Firefighters battled a 2-alarm fire at a commercial building in Exeter Township late Monday afternoon.
Crews got the call to respond shortly before 5:30 p.m. to a building at 100 Giblraltar Road, behind the Burger King restaurant on Perkiomen Avenue.
Initial reports from the scene were that the first firefighters to arrive found smoke pouring from the building.
A second alarm was quickly struck, summoning additional manpower to the scene.
Fire officials said a furnace left running in the Four Seasons Flowers warehouse sparked the blaze.
"We found out that the unit was operating but was unattended. The unit should have been attended and it should have been shut down properly," said Chief Robert Jordan, Exeter Township Fire Department.
The fire marshal's office will continue the investigation, officials said.