The largest automotive recall in U.S. history grows bigger.

FOX's Lilian Woo reports:

Another 2.7 million vehicles getting recalled because of potentially dangerous air bag inflators by Takata. But this time, the recall affects airbags the company thought were safe. These contain a drying agent which is supposed to stop a chemical in the airbags from degrading.

Now the National Highway Traffic Safety Administration says tests done by Takata show for the first time a type of desiccated inflator "will pose a safety risk if not replaced." Also that it has no reports of such inflators rupturing.

Among the vehicles affected, the Versa Subcompact Hatchback and Sedans from the 2007 through 2012 model years and some Mazda 6,000 B Series trucks.

Ford says it will file a list of models within five days.

Lilian Woo, FOX News.

Follow Lilian Woo on Twitter: @LilianNY