The U.S. Environmental Protection Agency (EPA) has initiated an advance notice of proposed rulemaking (ANPRM) under the Toxic Substances Control Act to assess potential risks linked to N-(1,3-Dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD) and its derivative, 6PPD-quinone. This action follows a petition from the Yurok Tribe, Port Gamble S’Klallam Tribe, and Puyallup Tribe of Indians in August 2023 requesting regulations to prohibit the use of 6PPD in tires.
Assistant Administrator for the Office of Chemical Safety and Pollution Prevention Michal Freedhoff stated, “Today, we’re following through on the commitment we made to our Tribal partners to gather more information about this chemical used in rubber products to help protect coho salmon.”
Representative Derek Kilmer emphasized the significance of addressing toxic stormwater runoff as a threat to Puget Sound salmon recovery. He expressed gratitude for EPA's responsiveness to tribal petitions and highlighted the federal government’s responsibility towards Tribes in protecting Pacific Northwest salmon.
Rep. Marilyn Strickland noted that "Salmon are a keystone species," pointing out research indicating that 6PPD-Q is lethal to them. She praised EPA's efforts as a crucial step toward resolving this issue.
6PPD has been utilized in vehicle tires for over sixty years for durability and is also present in other rubber products like footwear and playgrounds. It reacts with ozone pollution forming 6PPD-quinone, which can enter waterways via stormwater runoff containing tire wear particles. Studies have shown that concentrations of 6PPD-quinone are lethal to coho salmon after brief exposure.
The ANPRM seeks data on environmental effects, human health impacts, exposure pathways, persistence, bioaccumulation, alternative uses of 6PPD, and releases from consumer products. The EPA also aims to explore alternatives to 6PPD and their potential transformation products.
Research funded by EPA first identified the link between 6PPD-quinone and salmon deaths in Puget Sound in 2020. Since then, EPA has collaborated with various stakeholders to address knowledge gaps concerning 6PPD usage and its risks.
Ongoing research includes investigating ecotoxicity and green infrastructure solutions for stormwater contamination by the Office of Research and Development. The Office of Water has developed methods for detecting 6PPD-quinone in water bodies and established screening values for protection against its effects on aquatic life.
In March 2024, EPA proposed a rule requiring manufacturers of 6PPD to report unpublished health studies related to these chemicals. A final rule is expected by year-end.
EPA encourages public comments on the ANPRM within sixty days post-publication via docket EPA-HQ-OPPT-2024-0403 at Regulations.govExit EPA’s website.
