July 28, 2022

EPA Revises Risk Determination for 1-Bromopropane

EPA proposes to find that the volatile organic compound 1-bromopropane (1-BP), also known as n-propyl bromide, presents “an unreasonable risk of injury to human health” in a draft revised risk determination released last week. According to EPA, 1-BP is used as a solvent in degreasing operations, spray adhesives, and dry cleaning; as a reactant in the manufacture of other chemical substances; and in laboratories. Examples of commercial and consumer products that contain 1-BP include spot cleaners, stain removers, aerosol degreasers, and insulation for building and construction materials.

The revised risk determination for 1-BP incorporates policy changes announced by EPA in June 2021 concerning personal protective equipment, risk management, unreasonable risk determinations, and exposure pathways. Unlike EPA’s previous risk evaluations, which assumed that personal protective equipment was always provided to workers and worn properly in occupational settings, EPA’s new draft revised risk determination does not assume the use of PPE. This “reflects EPA’s recognition that certain subpopulations of workers exist that may be highly exposed” for a number of potential reasons, the agency explains in a press release. For example, some workers may have increased exposure if they are not covered by OSHA standards or if OSHA has not issued a permissible exposure limit for a chemical substance, which is the case for 1-BP.

“As EPA moves forward with a risk management rule for 1-BP, the agency will strive for consistency with existing OSHA requirements or best industry practices when they are sufficiently protective,” EPA states.

The new risk determination also differs from previous risk evaluations in that it proposes that 1-BP presents unreasonable risk as a whole chemical substance, rather than making separate risk determinations for individual conditions of use. EPA’s new “whole chemical approach” applies “when it is clear the majority of the conditions of use warrant one determination,” the agency explains.

EPA’s final risk evaluation of 1-BP, which was published in August 2020, identifies adverse health effects to workers; occupational non-users, or workers in the general area of 1-BP use; consumers; and bystanders associated with the use of the substance. Among the adverse health effects are developmental toxicity from acute and chronic inhalation and dermal exposures to 1-BP as well as cancer from chronic exposures. EPA’s new draft revised risk determination does not affect the scientific analysis of its 2020 risk evaluation, which “continues to characterize risks associated with individual conditions of use to support any determination of unreasonable risk for 1-BP as a whole chemical substance and to inform risk management,” the agency notes.

EPA is accepting comments related to the draft revised risk determination for 1-BP until Aug. 19. Further details about this agency action are available in the Federal Register.

EPA also recently published draft revised risk determinations for three other solvents: methylene chloride, perchloroethylene (PCE), and n-methylpyrrolidone (NMP). The agency similarly proposed to find that methylene chloride, PCE, and NMP present unreasonable risks of injury to human health. EPA is accepting comments related to its draft revised risk determinations on PCE and NMP until Aug. 1. Stakeholders have a few more days—until Aug. 4—to submit comments related to the revised risk determination for methylene chloride.

Related: A final rule issued by EPA in January added 1-BP to the Clean Air Act list of hazardous air pollutants. The agency’s action marked the first time a substance had been added to the list since it was created in 1990.