U.S. EPA Issues Proposed Rule on Significant New Use Rules for Certain Chemical Substances Under TSCA

"On April 4, 2025, the United States Environmental Protection Agency (EPA) issued a proposed rule on Significant New Use Rules on Certain Chemical Substances under the Toxic Substances Control Act (TSCA). This proposed rule establishes Significant New Use Rules (SNURs) for certain chemical substances that were previously subject to Premanufacture Notices (PMNs) and EPA Orders issued under TSCA. The SNURs are designed to ensure that EPA is notified before any new uses of these substances commence. Under the proposed SNURs, any person who intends to manufacture (including import) or process any of the listed chemical substances for a use identified as a “significant new use” must submit a notification to EPA at least 90 days prior to beginning that activity. . In addition, the manufacture or processing for the significant new use may not commence until EPA has conducted a review of the required notification, made an appropriate determination regarding that notification and taken such actions as required by that determination. Public comments on the proposed rule must be submitted on or before May 5, 2025. The some of substances subject to the proposed SNURs in this document are as follows: 1) Oxirane, 2-methyl-, polymer with 2,4-diisocyanato-1-methylbenzene, 2-methyloxirane polymer with oxirane ether with 1,2,3-propanetriol (3:1), and oxirane, cashew nutshell liquid- and Pr alc.-blocked (TSCA Order Basis: EPA identified potential health concerns related to Skin sensitization, Irritation to the skin, eyes, and respiratory tract). 2) Alcohols, C8-10- iso-, C9-rich, ethoxylated (TSCA Order Basis: EPA identified potential health concerns related to lung effects (surfactancy) and irritation to the skin, eyes, and respiratory tract. Based on comparison to analogous chemical substances, EPA has also identified concerns for acute toxicity (mortality), skin and eye irritation, systemic effects and reproductive/developmental effects). 3) Reaction product of polyester with alpha.-hydro-.omega.- hydroxypoly (oxy-1,4- butanediyl) and 1,1′-methylenebis[isocyanatobenzene](TSCA Order Basis: EPA identified potential health concerns related to skin and respiratory sensitization, skin, eye, and respiratory tract irritation, acute toxicity, and pulmonary effects for the residual). 4) Benzene, [2-[(2- methyl-1-undecen-1-yl) oxy]ethyl]- (TSCA Order Basis: EPA has identified concerns for skin sensitization, systemic, and developmental effects). 5) Siloxanes and silicones, alkyl methyl, dimethyl (TSCA Order Basis: EPA has identified concerns for acute toxicity, skin irritation, and eye irritation). 6) Protein sodium complexes, polymers with aromatic acid chloride, ethylene diamine and amino acid (TSCA Order Basis: EPA has identified concerns for lung overload, lung surfactancy, irritation to the skin, eyes, respiratory tract, skin and respiratory sensitization). 7) Aryl-substituted- heterocyclic-polyamine, reaction products with polyethylene glycol alkyl- ether, and nitrogen and alkyl- substituted benzene (TSCA Order Basis: EPA has identified concerns for lung effects, irritation to the skin, eyes and respiratory tract). 8) Thermomycolin, Malbranchea cinnamomea origin, expressed in genetically modified Trichoderma reesei (TSCA Order Basis: EPA has identified concerns for irritation to the skin, eyes, and respiratory tract, respiratory sensitization and allergenic effects and point-of-contact effects in the Gastrointestinal (GI) tract). "