Durant firefighters responded Sunday to an apartment at Sooner Apartments after being dispatched to investigate a smoke odor.
When firefighters arrived, they found a mattress burning and they used a water cannon to put out the fire, according to a DFD report.
City Fire Marshal Wade Boyd investigated the fire and determined the apartment unit did not have electricity, the report stated, and there were many cigarette butts on a coffee table beside the bed.
The tenant told firefighters he did not remember if he had been smoking when he was last in the room. The fire was ruled accidental.