Subaru of America (Subaru) is recalling certain 2005-2006 Baja, 2006-2008 Impreza (including WRX and STI models), Tribeca, and 2006 Saab 9-2X vehicles, originally sold, or 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 rupture due to propellant degradation occurring after long-term exposure to absolute humidity and temperature cycling.