Residents of a mobile home that caught fire Monday morning at Santiago Sunset Estates in Kennewick were smoking on their deck the evening before, said deputy fire marshal Joe Terpenning of the Kennewick Fire Department.
A neighbor saw a glow about 3 a.m., and when he investigated he saw the deck was on fire, Terpenning said.
When firefighters arrived, the heat of the fire had broken the sliding glass door to the deck and the fire had spread inside the residence.
The three adults living in the house were outside when firefighters arrived.
One man had been sleeping on a couch just eight feet from the door, Terpenning said.
The home is not habitable, but was not entirely destroyed, he said.
Sunday evening the residents had been smoking on the deck and were not sure if they put the butts in a can or in potting soil, he said.
The strong winds overnight had knocked the can over, possibly sparking the fire.
Or the potting soil, which is combustible, may have smoldered for hours and then caused the fire as the wind kicked up, Terpenning said.