WASHINGTON – Thousands of motorists may be driving cars and trucks installed with dangerous counterfeit air bags, and they should have them replaced at their own expense, the Obama administration warned Wednesday.

Most at risk are motorists who have had their air bags replaced over the past three years by a repair shop other than a new car dealership, the National Highway Traffic Safety Administration officials said.

Only 0.1 percent of the U.S. vehicle fleet – about 250,000 cars on the road – are makes and models for which counterfeit air bags are known to be available, the agency said. Auto industry officials briefed by the agency said they were told that tens of thousands of car owners may be driving with counterfeit air bags.

In government tests last month of 11 counterfeit bags, 10 didn't inflate or failed to inflate properly. In one test, a counterfeit bag shot flames and shards of metal shrapnel at a crash dummy instead of inflating, said agency Administrator David Strickland, who showed a video of the test at a news conference.

The agency is asking car owners to check a government website,, for information on how to contact auto manufacturer call centers to learn if their vehicle model is among those for which counterfeit air bags are known to have been made.

No deaths or injuries have been tied to the counterfeit bags, the agency said. But it's unclear whether police accident investigators would be able to identify a counterfeit bag from a genuine one, industry officials said.

About 1.5 million air bags are deployed each year in police-reported tow-away crashes, Clarence Ditlow of the Center for Auto Safety said.