Region 8

Montana Pole and Treating

Montana Pole and Treating Plant site location map Site Type: Final NPL
City: Butte
County: Silver Bow
Street Address: 202 W. Greenwood Ave.
ZIP Code: 59701
EPA ID: MTD006230635
SSID: 0869
Congressional District: At Large

What's New?

Updated July 2011

The third five-year review has been completed for the Montana Pole and Treating Plant (MPTP). The purpose of the review is to determine whether the remedy at the site, as selected and implemented subsequent to the Record of Decision (ROD), is protective of human health and the environment. The methods, findings and conclusions of the review are documented in the five-year review report, which is available in the Site Documents section below.

The Montana Department of Transportation (MDT) construction activities associated with the Interstate 15/90 bridge replacement that commenced in spring 2010 will continue and be completed in 2011.

Recent dewatering efforts associated with upgrades to Butte/Silver Bow’s wastewater treatment plant have resulted in concentrations of pentachlorophenol above the ROD cleanup level migrating to the north of Silver Bow Creek. A November 2010 report titled Information Summary, Conceptual Model, and Groundwater Modeling Report: Butte Metro Sewer Treatment Plant Dewatering is provided in the Site Documents section below. This report includes key observations and conclusions associated with this dewatering effort as well as a summary of groundwater modeling performed to better understand the impacts dewatering has on the MPTP site. Based on these efforts, there are plans to excavate remaining sources of PCP beneath several power poles located between the Near Creek Recovery Trench (NCRT) and Silver Bow Creek in summer 2011. The MPTP treatment plant will also be upgraded to allow for treatment of additional water to be pumped from the NCRT during future WWTP dewatering (as a mitigation strategy).

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Site Description

The Montana Pole and Treating Plant (MPTP), located in Butte, Montana, operated as a wood treating facility from 1946 to 1984. During most of this period, a solution of about 5 percent pentachlorophenol (PCP) mixed with petroleum carrier oil similar to diesel was used to preserve poles, posts, and bridge timbers. The PCP solution was applied to wood products in butt vats and pressure cylinders (retorts). Creosote was used as a wood preservative for a brief period in 1969. Hazardous substances from the pole-treating operations were discharged into a ditch next to the plant. The substances then began to run towards Silver Bow Creek.

Map of the Superfund site boundary

In March 1983, a citizen filed a complaint concerning oil seeping into Silver Bow Creek near the site. The Montana Department of Health and Environmental Services (MDHES), now the Department of Environmental Quality (DEQ), investigated the complaint and discovered an oil seep on the south side of Silver Bow Creek in the same direction the water flows, directly below the site. Further investigation of the site revealed oil-saturated soils adjacent to the creek and on MPTP property. Subsequent sampling confirmed the presence of PCP, polynuclear aromatic hydrocarbons (PAHs), and dioxins/furans in site soils and oil samples.

Much of the land in the vicinity of the site has been used industrially, usually associated with past and present mining activities, though commercial and residential areas are immediately adjacent to the site. Two neighborhoods are within a quarter mile of the site. Groundwater use in the area is limited.

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Site Risk

The groundwater and soils at the Montana Pole site had become contaminated with PCPs, dioxins and furans. The site was proposed for addition to the EPA's Superfund National Priorities List (NPL) in June 1986. The final date of its addition to the NPL was July 1987. The main reason for putting this site on the NPL was that groundwater beneath the site had become contaminated with oily wood-treating fluid that had spilled, dripped or discharged onto the ground surface. The oily wood-treating fluid migrated downward, contaminating the soil that it passed through, and entered the groundwater. Some of this fluid made its way to the surface of groundwater and Silver Bow Creek, and some of the fluid attached to soil particles above and below the water table. A portion of this fluid dissolved in groundwater and surface water where it migrated downstream both above and below the ground surface toward potential human and ecological receptors, preventing the groundwater and surface water from being used for its designated classifications, beneficial uses, and specific standards. The Record of Decision (ROD) issued in 1993 establishes performance standards for these and all other contaminants of concern at the site.

