EPA is initiating a proceeding for N-(1,3-Dimethylbutyl)-N′-phenyl-p-phenylenediamine (“6PPD”) (CASRN 793-24-8) and its transformation product, 6PPD-quinone under section 6(a) of the Toxic Substances Control Act (TSCA). This action is in response to an August 2023 petition filed under TSCA section 21, which allows citizens to petition EPA to initiate a proceeding for the issuance, amendment, or repeal of rules under TSCA sections 4, 6, or 8. The petition filed by Earthjustice on behalf of the Yurok Tribe, the Port Gamble S'Klallam Tribe, and the Puyallup Tribe of Indians requested that EPA promulgate a rule under TSCA sections 6(a)(2)(A)(i) and 6(a)(5) to prohibit the manufacture, processing, use, and distribution of 6PPD in and for tires due to ecotoxic effects on aquatic environments and organisms caused by its byproduct, 6PPD-quinone. This petition was granted by the EPA on November 1, 2023, wherein EPA committed to (a) publish an advance notice of proposed rulemaking (ANPRM) for 6PPD under TSCA section 6 in Fall 2024; and (b) begin additional data gathering activities under TSCA to address data needed to understand and characterize risk associated with 6PPD under a separate regulatory action.