An investigation was under way Wednesday to determine the cause of an explosion that destroyed a small cabin in Julian, injuring two people.

Roger and Loraine Spilman were injured inside their home off Salton Vista Drive, near Dolores Drive after authorities said a leaking propane tank was somehow ignited.

The explosion occured around 6:15 p.m. Tuesday, said Cal Fire Captain Mike Mohler. Officials believe it happened in the laundry room, located in the back of the house.

"He just leaned over to get clothes out of the dryer and it just exploded in his face," said daughter-in-law Kathryn Spilman

Roger Spilman's son, also named Roger, and daughter-in-law, Kathryn, live across the street from where the explosion took place.

According to them, the family remains hospitalized at UCSD Medical Center, where they were airlifted.

"He has some pretty severe burns on his arms and his head," said Roger Spilman, Jr. "My stepmother just received a couple of bumps and bruises, a couple of stiches. She's going to be fine. The ceiling fell in on her."

Fire crews spent about half-an-hour digging Loraine from under the rubble. As for the house, officials said it's a complete loss.

"It was big enough that it took stuff inside the kitchen cabinets, and blew them out of the cabinets. It was a big mess," said Capt. Chris Cornette of Cal Fire.

The blast also shook nearby homes.

"This curtain moved, and that whole wall jumped," said neighbor Jill Gibbs. "It was an enormous boom."

Photos taken by investigators showed that much of the cabins ceiling was destroyed by  the blast. They said the structure was so badly damaged that it would have to be demolished.

According to family members, the Spilman's just moved into their home about three weeks ago.

"Right now we're making room in our house for them temporarily, and we're just going to go from there when they get out," said Kathryn Spilman.