Ford has been forced by US safety regulators to massively expand a recall programme on its F-150 pickup truck models.
The recall began in February on 150,000 cars but the National Highway Traffic Safety Administration (NHTSA) says the airbags are potentially dangerous and could deploy at any time.
A wiring fault on cars manufactured between 2004 and 2006 is said to be the reason for the problems.
Ford says that it isn't aware of any accidents caused by the fault, but the NHTSA disagrees, saying it knows of 269 cases where the airbags have fired, causing 98 injuries.
"We urge all of our customers to seek service immediately for an airbag warning lamp that is illuminated," a US spokesman said.
The company knew about the issue as far back as 2006 when it made changes to the F-150's design, but has only recently decided to issue the recall for the wiring fix.
The NHTSA has welcomed the decision: "We are pleased that Ford shares our commitment to safety and is taking action to protect consumers."