DETROIT (Aug. 3)—Ford Motor Co. has launched an internal investigation into reports of tread separation on Firestone ATX, ATX II and Wilderness tires installed as original equipment on Ford Explorers and other company vehicles. Ford is reviewing 40 million vehicles and earmarking all tire-related accidents, said Helen Petrauskas, Ford vice president of environmental and safety engineering. "We are going back as far as we can in our records to look at complaints on tires and to see if there is a pattern," Petrauskas told Automotive News, a sister publication to Rubber & Plastics News. While Petrauskas did not rule out the possibility of dropping Bridgestone/Firestone Inc. as a supplier if consumer fears escalate, a Ford spokeswoman said later that the company does not now plan to do so. "The situation with Firestone is complicated, we´re investigating it, and that´s all we can say," she said. "They´re a valued supplier."