The US Environmental Protection Agency (EPA) finalized Significant New Use Rules (SNURs) on August 26, 2026 for a batch of premanufacture-notice (PMN) chemical substances designated "24-5.5e," requiring manufacturers, importers, and processors to notify the agency at least 90 days before starting any designated new use. The final rule, published in the Federal Register (91 FR 54992; Document 2026-17400; RIN 2070-AB27), amends 40 CFR Part 721 and takes effect October 26, 2026.
Issued under TSCA Section 5(a)(2) (15 U.S.C. 2604(a)(2)), the SNURs apply to chemical substances that were the subject of PMNs and are already subject to EPA Orders under TSCA Section 5(e)(1)(A). They designate as a "significant new use" any manufacture, processing, use, distribution, or disposal that does not conform to the restrictions in those underlying Orders, consistent with TSCA Section 5(f)(4). The trigger is prospective: EPA states that no entity presently engages in the designated new uses, so the 90-day Significant New Use Notice (SNUN) duty activates only when a company intends to commence one. The full text is on the Federal Register.
Who must notify EPA, and by when?
Any person intending to manufacture (statutorily defined to include import) or process a covered substance for a designated significant new use must submit a SNUN to EPA at least 90 days before commencing that activity. The rule is effective October 26, 2026; for judicial review it is promulgated at 1 p.m. EST on September 9, 2026. The cutoff date for "ongoing" uses is the publication date of the proposed rule, November 3, 2025 (90 FR 49148): uses begun after that date are treated as new and cannot be grandfathered.
SNUNs must be filed on EPA Form 7710-25 using e-PMN software under 40 CFR 720.40 and 721.25. Until EPA reviews the notice, makes a determination, and takes any required action, the new use may not commence. A SNUR does not list a chemical on the TSCA Inventory; firms must still confirm inventory status separately.
Which substances and uses does the rule cover?
The SNURs codify new entries across 40 CFR 721.12147 through 721.12182, each tied to a PMN number and the restrictions of its consent Order. The designated significant new uses typically involve production-volume ceilings, prohibited consumer-product uses, worker-exposure thresholds, and release controls. Several substances carry a "toxic to aquatic life" hazard-communication duty, and the rule sets a 0.01 mg/m3 8-hour time-weighted average (TWA) exposure threshold and requires that air releases be prevented unless exhaust from enclosed equipment is treated with combined capture and control technology achieving at least 99.8% capture and control efficiency.
EPA deferred two substances to separate actions: the SNUR proposed at 40 CFR 721.12154 for P-22-0126 is not finalized because new information needs further review, and P-22-0187 was not proposed for the same reason. Firms tracking those PMNs should watch for a later notice rather than rely on this batch.
What changed between the proposed and final rule?
Responding to public comments, EPA restored several consent-order conditions that were erroneously omitted from the November 2025 proposal:
| PMN / citation | Correction added in the final rule |
|---|---|
| P-18-281, P-21-77 (721.12147) | 0.01 mg/m3 8-hour TWA threshold; air-release control at 99.8% capture; respiratory protection under 721.62(a)(6) |
| P-20-73 (721.12148) | No use in a consumer product (721.80(o)) |
| P-22-2 (721.12149) | Ongoing use identified; APF 50 respirator allowed when handled as a liquid |
| P-23-30 (721.12160); P-24-71 to P-24-74 (721.12179 to 721.12182) | "Toxic to aquatic life" hazard communication added |
What does compliance cost, and who is exposed?
The rule affects chemical manufacturers and petroleum refiners (NAICS 325 and 324110) and, through TSCA's trade provisions, foreign exporters into the United States. EPA estimates a SNUN costs about $45,000 per submission for large businesses and $14,500 for qualifying small firms, covering preparation, the user fee, and Central Data Exchange registration. The TSCA Section 5(e) user fee is $37,000, reduced to $6,480 for small businesses under 40 CFR 700.45. EPA estimates the per-unit burden at 30 to 170 hours.
Importers must also certify shipment compliance under TSCA Section 13 (15 U.S.C. 2612), 19 CFR 12.118 to 12.127, 19 CFR 127.28, and 40 CFR Part 707 subpart B. Exporters of a listed substance face a one-time TSCA Section 12(b) (15 U.S.C. 2611(b)) export notification per destination country under 40 CFR Part 707 subpart D and 721.20, at an estimated $106 per unit. Engagement is thin: EPA received only 7 SNUNs in FY2020, 9 in FY2021, 9 in FY2022, 23 in FY2023, and 7 in FY2024 across all SNURs combined, so the near-term reach is narrow but the pre-market gate is binding once triggered.
Obsidian's continuous, per-jurisdiction monitoring surfaces this kind of TSCA new-use designation the moment EPA publishes it in the Federal Register.
Take advantage of this real-time watch
Compliance teams should now confirm whether any substance on their register maps to the cited PMN numbers, diarize the October 26, 2026 effective date and the September 9, 2026 judicial-review promulgation, brief regulatory affairs and trade-compliance staff on the import-certification and export-notification duties, and queue a watch for the deferred P-22-0126 and P-22-0187 actions. EPA's technical contact is Andrew Sullivan, New Chemicals Division, at (202) 564-0605.
