A campus-wide emergency text message alerted University of Minnesota students of odor issues in Moos Tower and Weaver-Densford Hall on Wednesday morning. Several calls were made to University police dispatchers about a “rotten egg smell” reminiscent of natural gas.

Tim Busse, spokesman for University Services, said mercaptan, a chemical used in labs, was accidentally released into the building’s HVAC system.

Mercaptan is sometimes added to odorless natural gas for detection purposes, so it smells like a leak of natural gas, which is a toxin.

“There was an overwhelming amount of calls coming in— people concerned for their safety and people just complaining about the gross smell,” Busse said. “We sent out the alert to ease people’s worries and to assure them there was no danger and no action was necessary.”

Shortly after noon, another text alert was issued informing students the odor issue had been resolved.