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Proposed Plan
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St. Regis Paper Company Superfund Site
Leech Lake Reservation, Minnesota
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Community Participation
EPA provides information regarding the St. Regis
Paper Company Superfund site to the community by
maintaining an Administrative Record for the site,
updating the St. Regis site web page (please see
www.epa.gov/superfund/st-regis-paper), sending fact
sheets to those on our site mailing list, and publishing
announcements in The Bemidji Pioneer and Cass Lake
Times.
Through these means, EPA encourages the public to
gain a more comprehensive understanding of the
Superfund activities that have been conducted at the
site.
EPA maintains the site Administrative Record, which
contains the information EPA used to develop the
preferred alternative, at the following locations:
Cass Lake Public Library EPA Region 5
223 Cedar Avenue Records Center,
Cass Lake, MN 56633 7th floor
77 W. Jackson Blvd.
Leech Lake Band of Chicago, IL 60604
Ojibwe Division of
Resource Management Cass Lake City Clerk
6350 Highway 2 NW 332 Second St. NW
Cass Lake, MN 56633 Cass Lake, MN 56633
EPA will be accepting written comments from the
public on this Proposed Plan from March 28, 2016 to
May 27, 2016. Comments may be sent to:
Heriberto Leon
Community Involvement Coordinator
By fax: 312-697-2754
By email: leon.heriberto@epa.gov
By U.S. mail: U.S. Environmental Protection Agency
Mail Code SI-7J
77 W. Jackson Blvd. Chicago, IL 60604
1 Introduction
The U.S. Environmental Protection
Agency (EPA), in consultation with
the Leech Lake Band of Ojibwe
(LLBO) and the Minnesota Pollution
Control Agency (MPCA), is issuing
this Proposed Plan to present its
preferred cleanup method for
addressing dioxin-contaminated soil in
residential areas at the St. Regis Paper
Company Superfund site ("St. Regis
site" or "Site") on the Leech Lake
Reservation (Cass Lake), Minnesota.
EPA refers to the residential areas as
"operable unit 7" (OU7) of the St.
Regis Site.
EPA's recommended cleanup plan is
Alternative 15B, which consists of
the excavation of contaminated soil
from residential properties, backfilling
the excavations using clean soil, and
managing most of the excavated soil
in an on-site facility. Heavily-
contaminated soil would be trucked
off site for disposal. EPA would also
monitor the stored soil. The estimated
total cost of Alternative 15B is $18.5
million. It would take about three
construction seasons to complete the
residential area soil cleanup work.
EPA will explain the rationale for
proposing the preferred alternative in
this document, as well as describe all
the cleanup alternativesevaluated to
address OU7. This document also
describes St. Regis site history,
including previous investigations and
response actions performed.
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EPA, as the lead agency for the St. Regis site, is issuing this Proposed Plan as part of its public
participation responsibilities under Section 117 of the Comprehensive Environmental Response,
Compensation, and Liability Act (CERCLA) of 1980, as amended, 42 U.S.C Section 9617,
commonly known as Superfund, and Section 300.430(f)(2) of the National Oil and Hazardous
Substances Pollution Contingency Plan (NCP). The LLBO and MPCA are providing support.
This Proposed Plan summarizes information from the December 2015 Supplemental Feasibility
Study (SFS) Report and other documents that comprise the site Administrative Record. EPA
encourages the public to review the Administrative Record to gain a more comprehensive
understanding of the cleanup and investigative activities that have been conducted at the site.
EPA, in consultation with LLBO and MPCA, will select a remedy to clean up OU7 in a
document called a Record of Decision (ROD) after reviewing and considering all information
submitted during a 60-day public comment period. The ROD will include a Responsiveness
Summary that summarizes EPA's responses to public comments on this Proposed Plan. EPA
may modify the preferred alternative or select another response action presented in this Proposed
Plan based on new information or public comments. Therefore, the public is encouraged to
review and comment on all the alternatives presented in this Proposed Plan. The public is
encouraged to review the supporting documents for the St. Regis Paper Company site at any of
the following locations: the Cass Lake Library, the LLBO Division of Resource Management,
and the Cass Lake City Clerk's Office. EPA will hold a public meeting at the Cass Lake-Bena
Elementary School at 15 4th Street NW, Cass Lake, Minnesota, on Saturday, April 9, 2016, at
2:00 p.m. to present the alternatives evaluated in this proposed plan and take public comments at
the meeting.
