Quebec provincial police say at least three employees were missing after an explosion at a propane facility Thursday in St-Roch-de-l'Achigan, Que., north of Montreal.

Sgt. Éloïse Cossette told an evening news conference that three employees of Propane Lafortune had not been seen since the explosion, describing them as "three potential victims."

“Our thoughts are with the families of these people, with whom we are currently in contact," she told reporters, adding that police have started an investigation and were dealing with a large scene that would require several days to comb through.

She didn't provide any other details about the three missing people other than that they were employees and the search was ongoing. Police have not ruled out that other people could have been on site when the explosion occurred.

The fire was finally brought under control Thursday evening at the well-known business in the community.

Fire Chief François Thivierge said earlier that authorities were called following an explosion at 11:17 a.m., and the first units to arrive tried to intervene but had to retreat due to a risk of further explosions from the propane tanks on-site.

Thivierge said first responders were mindful of safety concerns and the environmental risk of oil or gas ending up in the nearby Achigan River.

The situation was also initially too dangerous for paramedics, said Érik Lauzon, operations director for the Lanaudiére-Laurentides ambulance service. Ambulances were on-site, he said in an interview, but they were unable to approach the scene because of the risk of explosion.

Thivierge said officials used a drone to assess the risk and were able to continue their operation once they deemed it safe. About 50 firefighters were on the scene and they were expected to remain into the night, he added. Crews from the neighbouring municipalities of Rawdon, Ste-Julienne, St-Lin-Laurentides and Repentigny were called in to help combat the blaze.

Police say at least three missing in #propane explosion north of Montreal. #Quebec #explosion #SaintRoch #PropaneLafortune

Authorities established a one-kilometre evacuation zone around the site, but by 6:30 p.m., about 50 people forced from their homes were able to return.

Stéphanie Therrien, deputy director general for the Montcalm regional municipality, said earlier that three or four employees were unaccounted for. "Unfortunately, there are employees who are still missing," she said in an interview. Therrien said it was unlikely anyone was able to escape the violent fire that followed the explosion.

"There might have been witnesses who tried to get inside to help, but since the roof was collapsing, they had to come out as quickly as possible," Therrien said.

Karine Lamarche, who lives near the site, said an explosion shook her home late Thursday morning.

“It was shaking, I thought something had fallen on the house,” she said. It was only later, as she drove to pick up her mail, that she rounded the bend toward Propane Lafortune and saw the aftermath.

“I saw the big smoke up in the sky, a lot of fire coming from the ground and going up in the air. There was a lot of black smoke,” she said. Later, as she returned home, a security perimeter had been erected and some nearby homes were being evacuated.

"We know the people who work there a little bit, we heard like everyone else that people were missing," Lamarche added. "It's a shame, it's sad. It touches me, because it's a company that's right next door."

The mayor of St-Roch-de-l'Achigan, Sébastien Marcil, held back tears as he spoke to reporters.

"It's the uncertainty," Marcil said. "There are three people who are unaccounted for, three of our citizens, and we're looking for them and we're waiting for answers."

In an emailed statement, the Lafortune family said it has offered its full co-operation to authorities and quickly called emergency services after the explosion and fire.

"We are deeply upset by this event and we are monitoring the situation closely," the statement said.

"This is the first time in 60 years that our company has experienced such an ordeal. Our hearts go out to our employees, their families and anyone who may be affected by this difficult situation."

Cossette said it's too early to speculate on the cause of the explosion. Residents who were displaced or traumatized by the blast were able to seek shelter and mental health services in the basement of the St-Roch-de-l'Achigan church.

Quebec Public Security Minister François Bonnardel said on Twitter that his department is monitoring the situation and his thoughts are with the workers.

This report by The Canadian Press was first published Jan. 12, 2023.

By Sidhartha Banerjee in Montreal with files from Morgan Lowrie, Mathieu Paquette and Helen Moka

Keep reading