The building houses Bouthillier-Rioux Inc., a company that delivers heating oil and diesel fuel. The industrial building is surrounded by residences.
André Paquette, spokesman for the Montreal Fire Department, said about 125 firefighters were called to the scene around 4 p.m.
Several residences were evacuated. No injuries were reported.
Hydro-Québec cut power to 2,300 clients as a precaution.