At ~ 2:04 PM, Westmoreland 911 dispatched Station 20 (Murrysville VFC) for a Carbon Monoxide (CO) Alarm at a home on Nature Trail Lane. Station 20 responded with Engine 20 (4 firefighters including Assistant Chief 20), and Rescue 20 (4 firefighters), with Chief 20 at the station. Westmoreland 911 also dispatched Station 610 (Murrysville Medic One) to support Station 20. Engine 20, Rescue 20 and Medic 612 arrived on scene, with Assistant Chief 20 establishing command. Station 20 firefighters entered the structure, and surveyed the interior with 4-Gas Meters, finding no evidence of Carbon Monoxide. Command 20 explained to the homeowner that there was no evidence of CO within the structure, and recommended that the alarm provider come to the location to inspect the system. Command 20 returned the structure to the homeowner, and returned Engine 20 and Rescue 20 to service and station.