From Thursday, August 27th through Sunday, August 30th, MIT Emergency Management posted the following messages on emergency.mit.net regarding an incident at Building 18. As that resource is intended for active issues, these updates, which reflect MIT’s public information on this topic, are archived below.
Building 18 to reopen at 6 a.m. Monday
Aug. 30, 2026, 10:16 p.m.
Appropriate decontamination protocols have now been completed in the lab space of the student who reported attempting the synthesis of dimethyl mercury. Given the actions we have taken and the information received, as well as consultations with industrial hygienists, medical experts at MIT Health, and outside experts, it is our assessment that it is now safe to reopen Building 18. The building will reopen at 6 a.m. tomorrow, Monday, August 31.
Decontamination of the sealed suite in the impacted residence hall has also been successfully completed. The residence hall, which was never closed, remains open. For a campus map, visit https://whereis.mit.edu.
Building 18 - update— Aug. 29, 2026, 3:36 p.m.
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.
Also out of an abundance of caution, high-touch surfaces in the common areas of the individual’s residence hall were professionally cleaned under the supervision of MIT Environmental Health and Safety (EHS), and decontamination of the resident’s sealed unit is ongoing, as has been shared with residents of the building. The residence remains open and in normal operation, and no restrictions have been placed on the building.
With a focus on public health, decontamination efforts have been ongoing and baseline testing was offered to individuals who were in proximity to the student and their work environment on Wednesday, August 26. As the chemistry department, industrial hygienists, MIT Health medical experts, and other resources consulted collect additional information, we continue to believe there is a very low risk of secondary or tertiary exposures. At this time testing is not recommended by MIT Health officials for any members of the community who did not enter the individual’s lab space on Wednesday.
We continue to gather information about this situation and will update this page if we have more to share. For a campus map, visit https://whereis.mit.edu
Building 18 - update— Aug. 28, 2026, 11:21 a.m.
Building 18 remains closed today as specialized decontamination efforts continue out of an abundance of caution. This work will continue throughout the day, and the building will remain closed until the work is complete.
It remains the case that, based on the information available, this was a localized issue with only one student directly exposed, and this student was the individual working with the compound. Their reported use of the material was unauthorized.
As has been shared with those who work in the building, based on the information available to the department, industrial hygienists, MIT Health medical experts, and other resources consulted, the risk of secondary or tertiary exposures is low, given the compound's characteristics and the information available. For a campus map, visit https://whereis.mit.edu
Building 18 closed— Aug. 27, 2026, 1 p.m.
Out of an abundance of caution, Building 18 is closed for the day following notice of an individual exposed to a hazardous material in a second floor laboratory. City emergency responders were on scene overnight, and cleanup is underway. Building occupants will be notified when the building reopens.
An investigation into the incident is ongoing.
Focused outreach is underway for those who access the impacted laboratory. Support resources are available for members of the MIT community. A comprehensive list of student support resources is accessible at https://doingwell.mit.edu/support/. MyLife Services is among the resources available to all others on campus, with more information at https://health.mit.edu/mit-mit/employees/employee-support-programs.
This page will be updated when the building reopens. For a campus map, visit https://whereis.mit.edu
