49 Fire responded to 144 Choctow Ridge Rd. on a report of an odor of gas in an occupied residential duplex. Upon the arrival of Chief 49, he discovered the entire structure to be heavily charged with natural gas. Engine 102 arrived first, closely followed by Engine 108 and Rescue 49. E102's crew stretched a handline to the front door and a crew led by Captain 49 made entry into the structure to complete a primary search. The source of the gas leak was found to be a free flowing gas stove that was inadvertently left on by the home owner prior to her leaving for a few hours. The stove was secured and both sides of the duplex were vented. Also on location was Branchburg PD, 74 Rescue and PSEG Gas.