The Ontario Fire Marshall’s office is investigating the cause of a house explosion and fire just outside Mount Forest that sent two people to hospital Thursday night.

A 70-year-old woman and 46-year-old man, who neighbours say are mother and son, are in stable condition at a London hospital.

Emergency crews were called to their log home on Sideroad 2 late Thursday afternoon, after receiving reports of an explosion and fire.

Ian Foertsch was hunting deer when he felt the explosion and heard the screams of the man. “When I heard the blast and all the screaming and stuff, I was kind of shocked because you feel like you can do something about it but being a distance away, you don’t know if you can get there in time,” he said.

Another neighbour said the force of the explosion sent the 70-year-old woman flying across the room and into a wall. They also said the son, who had burns to his body, helped carry his mother out of the house and stayed with her until an ambulance arrived.

The man and woman are part of the family that owns Chalmers Fuel in Teviotdale.

Investigators are now combing through the wreckage of the home, trying to find the cause of the explosion. It could take several days because the house was completely destroyed and the remaining structure collapsed into the basement.

“We have some tests we have to do for the propane system in the house,” said OFM Fire Investigator Jim Gillespie. “Everything that’s in the basement has to come out so we can get access to the furnace and hot water heater so we can examine them to see what, if any, role they played in the explosion.”