This would be the final remedial action proposed for OU7. EPA plans to address the remainder
of the St. Regis site at a later date.
2 Site Background
2.1 Site Location and Description
The St. Regis site is located in the city of Cass Lake, Cass County, Minnesota and is fully within
the exterior boundaries of the Leech Lake Reservation (see Figure 1). The site is located on
approximately 125 acres of commercial and railroad property that were used by a wood
treatment facility as well as some surrounding residential properties. Creosote and other
chemicals were used to treat wood, and wastewater was placed in ponds and occasionally used
for irrigation. Sludge from the wood treatment process was disposed of on the eastern edge of the
site and was also burned in a waste pit at the Cass Lake City Dump.
EPA placed the St. Regis Paper Company site on the National Priorities List (NPL) in 1984 and
is currently managing the site in several operable units (see Figure 2). OU1 consists of the
northern former facility operations area, OU2 is a former operations area to the southwest of
OU1, and OU3 is the city dump site. OU7 is comprised of residential areas and the LLBO
Department of Resource Management property, although many of the residential properties are
vacant. Some of the OU7 properties are occupied by residents and small businesses. For
administrative convenience, some phases of work at the Site were assigned OU numbers 4, 5 and
6, but these were not official designations and do not correspond to areas of the Site. Portions of
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the site are owned by International Paper Corp. (IP), BNSF Railway Company (BNSF), the City
of Cass Lake, and Cass Forest Products, Inc.
Figure 1: The St. Regis Paper Company Superfund Site
Figure 2: St. Regis Paper Company Site Operable Units (OU3 not shown)
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2.2 Site History
The wood treatment facility operated from about 1958 until 1985. Between 1985 and 1988, the
former owner/operator, Champion International Corp. (Champion), conducted a remedial
investigation (RI) and feasibility study (FS) at the site and then performed several remedial
actions under MPCA oversight. Champion excavated visibly contaminated soil and sludge and
placed it into a RCRA Subtitle C-compliant unit (containment vault) it had constructed on site
(see Figure 3). Champion also addressed groundwater contamination by constructing and
operating a groundwater pump-and treat system. Champion was subsequently acquired by IP.
Figure 3: Previous soil excavations, cover/grading, and vault construction
2.3 EPA Early Response Actions
In 1995, EPA became the lead agency for the St. Regis site. In 2000, EPA issued a Five-Year
Review Report for the St. Regis site in which it raised concerns about residual contaminant
levels in site soil. In response, in 2001 EPA sampled site soil, sediment, surface water, fish, and
groundwater to analyze them for site contaminants. In 2003, EPA required IP to sample soil in
the former operations areas. In 2004, EPA required IP to collect additional samples of soil,
sediment, surface water, house dust, groundwater, plants, and animals, and to use the analytical
results to prepare a Human Health and Ecological Risk Assessment (FIHERA) to determine the
potential current and future effects of wood treating contaminants on human health and the
environment.
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Between 2004 and 2006, EPA oversaw several soil removal actions on OU1 properties having
surface soil dioxin concentrations greater than 1,000 nanograms per kilogram (ng/kg or "parts
per trillion" (ppt)). In 2004, IP excavated shallow soil on city-owned property that exceeded
1.000 ppt dioxin and backfilled the excavations with clean soil (Figure 3). In 2005, BNSF,
excavated shallow soil on its property that exceeded 5,000 ppt dioxin and covered and fenced
areas that exceeded 1,000 ppt dioxin. In 2006, IP addressed two areas on a commercial property
operated by Cass Forest Products property on which soil exceeded 1,000 ppt by either capping
with fabric and gravel or fencing the area to prevent exposure. In all, these removal actions
resulted in the excavation and off-site disposal of more than 3,900 tons of dioxin-contaminated
soil from the former operations areas.
