Ford is recalling more than 310,000 trucks in the U.S. because the driver’s front air bag may not inflate in a crash.

DETROIT – Metal fragments from an exploding air bag inflator killed the driver of an older Volvo, touching off a U.S. recall of up to 54,000 cars, regulators said Saturday. NHTSA said the ZF/TRW inflator rupture that caused the death is the only known incident worldwide. The problem caused the largest series of auto recalls in U.S. history, with at least 63 million inflators recalled. NHTSA said Saturday that the ZF/TRW inflators did not use ammonium nitrate to inflate the air bags. Volvo says in documents posted by NHTSA that registration data found about 13,800 of the recalled cars are still in use.