At 0944 hrs this morning Station 24's bells alerted Gladwyne's firefighters for a gas odor inside a dwelling on the 900 block of Merion Square Road. Ladder 24 (AC24-3 McLean) arrived on scene and had a moderate odor of natural gas inside the garage and first floor kitchen. Ladder 24's crew checked the residence with multi gas detector and found 2ppm of CO in the basement. AC24-3 (McLean) notified Montgomery County Radio Room to dispatch PECO to the scene. Engine 24 (FF Hayden Jr) crew arrived on scene; secured the gas meter and set up PPV fan at the front door. Air 24 (AC24 Flanagan) arrived and provided manpower. A Short time later PECO arrived and checked the residence with their gas detector and gas was turned back on by PECO. Gladwyne Fire Company was released from the scene at 1030 hrs.