Mazda North American Operations (Mazda) is recalling certain 2009 B-Series trucks ever registered in the states of Alaska, Colorado, Connecticut, Idaho, Iowa, Maine, Massachusetts, Michigan, Minnesota, Montana, New Hampshire, New York, North Dakota, Oregon, Rhode Island, South Dakota, Utah, Vermont, Washington, Wisconsin, and Wyoming. These vehicles are equipped with certain air bag inflators assembled as part of the passenger frontal air bag modules used as original equipment or replacement equipment. In the event of a crash necessitating deployment of the passenger frontal air bag, these inflators may explode due to propellant degradation occurring after long-term exposure to absolute humidity and temperature cycling.