DETROIT (AP) — U.S. safety regulators have backed away from seeking a recall of nearly 50 million air bag inflators. They will instead investigate further after the auto industry raised questions about whether all the inflators are defective. The move by the National Highway Traffic Safety Administration is different from a decision reiterated in January that the inflators made by ARC Automotive should be recalled. The agency has said inflators in about 49 million vehicles are at risk of exploding and hurling shrapnel into drivers and passengers. They’re responsible for at least seven injuries and two deaths in the U.S. and Canada.