An explosion and fire at a plant seriously injured four people and produced a dark cloud of potentially toxic smoke Thursday.
The incident occurred in Quebec's Eastern Townships at a facility belonging to Neptune Technologies & Bioressources, which produces health products derived from marine life like Omega-3.
A Sherbrooke police spokesman said the explosion led to a fire, which produced clouds of smoke that authorities feared was toxic.
He confirmed four people were seriously injured. He couldn't immediately say if their lives were in danger.
"It's a major fire. There are a number of injuries," said Rene Dubreuil of the Sherbrooke police.
"For now we're trying to secure the area and take care of the injured."
Environment Quebec said the toxicity concern stemmed from the plant's acetone reserves, which were struck by the fire.
Acetone is flammable and, when ingested, can cause irritation.
Officials said they were more concerned about the possibility of soil or water contamination than of the risk associated with breathing the air near the blast site.
It's unclear what caused the explosion.
Within minutes, police said, employees were evacuated from the facility and supervisors performed a head count outdoors.
Police then set up a security perimeter, clearing the industrial park.
"We're asking people to stay away from the area. These are possibly toxic clouds," Dubreuil said.
Thick black plumes were seen rising from the facility.
The Laval-based company announced plans last year to expand its Sherbrooke facility. The federal government supported the project with an interest-free loan and the Quebec government provided a grant, according to an announcement made earlier this year by then-premier Jean Charest.