In the residential area (OU7), EPA found that indoor settled dust samples collected from five
homes exceeded the screening level (SL) value of 2 nanograms per square meter for dioxin (the
SL value is based on the New York World Trade Center response). Thus, in 2005, EPA issued an
interim Record of Decision (ROD) that called for cleaning the interiors of residences, applying a
3-inch layer of clean soil and grass on yards, and applying dust suppressant to unpaved roads.
EPA subsequently ordered IP to conduct this work and IP continues to periodically clean the
interiors of residences and apply dust suppressant to unpaved roads as required.
In 2011, IP completed the HHERA for EPA approval. The HHERA estimated potential health
risks for residential-use, commercial-use, recreational-use, tribal lifeway, and ecological
pathways for exposure to site contaminants in soil, indoor dust, shallow groundwater, sediment,
forested property, wetland surface waters, homegrown produce, fish, and wild rice. EPA then
issued a proposed cleanup plan to address potential health risks posed by contaminated soil, but
it did not subsequently issue a ROD to select a remedy. Instead, based on public comments
received, EPA worked with the LLBO, MPCA, IP, and other stakeholders to take further soil
samples to better determine the extent of contamination. IP took the extra soil samples in 2013
and 2014 and completed a SFS Report for soils in December 2015.
3 Site Characterization
3.1 Contaminants of Concern
EPA has identified dioxin and polycyclic aromatic hydrocarbons (PAHs), expressed as benzo(a)
pyrene equivalent [B(a)PE], as contaminants of concern (COCs) in soil. These compounds are
being designated as COCs because they are persistent and present in the soil at concentrations
above risk-based levels. Dioxin was an impurity in pentachlorophenol (PCP), a chemical that
was used in the wood treatment process as a preservative and an insecticide. Dioxin has been
shown to be very toxic in animal studies and, in humans, can cause toxic effects and is a
probable carcinogen. PAHs are a group of chemicals formed during the incomplete burning of
coal, oil, gasoline, wood, garbage, or any plant or animal material. It is found in cigarette smoke,
soot, and creosote. Long-term, low level exposure to PAHs could cause carcinogenic and/or non-
carcinogenic human health effects.
Table 1 shows the range of concentrations of COCs in site soils by OU. Concentrations in the top
foot are listed independently of other depths because surface soil concentrations account for
direct contact risks to workers and residents.
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Table 1: Dioxin and B(a)PE Levels by Operable Unit and Depth
ou
Depth
(feet)
Dioxin Concentration Detected (ppt)
B(a)PE Concenti
(mg /
ation Detected
kg)
#of
Samples
Min
Max
Median
#of
Samples
Min
Max
Median
1
0-1
122
3.6
6,300
324
75
0.01
3.16
0.23
>1
110
0.10
23,700
1.0
100
0.001
26
0.001
2
0-1
26
3.9
834
185
26
0.007
9.73
0.163
>1
20
0.20
205
0.43
18
0.001
0.04
0.001
7
0-1
35
6.56
537
34
20
0.011
11.7
0.239
>1
34
0.13
2550
0.87
37
0.001
2.9
0.003
3.2 Site Geology
The St. Regis site is located in an area of the City of Cass Lake primarily used by industry but
containing residential properties. The terrain is relatively flat with sandy soil. The water table is
shallow and is generally less than 15 feet below ground surface.
4 SUMMARY OF SITE RISKS
IP conducted the HHERA to determine the current and future health effects caused by site
contaminants on human health and the environment. The EPA-approved HHERA estimated
potential health risks for residential use, commercial use, recreational use, tribal lifeways, and
ecological pathways for exposure to site contaminants in soil, indoor dust, shallow groundwater,
sediment, forested property, wetland surface waters, homegrown produce, fish, and wild rice.
The HHERA evaluated current and potential future residential exposure in OU7 because it is
zoned residential by the City of Cass Lake.
