At ~3:32 PM, Westmoreland 911 dispatched Station 20 (Murrysville VFC) for a report of Carbon Monoxide (CO) in an office building on Reed Avenue. Station 20 responded with Engine 20 (2 firefighters including Assistant Chief 20), with 1 firefighter going to the scene, and 7 firefighters on station standby. Westmoreland 911 also dispatched Station 610 (Murrysville Medic One) for the incident. Engine 20 arrived on scene, and Assistant Chief 20 established command. Rescue 20's crew surveyed the interior of the structure with 4-gas meters, and found no evidence of CO within the structure. Command 20 returned Rescue 20 and Station 610 EMS to service and station.