ATLANTA (CNN) -- Firestone announced a renewed recall effort Friday for its radial tires, mainly spares, still remaining on the Ford Explorer and similar SUVs from the 1990s.

The action followed talks with the federal highway safety agency after a complaint about recent deaths and injuries in rollovers involving SUVs, often bought used, that had older Firestone spare tires.

Firestone said it will send letters to owners of Ford Explorers, Mercury Mountaineers or Mazda Navajos made prior to the 2000 model year. Mazda, like Mercury, is part of the Ford Motor Co. (See details on www.Firestone.com)

Six years ago, Firestone recalled an estimated 6.5 million of its Radial ATX and Wilderness AT tires after numerous rollover deaths.

Firestone says 6.3 million tires were replaced, making it the most successful recall ever. But independent safety consultant Sean Kane said as many as 200,000 were missed for a number of reasons. For example, Kane said, substitute tires were often scarce or owners simply didn't think about turning in the spares.

On the Explorer and some other Ford SUVs, the spare is attached to the undercarriage of the vehicle, and an owner would need to crawl under it to be able to read the brand name.

In a letter to the National Highway Traffic Safety Administration, Kane listed these accidents, among others:

-- Michael Enriquez, 28, of Deltona, Fla., was permanently paralyzed when his 1993 Ford Explorer rolled over and slid upside-down into an oncoming car near Orlando in May 2005. The other driver was killed. Witnesses told police the tread came off Enriquez' right rear tire. It was a Firestone made 12 years earlier. The Florida Highway Patrol cited the tread separation as the cause of the crash.

-- An 11-year-old boy, William Moreno of Duarte, Calif., was killed this May when his family's 1994 Ford Explorer overturned and rolled down a hill beside Interstate 15 in Riverside County. Another driver told the California Highway Patrol "he saw the tire tread come off the left rear tire."

-- In June two years ago, Anthony Scudera, 20, of Sunrise, Fla., noticed a leak in a rear tire while washing his mother's 1993 Ford Explorer. He replaced the tire with the spare, which was an older Firestone. Just three days later, as Scudera was driving to work on Interstate 75, the Florida Highway Patrol said, he had a right rear blowout and rolled over. Scudera, who was not wearing a seat belt, was ejected and killed.

"I had no idea how dangerous that tire was," his mother, Linda Scudera, told CNN. "The treads peeled completely off the tire, my car went out of control. My son didn't even have a chance."

Both Mrs. Scudera and Michael Enriquez are suing Firestone. The company denies any responsibility for those accidents and, in each case, blames the drivers.

A Firestone spokesperson told CNN it wants to get all pre-2000 tires off the SUVs. "Bring them into a company-owned store and we will replace them," she said. "No questions asked. Free of charge. It is in everyone's interest to get those tires off the road."

Firestone said it is also writing all its dealers to remind them to check their customers' spare tires and to replace any tire that is outdated.

The 2000 recall covered all Radial ATX tires in the size P235/75R15 and certain Wilderness AT tires in the same size that were made at Firestone's since-closed plant in Decatur, Illinois. A Wilderness AT tire made in Decatur is identified by the letters VD at the beginning of the 10-digit code found on the side of the tire, Firestone said.

A second replacement program in 2001 covered other Wilderness AT tires in either size P235/75R15 or P255/70R16 made from 1994 through May 1998. If the 10-digit code ends with the number 4, 5, 6 or 7, that size Wilderness tire was made in 1994-97. If the last number is 8 and the two numbers before it are anywhere from 01 to 18, then that tire was made in those first months of 1998, according to Firestone.

In a random test, NHTSA recently checked a number of older Ford SUVs in the Washington, D.C., area and found up to 10 percent still carrying the older Firestones as spares, even though they should have been replaced long ago.

On its Web site, Ford Motor Co. recommends all tires, including the spare, be replaced after six years, regardless of which brand they may be.

Kane said that even if spares look brand new, older tires can suffer from aging. "These are bad tires that are now worse," he said.

By CNN's Drew Griffin and James Polk