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Site Type: Proposed NPL
Updated September 2014
EPA conducted a Preliminary Assessment/Site Inspection at the Smurfit-Stone Mill site in 2011 and 2012 that identified environmental contamination at the site. As a result of this limited investigation, EPA is pursuing a thorough environmental investigation of the site, known as a Remedial Investigation, to determine the nature and extent of contamination. Currently EPA is identifying and notifying parties potentially responsible for the environmental contamination. EPA is working with these parties to develop a plan for the comprehensive Remedial Investigation, the first step toward cleaning up the site.
The Smurfit-Stone Mill was a large integrated pulp and paper mill that operated from late 1957 through early 2010. The former mill is located on the eastern bank of the Clark Fork River 11 miles northwest of the city of Missoula, in Missoula County, Montana, and covers approximately 3,200 acres. The mill is located approximately three miles south of the town of Frenchtown and, therefore, has often been referred to as the Frenchtown Mill.
The core industrial footprint of the mill site covers approximately 100 acres. Over 900 acres of the site consist of a series of unlined ponds used to store both treated and untreated wastewater effluent from the mill, as well as primary sludge recovered from treated wastewater. Some ponds initially used to store wastewater were subsequently drained and used for the land-filling of various solid wastes produced at the mill. The site includes landfills used to dispose of solid wastes including general mill refuse, boiler fly ash, lime kiln grits, ragger wire and asbestos.
The site began operation as a pulp mill in the fall of 1957. Later expansions and improvements allowed the facility to produce paper, primarily rolls of kraft linerboard that is used in the production of corrugated containers (i.e., the outside layers of cardboard boxes). Linerboard produced at the mill was shipped to box plants, where it was used to make a variety of corrugated containers. The mill ceased operations in January 2010.
Various hazardous chemicals were used or produced on-site, including high pH fluids as part of the pulping process and bleaching chemicals, to remove color, when desired. The use of chlorine for the bleaching of pulp produces chlorinated organic compounds, including dioxins and furans, through the reaction of chlorine with residual lignin.
Source areas at the site confirmed through chemical analysis include two sludge ponds, an emergency spill pond, an exposed soil pile adjacent to landfill A, one wastewater storage pond and a soil land farming area. These were the only areas sampled, as they were determined to have the highest potential for containing hazardous substances, or, in the case of the wastewater storage pond, were determined to be the most at risk in the event of a catastrophic flood. Additional potential areas of interest at the site that have not been sampled include two sludge ponds, 11 wastewater storage ponds, three wastewater treatment aeration basins, two polishing ponds, the industrial core and log loading facilities.
The assessment revealed elevated levels of dioxins, furans and metals, including manganese, arsenic, lead, barium and cadmium in a series of soil samples collected from sludge ponds and wastewater holding ponds. Semi-volatile organic contaminants including naphthalene, methylphenol and phenanthrene were detected in soil samples as well.
Analytical results indicate elevated concentrations of dioxins and furans in the sediment of the Clark Fork River. Although no contaminants of concern were detected in domestic wells sampled near the site, shallow groundwater sampled at the site had elevated concentrations of dioxin and furan congeners, and metals including manganese and arsenic greater than Maximum Contaminant Levels and/or cancer risk screening concentrations.
Potential Site Risk
|Media Affected||Contaminants||Source of Contamination|
|surface soils (former sludge, wastewater and emergency spill ponds)||dioxins, furans, various metals including arsenic, cadmium, lead and manganese; semi-volatile organic compounds such as methylphenol, di-n-butyl phthalate, phenanthrene and naphthalene||direct contact with primary sludge, wastewater|
|surface water||dissolved manganese||primary sludge and wastewater ponds|
|river sediments||dioxin, furans||primary sludge and wastewater ponds|
|groundwater||dioxins, furans, various metals including manganese, arsenic, chromium and lead||leaching from primary sludge and waste water ponds|
The data confirm that contaminants including dioxins, furans, arsenic and manganese are present in the surface and subsurface soils at the site. These contaminants have also migrated to groundwater and the sediments of the Clark Fork River.
