At ~10:53 AM, Westmorland 911 dispatched Station 20 (Murrysville Volunteer Fire Company) for a Carbon Monoxide Alarm Activation on William Penn Highway. Station 20 responded with 2 firefighters (including Assistant Chief 20) going directly to the scene; and Station 78 (Sardis VFC) was dispatched to assist Station 20. Upon arrival of the firefighters from Stations 20 and 78, the building's occupants had been evacuated into the nearby parking lot, and the firefighters surveyed the building using Carbon Monoxide and Multi-Gas Detectors. No traces of hazardous gases were detected, and Assistant Chief cleared the building for reentry by the occupants. Assistant Chief 20 released all apparatus and personnel for return to station.