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On August 11, 2020, the U.S. Environmental Protection Agency (EPA) published the final risk evaluation for 1-bromopropane (1-BP). After evaluating 25 conditions of use, EPA determined that 16 present an unreasonable risk to workers, occupational non-users (ONU), consumers, and bystanders. EPA found no unreasonable risk to the environment from any conditions of use and no unreasonable risks to the general population. According to EPA, the next step in the process required by the Toxic Substances Control Act (TSCA) is developing a plan to reduce or eliminate the unreasonable risks found in the final risk evaluation. EPA states that it “is moving immediately to risk management for this chemical and will work as quickly as possible to propose and finalize actions to protect workers, occupational non-users, consumers, and bystanders.” EPA states that the action it could take to address these risks includes regulating how 1-BP is used or limiting or prohibiting the manufacture, processing, distribution in the marketplace, use, or disposal of 1-BP, as applicable. As with any chemical product, EPA “strongly recommends that users of products containing 1-BP continue to carefully follow all instructions on the product’s label and safety data sheet.”
Background
TSCA Section 6, as amended by the Frank R. Lautenberg Chemical Safety for the 21st Century Act (Lautenberg Act), requires EPA to conduct risk evaluations to “determine whether a chemical substance presents an unreasonable risk of injury to health or the environment, without consideration of costs or other nonrisk factors, including an unreasonable risk to a potentially exposed or susceptible subpopulation identified as relevant to the risk evaluation by the Administrator, under the conditions of use.” The statute identifies the minimum components EPA must include in all risk evaluations. For each risk evaluation, EPA must publish a document that outlines the scope of the risk evaluation to be conducted, which includes the hazards, exposures, conditions of use, and the potentially exposed or susceptible subpopulations that EPA expects to consider. Each risk evaluation must also: (1) integrate and assess available information on hazards and exposure for the conditions of use of the chemical substance, including information on specific risks of injury to health or the environment and information on relevant potentially exposed or susceptible subpopulations; (2) describe whether aggregate or sentinel exposures were considered and the basis for that consideration; (3) take into account, where relevant, the likely duration, intensity, frequency, and number of exposures under the conditions of use; and (4) describe the weight of the scientific evidence for the identified hazards and exposure. The risk evaluation must not consider costs or other nonrisk factors. A detailed summary and analysis of the final risk evaluation rule is available in our June 26, 2017, memorandum, “EPA Issues Final TSCA Framework Rules.”
According to EPA, 1-BP is used as a solvent in commercial and industrial applications and as a reactant in the manufacturing of other chemical substances. Common commercial uses of 1-BP are as a solvent in vapor degreasing, dry cleaning, spot cleaners, stain removers, adhesives, sealants, and automobile care products. Consumer uses include adhesives, degreasers, cleaners, and automobile care products.
Risk Evaluation for 1-BP
In the final risk evaluation, EPA reviewed the exposures and hazards of 1-BP conditions of use and made the following final risk findings on this chemical. EPA states that in making these unreasonable risk determinations, it considered the hazards and exposure, magnitude of risk, exposed population, severity of the hazard, uncertainties, and other factors.
- EPA found no unreasonable risk to the environment from any conditions of use: EPA assessed the impact of 1-BP on aquatic and sediment-dwelling species through surface water and sediment exposures to terrestrial species. After reviewing these data, EPA found no unreasonable risk to the environment;
- EPA found no unreasonable risk to the general population: EPA states that the general population could be exposed to 1-BP either through releases to water and air or through waste disposal. EPA found that it was unlikely the general population would be exposed to 1-BP through surface water, drinking water, and sediment.
- EPA found that the following conditions of use do not present an unreasonable risk to health:
- Manufacturing: both domestic manufacture and import;
- Processing: as a reactant; incorporation into articles: repackaging; and recycling;
- Distribution in commerce;
- Commercial and consumer uses of building and construction materials (insulation); and
- Disposal.
- Manufacturing: both domestic manufacture and import;
The no unreasonable risk determinations on these conditions of use are considered final agency action and are being issued by order pursuant to TSCA Section 6(i)(1).
EPA states that potential exposure to 1-BP in ambient air and hazardous waste are under the jurisdiction of other EPA-administered statutes, such as the Clean Air Act (CAA) and the Resource Conservation and Recovery Act (RCRA). Therefore, these exposure pathways are not part of this risk evaluation. EPA notes that in June 2020, it granted petitions to add 1-BP to the CAA list of air toxics.
EPA found unreasonable risks to human health from 16 out of 25 conditions of use of 1-BP:
- Consumers and bystanders: EPA states that it found unreasonable risks to consumers and bystanders from all consumer uses of 1-BP evaluated except one (insulation off-gassing). According to EPA, common consumer uses include aerosol spray degreasers/cleaners, spot/stain removers, adhesives used in arts and crafts, and automobile care products, such as air conditioning system cleaners. Unreasonable risks to consumers can come from short-term inhalation and dermal (through the skin) exposure. Unreasonable risks to bystanders can come from short-term inhalation exposure; and
- Workers and ONUs: EPA states that it found unreasonable risks to workers from most commercial uses of 1-BP. Additionally, EPA found unreasonable risks from most commercial uses of 1-BP to workers nearby but not in direct contact with 1-BP (known as ONUs). According to EPA, common commercial uses include solvents for vapor degreasing and cleaning, adhesives, dry cleaning solvents, cleaners for metal and electronic components, and automotive care products, including brake cleaner and air conditioning fluid. Unreasonable risks to workers and ONUs can come from both short- and long-term inhalation exposure.
Commentary
As readers recall, there are ten chemicals included in the first tranche of risk evaluations required by Lautenberg. This is the second risk evaluation EPA has issued in final; the first covered methylene chloride. According to EPA, the remaining eight risk evaluations in this first tranche are targeted for completion by the end of 2020. As with methylene chloride, the risk evaluation determined that unreasonable risks to health were presented by many of the conditions of use EPA evaluated. Risk management efforts will now commence regarding these conditions of use, and a final Section 6(a) regulation is required to be issued within three and one half years. In addition, for the conditions of use that were determined not to present an unreasonable risk, these decisions represent final agency actions that are subject to legal challenge. We expect, as was seen for methylene chloride, that legal challenges to the Section 6(i)(1) orders will ensue for some and perhaps all of these conditions of use, for reasons including but not limited to EPA’s exclusion of certain exposure pathways (i.e., from ambient air and disposal) because they are regulated under other authorities implemented by EPA.
In preparing the risk evaluation in final, EPA refined some of the representative exposure scenarios for certain of the conditions of use evaluated. This included development of an occupational scenario for the commercial use of 1-BP in insulation. In a change from the draft version, this use was found not to present an unreasonable risk in the final risk evaluation. In addition, to improve clarity, EPA issued a single unreasonable risk determination for dry cleaning solvent, spot cleaner, and stain remover. In another change, EPA issued an unreasonable risk determination for the liquid cleaner and liquid spray/aerosol cleaner that is separate from the unreasonable risk determination for other industrial and commercial uses.