4.1 Human Health Risks
In assessing the risks to humans, contaminant screening levels for residential and
industrial/commercial workers were based on a target excess lifetime cancer risk (ELCR) of
1 x 10"6, or one additional instance of cancer in one million persons exposed over a lifetime, and
a noncancer hazard index (HI) quotient of one (1). The HI quotient is a way of expressing the
potential for noncarcinogenic health effects that may occur due to exposure to a dose of a
chemical. A HI quotient greater than one indicates that there may be a concern for potential
health effects. EPA's target acceptable cancer risk range is 10"6 to 10"4ELCR.
The HHERA found the following unacceptable risks to human health:
In OU7, potential increased risk of adverse noncarcinogenic health effects at one property
that may have a future child resident - HI = 2.
In OU1, potential increased risk of adverse noncarcinogenic health effects to a short-term
utility worker who digs a trench in the immediate vicinity of the groundwater extraction
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systems at the Site without adequate protective wear. These risks will be addressed in a
future remedial action.
The HHERA found that exposure to groundwater was an incomplete exposure pathway in OU7.
This means that residents and other persons in OU7 are not in contact with contaminated
groundwater.
Primary uncertainties in the HHERA are found in the collection and use of soil data, for example
use of sampled homes to represent unsampled properties, as well as in the assumptions made
concerning the carcinogenic potential of dioxin; characterization of tribal lifeways; and
quantifying exposure levels.
4.2 Ecological Risks
EPA evaluated the potential for adverse effects on ecological receptors by establishing baseline
conditions at the site and then calculating potential impacts based on factors such as exposure
levels of site contaminants and the potential effects that the chemicals could have on organisms.
As for human health risks, EPA calculates a hazard quotient (HQ) for organisms, with a
threshold value of 1. Generally, the higher the HQ, the greater the likelihood an effect will occur.
Although probabilities cannot be specified based on a point-estimate approach, an HQ of 1 is
usually regarded as indicating a low probability of adverse ecological effects. An HQ greater
than 1, however, does not imply that adverse effects will occur - only that adverse effects could
occur.
The HHERA evaluated ecological risks associated with the site former wood treating operations
at the site and found that one sample taken near the contaminated soil containment vault in OU2
was acutely toxic to soil invertebrates and had high values of Site-related contaminants. This
ecological risk will be addressed in a future remedial action. The HHERA found no unacceptable
ecological risks in soils in OU7.
4.3 Conclusion
It is EPA's judgment that the measures identified in the Preferred Alternative in this Proposed
Plan, or other active measures considered in the Proposed Plan, are necessary to protect public
health and the environment from actual or threatened releases of hazardous substances into the
environment at OU7.
5 SCOPE AND ROLE OF THE ACTION
The proposed action will address contaminated soil in OU7, which comprises residential
properties. EPA is addressing contaminated groundwater in OU1 and OU3 by an established
pump and treat remedy. Future remedial actions will address contaminated groundwater in OU2,
the risk of direct contact with groundwater to utility/construction workers in OU1, and
contaminated soil in OU1, OU2 and OU3.
EPA expects that this remedial action will be the final action in OU7.
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5.1 Principal Threat Waste
Principal threat wastes are those source materials considered to be highly toxic or highly mobile
that generally cannot be reliably contained or would present a significant risk to human health or
the environment should exposure occur. They include liquids and other highly mobile materials,
or materials having high concentrations of toxic compounds.
EPA has determined that dioxin and PAHs in OU7 soil do not constitute principal threat waste.
Although the maximum concentrations of dioxin and B(a)PE from some individual sample
points (as listed in Table 1) are high, the median concentrations in the top foot are more
representative of the levels to which exposure occurs. In addition, at the most contaminated OU7
property, the ELCR is less than 10"4 and the hazard index to one receptor is at most
approximately 2, which does not indicate highly toxic material. Dioxin and PAHs also are not
mobile in OU7 soil because they are not moving from the shallow layers of soil, where
contamination is greater, into the underlying soil that has much lower concentrations.
6 REMEDIAL ACTION OBJECTIVE
EPA developed the following Remedial Action Objective (RAO) to protect the public and the
environment from potential health risks posed by dioxin and PAHs in OU7 soil:
Prevent unacceptable potential risk to human health from future exposure to site-related
COCs in OU7 soil through ingestion of soil and garden produce, inhalation of soil and
indoor dust and dermal adsorption routes of exposure at residential properties in OU7.