Media Affected Contaminants Source of Contamination
groundwater, sediment, surface water, soils PCPs, PAHs, dioxins, furans wood treatment activity

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Cleanup Progress

Cleanup Approach

In July 1985, EPA's Emergency Response branch began a removal action on the site to minimize impacts to Silver Bow Creek and to stabilize the site. Approximately 10,000 cubic yards of soils were excavated and two groundwater interception/oil recovery systems were installed to alleviate oil seepage into the creek. Contaminated areas of the site and features of the groundwater recovery system were also fenced to restrict public access.

In October 1989, EPA granted MDHES the initial enforcement funding to conduct potentially-responsible-party administrative-order negotiations and issuance. In April 1990, MDHES signed an administrative order on consent with the Atlantic Richfield Company (ARCO) under which ARCO agreed to conduct a remedial investigation and feasibility study (RI/FS) at the site. Following MDHES and EPA approval of the RI/FS work plan, ARCO began the RI/FS in June 1990.

In June 1992, EPA proposed an additional removal action to control and recover the light nonaqueous phase liquid (floating oils) identified during the remedial investigation. The action included installation of an 890-foot sheet piling on the south side of Silver Bow Creek. The sheet piling was approximately 50 feet south of the creek. Ten recovery wells were installed on site. Eight of the wells were located south of Silver Bow Creek in a north-south line running perpendicular to the creek. Two wells were installed parallel to the creek—one on each end of the sheet piling. The wells were approximately 25 feet deep. Each well had two pumps: one to collect free-floating oil and pump it to an on-site storage tank, and the other to pump contaminated groundwater to an on-site granular activated carbon (GAC) treatment facility built by EPA. The water treatment facility went into operation January 22, 1993, at which time a system previously installed by EPA Emergency Response in 1985 was shut down.

Based upon requirements in the Superfund law, the detailed analysis of alternatives and public comments, MDHES and EPA issued a Record of Decision in 1993 that documented the appropriate remedy for the site. The selected remedy, which is well underway, provides maximum source reduction, remediates groundwater to the extent practicable and limits releases to Silver Bow Creek to allowable levels. All accessible contaminated soils and LNAPL have been excavated to the extent practicable, preventing this material from continuing to contaminate groundwater.

Implementation of the cleanup is occurring in a number of phases. The primary remedy components completed during Phase 1 of the remedial action (May 1996 to November 1997) consisted of constructing the land treatment unit (LTU) and 13 soil staging and pretreatment piles (SSP), building an addition to the water treatment plant, constructing two contaminated-groundwater recovery trenches, and excavating the northside contaminated soils. The Phase 1 construction activities are summarized in the Phase 1 Construction Report dated August 2001.

Phase 2 of the remedial action (March 1999 to May 1999) consisted of removal and disposal of hazardous and non-hazardous waste debris remaining on site. Phase 2 remedial actions are summarized in the Remedial Action Report, Montana Pole and Treatment Plant Site Phase 2 - Debris Removal dated September 26, 2000.

Phase 3 of the remedial action (October 1999 to December 2000) consisted of excavating the southside contaminated soils, offloading Phase 1 treated soils from the LTU, placing approximately 132,000 cubic yards of contaminated soil on the LTU, installing the north and south in-situ treatment systems, and relocating sewer and potable water lines. The in-situ treatment system was operated through November 2002, when a pump required extensive repair. While the pump was out for repairs, analytical data from samples subsequently collected from Silver Bow Creek—a ROD-defined point of compliance—showed significant decrease in PCP concentrations. Since that time, PCP concentrations in surface water samples from Silver Bow Creek have generally remained below the ROD cleanup standard. For this reason, the in-situ system has not been reactivated.

