Ford and Mazda are warning the owners of more than 475,000 older vehicles in the U.S. not to drive them because they have dangerous Takata air bag inflators that have not been replaced.

The warning issued Tuesday covers more than 374,000 Ford, Lincoln and Mercury vehicles from the 2004 through 2014 model years and nearly 83,000 Mazdas from the 2003 through 2015 model years.

The National Highway Traffic Safety Administration says the inflators can explode with too much force in a crash, blowing apart a metal canister and shooting fragments that can severely injure or kill people. All were recalled previously but repairs have not been completed.

Ford models covered by the warning include 2004 to 2011 Ranger pickups, 2005 through 2014 Mustangs, 2005 and 2006 Ford GTs, 2006 through 2012 Fusions and 2007 through 2010 Edge SUVs.

Affected Mercury and Lincoln models include the Milan, MKZ and Zephyr from 2006 through 2012, and the MKX from 2007 through 2010.

Mazdas covered by the warning are the 2004 to 2009 B-Series pickup, 2003 through 2013 Mazda 6, the 2006 and 2007 Speed6 and the 2004 through 2011 RX-8. Also included are the 2004 through 2006 MPV, the 2007 through 2012 CX-7 and the 2007 through 2015 CX-9.

The government says 27 people have been killed in the U.S. by faulty Takata inflators, which used volatile ammonium nitrate to create a small explosion to inflate air bags in a crash. The chemical can deteriorate over time when exposed to high temperatures and humidity. More than 400 people in the U.S. have been hurt.

Worldwide at least 35 people have been killed by Takata inflators in Malaysia, Australia and the U.S.

Potential for a dangerous malfunction led to the largest series of auto recalls in U.S. history, with at least 67 million Takata inflators involved. The U.S. government says many have not been repaired. About 100 million inflators have been recalled worldwide. The exploding air bags sent Takata into bankruptcy.

Owners can check to see if their vehicles are covered by going to the NHTSA website and keying in their vehicle identification or license plate numbers.Ford and Mazda also have recall websites.

If a vehicle has an unrepaired Takata inflator, owners should stop driving them and call a dealer to set up a repair appointment. Ford and Mazda are offering free towing or mobile repairs and loaner vehicles if necessary, NHTSA says.

“Even minor crashes can result in exploding Takata air bags that can kill or produce life-altering, gruesome injuries,” the agency said in a statement. “Older model year vehicles put their occupants at higher risk.”

Ford says more than 765,000 inflators in Ford and Lincoln vehicles worldwide should not be driven until the air bag inflators have been replaced. In the U.S., the company has made more than 121 million attempts to contact owners including emails, phone calls, text messages and visits to customer homes. The company says over 95% of its U.S. customers have had their inflators replaced.

Nissan, Honda, Stellantis, Ford, BMW and Toyota and Mazda have previously issued similar “do not drive” warnings for some of their vehicles equipped with Takata inflators.