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Congressional District # 08


EPA ID# MND057597940
Last Updated: September, 2014

Site Description

The St. Regis Paper Company (St. Regis) Superfund site occupies 125 acres within the exterior boundaries of the Leech Lake Band of Ojibwe Indian Reservation in the city of Cass Lake in Cass County, Minnesota. The site is located north of the Chippewa National Forest and west of Pike Bay and Cass Lake.

The St. Regis Paper Company began wood treatment activities at the site in the 1950s while leasing the land from the Great Northern Railroad (now the Burlington Northern Santa Fe Railway Company (BNSF)). The company pressure-treated lumber with creosote, pentachlorophenol (PCP), and copper chromium arsenate and discharged wastewater from these processes into a number of disposal ponds located at the site. Between 1957 and 1960, wastewater and sludges were hauled from the ponds to a pit within the former Cass Lake city dump and burned. The disposal from the ponds occurred almost daily at an estimated rate of 500 gallons per day for a total of 547,500 gallons over the three-year period. From 1960 to 1975, the company hauled unknown quantities of sludge to the city dump pit. The pit, containing ash and unburned residuals, was eventually covered.

EPA placed the St. Regis site on the Superfund National Priorities List in 1984. In 1985, Champion International Corporation (Champion) acquired the property through a merger with the St. Regis Paper Company and closed site operations. A large portion of the former operations area was then deeded to the city of Cass Lake. Other portions of the site are located on BNSF and Cass Forest Products properties. Champion was acquired by International Paper (IP) in 2000 and IP is the current owner of the former Champion portion of the St. Regis site.

Site Responsibility

The St. Regis site is being addressed through potentially responsible party (PRP) actions under state and federal oversight. EPA conducts oversight of PRP work with assistance from its support agency partners, the Leech Lake Band of Ojibwe (LLBO) and the Minnesota Pollution Control Agency (MPCA).

Threats and Contaminants

Groundwater, soil, and sediment on and in the vicinity of the St. Regis site have been contaminated with polycyclic aromatic hydrocarbons (PAHs), heavy metals, and pentachlorophenol (PCP). Dioxins and furans, impurities in PCP, are also chemicals of concern (COCs). 

Human exposure to dioxins and the other COCs at the site could occur through ingestion of contaminated soil and dust or groundwater. Long term exposure could cause cancer or have other toxic effects.

Cleanup Progress

In 1986, MPCA signed two Minnesota Enforcement Decision documents that outlined its selected response actions for the cleanup of the St. Regis site. These actions included construction of groundwater extraction wells and a treatment facility, removal of contaminated materials from the Cass Lake City Dump Pit, construction of an on-site vault to hold contaminated soil and materials from the city dump pit, and an extension of the Cass Lake municipal water system.

In 1987, then-owner Champion constructed groundwater extraction wells at both the treatment facility area and the city dump area. The contaminated groundwater is extracted and treated on site and then discharged into a channel between Pike Bay and Cass Lake. The on-site containment vault was constructed to contain 37,500 cubic yards (yd3) of contaminated soil and sludge from the wastewater lagoons and 4,500 yd3 of contaminated soil and sludge from the city dump pit. Current owner IP has monitored and maintained the groundwater treatment system and soil vault since 2000.

EPA conducted a Five-Year Review (FYR) at the St. Regis site in 1995 and in 2000, and conducted field sampling work in October 2001 to collect additional data, to evaluate whether the selected response actions at the site were protective of human health and the environment. The 2001 sampling results showed that dioxin was present at levels above Superfund Removal Action Levels in shallow soils on the site. In August 2003, IP conducted additional confirmatory and contaminant delineation sampling under an EPA order. IP and BNSF then conducted removal actions on shallow soils with dioxins levels above above 1 part per billion (ppb) Toxicity Equivalent (TEQ) during 2004, 2005, and 2006 under EPA orders.

