Advance Notice of Proposed Rulemaking on 6PPD and Its Transformation Product, 6PPD-quinone
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ANPRM Summary
EPA has issued an advance notice of proposed rulemaking (ANPRM) under Section 6 of the Toxic Substance Control Act (TSCA) to gather information on the potential risks associated with N-(1,3-Dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD) and its transformation product, 6PPD-quinone. In August 2023, the Yurok Tribe, the Port Gamble S’Klallam Tribe and the Puyallup Tribe of Indians submitted a petition under TSCA Section 21 asking EPA to establish regulations under TSCA Section 6 prohibiting the manufacturing, processing, use and distribution of 6PPD in tires. EPA granted this petition in November 2023 and committed to publishing an ANPRM by Fall 2024 in order to gather more information that could be used to inform a subsequent regulatory action under Section 6 of TSCA.
The chemical 6PPD has been used in motor vehicle tires for more than six decades to make them more durable. It can also be found in other rubber products such as footwear, synthetic turf infill, and playgrounds. 6PPD reacts with ozone pollution in the air to form a transformation product called 6PPD-quinone which may be present in stormwater runoff from parking lots and streets due to the presence of tire wear particles. Runoff may be washed into streams and other bodies of water during rain events. As a result, aquatic organisms can be exposed to 6PPD-quinone. Concentrations of 6PPD-quinone in stormwater in the Pacific Northwest were found to be lethal to coho salmon after only a few hours of exposure.
EPA is issuing an ANPRM to solicit information on the chemicals, including but not limited to: environmental effects on aquatic and terrestrial ecosystems, potential human health effects, environmental fate and transport, exposure pathways, persistence and bioaccumulation, additional uses of 6PPD, and releases from consumer products such as sneakers, playgrounds, rubber-modified asphalt, reused tire or other rubber products. EPA is also seeking comment and information related to alternatives to 6PPD, as well as potential chemical transformation products associated with potential alternatives.
For example, there are data showing that 6PPD-quinone is toxic to fish, with coho salmon being the most sensitive species studied to date. However, there are still uncertainties about the potential impacts of 6PPD-quinone on human health, as well as the potential for exposure from other sources of 6PPD-quinone.
EPA has extended the comment period and will now accept written comments on the ANPRM for an additional 60 days until March 24, 2025, via docket EPA-HQ-OPPT-2024-0403 at www.regulations.gov.
View the ANPRM for 6PPD and 6PPD-quinone.
EPA’s Work on 6PPD
It was EPA-funded research that first established the link between 6PPD-quinone and salmon deaths in the Puget Sound region in 2020. Since then, EPA has been engaged in ongoing efforts with other federal agencies, states, Tribes, industry, and other stakeholders to address information gaps and address concerns regarding the use of 6PPD and the risks of 6PPD-quinone.
EPA is continuing to fund research activities to expand its understanding of the impacts of 6PPD-quinone, and to fill data gaps. For example, the Office of Research and Development is continuing further investigation of 6PPD-quinone, including work on fate and transport, ecotoxicity, and green infrastructure solutions for stormwater contamination. The Office of Water developed a draft analytical method for detection of 6PPD-quinone in surface and stormwater and finalized screening values for 6PPD-quinone and 6PPD to protect sensitive salmon and other aquatic life. The Agency is also coordinating with the National Science and Technology Council’s Joint Subcommittee on Environment, Innovation and Public Health on potential cross-governmental research on human health effects.
EPA finalized a rule in December 2024 under Section 8(d) of TSCA that requires manufacturers (including importers) of 6PPD to report lists and copies of unpublished health and safety studies on 6PPD and 6PPD-quinone to EPA.
Additional Resources
- Learn more about 6PPD-quinone and EPA’s actions.
- Learn more about the TSCA Section 21 petition on 6PPD in tires.