BANGOR – A fire that damaged a South Park Street apartment building Wednesday, displacing three residents, was accidentally started by flames from a propane torch being used for repairs on the building’s front steps.

As part of his investigation into the fire, Assistant Fire Chief Rick Cheverie found that the torch was being used by a worker to warm patching material for the front steps at 53-55 South Park St. and ignited the front wall of the building. The fire was described as unintentional.

Bangor firefighters were called to the residence at 2:22 p.m. and arrived within five minutes. They tore away sections of the front exterior wall to get at the fire. Cheverie said that because it was an older building, the fire could have easily spread much further. With studs running to the roof, some of them not insulated, flames could have gotten “into the walls and gone everywhere,” he said.

Firefighters also broke windows on the building and used fans to help clear the heavy amount of smoke inside, which could be seen coming from the back of the building. They hosed sections of the front wall where fire had been detected.

Only one occupant of the yellow, green-trimmed building was home at the time but no injuries were reported, Cheverie said. A cat had been inside one of the apartments at one point, but officials weren’t sure if it had escaped or remained inside the building.

One of the building’s owners, Jim Bryner, said he had been called about the fire and arrived to see smoke and flames coming from the structure. He said the building was insured.

Bryner acknowledged that maintenance was being done on the building as part of regular upkeep, but at the time Cheverie had not made his determination and Bryner declined to speculate whether the fire was connected to the work being done.

Police cruisers and fire department vehicles and barricades blocked off the section of the road that runs between French and Center streets. The building that burned is located next door to the Good Samaritan Agency. Representatives of the American Red Cross disaster relief were on hand to provide assistance.