Warning: Your airbag might be a fake—and might not inflate in an accident.

The National Highway Traffic Safety Administration (NHTSA) recently warned that counterfeit airbags had been used as replacement parts in vehicles involved in crashes. In addition to not inflating, these airbags also can release metal shrapnel in a crash.

Though the NHTSA hasn’t determined the full scope of the problem, it estimates less than 0.1 percent of U.S. vehicles are affected. But even that small percentage is a serious safety concern, and one drivers need to be aware of so they can determine whether they may be at risk.

If you’ve had your airbag replaced in the past three years, and it was replaced by a shop other than a new car dealer, you could have a counterfeit product. Airbags bought online also could be fake. If you recently purchased a used car and aren’t familiar with your car’s history in the past three years—and it could have been in a crash—you also may be at risk.

Unfortunately, the counterfeit airbags look nearly identical to certified airbags, and even have the branding of major auto companies. If you think you’re at risk, contact your auto manufacturer for a vehicle inspection.