On November 30, 1998, the National Highway Traffic Safety Administration received a letter from a Ford Explorer owner who said his Firestone tire tread peeled off like an orange. "Imagine my shock when the mechanics looked at my tire and told me I was lucky to be alive," the letter said, adding that the mechanics told him that Firestone tires on Explorers "are known to lose tread and contribute to or cause Ford Explorers to flip."
             This was among as many as 26 consumer complaints about Firestone tires, filed since the early 1990s that NHTSA overlooked in January when reviewing whether to open an investigation into reports of Firestone tire problems.
             NHTSA had missed the consumer complaints because of how its database is organized: They weren't filed under "Firestone" as tire problems; they were filed under "Ford" as vehicle problems.
             NHTSA, the federal agency responsible for tracking information about potential auto safety defects, did open an investigation into Firestone tires May 2--after news reports of tire failures that resulted in fatal accidents. And NHTSA spokesman Rae Tyson said yesterday that the additional complaints would not have prompted the agency to move any sooner.
             In the past, the agency has opened investigations with far fewer complaints. It looked into problems with Michelin tires in 1994 based on five complaints.
             The overlooked complaints--detailing incidents of tire blowouts, tread separations, and other accidents involving Firestone tires mounted on Ford vehicles--illustrate how difficult it has been for federal investigators to piece together a clear picture of what went wrong with the 6.5 million tires that Firestone recalled last month. The letters might have provided earlier clues to the scope and gravity of the problems--which have since been linked to 88 deaths in the United States.
             In January, a safety-defects specialist with the National Highway Traffic Safety Administration told his superiors...