This article was updated to reflect new information at 11:43 a.m., 12/16/2021.
Students inside Chamberlin Hall and several other University of Wisconsin-Madison campus buildings reported being evacuated due to a potential gas leak around 5 p.m. on Wednesday. All buildings have since been cleared, and the source of the odor has been identified.
The UW-Madison Police Department received multiple reports of “natural gas-like odor” and activated fire alarms Monday evening near Chamberlin and Van Vleck Halls.
UWPD, the Madison Fire Department, and Madison Gas and Electric Company were all on scene near the intersection of Observatory Drive and N. Charter St. Eastbound traffic on Observatory Dr. was momentarily diverted down Charter St. away from Sewell Social Sciences, but has since reopened.
Though UWPD received multiple calls reporting a gas leak around 5 p.m., sensors did not detect any natural gas.
The source of the odor has since been identified as a “highly concentrated non-toxic chemical” a nearby lab disposed of. Police say the odor may linger through Thursday, but stress “there is no threat or emergency and there never was.” Officers also reported that winds may have carried the natural-gas odor.
According to police officers on scene, Sewell Social Sciences, Van Vleck, Ingraham and Bascom Halls were also evacuated but are now cleared.
Police initially thought Elizabeth Waters Hall may be affected but found no natural-gas odor was present outside the residence hall. The dorm was not evacuated and is clear.
City buses were temporarily rerouted to avoid the area, according to the police scanner. Student reports also indicate some exam rooms were relocated.