At ~ 11:01 PM, Westmoreland 911 dispatched Station 20 (Murrysville VFC) to assist Station 64 (White Valley VFC), for an activated smoke detector at the Valley Stream Apartments. Station 20 responded with firefighters going to the station to crew Truck 20. Westmoreland 911 dispatched the following additional stations to support Station 64: Station 22 (Export VFC), Station 30 (Delmont VFC), and Station 63 (Claridge VFC), and Station 90 (Forbes Road VFC). Chief 64 was first on scene, established the command, found no smoke or fire coming from the structure, and found that the smoke detector in question was defective. Command 64 cancelled all responding units except for Station 64. Truck 20 remained in service and in station.