More than 30 million US drivers don't know if they're at risk from a rare but dangerous airbag blast

More than 33 million people in the United States are driving vehicles that contain a potentially deadly threat: Airbag inflators that in rare cases can explode in a collision and spew shrapnel. Few of them know it. And because of a dispute between federal safety regulators and an airbag parts manufacturer, they aren’t likely to find out anytime soon. The National Highway Traffic Safety Administration is demanding that the manufacturer, ARC Automotive of Knoxville, Tennessee, recall 67 million inflators that could explode with such force as to blow apart a metal canister and expel shrapnel. But ARC is refusing to do so, setting up a possible court fight with the agency.