Over the last six years, our firm has written extensively about 1,4-Dioxane, from U.S. EPA’s proclamations to state laws and regulations, litigation, and distinctions between federal and state perspectives. (see compilation of blog posts here.)
Today we are providing an update on the EPA’s final revised Unreasonable Risk Determination for 1,4-Dioxane, which includes new air and water exposure pathways that had not been previously evaluated, as well as evaluation of 1,4-Dioxane generated as a byproduct.
According to EPA, 1,4-Dioxane is primarily used as a solvent in commercial and industrial applications. It can also be produced as a byproduct of several common manufacturing processes. Even though it is not intentionally added, 1,4-Dioxane produced as a byproduct may remain present in consumer and commercial products, including soaps and detergents, cleaning products, antifreeze, textile dyes, and paints/lacquers.
1,4-Dioxane is released to the environment from industrial releases and from consumer and commercial products that are washed down the drain or disposed of in landfills. EPA says that people may be exposed to 1,4-Dioxane through occupational exposure, consumer products, or contact with water, land, or air where 1,4-Dioxane has been released to the environment.
TSCA section 6(b)(4) requires EPA to conduct a risk evaluation to determine whether a chemical substance presents an unreasonable risk of injury to health or the environment, without consideration of costs or other non-risk factors. EPA has determined that 1,4-Dioxane presents an unreasonable risk of injury to health under various conditions of use, including in manufacture and processing, as well as in the context of industrial/commercial use as a processing aid, adhesives/sealants, hydraulic fracturing, and paints and coatings, and in the context of consumer uses for laundry and dishwashing products, among other things. To the contrary, EPA found that certain conditions of use did not significantly contribute to the unreasonable risk from 1,4-Dioxane, including commercial use of automobile antifreeze, and consumer use of textile dyes and spray polyurethane foam.
EPA maintains that it is appropriate to conclude that any processing of 1,4-Dioxane significantly contributes to the unreasonable risk. EPA also emphasizes that this determination identifies any manufacturing, processing, or disposal of 1,4-Dioxane – including as a byproduct – as significantly contributing to the unreasonable risk if the 1,4-Dioxane contaminates surface water that is the source of drinking water.
Consistent with the statutory requirements of TSCA section 6(a), EPA will propose “risk management regulatory action to the extent necessary so that 1,4-Dioxane no longer presents an unreasonable risk” (focusing on the conditions of use listed). EPA has found that exposures to the general population via drinking water sourced from surface water contaminated with 1,4-Dioxane “significantly contribute to the unreasonable risk presented by 1,4-Dioxane.” Therefore, EPA has decided that regulatory actions under both TSCA and the Safe Drinking Water Act (SDWA) may be appropriate.
EPA will now move forward on risk management to address the findings of this report. EPA will begin developing a proposed rule under TSCA section 6 to protect people from the unreasonable risks EPA identified. More information on 1,4-Dioxane can be found on the EPA’s website here.
