DEQ Releases the Final Explanation of Significant Differences for the Montana Pole Superfund Site in Silver Bow County -

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DEQ Releases the Final Explanation of Significant Differences for the Montana Pole Superfund Site in Silver Bow County

Monday, March 29, 2021/Categories: Department of Environmental Quality/Tags:

HELENA—The Montana Department of Environmental Quality released the final Explanation of Significant Differences (ESD) today for the Montana Pole & Treating Plant in Butte, Mont. in Silver Bow County. The ESD proposes changes to the original cleanup plan to make the site more protective of human health and the environment. Now that the ESD is complete and approved by the Environmental Protection Agency (EPA), construction can begin on final cleanup for the south side of the site allowing for future redevelopment.  

The former wood-treating plant was deemed a Federal Superfund site after its closure and has already undergone cleanup of soil, groundwater, solid and hazardous waste. The changes in the ESD establish more protective cleanup levels than what was in the original Record of Decision. While the site reached cleanup levels established in the original Record of Decision for pentachlorophenols (PCP) and polycyclic aromatic hydrocarbons (PAHs), the cleanup level for dioxin was not achieved. Changes in the ESD include making the PCP cleanup level more protective of groundwater than what was in the original decision and a new, more protective, dioxin cleanup level will allow for industrial or commercial redevelopment. All contaminants are the result of the wood treating process that occurred onsite and are located in the soils.  

Construction for remediation cleanup will include placing the treated soils in an onsite designated engineered repository area called a Corrective Action Management Unit (CAMU). Construction will begin this summer on the cleanup. The new cleanup levels will allow for commercial and industrial redevelopment for 27 acres of the site. The remaining 9 acres is the site of the CAMU, which will be comprised of the treated soils area and additional soils removed to achieve the new cleanup levels. The operation and maintenance of the CAMU will be overseen by the state to ensure protectiveness and will have regular Five Year Reviews. Five Year Reviews are a standard process required whenever contamination is safely left onsite. The reviews make sure the site remains protective.  

DEQ, along with the EPA, is hosting two remote meetings via Zoom. The first meeting on April 20, 2021 is for the local neighborhood residents to discuss the final ESD. Equally important, DEQ and the local neighborhood residents will identify potential concerns with the construction process—including dust, odors, and traffic—and how those concerns will be addressed. The second meeting is a presentation to the public at EPA’s monthly community meeting on April 26. Those meetings are currently monthly and are an opportunity for the public to learn more about Superfund sites in Butte. Both meetings will include a presentation and opportunity for a question and answer session.    

DEQ and the EPA will also present at Butte’s Citizens Technical Environmental Committee (CTEC) in May.  

What: Remote public meetings held via Zoom  

When:Neighborhood Meeting:  April 20, 2021 from 6 p.m. to 7:30 p.m.  
EPA Community Public Meeting: April 26, 2021 from 6 p.m. to 8 p.m.  

Where: Participants can sign up to attend the meetings held via Zoom and receive instructions about how to access the meeting by registering at:  

The meetings are accessible both online and by telephone. If you are calling by phone and would like a printed copy of the presentation to follow along, the presentation will be posted to the DEQ website a day in advance or you can request a mailed copy. DEQ will make reasonable accommodations for those with disabilities who wish to participate in the meetings. If you require an accommodation or would like to register for the meetings by phone, please contact Moira Davin, Public Relations Specialist at: 406-461-2503 or by email at:  

Participants are asked to join the meetings a few minutes early to test their connection.  

DEQ prepared a draft ESD and accepted public comment. All comments are addressed in the final ESD in the responsiveness summary. To view the final ESD please visit the DEQ website at: or view a hard copy located at the Montana Tech Library (1300 W Park St, Butte). 


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