On November 2, 2023, the U.S. Environmental Protection Agency (EPA) announced that it granted a petition filed under Section 21 of the Toxic Substances Control Act (TSCA) to address the use of the chemical N-(1,3-Dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD) in tires. As reported in our August 9, 2023, blog item, on August 1, 2023, Earthjustice filed a citizen petition asking EPA to establish regulations prohibiting the manufacturing, processing, use, and distribution of 6PPD for and in tires. Earthjustice filed the petition on behalf of the Yurok Tribe, the Port Gamble S’Klallam Tribe, and the Puyallup Tribe of Indians.

In its announcement, EPA states that 6PPD has been used for more than six decades in motor vehicle tires to make them more durable, and it can also be found in other rubber products such as footwear, synthetic turf infill, and playgrounds. According to EPA, 6PPD reacts with ozone pollution to form 6PPD-quinone, which may be present in stormwater runoff from parking lots and streets due to the presence of tire wear particles. The runoff may be washed into streams and other bodies of water during rain events, exposing aquatic organisms to 6PPD-quinone. EPA notes that 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 intends to publish an advanced notice of proposed rulemaking under TSCA Section 6 by fall 2024 to obtain more information to inform a subsequent regulatory action. EPA states that it also plans to issue a final TSCA Section 8(d) rule to require manufacturers (including importers) of 6PPD to report lists and copies of unpublished health and safety studies to EPA by the end of 2024.