The proposed action will reduce potential human health risks associated with exposure to
contaminated soil to below 10"6 ELCR. The RAO will be achieved by excavating and removing
contaminated soil and replacing it with clean soil so that exposure to residual contaminants is at
or below proposed target clean up levels.
7 PRELIMINARY CLEAN UP LEVELS
7.1 Contaminants of Concern
The COCs identified in the HHERA include dioxin and B(a)PE. These contaminants are
described in the Site Characterization section of this Proposed Plan.
7.2 Preliminary Remediation Goals
Preliminary Remediation Goals (PRGs) are used in developing and evaluating alternative
remedial actions for a site. Final cleanup levels will be established in the ROD. EPA developed
the proposed cleanup levels for the soil contaminants identified in the HHERA based on both
protective risk-based calculations in the HHERA and a review of federal and tribal regulations,
which are referred to as Applicable or Relevant and Appropriate Requirements (ARARs). Table
2 summarizes the PRGs, background concentrations, and estimated depths to reach PRGs in
OU7.
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Based on the results of the HHERA, EPA considers 63 ppt for dioxin (Level 2 PRG-R) and the
background level of 1.6 milligrams per kilogram (mg/kg (or "parts per million" (ppm); Level 1
and Level 2 PRG-R) for B(a)PE in soil to be protective of human health in OU7. These values
represent the middle of EPA's target risk range of 10"6 to 10"4 ELCR. EPA selected this level of
protection, 10"5 ELCR, based on uncertainties identified in the HHERA, including consideration
of LLBO tribal lifeways and uncertainties associated with estimating dioxin cancer risks.
In 2000, LLBO promulgated the Hazardous Substances Control Act (HSCA) which established
contaminant cleanup levels for Leech Lake Reservation lands. HSCA establishes a 10 ppt
cleanup level for dioxin in soil (Level 1 PRG), which represents approximately 2 x 10"6 ELCR
for residential use and is at the low end of EPA's target risk range. The dioxin soil remediation
value, as described in HSCA, is a potential ARAR for the proposed OU7 soil cleanup. Therefore,
in addition to considering alternatives that meet EPA's acceptable risk range, EPA considered
alternatives that lower the dioxin concentrations in surface soil to 10 ppt or less.
Table 2: Cleanup levels for COCs in OU7 soil
Chemical
Basis
PRG Level
Cleanup
Level
Background
(95%
percentile)
Estimated
Average Depth to
PRG in OU7 (ft.)
Dioxin
Regulatory
requirement;
HSCA
Level 1
10 ppt
7.5 ppt
2.0
Risk-based; 10"5
ELCR (residential)
Level 2-R
63 ppt
1.3
B(a)PE
Background
Concentration
Level 1
and Level
2-R
1.6 ppm
1.6 ppm
1.3
Figure 3 illustrates, of those properties that have been sampled, which ones are known to exceed
the Level 1 PRG. Figure 4 illustrates, of those properties that have been sampled, which ones are
known to exceed Level 2 PRG-R. For both figures, properties that are not shaded either yellow
or green have not yet been sampled but likely have contaminant levels similar to other adjacent
properties.
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Figure 3: OU7 Properties that exceed the Level 1 PRG.
Figure 4: Properties that exceed the Level 2 PRG-R.
8 SUMMARY OF REMEDIAL ALTERNATIVES
EPA considered six alternatives for addressing residential surface soil at the St. Regis Paper
Company site. The alternatives are summarized below and further explained in the SFS Report.
Each alternative was evaluated against EPA's nine criteria as described in Section 9.
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Table 3: Summary of the OU7 Remedial Alternatives
Alternative
Description of Alternative
S10
No further action.
Sll
Excavate soil on properties exceeding Level 2-R PRGs.
S12
Excavate soil on properties exceeding Level 2-R PRGs; place a 12 inch clean soil
cover on properties exceeding Level 1 PRGs.
S13
Excavate soil on properties currently in residential use exceeding Level 1 PRGs
and place a 12-inch clean soil cover on other properties exceeding Level 1 PRGs.