Dioxins and furans are the short names for a family of toxic substances that all share a similar chemical structure and health effects. Studies have shown that exposure to dioxins at high enough levels may cause a number of adverse health effects, including cancer.
EPA considers 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8 TCDD), 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin (1,2,3,4,6,7,8-HpCDD), 1,2,3,6,7,8-hexachlorodibenzo-p-dioxin (1,2,3,6,7,8-HxCDD) and 2,3,4,7,8-pentachlorodibenzofuran (2,3,4,7,8-PeCDF) to be hazardous substances. All four have been detected in sediments of the Clark Fork River, in the groundwater beneath the site, and in surface soils within the Smurfit-Stone Mill site. While a formal risk assessment has not been conducted, potential risks include ecological impacts, human food chain exposures and further contaminant migration.
An Analytical Results Report for a Combined Site Inspection and Removal Assessment was completed for the Smurfit-Stone Mill site in August 2012. Results from that report are summarized here. The full report for this investigation, as well as other investigations, is available in Site Documents below.
Soil Exposure Pathway – Soil samples were collected from sludge ponds, wastewater holding ponds and an emergency spill pond at the site. Samples were not collected from landfills at the site. Multiple congeners of dioxin were detected at levels greater than background concentrations. Metals and other inorganics, such as arsenic and manganese, were detected above background concentrations in two sludge ponds. Sludge ponds 3 and 17, and emergency spill pond 8, had the highest concentrations of contaminants of the locations sampled on the site. It should be noted that only a subset of ponds at the site were sampled.
Groundwater Migration Pathway – Shallow groundwater at the site had detections of multiple dioxin congeners and manganese. Arsenic was also present in the shallow groundwater at levels exceeding federal drinking water standards. Nearby down-gradient and cross-gradient domestic wells draw water from a deeper aquifer, and the wells that were sampled did not show any indication that they are currently impacted by the site.
Surface Water Migration Pathway – Sediments from the Clark Fork River had detections of multiple dioxin and furan compounds at higher than background concentrations. Additionally, dissolved manganese in the surface water was detected at higher than background concentrations. This stretch of the Clark Fork River is used by anglers. Fish tissue samples were not collected as part of the site assessment. With the limited amount of data captured as part of this sampling event, it is unknown if bioaccumulation of these contaminants is a concern.
Air Migration Pathway – Air samples were not collected as part of this sampling event. It has been reported to MDEQ and Missoula County Health Department that fugitive dust emissions have occurred since operation at the site has ceased and the ponds have dried up. These dusts may contain similar compounds as those detected in other surface soil samples from the site.
EPA proposed the Smurfit-Stone Mill site to the National Priorities List (NPL) in 2013. EPA continues to review public comments received on the proposal. In regard to ongoing work, EPA is currently pursuing a thorough environmental investigation of the site, known as a Remedial Investigation. The Remedial Investigation will determine the nature and extent of contamination, delineate the contamination source areas and determine how contaminants may impact human health and the environment. The results of the Remedial Investigation are used to justify cleanup decisions at the site. EPA is identifying and notifying parties potentially responsible for the environmental contamination and will be working with these parties to develop a plan for a comprehensive Remedial Investigation in an efficient manner. Throughout, EPA and the community will work collaboratively to determine a path forward to ensure that the site is fully characterized and any necessary cleanup occurs in a timely manner.
You will need Adobe Reader to view some of the files on this page. See EPA's PDF page to learn more.
Federal Register notice of National Priorities List, Proposed Rule No. 59 (PDF), December 12, 2013(9 pp, 254 K)
Federal Register notice of National Priorities List, Proposed Rule No. 58 (PDF), May 24, 2013(8 pp, 226 K)
Letters supporting NPL proposal from Montana Governor Schweitzer, the Confederated Salish and Kootenai Tribes Tribal Council, Missoula County Commissioners, Missoula County Board of Health and the Missoula County Water Quality Advisory Council, November–December 2012
Public Presentation: Overview of EPA Activities, November 8, 2012
Results Fact Sheet, November 8, 2012
Frequently Asked Questions
- 1. How did the EPA learn about the site?
