Police and fire personnel were called to Lash Miller Laboratories on 80 St. George Street after reports of smoke in a third floor lab.
Students evacuated the building at approximately 5:33 pm after a fire alarm sounded. Several police cars and ambulances could be seen blocking a portion of St. George Street from Harbord Street to College Street.
A Toronto Police investigation confirmed that a rag on equipment in the lab was the cause of the smoke.
Students were given the clear to re-enter the building at approximately 6:10 pm, despite initial smells of smoke from the Davenport wing. Police and fire personnel left the scene at 6:17 pm.
Campus Police declined to comment on the incident.