Eight children are being cared for by relatives and four adults have serious injuries after an explosion in a residential garage in Barrie, Ont., that has been linked to "drug-related" activity.

Barrie police Const. Sarah Bamford said investigators are seeking warrants to review the site of the explosion.

“What we do know is the activities that took place in there (were) drug-related,” she told reporters Saturday afternoon.

The explosion happened Friday night just before 9 p.m. in a garage on Collette Crescent.

Four adults who were in the garage were rushed to Toronto-area hospitals with serious injuries. A male and female remain in critical condition Saturday evening, while two men are in stable but serious condition.

Police say six adults and eight children, who ranged in age from three weeks to 15 years old, had been in the house at the time of the explosion.

Zachary Taylor Armstrong, 15, and his girlfriend, escaped from the house after the blast.

“We ran to like the top of the stairs and we (saw) the door fly open and a big wall of flames coming out, and there were people crawling out of the garage,” he tells CTV News.

With the front door blocked, he and his girlfriend were forced to jump off a bedroom balcony, he says.

“(It was) really scary,” Armstrong said.

Bamford also said Children’s Aid Society had been notified of the possible danger to the children, some of whom sustained minor injuries.

“The children that were inside the residence have been reunited with family members and they are currently in the care of adults right now,” Bamford said.

Residents of nearby homes are not in any danger.

The fire caused an estimated $400,000 in damage to the house.

Police say they suspect the explosion involved butane canisters, which are typically used in the production of cannabis.

The Office of the Ontario Fire Marshal is investigating.

With a report from CTV Toronto's Heather Wright