A faulty heater caused a fire in a mixed-use Union Street building Friday afternoon.

ROCKLAND – A malfunctioning heater is blamed for a fire which damaged a mixed-use building on Union Street Friday afternoon.

The gas-fed heater was in a second-floor apartment of the building at 331 Union St., Rockland Fire Chief Scott Duffey said.

“With the cold temperatures, it was running and running and had a malfunction of some sort,” Duffey said.

The fire was reported at 1:09 p.m. and the apartment was unoccupied at that time, the chief said.

The fire did move into the wall of the unit, tripping an alarm which brought firefighters to the scene.

Duffey said fire was quickly extinguished by the first arriving companies, with smoke damage mainly confined to the apartment. A hair salon on the first floor suffered heavy water damage, he said.

No injuries were reported.

The Red Cross will help provide temporary housing for the residents of the building. Two of the building’s four apartments were vacant, the chief said.

Extra firefighters and equipment were brought to the scene due to the low temperatures and high winds, the chief said. Mutual aid was provided by the Abington, Weymouth, Hanover, Norwell and Whitman fire departments.