08/30/2026
BREAKING NEWS — Around 9:30 p.m. on Wednesday, Aug. 26, MIT Environment, Health, and Safety (EHS), the Cambridge Fire Department, and Pro EMS responded to a report of dimethylmercury exposure in Building 18, home to the Department of Chemistry. As of the time of publication, the building remains closed for decontamination efforts, but the Institute believes the risk for further exposure is “very low.”
According to the Institute’s official emergency response, a graduate student working in Building 18 “self-reported to a local emergency room and claimed to have synthesized dimethyl mercury.” While the student is still being medically supervised, their initial blood test, received on Aug. 29, “shows no sign of exposure to mercury.”
“Emerging information calls into question whether [dimethylmercury] was in fact synthesized,” the notice adds.
Dimethylmercury is an extremely toxic substance, and exposure to low amounts of it — for instance, through inhalation or skin absorption — is known to be fatal if left untreated.
In an email to the chemistry department, professor and department head Matthew Shoulders wrote, “MIT does not allow the purchase or synthesis of dimethylmercury.”
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Grace Zhang ’28 has the story.
Photo courtesy of Boheng Cao ’28.
