Federal regulators will review the use of a chemical found in tires after a petition from Native American tribes in California and Washington state. The Yurok tribe in California and the Port Gamble S’Klallam and Puyallup tribes in Washington want the rubber preservative 6PPD banned because it kills salmon as they return to their natal streams to spawn. The chemical is added to virtually every vehicle tire as a rubber preservative. The U.S. Environmental Protection Agency’s announcement is the start of a long regulatory process that could see the chemical banned. Tire manufacturers say they are trying to identify alternatives that can still meet federal safety standards.