SLIPPERY ROCK TWP, Lawrence County — Firefighters spent nearly three hours early this morning putting out a fire at a manufacturing facility on Route 422.

The fire broke out after midnight at Advanced Feedscrews, which is a few miles from the Butler County line.

George Johnson of the Slippery Rock Township Volunteer Fire Department said that the electrical fire caused minimal damage.

When firefighters arrived on scene, all they could see was smoke — there was no visible fire. Crews spent a while looking for a source of the smoke, and eventually found that the fire started in the ceiling and spread through the walls.

“Firefighters made an excellent stop to keep the fire from spreading,” Johnson said.

He said the building is constructed of steel and the walls contained fire-retardant insulation, which kept the fire from spreading quickly.

Johnson said there was not much damage to the building. All of the machinery was intact. The company manufactures and rebuilds feedscrews and barrels.

Seven employees were in the building at the time, and they reported the smoke.

About 30 firefighters responded to the fire. In addition to Slippery Rock Township, firefighters from Hickory Township, Scott Township and Portersville, as well as medevac Ambulance, were there.

Crews went back into service shortly before 3 a.m.