S14
Excavate soil on properties not owned by IP exceeding Level 1 PRGs, and place
12-inch clean soil cover on properties owned by IP exceeding Level 1 PRGs.
S15
Excavate soil exceeding Level 1 PRGs.
8.1 Common Elements
All of the alternatives, with the exception of the "No Action" alternative (Alternative S10),
contain common components. The shared features of Alternatives Sll through S15 include:
Excavation of soil on some or all properties in OU7 to the depth needed to reach the
selected PRG. Excavated areas would be backfilled with tested clean soil and
revegetated.
Two options for managing excavated soil: trucking to an off-site landfill (the "A"
alternatives), and containment on-site (the "B" alternatives).
o For the "A" alternatives, excavated soil would be tested and classified according
to its suitability for disposal in a RCRA Subtitle D landfill or RCRA Subtitle C
disposal facility.
o For the "B" alternatives, excavated soil would be tested and classified according
to its suitability for onsite consolidation, containment in a RCRA Subtitle D
landfill, or offsite disposal in a RCRA Subtitle C disposal facility.
All OU7 properties would be suitable for future residential use at the completion of the
remedial action.
Monitoring and control of air quality (dust) during construction.
Once construction is final, the interim remedy for OU7, which being performed by the
PRPs under a 2005 Unilateral Administrative Order, would no longer be performed.
Until soil in OU1 and OU2 is remediated, collection of soil samples from the OU7 soil
excavation or cover work in representative residential properties to confirm that no
recontamination from the adjacent OUs is occurring.
Alternatives S12, S13 and S14 also share the following features:
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Clean soil cover, rather than excavation, in a portion of OU7, comprised of a marker
material covered by the layer of clean fill and top soil, followed by vegetation.
Institutional Controls (ICs) in OU7 to restrict activities in the covered portions of the site
property to preserve the soil cover. For example, a deed notice might be filed on a
covered property that notifies future owners of the contamination below the cover, and
prohibits any digging below the cover unless proper precautions are taken.
8.2 Cleanup Alternative S10 - No action
Estimated Capital Cost: $0
Estimated O&M Cost: $0
Estimated Present Worth Cost (30 years): $0
Estimated Construction Timeframe: Not Applicable
Estimated Time to Achieve RAOs: Not Applicable
EPA includes a "No-Action" Alternative as a basis for comparison to the other cleanup
alternatives. Interim Action activities-house cleaning and dust suppression-would no longer be
performed. Since no action would be taken, this option would not protect human health and the
environment from either current or future risk.
8.3 Cleanup Alternative SI 1-A and -B
Estimated Capital Cost: $12,000,000 (A) /$7,900,000 (B)
Estimated O&M Cost: $62,000 (A) / $62,000 (B)
Estimated Present Worth Cost (30 years): $12,100,000 (A) / $8,000,000 (B)
Estimated Construction Timeframe: 1 year
Estimated Time to Achieve RAOs: 1 year
Alternative SI 1 would excavate contaminated soil above Level 2 PRGs-R, which for most
properties will be achieved in the first foot of excavation.
8.4 Cleanup Alternative S12-A and -B
Estimated Capital Cost: $14,200,000 (A) / $9,900,000 (B)
Estimated O&M Cost: $93,000 (A) / $93,000 (B)
Estimated Present Worth Cost (30 years): $14,300,000 (A) / $10,000,000 (B)
Estimated Construction Timeframe: 2 years
Estimated Time to Achieve RAOs: 2 years
Alternative S12 would excavate contaminated soil above Level 2 PRGs-R, which for most
properties will be achieved in the first foot of excavation, and would apply a clean soil cover to
properties with soil contamination that exceeds Level 1 PRGs but is less than Level 2 PRGs-R.
8.5 Cleanup Alternatives S13-A and -B
Estimated Capital Cost: $13,500,000 (A) / $10,200,000 (B)
Estimated O&M Cost: $96,000 (A) / $96,000 (B)
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Estimated Present Worth Cost (30 years): $13,600,000 (A) / $10,300,000 (B)
Estimated Construction Timeframe: 2years
Estimated Time to Achieve RAOs: 2 years
Alternative S13 would excavate contaminated soil that exceeds Level 1 PRGs on properties with
current residents and/or habitable buildings (see Figure 5), and would apply a clean soil cover to
other properties with soil contamination that exceeds Level 1 PRGs.
