Hub Mall and the Rutherford Library at the University of Alberta in Edmonton were evacuated Tuesday morning in response to fears hydrogen sulphide had been released into the air.
Around 10:15 a.m., fire crews were called about a medical emergency at an apartment in Hub Mall and the possible presence of H2S in the area.
Staff were alerted to the emergency by email around 10:40 a.m. Announcements were also made over the public address system.
According to a news release from Edmonton Fire Rescue, the order was changed to a "stay in shelter" alert, where residents were ordered to stay in their rooms, because of a possibility the gas was in the hallway.
What was described as a "chemical release" by Edmonton Fire Rescue was later found in the apartment. Emergency officials declared the two buildings safe and lifted the order at 12:17 p.m., the university's website said. The buildings were also ventilated through the use of fans.
One person is dead. The death is not considered suspicious and no further information will be released.
Two other occupants in the apartment were treated at scene and released. A member of the university's staff was also examined but was not hurt.