U.S. NMP Regulation: History Leading to Final Rule Publication and Multiple Delays
Overview
EPA has published a proposed rule under TSCA Section 6 imposing substantial restrictions on N-methylpyrrolidone (NMP), a major industrial solvent. NMP is an organic solvent extremely widely used in lithium-ion battery electrode manufacturing, semiconductor manufacturing, coatings, and cleaning agents, and the proposed restrictions are grounded in worker health risks including reproductive toxicity. The proposal calls for a full prohibition on certain uses, mandatory implementation of an inhalation and dermal exposure control program (ECEL/ECDL) for remaining major processes (battery, semiconductor manufacturing, etc.), and strict personal protective equipment (PPE) requirements.
EPA published its proposed risk management rule for NMP under TSCA Section 6 in June 2024, originally anticipating final rule publication within 2025. However, as of August 24, 2026, the final rule remains unpublished. EPA's Unified Agenda, published July 3, 2026, sets a target of late July 2026 for final rule publication—though this target itself has been pushed back repeatedly, and review and coordination at the Office of Management and Budget (OMB) and elsewhere appears to be continuing even now. As with other TSCA Section 6 rules (methylene chloride, TCE, PCE, etc.), there are indications that the substantive content of the NMP final rule itself may be relaxed relative to the original proposal.
Enforcement Timeline
June 14, 2024: EPA publishes the proposed risk management rule for NMP under TSCA Section 6
July 29, 2024: The public comment period closes
2025 (original target): Originally anticipated timeframe for final rule publication, not met, and pushed back repeatedly
July 3, 2026: EPA publishes its Unified Agenda, setting a target of late July 2026 for publication of the NMP final rule
As of August 2026: Formal publication of the final rule in the Federal Register remains unconfirmed (believed to be under continued review and coordination at OMB and elsewhere)
After final rule publication: Application of prohibited uses and WCPP (Workplace Chemical Protection Program) requirements is expected to begin in phases (specific deadlines to be confirmed upon final rule publication)
Business Impact
Manufacturers using NMP in lithium-ion battery and semiconductor manufacturing face substantially increased capital investment costs to implement extremely strict exposure prevention measures at their U.S. facilities—including establishing sealed processes and providing protective clothing and supplied-air respirators. Because NMP use in certain consumer products and cleaning agents will be prohibited, companies must urgently select alternative solvents and conduct safety evaluations.
Delayed response risks substantial fines for TSCA violations (up to tens of thousands of dollars per day), as well as shipment stoppages for batteries and electronic components in the U.S. market and loss of competitiveness across the supply chain.
Companies supplying lithium-ion battery materials (such as cathode slurry), semiconductor manufacturing chemicals, and precision electronic components to the U.S. market, or operating battery or semiconductor plants in the United States, continue to face a situation where investment decisions on regulatory response (WCPP preparation or transition to alternative solvents) must be deferred, given that the content and effective timing of the final rule remain uncertain. Given the trend toward relaxation seen in other TSCA Section 6 rules, companies should closely monitor the specific requirement level once the final rule is published.