DEQ Press Releases

Harbage, Rebecca

DEQ Seeks Public Comment on Colstrip Steam Electric Station Report

HELENA – The Montana Department of Environmental Quality is seeking public comment on the Units 1 and 2 Revised Remedy Evaluation Report, Part 2, submitted by Talen Montana, LLC, the operator of the Colstrip Steam Electric Station. Talen was required to submit the report under the Administrative Order on Consent (AOC) between DEQ and Talen. The AOC requires an investigation and remediation of groundwater contamination caused by leaking ash ponds. 


The report has been split into two parts. The first part of Talen’s proposed remedy addressed the control of existing groundwater contamination through a capture-and-clean water injection well system. This part was conditionally approved by DEQ in June 2020.


The second part of the report addresses prevention of future groundwater contamination by controlling the source (the Stage I and Stage II Ponds). Alternatives presented range from capping and closing the ponds in place, to full excavation and removal of the ash to a new, lined landfill that would be constructed on Talen’s property. Talen has identified a partial removal alternative as its preferred remedial alternative. This would consist of removing ash that would be within five feet of the high groundwater table, placing the ash elsewhere in the existing pond footprint, and capping the Stage I and Stage II Ponds. DEQ is currently reviewing the report and will select a remedy after public comments are collected and reviewed.


The report is now available for public review and comment. Copies of the reports are available at DEQ’s office at 1520 E Sixth Ave, Helena; Talen Montana’s office, 303 N Broadway, Suite 400, Billings; and the Bicentennial Library, 419 Willow Ave, Colstrip. The reports are also available by accessing “Documents” at:


DEQ will accept public comments on the report through Oct. 26, 2020. DEQ will also host a remote public meeting on Oct. 14, 2020, at 7:00 p.m., at which DEQ will present details on the remedial alternatives discussed in the report. A recording of the meeting will be made available on DEQ’s website. For details on how to submit comments or access the public meeting, please visit the DEQ website at:


DEQ will make reasonable accommodations for persons with disabilities who wish to participate in the meeting. If you require an accommodation, please contact Sara Edinberg at least one week before the meeting at 406-444-6797 or by email at:


Previous Article DEQ Announces Submitted Draft Plan to Remove Wastes in Bonner Mill Site Repository in Missoula County
Next Article DEQ Releases Draft Environmental Impact Statement For The Rosebud Coal Mine