Via the MIT internal emergency alert page (the Aug. 29, 2026, 3:36 p.m. edit):
Offices across campus have been responding to a reported hazardous material incident involving a single individual in a chemistry laboratory. The Institute became aware of the matter after the individual, a graduate student, self-reported to a local emergency room and claimed to have synthesized dimethyl mercury, a compound that is not authorized as part of their research program. Emerging information calls into question whether this compound was in fact synthesized. We are also able to disclose, with the student’s permission, that while the student remains under medical supervision, their initial blood test result, which was received today, shows no sign of exposure to mercury.
Building 18 remains closed at least through Sunday as specialized decontamination efforts continue out of an abundance of caution. This work will continue, and the building will remain closed until the work is complete.
This is a pretty strange story. Sounds like the things that we know are that 1) MIT worked on specialized decontamination because 2) there was concern that Building 18 surfaces may have been contaminated with 3) dimethyl mercury (?), perhaps synthesized by a graduate student?
I've been doing this long enough to know to hold initial reports with some skepticism without independent and orthogonal confirmation. I sure would like to know what happened. Here's hoping that we find out more.