A coalition of local officials and environmental organizations has filed a federal legal challenge against an Environmental Protection Agency decision to allow underground wastewater injection near Lake Frances in northcentral Montana, targeting permits issued to Montalban Oil and Gas for disposal wells that would serve the Great Falls biorefinery operated by Montana Renewables.
The Permits and the Challenge
The EPA approved the permits on May 1, authorizing the conversion of two unproductive oil wells in Pondera County into underground wastewater injection sites. The wells would receive industrial wastewater generated by Montana Renewables, a subsidiary of Calumet, which runs a biorefinery in Great Falls. The injection zones sit more than 3,400 feet below the surface in the Madison Aquifer.
As part of its approval, the EPA also granted an exemption from the federal Safe Drinking Water Act covering 6.6 square miles of the Madison Aquifer — a move the petitioners argue was made on faulty assumptions about geology, contamination risk, and whether the aquifer could ever realistically serve as a drinking water source for Pondera County residents.
The petition was filed in the U.S. Court of Appeals for the Ninth Circuit. Petitioners include Pondera County itself, the Glacier-Two Medicine Alliance, the Golden Triangle Resource Council, and the Madison Aquifer Coalition. They are represented by the Western Environmental Law Center and EarthJustice.
What the Petitioners Argue
At the core of the challenge is a dispute over the EPA’s hydrogeological modeling. Petitioners contend the agency used an outdated analytical framework and made inaccurate assumptions about how the aquifer system behaves — particularly whether wastewater injected at depth could migrate upward and contaminate shallower aquifers used for drinking water.
Pondera County Commissioner Zane Drishinski said the agency’s work did not hold up to scrutiny. “The EPA relied on an outdated model and wildly inaccurate assumptions about the geology, water quality, and economic viability of the Madison Aquifer,” he said.
County Sanitarian Corrine Rose pointed to statements made during a public meeting held in January 2024, when the permitting process was still in early stages. “At the initial public meeting in January 2024, Montana Renewables CEO Bruce Fleming claimed the wastewater was so clean you could drink it,” Rose said. Permit documents, however, describe the wastewater as containing phosphorus, nitrogen, salts, and other impurities.
Montana Renewables’ Current Operations
Montana Renewables is not yet injecting any wastewater into the Pondera County wells. A company spokeswoman confirmed as of this week that no wash water has been sent to the sites. The company currently ships its wastewater to a permitted disposal facility in Idaho while its own on-site treatment infrastructure remains in the engineering phase.
The company received a significant financial boost in late 2024 when the U.S. Department of Energy issued a $1.67 billion loan guarantee to support its Great Falls refinery operations — a substantial federal commitment that underscores the project’s scale and the stakes involved for all parties. The Montalban Oil and Gas wells in Pondera County are owned separately; Montana Renewables is listed as the sole intended source of wastewater for those disposal sites.
What Comes Next
The case now heads into the federal appellate process, where the Ninth Circuit will consider whether the EPA’s permitting decision and the associated aquifer exemption were legally and scientifically sound. No hearing date has been publicly announced.
The dispute reflects a broader tension in Montana between energy development and resource protection — particularly over groundwater, which communities across the state rely on for agriculture and municipal supply. The Madison Aquifer is one of the region’s most significant underground water resources, and questions about its long-term protection have drawn attention from both local officials and national advocacy groups.
For context on other ongoing natural resource reviews in the state, a separate public comment period opened recently for a Stillwater Mine expansion in southcentral Montana, illustrating the range of environmental permitting questions currently before regulators.
