At~9:31 AM, Westmorland 911 dispatched Station 20 (Murrysville VFC), for the activation of a Carbon Monoxide Alarm at a home on Edinburg Drive. Station 20 responded with Truck 20 (3 firefighters), with Chief 20 going directly to the scene, and an additional firefighter manning Station 20. Upon Truck 20's arrival, Murrysville Medic One was on scene. Truck 20's crew made entry into the home, and upon metering the interior found a high concentration of carbon monoxide (110-120 PPM). It was found that the gas water heater had started to fail causing the improper combustion of natural gas. The firefighters shut off the home's gas supply, and ventilated the structure. Chief 20 notified Westmorland 911 of the situation, and requested that People's Natural Gas come to the scene. Truck 20 and Chief 20 remained on scene until the home was safe for the family to re-enter.