A bridge undergoing construction collapsed Saturday near Lucknow, Ont., injuring at least six people.
A block of concrete crumbled just before 12:30 p.m. while a construction crew stood on the structure.
Two people reportedly suffered serious but non-life threatening injuries, while at least four others were treated for minor cuts and bruises.
Earlier reports had said one person was airlifted to a London-area hospital, but officials said late Saturday that was not the case.
There may be more injured as several crew members were taken to the hospital in private cars, Ontario Provincial Police Const. Dennis Harwood told CTV.ca in a telephone interview from Tillsonburg, Ont.
The workers were pouring cement on the bridge at the time of the accident, he said. The bridge is brand new, replacing an old structure that once stood on the site.
Harwood also said it's too early to determine what caused the collapse.
The bridge, which runs over a creek, was closed to traffic at the time but about 15 construction workers were working on it when it collapsed.
Capt. Stephen MacPherson of the Goderich Volunteer Fire Department rushed to the scene, and told The Canadian Press he was amazed none of the workers had been trapped under the wreckage.
"It's amazing. I have no idea how it was done. Nobody was pinned," he said.
MacPherson added that several workers escaped injury but appeared traumatized by the incident.
"There's a lot of shock out there," he said.
Harwood told CTV.ca that the Ministry of Labour will investigate the matter and determine what went wrong.
"The Ministry of Labour is currently at the scene and will take over the investigation," he said.
The two-lane bridge is located on Amberley Road, near Bruce Road 86 and Highway 21, about 200 kilometres west of Toronto.
It had been under construction since July and was 10 weeks behind schedule, according to The Canadian Press, which obtained the information from a Nov. 5 agenda of a local town council meeting.
