General Motors LLC (GM) is recalling certain 2007-2008 Chevrolet Silverado 2500 and 3500 and GMC Sierra 2500 and 3500 vehicles equipped with non-desiccated, passenger frontal air bag inflators containing phase stabilized ammonium nitrate (PSAN) propellant that were used as interim remedy parts for previous Takata recalls. These inflators may explode due to propellant degradation occurring after long-term exposure to high absolute humidity, high temperatures, and high temperature cycling.