After the Smurfit-Stone Mill closed and sat vacant for most of a year, the Montana Department of Environmental Quality (MDEQ) requested that EPA conduct a preliminary assessment and site inspection (PA/SI) to determine environmental impacts from the former operation.
- 2. What is the EPA doing?
EPA completed a preliminary assessment and site inspection in September 2011 and August 2012, respectively, at the request of Missoula County and Montana Department of Environmental Quality. A site inspection includes environmental sampling to determine what wastes are present at the site and if the waste is migrating off-site. EPA collected samples from the surface soils and subsurface soils at the site, as well as from the groundwater, nearby domestic wells and surface water and sediment samples from the Clark Fork River, which flows by the western edge of the site. The analytical data from these samples has been included in EPA’s Analytical Results Report, which can be found in Site Documents below.
EPA proposed that the site be added to the National Priorities List (NPL) in 2013, making it eligible for additional study and cleanup resources under the Superfund program. EPA continues to respond to public comments received on that proposal.
EPA is currently identifying and notifying parties potentially responsible for the contamination. EPA is working with these parties to plan a comprehensive Remedial Investigation, the first step toward cleaning up the site.
- 3. What contaminants have been found at the site?
The data we have collected indicate multiple contaminants present above background conditions in the surface and subsurface soils at the site. Various dioxin and furan compounds, common byproducts of bleaching operations, were detected in the sludge ponds soils, emergency spill pond soils and the wastewater storage pond soils. Arsenic, manganese, phenanthrene, di-n-butyl phthalate, cadmium, lead, zinc and 4-methylphenol were detected in the emergency spill pond or a sludge pond. Based on the sampling results, EPA does not believe there is an imminent human health danger posed by the site. The ponds with the highest concentrations of contamination are sludge ponds 3 and 17, and emergency spill pond 8. The primary treatment clarifier sludge was disposed of in the sludge ponds, so it makes sense that these areas have the highest concentrations of contamination of all the sample locations on the site. Soils in landfills at the site were not sampled, but groundwater was sampled at sites believed to be down-gradient of the landfills.
- 4. Have any contaminants migrated from the site to the groundwater or Clark Fork River?
Yes. Multiple dioxin and furan compounds have been detected in groundwater and in sediments in the Clark Fork River. Arsenic, chromium, manganese and zinc were detected in the shallow groundwater beneath the site. Nearby domestic wells did not appear to be impacted. Manganese was detected in the stretch of the Clark Fork River that is on the western edge of the site. EPA does not believe there is an imminent human health danger posed by the site.
- 5. Does an emergency situation exist?
No. While documented releases to the groundwater and Clark Fork River exist, sampling data does not indicate that an emergency situation currently exists.
- 6. Is drinking water in the area safe?
At this time EPA is not aware of any people who are drinking contaminated water. Nearby drinking water wells were sampled and did not show any evidence of impact from the site. Missoula’s water supply comes from upstream sources and Frenchtown’s water supply is a groundwater source further down-gradient than the sampled domestic wells.
- 7. Are the fish and crayfish in the area and down river safe to eat?
No fish or crayfish studies were conducted during EPA's site assessment. A thorough risk assessment, including the evaluation of human food chain concerns, would be conducted as part of a Remedial Investigation.
- 8. I’ve seen dust blowing off of the site. Have air samples been collected?
No air samples have been collected as part of the site assessment to determine the contaminants present in the dust. It is possible that the soil migrating off of the site might contain similar contaminants as the surface soils detected elsewhere on the site. This pathway of concern would be investigated as part of the Remedial Investigation.
- 9. What would happen if the site flooded?
While flooding is a possibility and concern, we have yet to fully characterize the site and thus cannot speculate what would happen in the event of a flood. Flooding hazards would be evaluated as part of a Remedial Investigation.
- 10. Is this a Superfund Site?
