Recently, the U.S. Environmental Protection Agency (EPA) released draft risk evaluations for cyclic aliphatic bromide cluster (HBCD) and 1,4-Dioxane, triggering a 60-day public comment period. HBCD and 1,4-Dioxane are among the first 10 chemical substances to be designated for risk evaluation under the June 2016 Amendments to the Toxic Substances Control Act (TSCA), which required EPA within three years to perform an assessment of prioritized chemical substances and determine whether they pose an unreasonable risk. EPA found that HBCD did not pose unreasonable risks, while 1,4-Dioxane could pose an unreasonable risk to workers in some circumstances, including manufacturing, and some processing and industrial uses.

Under TSCA, if EPA finds that a chemical substance poses an unreasonable risk of injury to health or the environment, it will apply certain requirements as necessary to ensure that the chemical substance no longer presents a risk. These requirements can include: prohibitions on manufacturing, processing or distributing of the substance; limits on uses of the substance, such as the concentrations used or produced; requirements for labels or warnings; record requirements; method of use requirements; disposal requirements; and notice requirements to manufacturers, processors or the public.

HBCD is a chemical substance used as a flame retardant, mainly in construction materials. This chemical substance is commonly found in structural insulated panels and polystyrene foam (both EPAS and XPS). 1,4-Dioxane is generally used as a processing aid, laboratory chemical, adhesive or sealant, and a dry film lubricant. It is used in a wide range of products, including spray polyurethane foam and printing compositions.

EPA’s draft risk evaluation finds 1,4-Dioxane could pose an unreasonable risk to "workers in certain circumstances." Based on this, EPA may impose additional requirements for companies processing or manufacturing 1,4-Dioxane. The draft risk evaluation did not identify 1,4-Dioxane as posing an unreasonable risk to the environment. For HBCD, EPA's draft risk assessment showed that it did not pose an unreasonable risk to the general population, consumers, workers or the environment.

Because of the draft risk evaluation results, companies working with 1,4-Dioxane may be required to establish more protections for employees once the evaluations are finalized. For example, EPA may enact stricter limits on the manufacturing and processing, limits on concentrations used or produced, notice to employees of risks associated with 1,4-Dioxane, and others. Because of this, companies should analyze whether extra precautions to protect employees exposed to 1,4-Dioxane may be required by EPA, and if so, apply those now prior to the finalization of this risk evaluation. Alternatively, if there are other considerations EPA should take into account before final risk evaluations are developed, that information should be provided to EPA during the comment period.

Earlier this year, EPA proposed the next 40 chemical substances or mixtures to be evaluated for prioritization. This prioritization is expected to be final this year, then the risk assessment process will proceed for each substance.