EPA also ordered IP to conduct a Human Health and Ecological Risk Assessment at the site. In 2004, IP sampled area soil, house dust, sediment, surface water, plants, invertebrates, and fish in support of the human health and ecological risk assessments.  In 2005, after analysis of the data from the sampling, EPA decided that an interim cleanup approach was needed for dioxin and arsenic contamination in residential settled dust that was above screening levels. The interim cleanup actions included an initial comprehensive cleaning of site area residences that included carpet replacement, HEPA vacuum cleaning, wet wiping, steam cleaning of soft furniture, and cleaning of draperies and rugs. In addition, supplemental periodic cleaning of homes, clean soil yard cover, and dust suppression to the unpaved roads was required. In 2006, under an order from EPA, IP conducted all initial cleanings, the yard work, dust suppression, and continues the periodic house cleanings. Periodic cleanings continue to date.

EPA conducted a FYR at the site in 2005 and concluded that additional information was needed to determine whether the groundwater remedial action was protective of human health and the environment.  IP drilled new soil borings and monitoring wells in 2006, 2007-2008, and 2009 and defined the extent of a tarry liquid in the City Dump plume. IP also conducted a site-wide pumping test and an investigation near groundwater wells owned and operated by the LLBO to determine the effectiveness of the till aquitard between the contaminated upper aquifer and the lower aquifer from which the Band takes drinking water.

In 2008, EPA approved the human health portion of the risk assessment and concluded that there are unacceptable risks to human health and the environment from contaminated soil at the site. EPA and the PRPs then signed an Administrative Order on Consent for a Feasibility Study (FS) to develop remedial alternatives for soil clean up at the site in September 2008. EPA approved the FS Report in April 2011 and announced its preferred remedy for contaminated soil in a Proposed Plan it issued in June 2011 for comment. EPA’s agency partners and many residents of the Cass Lake area opposed the proposed remedy, and the agency partners asked EPA to require IP to conduct additional soil sampling before EPA selected a remedy. To engage area stakeholders, EPA formed a soil technical workgroup to help plan the collection of additional soil data. Additional soil samplng was planned and completed in 2012 and 2013 and EPA is now working with its agency partners and the PRPs to revise the FS report by the end of 2014. In 2015, EPA plans to either issue a revised proposed plan for public comment or a Record of Decision to select the 2011 proposed remedy.

EPA conducted a FYR in 2010 and found that for the groundwater treatment remedy, hydraulic capture was incomplete in the former operations area and possibly also in the City Dump burn pit area. IP collected groundwater and soil samples between 2012 and 2014 to evaluate contaminant plume capture in these areas. IP is also generating a new groundwater model under EPA oversight to evaluate the overall effectiveness of the groundwater extraction and treatment system.

The 2012-2013 supplemental soil investigation found high levels of site contaminants and visually contaminated soil down to the water table in the southwestern area of the site where waste was historically dumped. IP collected more soil and groundwater samples in early 2014 to further assess groundwater quality in this area and will collect additional samples in fall 2014 or spring 2015 to continue the investigation.

EPA also plans to complete the fifth FYR of the St. Regis site in June 2015.

Success Story

During the past 9 years, the level of effort on this site has been very high from EPA, state and Tribal regulators, the local community, and the potentially responsible parties.  Removal actions and interim remedial actions have been taken to reduce health risks to the local residents while EPA works to select a final cleanup remedy. 

Community Involvement

EPA held a public meeting in July 2012 regarding the additional sampling that will be done before a final soil cleanup action is selected. EPA sent the first issue of a bi-annual newsletter in March 2013.

Congressional Interest

Congressman James Oberstar and Senator Klobuchar have maintained an interest in the St. Regis site. State Representative John Persell is the Superfund Coordinator for the Leech Lake Band of Ojibwe. Staff from Senator Al Franken’s office requested information on the Human Health and Ecological Risk Assessment in November 2012, and requested additional information from EPA in August 2013.

Property Reuse

The city of Cass Lake zoned the former operations area and much of the adjacent properties as commercial/industrial in January 2006. The surrounding residential properties are zoned residential. In 2012, Cass Lake announced a draft plan to redevelop the city-owned property on the site. In December 2013, the PRPs informed EPA of a tentative plan to prepare 5 acres of the site for a propane distribution facility.


Remedial Project Manager, U.S. EPA
leslie patterson (patterson.leslie@epa.gov)
(312) 886-4904

Community Involvement Coordinator, U.S. EPA
heriberto leon
(312) 886-6163




Site Profile Information

This profile provides you with information on EPA's cleanup progress at this Superfund site.


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