Firefighters had difficultly battling an Ames fire Monday, because the flames were inside walls.
It happened at a plastics company at 520 Bell Avenue just before 8:00 a.m.
Firefighters found the fire in the walls on the second floor. Crews had to use hand tools just to expose the fire, since it was behind metal walls.
Officials say contractors working on a remodeling project were welding in the area before the fire. No employees were hurt.
One firefighter was treated for heat stress.
The Nevada Fire Department assisted the Ames Fire Department in putting out the fire.