Larksville, PA — Firefighters are investigating after a carbon monoxide alarm has forced more than a dozen people out of their apartments.

Officials say a carbon monoxide alarm went off just before 10 p.m. on Saturday at an apartment building along Wilson Street in Larksville.

Crews believe the chimney got blocked up or the furnace malfunctioned – no flames broke out in the building.

The cause of the alarm is still under investigation in Luzerne County.