Gelman Dioxide Plume Update

Written by Kathleen Knol, Scio Township Trustee:


Gelman Sciences, located on South Wagner Road in Scio Township, used about 850,000 pounds of 1,4-dioxane in its manufacturing of medical filters; discharging the toxic chemical on its property from 1966 to 1986. Process waste containing 1,4 dioxane was discharged in various ways on the Gelman site, including into onsite unlined sewage treatment ponds, later by “spray irrigation” onto its lawns and into a mile-deep injection well. It is not known how much dioxane was released into the environment by each method. Additionally, it is not known how much dioxane remains at the core site on the Gelman property in Scio Township.

Gelman Sciences has been subsequently purchased by Pall Corp, and later by Danaher Corp., a multi-billion dollar corporation.

The plume seen here from its source on Wagner Rd spreading mostly northeast beyond I-94 toward the Huron River

The Michigan Department of Environmental Quality has overseen the limited cleanup that Gelman has performed using pump and treat remediation. This treatment is governed by a 1992 Consent Judgement and subsequent modifications. This approach has allowed the plume to continue spreading in many directions. The dioxane plume is currently spreading through Ann Arbor and toward the Huron River at concentrations which exceed the cleanup standard. Many Scio Township wells have been contaminated with dioxane, necessitating annexation to the City of Ann Arbor and connection to municipal water. Currently, the dioxane plume is estimated to be approximately 4 miles long and 1 mile wide.

Approximately 250 monitoring wells have been placed to attempt to track the movement of the plume. Select residential wells are also monitored by Washtenaw County. Many of these wells are sampled for dioxane on a schedule negotiated by the DEQ and Gelman.

The United States EPA has characterized 1,4-dioxane as a likely carcinogen by all routes of exposure. It is a colorless liquid that dissolves easily in water, it does not evaporate readily and it travels with the groundwater. In October of 2017 the DEQ reduced the drinking water standard for 1,4 dioxane from 85 parts per billion (ppb) to 7.2 ppb. The new 7.2 level brings the state’s dioxane standards closer to the 2010 EPA guideline of 3.5 ppb for 1-in-100,000 cancer risk. However, many states have drinking water standards for allowable dioxane below 7.2.

Recent Activity

Scio Township, Washtenaw County, the City of Ann Arbor and the Huron River Watershed Council have been allowed to enter the ongoing Gelman case as intervening parties by Washtenaw County Circuit Court Judge Tim Connors. This has allowed these parties and their attorneys to participate with the DEQ and Gelman in the ongoing settlement negotiations. It is hoped that the parties will be able to push for a more comprehensive cleanup plan and improved monitoring of the expanding plume.

Gelman filed an application for leave to appeal with the Michigan Court of Appeals contesting the decision of Judge Connors to allow the local governments and the Watershed Council to intervene in the Circuit Court case. This appeal was denied unanimously by a three judge Court of Appeals panel. Gelman has subsequently filed another application for leave to appeal with the Michigan Supreme Court, again contesting the decision to allow the intervenors into the legal action. The Michigan Supreme Court denied Gelman’s appeal on January 12, 2018.

Scio Township, Ann Arbor Township and the Sierra Club had petitioned the EPA to review the Gelman contamination site for consideration to be declared a Superfund site. In November of 2017, the EPA announced that they will let the DEQ continue to oversee the regulatory attempts to manage the spreading plume and the risks associated with the dioxane contamination. The EPA will retain oversight with additional progress reports by the DEQ, and the Gelman contamination site will remain on the EPA’s active Superfund program site inventory. In pursuing involvement in the Circuit Court case and in the petition to the EPA, Scio Township is seeking to improve the dioxane contamination cleanup and hold the polluter accountable.

Originally published in the Winter 2018 edition of the Scio Township Community Report.

Additional information

Scio Residents for Safe Water (SRSW),

DEQ, Dan Hamel, Environmental Quality Analyst


EPA, Michael Berkhoff, Remedial Project Manager U.S. EPA

Region 5, Superfund Division,

Washtenaw County Environmental Quality

Jennifer Conn,Environmental Quality Analyst,

Coalition for Action on Remediation of Dioxane (CARD)


Scio Township

Bryce Kelley, Scio Township Manager,

Kathleen Knol, Scio Township Trustee,

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