious chemical shifts,’ says Kent Sugden. Now a professor of chemistry and biochemistry at the University of Montana, US, in 1996 Sugden was a research associate at Dartmouth. He had made NMR standards of nontoxic mercury salts for Wetterhahn, but when she did not get the expected results she went back to using dimethylmercury to confirm her findings. He describes her as ‘a very thorough chemist’.