The site has been proposed by EPA to be included on the Superfund National Priorities List (NPL), but the proposal has not been finalized.
- 11. Does the site qualify for the National Priorities List (also known as Superfund)?
Yes. Based on documented impacts to the Clark Fork River and shallow groundwater, the site does qualify for the NPL.
- 12. When can the site be finalized to the NPL?
Sites are finalized to the NPL via a formal rulemaking process that typically takes place twice each year, in the spring and fall. EPA received public comments on its proposal to add the Smurfit-Stone Mill site to the NPL. At this time, EPA continues to respond to public comments. EPA will make a final decision once all comments have been considered.
- 13. Can the EPA oversee and ensure that cleanup occurs outside of the NPL process?
The Superfund Law provides EPA with the flexibility to work with parties who caused or contributed to the contamination at the site to lead the Remedial Investigation and cleanup effort. EPA is able to oversee and ensure that a thorough environmental investigation of the site occurs.
- 14. How soon could cleanup start?
A thorough investigation of the nature and extent of the environmental contamination at the site must take place. This kind of investigation will inform the decision of appropriate cleanup options.
- 15. How long will it take to clean up?
The length of the cleanup will be dependent on many factors, including the types of contaminants found and the extent of contamination. These factors have not been fully defined. The next step would be to conduct a Remedial Investigation to further define these unknowns.
- 16. How much will cleanup cost?
At this point we have no way of knowing, as we only have limited site data. Full site characterization is necessary prior to considering cleanup options and associated costs.
- 17. Who will be responsible for paying for any work at this site?
EPA adheres to the polluter-pays principal and will look for potentially responsible parties (PRPs) who caused or contributed to the contamination at the site to assist or pay for the investigation and cleanup of the environmental problems they have caused. If no PRPs are willing to assist or pay for the investigation and cleanup at the site, EPA may conduct the investigation and cleanup itself and recover the costs from potentially responsible parties after the cleanup is complete.
- 18. Can private investment and redevelopment occur if the site is placed on the NPL?
Yes. In fact, the EPA Superfund Redevelopment Initiative was developed for just this purpose and has been highly successful. Available tools and resources, as well as several case studies, can be viewed on our Superfund Redevelopment page.
- 19. Will EPA involvement impact redevelopment options?
No. Nothing would preclude redevelopment operations from continuing to take place at the site. EPA will ensure environmental contamination is taken care of. Removing the environmental concerns at the site is a positive step towards redevelopment.
- 20. Can someone buy contaminated property without becoming liable?
Yes. Beginning in 2002, a bona fide prospective purchaser (BFPP) may buy property with knowledge of contamination and maintain their protection from liability provided they conduct All Appropriate Inquiries (AAI0, comply with continuing obligations and can demonstrate no affiliation with a liable party.
- 21. What does "All Appropriate Inquires" mean?
"All Appropriate Inquiries," or AAI, is the process of conducting due diligence or a Phase I Environmental Site Assessment to determine prior uses and ownership of a property and assess conditions at the property that may be indicative of releases or threatened releases of hazardous substances. For liability purposes, a purchaser must conduct AAI prior to acquisition. More information is available on our All Appropriate Inquiries page.
- 22. What are continuing obligations?
In order to maintain their protection from liability, a new owner of a contaminated property must comply with the following continuing obligations: 1) comply with any land use restrictions and institutional controls; 2) take reasonable steps with respect to hazardous substance releases; 3) provide full cooperation, assistance and access to persons that are authorized to conduct response actions or natural resource restoration; 4) comply with information requests and administrative subpoenas; and 5) provide legally required notices.
Site Assessment Manager
U.S. Environmental Protection Agency, Region 8
1595 Wynkoop Street (EPR-B)
Denver, CO 80202-1129
800-227-8917 ext. 312-6664 (toll free Region 8 only)
Community Involvement Coordinator
U.S. Environmental Protection Agency, Region 8
1595 Wynkoop Street (OC)
Denver, CO 80202-1129
800-227-8917 ext. 312-6601 (toll free Region 8 only)