Four construction workers are in hospital - including one in critical condition - after dozens of bricks tumbled from the top of a three-storey wall of an old elementary school they were fixing.
A spokesman for the local ambulance service says one of the four men was more seriously injured with head and internal injuries.
"He is in critical condition at the Montreal General Hospital," said Urgences Sante spokesman Benoit Garneau.
Three others also were injured, two with minor injuries and one with slightly more serious injuries, but none are considered life-threatening, Mr. Garneau said.
Roofers and bricklayers had been doing renovations to the old school in Montreal's Ville-Emard district Wednesday morning.
Masons had been repairing an exterior brick wall of the St-Jean-de-Matha school, which was built in 1933, and were working on the top part when dozens of bricks began to tumble off the structure.
The bricks fell from the top two metres of the three-storey wall and landed on the nearby mechanical lift below, causing it to collapse, Mr. Garneau said.
Work had been underway on the wall for about two weeks. The school has not yet opened for classes and officials say it may remain closed until an inspection of the building is completed.
One witness said he saw bricks beginning to fall and others reported hearing a loud noise and seeing clouds of dust after the collapse. One worker was spotted limping from the scene and yelling.
Montreal police Constable Olivier Lapointe said there is no criminal aspect to the incident and the investigation has been turned over to the provincial workers' health and safety commission.
A commission spokesman says the investigation into the collapse is in its infancy.
"We have few details for the moment, but inspectors are already on site," said Pierre Turgeon.