By TOM KRISHER, AP Auto Writer

DETROIT (AP) - Another driver has been hurt by an exploding airbag inflator made by ARC Automotive of Knoxville, Tennessee, bringing to four the number hurt or killed by the inflators.

The company's devices have been under investigation for nearly four years by the U.S. National Highway Traffic Safety Administration.

Safety advocates say the agency is moving too slowly on the probe, which began in July of 2015, and other investigations. The agency says it's continuing to review information with ARC and vehicle manufacturers.

Last week, General Motors recalled more than 1,100 cars with the inflators after finding out that a driver had been hurt in late 2017.

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