A roofing company and a cement factory in Pointe Aux Trembles were destroyed Friday night after a major fire raged through the two buildings.

A hundred and twenty-five firefighters battled the five-alarm blaze that consumed B�ton B�langer at 12231 Sherbrooke St. E and Couvreurs Verdun at 12190 April St.

Investigators and firefighters were on the scene Saturday trying to figure out what happened.

It's believed that the fire originated in a tar tanker at Couvreurs Verdun.

No injuries

There were a few employees in the buildings when the fire began, just before 7 p.m.

"We know that there were at least two employees in the cement mixing plant ... and at least one other employee in the roofing company that's right beside it, but fortunately everyone got out safe and sound," said CTV Montreal's Annie DeMelt, reporting live from the scene Friday night.

Police established a large perimeter around the area, and a number of nearby businesses -- including restaurants, a car dealership and a d�panneur -- were evacuated as a precaution.

"A violent fire"

The blaze intensified as a series of propane tanks at the roofing company exploded.

"We heard maybe about two explosions, two loud bangs," said one area resident.

"It was a violent fire," said Montreal Fire Chief Gilles Ducharme. "We had to adopt a defensive strategy to protect the area all around those two buildings."

"No firefighters could go very close to the fire," he added.

Air quality concerns

Firefighters were initially concerned about a cloud of thick black smoke travelling south toward a residential area, carried by strong winds.

They made the rounds, going door to door, telling to residents to stay inside and keep their windows closed.

But Environment Quebec officials later confirmed the air quality was satisfactory.