The Bombardier plant at Mirabel has reopened after an early morning evacuation due to a bomb threat Friday.
Bombardier spokesman Marc Duchesne told CBC News that someone called in a threat against the assembly plant for the company's CSeries aircraft just before 6 a.m.
Police are now trying to determine who made the call.
Mirabel police and Bombardier's security services evacuated the facility while a police bomb-detection unit conducted a search with bomb-sniffing dogs.
Quebec provincial police blocked Exit 288 on Highway 50 in both directions during the operation.
Houses around the plant were also evacuated as a precaution.