EPA Updates
There are no significant updates from the Environmental Protection Agency (EPA). General EPA updates regarding the Gelman site are available on the EPA’s website
Agency Updates
Coalition for Action on Remediation of Dioxane (CARD)
CARD meetings were held virtually on May 6, and June 3. The April meeting was cancelled.
Michigan Department of Environment, Great Lakes, and Energy (EGLE) Update
- Slauson Middle School will be installing a closed loop Geothermal system, where 1,4-dioxane could be encountered in the groundwater. EGLE is working with the Washtenaw County Health Department to develop appropriate sampling and procedures to prevent further contamination and exposure. There may be an opportunity to install a permanent groundwater monitoring well.
- EGLE’s environmental lab can now report 1,4-dioxane at 0.2 parts per billion under Method 522.
- EGLE provided feedback on Gelman’s municipal water connection contingency plan on May 20, 2025. EGLE asked for additional documentation.
Washtenaw County Health Department
- Residential well sampling will begin in early June, with 127 homes scheduled to be sampled.
- Washtenaw County Health Department is the permitting agency for closed loop geothermal systems, however, these systems are not regulated at the state level.
- The City of Ann Arbor has updated their website related to 1,4-dioxane.
- The CARD Executive Committee submitted public comments to the Ann Arbor Planning Commission advocating for discussion of the 1,4-dioxane contamination in the Ann Arbor Comprehensive Land Use Plan. The first round of public comment closed on May 16, 2025. The project website is https://www.a2gov.org/planning/comprehensive-plan/
The next scheduled meeting will be held on Tuesday July 1, 2025, at 6 p.m. via Zoom.
Municipal Separate Storm Sewer System (MS4) Permit
No significant MS4 updates. Concentrations of 1,4-dioxane have been entering the Allen Creek Drain (ACD) stormwater system. The ACD system is part of Washtenaw County’s Municipal Separate Storm Sewer System (MS4). On December 15, 2022, the Washtenaw County Water Resources Commission Office sent a letter to Gelman indicating that action was required to remain in compliance with the County’s MS4 permit requirements regarding outstanding issues previously noted. The letter stated that the migration of 1,4-dioxane into ACD must cease or be in compliance with applicable State and County statutes and requirements.
EGLE Water Resources Division is exploring potential permitting options.
Pall Groundwater Treatment Update
Total volume of groundwater treated April through May 2025:
47,852,640 gallons
Mass of 1,4 Dioxane Removed:
April: 72.20 lbs
May: 81.91 lbs
Total: 154.11 lbs
The mass calculations were determined from the NPDES monthly discharge reports using the maximum daily influent concentration and maximum daily effluent concentrations.
Next Quarterly Report Due September 2025
- EPA Updates
- EGLE and CARD Updates
- MS4 Permit
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