Three girls are recovering from burns following a propane explosion — and, according to the RCMP, it happened after one of them lit a cigarette while they were inhaling the flammable gas.

The two 13-year-old girls and a 12-year-old girl were injured in Kamsack, Sask., Monday night. One with the most severe burns was taken to hospital in Regina, although all are expected to recover.

The girls were sitting in a car outside one of their homes when the explosion happened, a few blocks from the local RCMP detachment.

"The members that were on duty here ... could actually hear it," Staff Sgt. Greg Nichol said. "They described it like it felt like a semi had rumbled by the detachment."

The community has had problems with propane inhaling — or "huffing" —  in the past, but it seemed to have dropped off until recently, Nichol said.   "We just recently had been hearing that some local kids had become involved in it, and were experimenting with it, or doing it, and I guess it's probably been confirmed in this incident last night," he said.

The explosion blew out the car's windows, and sprayed debris five metres away.

"I saw the car. The girls are pretty lucky they weren't hurt worse, I'd say," Nichol said.

Children involved in this activity typically steal propane tanks from backyards, so people should be on the lookout for any suspicious activity, Nichol said.