Phase 4 of this project is a continuation of Phase 3 activities, and includes off-loading the LTU as surface soil lifts are remediated below action limits set for the site. Phase 4 began in April 2001 with offload of approximately 27,000 cubic yards of treated soils from the LTU. These treated soils were placed back onto the site. In 2004, eight of the 13 SSPs were determined to have met the cleanup standard for the site, and were dismantled; the treated soils were placed over the south side in situ system. In 2005, approximately 28,000 cubic yards of treated soils was offloaded from the LTU and backfilled on site, and the LTU was regraded. In 2007, approximately 32,000 cubic yards of treated soil was offloaded from the LTU and backfilled on site, and the LTU was regraded. Also in 2007, the last five SSPs were dismantled and approximately 8,000 cubic yards of treated soils from the SSPs were placed on the LTU for final treatment.

Phase 5 will address the contaminated soils beneath Interstate 15/90 that divides the site. In 2001, a preliminary remedial alternatives report was prepared to evaluate various potential remediation methods including surfactant flushing, soil vapor extraction, and hydraulic manipulation. On March 25, 2002, DEQ received EPA's concurrence to pursue modification of the selected remedy for the Montana Pole and Treating Plant through evaluation of excavation and remediation of additional contaminated soil in conjunction with the MDT interstate bridge removal project. Since that time, DEQ, MDT, and EPA have extensively evaluated the technical and economic feasibility of excavating and remediating the remaining contaminated soils. In March 2009, Tetra Tech submitted a report titled Final Treatability Study Workplan, Montana Pole and Treating Plant Site – Phase 5, which is available in the Site Documents section below. Based on the results of these evaluations, DEQ has concluded that it is not economically or technically reasonable to pursue excavation of these soils during MDT's interstate bridge removal project. The treatability study will be revisited and the contaminated soils remaining beneath the interstate remediated beginning in 2012, after MDT’s construction activities have been completed.

Phase 6 will consist of removal of all soils and drainage from the LTU once it meets specified performance standards and their use as fill material above historic high-groundwater levels in the excavated areas within the MPTP property as specified in the ROD. It also calls for disposal of the soil treatment facilities on the south side of the site and final reconfiguration of all disturbed areas. At that time, DEQ expects to turn the site over to Butte/Silver Bow City/County government. It is expected that the final land use at the site will be determined in conjunction with Butte/Silver Bow, with certain constraints on land use as specified by DEQ and EPA that are consistent with the ROD.

Environmental Progress

EPA and DEQ have taken measures to prevent further contamination of Silver Bow Creek. Additional actions were taken to remove the immediate sources of soil contamination, treat groundwater and restrict access to the site. These measures have reduced the potential for exposure to hazardous substances while further cleanup activities are under way. To date, more than 200,000 cubic yards of contaminated soils have been excavated from the site, and approximately 150,000 cubic yards of these soils have been treated on the LTU and backfilled; an additional 24,000 cubic yards of SSP soils have been treated and backfilled. The groundwater treatment system is operating as designed and has treated almost 1 billion gallons of water since startup.

Water, soil, and air monitoring are conducted as required in the Site-Wide Operations and Maintenance Manual. Monitoring requires regular collection of samples of groundwater, surface water, water treatment plant discharge, soil (LTU), and air. Samples are collected as needed to ensure compliance with the ROD and the cleanup levels stipulated in the ROD. The current frequency and methods for collecting samples is currently being revised for the third five-year review, which is expected to be completed in June of 2011.

In 2007, DEQ conducted an evaluation of the groundwater collection and treatment system at the MPTP site. The evaluation concluded that the system is currently preventing further migration of the dissolved groundwater contaminant plumes, and that it is limiting the release of contaminated groundwater to nearby Silver Bow Creek sufficiently to attain the applicable surface water standard.

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Community Involvement

Community involvement plays an important role in the Superfund process. EPA uses a number of different tools and resources to promote effective, on-going, meaningful community involvement. The goals of the Superfund community involvement program are to:

  • Keep communities affected by sites informed throughout the cleanup process.
  • Provide opportunities for communities to comment and offer their input about site cleanup plans.
  • Facilitate the resolution of community issues tied to a site.

