WASHINGTON (Nov. 15)-Bridgestone/Firestone´s cost-cutting measures in the mid-1990s and continuing use of inferior carbon black are two of the reasons behind thousands of failures of Firestone Steeltex tires, attorney Joseph Lisoni and others claimed at a Washington press conference. Lisoni, who petitioned the National Highway Traffic Safety Administration today to reopen its investigation of Steeltex tires, said his office has confirmed more than 7,000 cases of tread separations in Steeltex tires and 12 related deaths, and expects to confirm 3,000 more cases and 11 more deaths by the end of the month. "Our goal is to get these tires off the streets," said Lisoni, who filed a class action against Bridgestone/Firestone and its parent Bridgestone Corp. last August. A Bridgestone/Firestone spokeswoman called Lisoni´s accusations "utterly false" and "absolutely outrageous." The cost-efficiency measures the tire maker took had no effect whatever on quality, she said, and the allegedly inferior carbon black wasn´t even used to make Steeltex tires.