Emergency crews were called to a scene near the Ottawa airport, responding to leftover acid.
Ottawa Fire Hazmat and Ottawa Police Bomb Squad units were called to 1901 Research Private, a building near the airport but not associated, believing to belong to the Transportation Safety Board of Canada.
Ottawa Fire says dried Picric Acid was left in a container.
That type of acid is used in the making of munitions and explosives.
They say the acid could have become explosive if it came in contact with certain metals.
Crews have since cleared the scene, with police saying there was no risk to public safety.