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EPA places a high priority on land reuse as part of its Superfund response program mission. The Agency tries to select cleanup options that encourage and support future use of a site. We use two fundamental methods to facilitate reuse of Superfund sites:

  • Exploring future uses before the cleanup remedy is implemented, an approach that gives the Agency the best chance of designing cleanup remedies to support the likely future use of a site.
  • Working with landowners and communities to remove barriers not considered necessary for the protection of human health or the environment at those sites where remedies are already in place.

One option for reuse is the siting of clean and renewable energy projects on contaminated (or formerly contaminated) lands. As part of this effort, EPA is evaluating the potential for energy projects on these properties and working with landowners and communities to identify ways to remove barriers to such projects.

It is expected that the final land use at the site will be determined in conjunction with Butte/Silver Bow, with certain constraints on land use as specified by DEQ and EPA that are consistent with the ROD.

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Land Use Controls

Land use controls are the most common type of institutional control (IC). ICs are administrative or legal controls that help reduce the likelihood for human exposure to contamination. ICs can also help protect the integrity of the remedy. Examples of ICs are:

  • Zoning ordinances.
  • Environmental covenants.
  • Deed notices.
  • Well-drilling restrictions.
  • Building permits.
  • Informational advisories.

The remedy will result in waste being left on site above levels that allow for unlimited use and unrestricted exposure. Institutional controls will be implemented for the selected remedy that include adequate zoning restrictions, conservation easements and other controls to prevent any future residential use of the site, and appropriate controls to prevent any future water-well drilling in the contaminated groundwater plume. These non-engineered instruments will be employed to minimize potential for human exposure, limit land/resource use, and/or protect the integrity of the remedy.

A Controlled Groundwater Area was established on October 31, 2009. A copy of the Final Order for the Controlled Groundwater Area is available in the Site Documents section below.

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Five-Year Reviews

EPA or the lead agency conducts five-year reviews following the start of a Superfund cleanup when contamination is left on the site. These reviews are repeated every five years. We use these reviews to determine:

  • How the remedy is working.
  • If the remedy remains protective of human health and the environment.

The third five-year review has been completed for the Montana Pole and Treating Plant (MPTP). The purpose of the review is to determine whether the remedy at the site, as selected and implemented subsequent to the Record of Decision (ROD), is protective of human health and the environment. The methods, findings and conclusions of the review are documented in the five-year review report, which is available in the Site Documents section below.

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Site Documents

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Annual Sampling and Monitoring Reports

Presentation for the Citizens Technical Environmental Committee (CTEC), October 29, 2013

Third Five-Year Review Report (PDF), July 2011 (236 pp, 10.9 MB)

Final Order – Controlled Groundwater Area, October 2009

Preliminary Site Closeout Report, September 2001

Record of Decision (PDF), September 21, 1993 (79 pp, 157 K)

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Nikia Greene
Remedial Project Manager
U.S. Environmental Protection Agency
Region 8, Montana Office
Federal Building
10 West 15th Street, Suite 3200
Helena, MT 59626

Technical Assistance Grant Group

Citizens Technical Environmental Committee (CTEC)
Dave Williams, President
Janice Hogan, TAG Administrator
27 West Park Street
P.O. Box 0593
Butte, MT 59703-0593


Lisa DeWitt
Project Officer
Montana Department of Environmental Quality
1225 Cedar Street
P.O. Box 200901
Helena, MT 59620-0901
800-246-8198 (toll free in-state only)

Jeni Flatow
Information Specialist
Montana Department of Environmental Quality
1225 Cedar Street
P.O. Box 200901
Helena, MT 59620-0901
800-246-8198 (toll free in-state only)

Site Information Repository:

Montana Tech Library
1300 West Park Street
Butte, MT 59701

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Photo/Video Gallery

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The following links exit the site Exit

Citizens Technical Environmental Committee (CTEC)

Montana Tech Library

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