But customers are still filing complaints of abnormal blowouts, blowouts similar to the infamous tread separations involved in 14 million ATX and Wilderness tires recalled in 2000.
Now federal officials are deciding whether to reopen an investigation into their safety. Last year, they closed one probe into the tires finding no evidence of defects.
All the failures can be traced to drastic cost cutting, according to Bill Orr, a senior lab technician at Firestone's plant in Lavergne, Tennessee.
Orr told CBS News Correspondent Sharyl Attkisson Firestone was so worried about its rescue vehicle tires, the company asked him to examine some that had come apart. Yet at the time, Firestone told reporters it knew of no problems.
"That's not correct," says Orr. "I personally picked up four of those tires returned, I was told, from an emergency vehicle in South Carolina. If they weren't concerned with them, they would've sent them to downtown Nashville to a storage unit down there where a lot of liability products are held."
The tires Orr inspected may have come from an ambulance in South Carolina that had two blowouts in a row, once while a premature baby was on board.
"We looked at them -— belt edge separation on both sides. It was forming in the one that hadn't filed, but it had already formed and failed in three others," says Orr.
When Orr complained to his bosses that shoddy work and materials were producing dangerous tires, he was fired. Now, he's prepared to tell what he knows to federal safety investigators next week in Washington.
Rescue squads in at least 13 states have now reported problems, and most of them dumping their Steeltex tires for other brands.
But Firestone is standing by its tires saying federal officials have reviewed them "and clearly stated they found no evidence of defect … We are constantly evaluating our tires and are committed to taking action if it is warranted. In this case, it is not."
The government will decide whether to begin a new investigation by the end of the month. But no matter what, Firestone will be back in court fighting a giant class action suit brought by light truck and RV customers who claim the tires are faulty.