The man who lived at the house on East Seventh Avenue had left about an hour before the trouble started.
Firefighters say it's possible the wood stove was still on.
To complicate things -- there were no fire hydrants on the street.
"But they did get hydrants from the neighboring streets - they got water supply okay. It added an element of confusion a little bit also trying to get to the address as well as making sure they had fire hydrants," Benton County Fire Marshal Mark Yaden.
Crews from Kennewick, Pasco and Benton County helped put the fire out -- but say the damage was extensive.
And in Benton City utility lines were snapped by a tree trimmer about an hour ago. There's been no reported power outages but some phone calls may be affected.