US environmental regulators will investigate a common tire chemical after tribal petition

US environmental regulators are starting an investigation into a chemical used in tires, 6PPD, and its breakdown product, 6PPD-quinone. This follows a petition from several Native American tribes concerned about its impact on salmon.

For years, environmental regulators have focused on chemicals that are directly toxic. This investigation targets a chemical that becomes toxic only after it breaks down in the environment, which is a harder problem to track and regulate. It means regulators are now looking at the full lifecycle of chemicals, not just their initial form.