WASHINGTON - About 8.4 million Ford vehicles that can possibly catch fire remain on the road because of lack of owner information even after the largest U.S. safety recall ever, Automotive News reported.

The National Highway Traffic Safety Administration urged owners of the 14 million vehicles recalled between 1999 and 2009 for leaky cruise-control switches to take their unrepaired vehicles in to dealers. The switches on those vehicles may leak into the antilock brake system, Ford has said.

“If not repaired, the vehicles can catch fire, even if they are turned off, parked and unattended,” NHTSA's statement today said.

A NHTSA spokeswoman said that about 60 percent of the 14 million recalled vehicles -- or 8.4 million – have not been brought in for repair by owners.

Typically, about 30 percent of recalled vehicles are not returned for repair within a year-and-a-half of the announcement, said the spokeswoman, who asked not to be named.

Today's statement singled out used-car owners who may not know whether the vehicles they bought had ever been returned to dealers for needed repairs.

It also urged owners “to watch for potential warning signs of an imminent fire.”

Those signs include a cruise-control system or brake lights that stop working, low brake fluid and the illumination of brake warning lights on the dashboard.

Ford has notified owners about the recalls a number of times, company spokesman Wesley Sherwood said.

The repair rate for the Ford models has been “likely lower than typical” because of their age, he added.

NHTSA praised the automaker's notification efforts as “diligent.”

Among the models that have been recalled over the years are 1992-2003 E series, 1993-2003 F series, 1995-2003 Windstars, 1995-2002 Explorers and 1995-2003 Rangers.

Ford's series of eight recalls for the same defect amounted to the largest-ever U.S. recall, according to NHTSA data. The 14 million vehicles recalled are nearly double the size of the next biggest.

Ford's most recent recall of 4.5 million vehicles for leaky cruise-control switches was in October 2009 after customer complaints of 72 fires.