Police called transportation officials twice to report debris had fallen from a highway overpass in Laval, Que., within an hour of its collapse, which killed five people and seriously injured four others, the province confirmed Sunday.

Tonnes of concrete from the bridge suddenly dropped onto Highway 19 around the noon-hour Saturday, crushing two vehicles and causing three other cars and a motorcycle to plunge 15 metres. Four of the injured remained in hospital on Sunday.

Rescue workers start to remove debris at the site of the overpass that collapsed in Laval, Que., on Saturday.
(Ryan Remiorz/Canadian Press)

"There was a call to the department [of transportation] from the Quebec police force at 11:25 a.m., pointing out there was concrete on the highway," provincial Transportation Minister Michel Després told reporters.

"At 11:58, a representative from the department was present. They recovered the rubble there. They assessed the situation, and during that time, there was nothing detected by the person who had been sent there which would require the immediate closure of the overpass."

At 12:33, there was a second call from police to report that more concrete had fallen. Four minutes later, the overpass collapsed, Després said.

He said there was a "full technical inspection" of the overpass by transportation officials in May 2005 and it showed "nothing in it to explain what happened."

Public inquiry ordered

The Quebec government will hold a public inquiry into the collapse and has announced it has closed a second overpass of similar design and age.

Després said department officials worked overnight reviewing the design of all 4,500 Quebec overpasses and bridges and found 20 that need close review.