EPA Proposes Risk Management Rule for 1-Bromopropane

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On August 8, 2024, EPA published a proposed rule to restrict use of the solvent 1-bromopropane (1-BP) (CASRN 106-94-5).  The proposed rule is the result of the agency’s revised 2022 determination that 1-BP presents an unreasonable risk of injury to human health due to effects including neurotoxicity, developmental toxicity, and carcinogenicity.

According to EPA, 1-BP is used in a wide variety of applications, including “vapor degreasing, aerosol degreasing, adhesives and sealants, and in insulation.”  Data from the Chemical Data Reporting rule shows that annual production of the substance, also known as n-propyl bromide, increased from 15.4 to 25.8 million pounds between 2012 and 2015.  This increase was because 1-BP is “an alternative to ozone-depleting substances and chlorinated solvents,” according to a 2020 EPA risk evaluation.

Under the proposed rule, all consumer uses of 1-BP would be banned except for use in insulation.  EPA is also proposing to prohibit four industrial and commercial uses, including use in adhesives and sealants, dry cleaning solvents, and automotive care products.  EPA estimates that these banned uses represent about 3% of the current annual production of 1-BP.

Other industrial and commercial uses would be subject to a workplace chemical protection program (WCPP), which would implement an inhalation exposure concentration limit for 1-BP of 0.05 ppm as an eight-hour time weighted average.  Use of chemically resistant gloves would also be required for uses including manufacturing, processing, and disposal.

Notably, in an effort to protect fenceline communities, EPA is proposing to prohibit owners or operators from increasing releases of 1-BP to outdoor air to comply with WCPP requirements.

EPA is proposing staggered compliance dates for the prohibited uses, which would become effective in six months for manufacturers, nine months for processors, and in 12 months for distribution to retailers.  Non-federal entities subject to the WCPP would be required to conduct baseline airborne exposure testing within six months and ensure that the inhalation exposure limit is met within nine months.

1-BP was added to the Toxics Release Inventory list of reportable chemicals in 2015 and became the first addition to the list of hazardous air pollutants in 2022.  More on 1-BP’s addition to the list can be found in a previous blog post.

Comments on the proposed rule are due September 23, 2024.