Was your airbag replaced within the past three years? Did you buy a used car that sustained air bag deployment before you bought it? Did you buy a car with a salvage, rebuilt, or reconstructed title? Did you get a great deal on an air bag? In that case, be suspicious of your airbag, because it could kill you.

Gadzillions of cars could be driving around with airbags that fail to inflate during an accident, or that throw shrapnel at you when they do deploy, says the NHTSA.

The agency says ”the full scope and scale of the problem of counterfeit air bags is uncertain from currently available data,” but it “believes this issue affects less than 0.1 percent of the U.S. vehicle fleet.” At 250 million registered vehicles on the road, that would be around (or less than …) 250,000 cars with possibly lethal airbags lurking in the dash.

It also could be a big boon to new car dealerships. The NHTSA says that airbags replaced by new car dealerships are safe, but you should worry if and independent workshop did it.

Airbags are hidden away and cannot be checked by amateurs. The NHTSA recommends that possibly affected customers call their manufacturer and “have their vehicle inspected at their own expense and their air bag replaced if necessary.“

A dealer inspection likely will cost $100 or more. Replacing an airbag could go into the thousands.

The NHTSA released a list of nearly 100 vehicles that could have counterfeit air bags. Most popular brands and makes are on it.

The NHTSA does not say where the counterfeit airbags are from, but the Detroit News already fingered the usual suspects: “Most, if not all, of the replacement safety devices were made in China.”

Fake airbags are not the only problem. “Crooked body shops are stealing airbags from vehicles to make a quick dollar at your expense,” warns a website by the Coalition Against . Insurance Fraud. “Mechanics can easily remove your airbag without your knowing it.” They could even bill you $2,000 or more for “replacing” a good one with a fake one or none at all.