Four people were taken to hospital and treated for shock following an explosion at the Rio Tinto Iron and Titanium plant in Sorel-Tracy, about 90 kilometers northeast of Montreal.
Luc Bouchard, an employee at the plant, said the blast occurred at about 4:30 A.M. and the force could be felt throughout the town.
"Huge. All around the city they could hear the sound and felt the shake, like an earthquake I guess" Bouchard said. "Looks not so bad after all, we're lucky, very lucky."
Bouchard said it appears as though a gas line failed, causing the explosion.
The plant was evacuated, no one was hurt.
The local fire department and provincial police are investigating.