At ~7:42 PM, Westmoreland 911 dispatched Station 20 (Murrysville VFC) for a Residential Automatic Fire Alarm on Deerfield Court. Station 20 responded with Service 20 (Lieutenant 20) going directly to the scene, and 2 firefighters going to Station 20 to man Engine 20. Upon Lieutenant 20 arrival at the scene no fire was in evidence, upon investigation it was found that a baking accident in the home's oven had set off the kitchen smoke detector, and the home owner had already ventilated the kitchen. Thus, Lieutenant 20 cancelled Engine 20 before it departed station.