Lynn Bergeson
On June 15, 2024, the U.S. Environmental Protection Agency (EPA) issued proposed restrictions under Section 6(a) of the Toxic Substances Control Act (TSCA) to protect workers and consumers from exposure to N-methylpyrrolidone (NMP) (89 Fed. Reg. 51134). To address the unreasonable risks the EPA identified, the agency proposes a combination of worker and consumer protections. Given NMP’s ubiquitous applications, this is an important TSCA proposal. Here is a rundown of what you need to know.
Background
NMP is widely used to manufacture electronics, polymers, agricultural chemicals and petrochemical products. It is also used to produce specialized electronics, such as semiconductors and magnet wire, and lithium-ion batteries used in a variety of applications, including aerospace vehicles and electronic devices.
The proposed rule states that pursuant to TSCA Section 6(b), the EPA determined that NMP presents an unreasonable risk of injury to health, without consideration of costs or other non-risk factors, including an unreasonable risk to potentially exposed or susceptible subpopulations (PESS) identified as relevant to the 2020 NMP risk evaluation, under the conditions of use (COU). The EPA notes that all TSCA COUs of NMP are subject to the proposed rule. To address the unreasonable risk identified, the EPA proposes:
- Prohibiting the manufacture (including import), processing, distribution in commerce and use of NMP for five occupational COUs;
- Requiring container size limits and labeling requirements for the manufacture (including import), processing and distribution in commerce of NMP for seven consumer uses;
- Requiring prescriptive controls, including concentration limits and personal protective equipment (PPE) for seven occupational COUs;
- Requiring strict workplace controls, including an NMP Workplace Chemical Protection Program (WCPP) requiring prevention of direct dermal contact with NMP for all other occupational COUs. This includes the commercial use of paints and coatings and paint, coating and adhesive removers containing high concentrations of NMP in uses essential to the Department of Defense (DOD) and National Aeronautics and Space Administration (NASA);
- Requiring a concentration limit on NMP for the import, processing and distribution in commerce of one consumer use; and
- Establishing recordkeeping and downstream notification requirements.
Discussion
The proposed rule demonstrates the EPA’s approach to risk management is evolving as the agency learns more during its early implementation of TSCA Section 6. To the surprise and delight of many industry stakeholders, the EPA didn’t propose to ban most COUs and acknowledges the value and efficacy of workplace exposure protection. The EPA appropriately focuses on dermal exposure as NMP is well absorbed dermally and is also a penetration aid for solutes, so it is critical workers are not exposed dermally.
The agency’s WCPP requires reviewing which workers are likely to be exposed, including whether they may handle equipment or empty containers that may have NMP present. The WCPP also requires employers to evaluate NMP under the industrial hygiene hierarchy of controls: elimination, substitution, engineering controls and administrative controls — including an evaluation of their feasibility and effectiveness. If exposures can’t be eliminated, dermal protection is required. If inhalation exposure occurs during use of NMP in paints or coatings or their removal, respiratory protection is also required.
Importantly, the EPA did not find unreasonable risk for consumer products containing NMP below 45% by weight. Nonetheless, the agency proposed banning certain commercial and industrial uses in cases where the EPA claims it has insufficient exposure data. Whether this course of action meets or exceeds the “extent necessary” provision of TSCA Section 6(a) is unclear. The EPA’s proposal clearly illustrates the need for stakeholders throughout the supply chain to demonstrate the measures taken to ensure workers are properly protected through the hierarchy of controls.
The EPA has also provided a threshold for the applicability of the rule. The agency has selected 0.1% as the de minimis threshold, as it did for methylene chloride. EPA found that 0.1% was sufficiently protective and that a lower de minimis threshold is not required, so relying on the 0.1% threshold from the hazard communication standard is justified.
A key concern with the proposed rule is its reliance on non-reproducible science as the basis for its risk management actions. This is a common theme with the EPA’s risk evaluations and risk management activities, particularly for NMP and trichloroethylene. We expect many comments on this issue as EPA’s compliance with TSCA Section 26 continues to be challenging.
