EPA’s approach to 1,4-dioxane falls short of protecting fenceline communities

Clear water pouring from a pitcher into a glass.What’s New?

Recently, the Environmental Protection Agency (EPA) embarked on a critical Toxic Substances Control Act (TSCA) supplemental risk evaluation of 1,4-dioxane [PDF, 8.7MB]– a highly carcinogenic chemical that contaminates drinking water supplies across the country and is present in products, such as cleaning supplies and personal care products.

This draft supplemental risk evaluation represents a significant step forward because it addresses many of the omissions from the original 1,4-dioxane risk evaluation. Unfortunately, as we noted in our comments to EPA, a closer examination reveals several shortcomings in how EPA addresses risks to fenceline communities—people living, playing, and working near industrial facilities that release toxic chemicals into the air and water.

Why It Matters

The supplemental risk evaluation is the first to incorporate EPA’s new methodology for analyzing the health risks of toxic chemicals to fenceline communities.

Getting it right is key! How EPA assesses the risks to fenceline communities in this risk evaluation will be the model for estimating risks to those communities in future risk evaluations for other toxic chemicals.

Unfortunately, EPA has taken a piecemeal approach that systematically fails to account for real-world aggregate exposures and, in doing so, underestimates the increased risks to fenceline communities from 1,4-dioxane.

Our Take

We commend the agency for incorporating the risks from inhalation and drinking water exposure that were lacking in its 2020 1,4-dioxane risk evaluation, and also acknowledging the necessity of assessing fenceline community risks.

However, the supplemental risk evaluation systematically fails to account for the combined—or aggregate—exposures and, in doing so, underestimates the health risks to communities exposed to 1,4-dioxane.

EPA must account for the aggregate of all the different ways that an individual is exposed to 1,4-dioxane—whether that be by inhaling the chemical, drinking water contaminated with it, or coming into contact with soil or water containing the chemical. EPA must also fully account for all of the 1,4-dioxane being released by multiple facilities into a community, rather than considering the exposures and risks from individual facilities in isolation.

In our comments to EPA [PDF, 4.8MB] and its scientific advisory committee, we recommended that EPA aggregate exposures to 1,4-dioxane in the following ways:

  • EPA should consider risks to people who are exposed to 1,4-dioxane from multiple routes of exposure, such as inhalation, dermal, and oral exposures.
  • EPA should consider risks from multiple 1,4-dioxane uses at one time rather than only looking at the risks that a single 1,4-dioxane use in isolation poses to health.
  • EPA should fully consider aggregate risks from multiple neighboring facilities releasing 1,4-dioxane, as communities are experiencing contamination from all facilities nearby rather than just one.
  • EPA should consider the cumulative risks to communities exposed to 1,4-dioxane and other carcinogens, as exposure to multiple carcinogens increases the risk of getting cancer compared to being exposed to only one of these chemicals.

In conclusion, EPA’s approach to evaluating the risks associated with 1,4-dioxane is flawed in several critical ways and is at odds with TSCA’s mandate to use the best available science in its risk evaluations. The current piecemeal approach underestimates the true risks presented by 1,4-dioxane, which will result in less-protective risk management decisions, leaving communities vulnerable to this highly toxic chemical.

Next Steps

It’s imperative that EPA revise its 1,4-dioxane supplemental risk evaluation to consider, in aggregate, the full range of exposures of this toxic chemical that we and—in particular—fenceline communities face.

Go Deeper

Our previous blogs on 1,4 dioxane

This entry was posted in Chemical exposure, Chemical regulation, Cumulative impact, Cumulative risk assessment, TSCA and tagged , , . Authors: , . Bookmark the permalink. Both comments and trackbacks are currently closed.

One Comment

  1. Posted September 15, 2023 at 4:41 am | Permalink

    The article discusses the Environmental Protection Agency’s (EPA) supplemental risk evaluation of the highly carcinogenic chemical 1,4-dioxane. While it addresses some omissions from the original evaluation, there are concerns about how EPA assesses risks to fenceline communities, potentially underestimating their exposure. Getting this right is crucial as it sets a model for future evaluations of toxic chemicals’ risks to such communities.