1,4-Dioxane is a solvent used in a variety of commercial laboratory applications, dish soap and laundry detergent used by cleaning services or laundromats, and industrial manufacturing and processing applications of other chemicals such as adhesives and sealants². 1,4-Dioxane is also generated as a byproduct in a few manufacturing processes, increasing its presence in surface water when these products are washed down the drain². The United States Environmental Protection Agency (EPA) has determined that 1,4-dioxane presents an unreasonable risk of injury to human health, including the potential to cause cancer and harm the liver and nasal tissue².
In the EPA’s 2020 risk evaluation, 1,4-dioxane was one of the first ten chemicals reviewed under the amended Toxic Substances Control Act (TSCA). But the EPA did not evaluate general population exposures to the chemical in drinking water or air, did not evaluate all the ways people could be exposed to it as a byproduct, did not evaluate the potential for simultaneous exposure to more than one source of it, and did not evaluate potential exposures to communities that live near highly polluting facilities². After environmental groups, state attorneys general, and members of an external advisory panel criticized the EPA for not evaluating these general population exposures to 1,4-dioxane in drinking water, the EPA agreed to conduct supplemental analysis¹.
EPA found that 1,4-dioxane presents unreasonable risk to workers and the general population, including communities near industrial/manufacturing facilities. Inhalation and dermal exposures were the unreasonable risks found for workers who handle 1,4-dioxane in manufacturing and industrial applications and from commercial products that create 1,4-dioxane as a byproduct². Communities where drinking water is sourced from smaller or slow-flowing streams and industrial discharges have contaminated the water with 1,4-dioxane; or, large numbers of people living near the source of water have washed 1,4-dioxane in consumer products down the drain. Either of these activities or a combination thereof also pose unreasonable risk to exposure through drinking water².
The next step for the EPA is to begin risk management to address the unreasonable risk presented by 1,4-dioxane. The EPA will release a proposed rule under TSCA section 6 to protect people from the identified risks². Now that it is found that even small amounts of 1,4-dioxane contaminates can negatively impact drinking water sources, we may see lower detection limits for 1,4-dioxane analyzed by Purge and Trap in the future.
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