Toxic Dioxane Plume Near Ann Arbor Declared EPA Superfund Site

Decades-old groundwater contamination will now be overseen by federal agency.

Mar. 13, 2026 at 10:03am

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The U.S. Environmental Protection Agency has added the Gelman Sciences Inc. site in Ann Arbor, Michigan to the Superfund National Priorities List, a designation for the nation's most contaminated sites. This will shift oversight of the decades-old 1,4-dioxane groundwater plume from the state to the federal agency, allowing for more aggressive cleanup efforts.

Why it matters

The Gelman Sciences plume has contaminated dozens of residential wells, created a large "prohibition zone" where groundwater cannot be used, and is slowly moving toward one of Ann Arbor's main drinking water sources. The EPA's Superfund designation will provide more resources and enforcement power to address the long-standing environmental disaster.

The details

From 1963 to 2013, Gelman Sciences used the industrial solvent 1,4-dioxane in its manufacturing processes, improperly disposing of dioxane-containing wastewater and contaminating the groundwater. The resulting plume is over 4 miles long, 1 mile wide, and of uncertain depth, with dioxane levels up to 200,000 parts per billion - far exceeding the state's 7.2 ppb drinking water standard. Dioxane is considered a likely human carcinogen and can cause severe liver and kidney damage.

  • Gelman Sciences operated the facility from 1963 until its closure in 2013.
  • In 1992, the state and Gelman reached a consent judgment to address the contamination, which has been amended multiple times since.
  • The EPA announced the Superfund designation on March 12, 2026.

The players

Gelman Sciences Inc.

The former manufacturing company whose facility contaminated the groundwater with 1,4-dioxane.

U.S. Environmental Protection Agency (EPA)

The federal agency that has now taken over oversight of the Gelman Sciences contamination site, designating it a Superfund site.

Dan Bicknell

A Dexter resident who discovered the contaminated runoff from the Gelman site as a University of Michigan student in the 1980s, and has since advised local governments and citizen groups on the dioxane plume.

Jillian Kerry

The Scio Township Supervisor, who has worked for decades on the issues surrounding the Gelman dioxane plume.

Debbie Dingell

A U.S. Representative from Dearborn, Michigan who has advocated for more federal involvement in cleaning up the longstanding dioxane plume.

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What they’re saying

“With this Superfund designation, EPA will use its statutory authorities to hold the company responsible for near- and long-term actions to more expeditiously address possible risks to human health and the environment.”

— Ann Vogel, EPA Regional Administrator (freep.com)

“Bringing in these federal resources is going to allow for proper cleanup of the site.”

— Dan Bicknell (freep.com)

“It's been decades long, and the community has come together. The EPA will step in and will hold the polluter accountable.”

— Jillian Kerry, Scio Township Supervisor (freep.com)

“Adding the Gelman plume to the National Priorities List is a meaningful step forward that strengthens the tools available to address contamination.”

— Gretchen Whitmer, Governor of Michigan (freep.com)

What’s next

The EPA will now take the lead in overseeing the cleanup of the Gelman Sciences dioxane plume, using its Superfund authorities to hold the company responsible for remediation efforts.

The takeaway

This Superfund designation marks a major shift in the long-running battle to address the Gelman Sciences dioxane contamination, which has plagued the Ann Arbor area for decades. With the EPA now in charge, the community is hopeful that more aggressive and effective cleanup actions will finally be taken to protect public health and the environment.