Toyota and Nissan have joined Honda in no longer using Japan’s troubled Takata as an air bag supplier because its ammonium-nitrate based inflators can explode and injure passengers.

The action comes days after the National Highway Traffic Safety Administration said it would fine Takata for supplying faulty airbag inflators to more than 10 automakers.

Nissan and Toyota, however, cautioned that their announcements concern the chemical propellant, not the supplier. Toyota even said it would consider Takata inflators with another propellant “as long as we can confirm their safety and durability.”

Regulators have tied ammonium nitrate to airbag explosions in older cars that spent years in regions of high absolute humidity. The air bags have been tied to the deaths of at least eight, with 98 injuries. Millions of cars are under recall.

Airbags involve a lot more than just the inflators, and swearing off certain inflators in future vehicles doesn’t remove them from current cars. Amid the flight from ammonium nitrate airbag inflators in future products, concern shifts to the current cars that still have it.

The National Highway Traffic Safety Administration wants to ban all inflators with ammonium nitrate, a chemical that only Takata uses as the primary inflator propellant, spokesman Gordon Trowbridge says. Secretary of Transportation Anthony Foxx told reporters on Nov. 3 that such a ban could impact “potentially millions more cars.”

Takata did not comment on how many inflators going into new cars use ammonium nitrate. Some automakers have them on various models:

Honda. Three existing models — the 2016 Honda CR-V, 2016 Acura RDX and 2016 Acura RLX — have Takata inflators. The CR-V has one on the driver’s-side airbag, while both Acura models have Takata passenger-side inflators.

Mitsubishi. Tthe 2016 i-MiEV electric hatchback has a Takata inflator on the passenger side. A third automaker, Subaru, said no current cars have Takata inflators.

•Fiat Chrysler Automobiles. Spokesman Eric Mayne said the automaker’s new cars “are not equipped with components subject to the current Takata campaigns,” but he wouldn’t specify which new cars have Takata inflators apart from the recall. BMW, GM, Mazda, Nissan and Toyota declined to discuss which current cars have Takata inflators. Ford did not respond to our request at all.

DOT’s Foxx told reporters on Nov. 3 that Takata would eventually have to recall every single car with an ammonium nitrate inflator, barring future evidence that the chemical is safe. That means those Honda, Acura and Mitsubishi vehicles will likely need a replacement inflator down the road.