BARRIE, Ont. -- Police say illegal drug activity caused an explosion in a garage Friday night at a north-end home that seriously injured four people, and caused minor injuries to five children.

“The suspected cause of the fire was butane canisters exploding during the extraction of cannabis resin,” Const. Sarah Bamford said Saturday afternoon, adding police were waiting for search warrants to continue their investigation.

Firefighters were called to the home around 9:15 p.m.

Fire department spokeswoman Samantha Hoffmann said the 911 caller described flames as high as 20 feet coming from the home.

When crews arrived, they found the garage completely engulfed in flames and there were three men and a woman outside the home seeking medical attention.

Police said two of the men, aged 20 and 24, were visiting the home at the time of the explosion. The other two injured were a 37-year-old man and a 36-year-old woman who rented an apartment in the home.

Police said there were eight children and two other adults inside the home and that the kids ages ranged from three weeks to 15. All were safely removed from the home.

Four of the children lived in the home, three children lived there part-time and the infant was visiting, police said.

Five of the kids were treated for minor injuries either at the scene or at hospital. Police said the children are now in the care of relatives. The Children's Aid Society has been notified.

Four adults were seriously injured and were stabilized at a local hospital before being sent to other area hospitals for further treatment. They all remained in serious condition Saturday.

Firefighters brought the fire quickly under control, although they were still working on hot spots after 10:30 p.m.

Don Smith says he heard a series of explosions from the house next door before he saw anything.

“We were sitting in the house, watching TV, and we heard boom, boom, boom. It was a low sound, a low boom,” he said. “We heard people screaming. They were hurt, they were burned.

“They were in real bad shape. They were running up and down the street screaming.”

The cause of the fire is being investigated by fire officials and the Ontario Fire Marshal's Office.

bob.bruton@sunmedia.ca

cheryl.browne@sunmedia.ca