Calgary police were called to the Southern Alberta Institute of Technology (SAIT) late Friday morning after office staff received an envelope with white powder inside.
There was a substantial emergency response, including fire trucks, ambulances and police vehicles.
Firefighters also responded and took the lead on this call, police said.
The fire department was testing the white substance but police said no injuries were reported.
Police said they don’t know where the envelope came from.
Emergency Medical Services said no one on scene had medical symptoms.
Just before 2 p.m., officials determined the substance was not hazardous, a spokeswoman for the fire department told Global News.
Eleven people were quarantined but they’ve since been released. Everyone was able to return to the building.