“These airbag inflators may rupture when the vehicle’s airbag is commanded to deploy, causing metal debris to be forcefully ejected into the passenger compartment of the vehicle. A rupturing airbag inflator poses an unreasonable risk of serious injury or death to vehicle occupants,” NHTSA wrote.
ARC did not immediately respond to a request for comment.
The latest action comes amid an eight-year-long investigation of rupturing airbag inflators manufactured by ARC, a Knoxville, Tenn., Tier 2 supplier.
In a letter made public in May, NHTSA demanded that ARC recall 67 million airbag inflators produced through January 2018 that the agency “tentatively concluded” are defective.
ARC rejected NHTSA’s demand. The company stated that it “strongly disagrees with the agency’s ‘tentative conclusion’ that a safety defect exists” in the driver and passenger inflators.
ARC, which in January 2018 installed instruments to detect excessive slag and other debris in the welding process, said it believes the ruptures resulted from “one-off manufacturing anomalies” that were addressed by automakers in subsequent recalls.
NHTSA on Tuesday pushed back against that claim, stating the agency “believes that ruptures may result from the weld slag produced by the friction welding manufacturing process.”
“Should weld slag of a sufficient size become dislodged, it can cause a blockage of the inflator exit orifice when the airbag deploys,” the agency continued. “A blockage of sufficient size will cause an over pressurization and rupture of the inflator, leading to the potential forced propulsion of shrapnel or metal fragments from the inflator into the passenger compartment.”
Since the launch of the ARC investigation in 2015, automakers — including BMW, Ford and Volkswagen — have initiated eight recalls to address potential safety defects with ARC airbag inflators.
Most recently, General Motors called back nearly 1 million 2014-17 Buick Enclave, Chevrolet Traverse and GMC Acadia vehicles with the airbag inflators.
At least nine incidents globally — seven in the U.S. — of ruptured airbag inflators have been identified in NHTSA’s still-open investigation of ARC. Of those, dating from 2009 to as recently as March, seven injuries and two deaths have been reported.
“Additional inflator ruptures are expected to occur in the future,” NHTSA warned in its decision, “risking more serious injuries and deaths, if they are not recalled and replaced.”