The US Environmental Protection Agency (EPA) finalized revisions to the Toxic Substances Control Act (TSCA) risk determinations for n-methylpyrrolidone (NMP) and 1-bromopropane (1-BP). The EPA determined that NMP and 1-BP, as whole chemical substances, present an unreasonable risk of injury to human health when evaluated under their conditions of use.

The next step in the process is to develop risk management rulemakings to identify and require the implementation of measures to manage these risks.

NMP (also known as n-methyl-2-pyrrolidone or 1-methyl-2-pyrrolidone) is widely used during the manufacture and production of electronics, polymers, agrichemicals and petrochemical products. It has numerous industrial, commercial and consumer applications, including as a solvent in the production of electrodes for Li-ion batteries. (Earlier post.)

In the revised risk determination based on the 2020 risk evaluation, EPA found that NMP presents unreasonable risk to the health of workers and consumers.

EPA identified risks for adverse human health effects, including developmental post-implantation fetal loss from short-term exposure and reduced fertility and fecundity from long-term exposure. EPA found that NMP presents unreasonable risk to the health of workers for all occupational uses and to consumers from one consumer use.

Overall, EPA determined that 29 of the 37 conditions of use it evaluated drive the unreasonable risk determination. Eight out of 37 conditions of use do not drive the unreasonable risk, including the consumer use in paints and coatings in lacquers, stains, varnishes, primers, and floor finishes, the consumer use in paint and coating removers, and the consumer use in automotive care products.

The revised risk determination supersedes the condition of use-specific no unreasonable risk determinations previously issued by order under TSCA section 6(i) in the 2020 NMP risk evaluation.

1-BP (1-Bromopropane) is used as a solvent in commercial and industrial applications and as a reactant in the manufacturing of other chemical substances. Consumer uses include adhesives, degreasers, cleaners and automobile care products. 1-BP can be used as an automotive refrigerant flush.

In the revised risk determination based on the 2020 risk evaluation, EPA found that 1-BP presents unreasonable risk to the health of workers, occupational non-users (i.e., workers nearby but not in direct contact with this chemical), consumers, and bystanders to consumer use. EPA identified risks for adverse human health effects, including developmental toxicity from short- and long-term inhalation and dermal exposure to the chemical, and cancer from long-term inhalation and dermal exposure.

Overall, EPA determined that 23 of the 25 conditions of use EPA evaluated drive the unreasonable risk determination. Two out of 25 conditions of use do not drive the unreasonable risk: commercial and consumer use of 1-BP in insulation and building materials, and distribution in commerce.

The revised risk determination supersedes the condition of use-specific no unreasonable risk determinations previously issued by order under TSCA section 6(i) in the 2020 1-BP risk evaluation.

Risk Determination Approach for NMP and 1-BP. EPA used the whole chemical risk determination approach for NMP and 1-BP in part because there are benchmark exceedances for multiple conditions of use spanning across most aspects of the chemicals’ life cycles, from manufacturing (including import), processing, commercial use, consumer use and disposal. EPA is taking this approach for health of workers and consumers, and because the health effects associated with NMP or 1-BP exposures are severe and potentially irreversible (specifically developmental post-implantation fetal loss for NMP and developmental toxicity and cancer for 1-BP).

The revised risk determinations for NMP and 1-BP do not reflect an assumption that workers always and appropriately wear personal protective equipment (PPE), even though some facilities might be using PPE as one means to reduce workers’ exposure. This decision should not be viewed as an indication that EPA believes there is widespread non-compliance with applicable Occupational Safety and Health Administration (OSHA) standards. EPA has received public comments from industry respondents about occupational safety practices in use at their facilities and will consider these comments, as well as other information on use of PPE, engineering controls, and other ways industry protects its workers, as potential ways to address unreasonable risk during the risk management process.

EPA understands there could be occupational safety protections in place at some workplace locations. However, not assuming use of PPE in its baseline exposure scenarios reflects EPA’s recognition that certain subpopulations of workers exist that may be highly exposed because:

• They are not covered by OSHA standards (e.g., self-employed individuals and public sector workers who are not covered by a state plan);

• Their employers are out of compliance with OSHA standards;

• OSHA describes its chemical-specific permissible exposure limits (largely adopted in the 1970s) as being “outdated and inadequate for ensuring protection of worker health”; or

• There is no chemical-specific OSHA permissible exposure limit, as is the case for both NMP and 1-BP.

As EPA moves forward with risk management rulemakings for NMP and 1-BP, the agency will strive for consistency with existing OSHA requirements or best industry practices when those measures would address the identified unreasonable risk. EPA will propose occupational safety measures in the risk management process that would meet TSCA’s statutory requirement to eliminate unreasonable risk of injury to health and the environment.

Next steps for NMP and 1-BP. EPA is now moving forward on risk management to address the unreasonable risks presented by NMP and 1-BP. Note that in taking these actions, EPA has not conducted new scientific analyses on these chemicals. The risk evaluations continue to characterize risks associated with individual conditions of use in the risk evaluations of NMP and 1-BP in order to inform risk management.