Fire officials in Nanaimo say oily rags that spontaneously burst into flames caused a house fire that displaced four people over the weekend.

The blaze broke out at a home in the 200-block of Rovere Place early Saturday morning.

By the time firefighters arrived the house was fully engulfed by flames, with neighbours being woken up by the sound of sirens.

“I heard an explosion and thought it was a vehicle crash into a telephone pole or something,” said Greg McRae, who lives in the area. “So I ran outside down to the end of my driveway and realized there was a house fire across Hammond Bay Road.”

Four occupants escaped and after several hours crews were able to bring the fire under control, preventing it from spreading to other homes.

In the end, the home suffered extensive damage while a nearby home received minor damage to its exterior.

On Monday, investigators confirmed the fire was sparked by oily rags that spontaneously combusted due to a chemical in a garbage can.

As the rags heated up they began to smoulder, then caught fire.

It’s unclear whether the home had working smoke detectors.