A grad student at the Massachusetts Institute of Technology remains under medical supervision after potentially creating and exposing themselves to a dangerous neurotoxin.

The university reported that it closed the chemistry building, “out of an abundance of caution,” later posting on their website that a graduate student had gone to the emergency room after claiming to have synthesized dimethyl mercury on Wednesday.

“Emerging information calls into question whether this compound was in fact synthesized,” MIT said in a statement over the weekend, disclosing that the first blood test results from the student showed no signs of exposure to mercury.

Dimethyl mercury, a mercury compound, while useful in some laboratory procedures has been known to be fatal, even in small doses.

In 1997, a Dartmouth College professor died after she reported spilling a few drops onto her latex gloves, according to a study published in Human Pathology following her death.

The MIT student had not been authorized to use it as a part of their research, the university noted.

Housing the university's Department of Chemistry, MIT’s Building 18, also known as the Dreyfus Building, off Ames Street in Cambridge, was set to remain closed through Sunday as it is decontaminated.

“High-touch surfaces” in the common areas of the student’s residence hall were also cleaned while their unit in the building is sealed off for decontamination, the university said.

Blood testing was offered to individuals who were near the student and their work environment on Wednesday.

“We continue to believe there is a very low risk of secondary or tertiary exposures,” the university said.

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