Figure 5: Properties in OL'7 with Current Residents and/or Habitable Buildings
(72 ou,
ฉ
[?yi0U2
400 800
| ] OU7
ieet
HI OU7 Occupied Residential Property
OPERABLE UNITS
St. Regis Paper Co. Site
QUI Ownership (by Area)
International Paper
8.6 Cleanup Alternatives S14-A and -B
Estimated Capital Cost: $22,500,000 (A) I $15,300,000 (B)
Estimated O&M Cost: $80,000 (A) / $80,000 (B)
Estimated Present Worth Cost (30 years): $22,500,000 (A) / $15,400,000 (B)
Estimated Construction Timeframe: 2years
Estimated Time to Achieve RAOs: 2years
Alternative S14 would excavate contaminated soil that exceeds Level 1 PRGs on properties not
owned by the Responsible Parties, and would apply a clean soil cover to other properties with
soil contamination that exceeds Level 1 PRGs. The expected remedy (excavation or clean soil
cover) for those OU7 properties that have been sampled is shown in Figure 6.
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Figure 6: Excavation and Cover of OU7 Properties under Alternative S141
8.7 Cleanup Alternatives S15-A and -B
Estimated Capital Cost: $29,900,000 (A) I $18,400,000 (B)
Estimated O&M Cost: $62,000 (A) / $62,000 (B)
Estimated Present Worth Cost (30 years): $30,000,000 (A) / $18,500,000 (B)
Estimated Construction Timeframe: 3 years
Estimated Time to Achieve RAOs: 3 years
Alternative S15 would excavate all soil on OU7 with contamination above Level 1 PRGs. No
ICs would be required.
9 COMPARISON OF ALTERNATIVES
EPA uses nine criteria to evaluate remedial alternatives in order to select a remedy:
Table 4: Evaluation Criteria for Superfund Remedial Alternatives
Threshold Criteria
1. Overall Protection of Human Health and the Environment determines whether an
alternative eliminates, reduces, or controls threats to the public health and the environment
through institutional controls, engineering controls, or treatment.
1 Properties in OU7 that are not shaded have not been sampled, but will receive remedial action under Alternative
S14 appropriate to each parcel's property ownership and contamination level.
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2.
Compliance with Applicable or Relevant and Appropriate Requirements (ARARs)
evaluates whether the alternative meets Federal and State environmental statutes, regulations,
and other requirement that pertain to the site, or whether a waiver is justified.
Balancing Criteria
3.
Long-term Effectiveness and Performance considers the ability of an alternative to
maintain protection of human health and the environment over time.
4.
Reduction of Toxicity, Mobility, or Volume of Contaminants through Treatment
evaluates an alternative's use of treatment to reduce the harmful effects of principal
contaminants, their ability to move in the environment, and the amount of contamination
present.
5.
Short-term Effectiveness considers the length of time needed to implement an alternative
and the risks the alternative poses to workers, residents, and the environment during
implementation.
6.
Implementability considers the technical and administrative feasibility of implementing the
alternative, including factors such as relative availability of goods and services.
7.
Cost includes estimated capital and annual operations and maintenance costs, as well as
present worth cost. Present worth cost is the total of an alternative over time in today's dollar
value. Cost estimates are expected to be accurate within a range of +50% to -30%.
Modifying Criteria
8.
State Acceptance considers whether the State agrees with EPA's analyses and
recommendations, as described in the RI/FS and the Proposed Plan.
9.
Community Acceptance considers whether the local community agrees with EPA's
analyses and preferred alternative. Comments received on the Proposed Plan are an important
indicator of community acceptance.
9.1 Comparison of Remedial Alternatives
The comparison of the OU7 cleanup alternatives with respect to the nine criteria is discussed
below and summarized in Table 8.
9.1.1 Overall Protection of Human Health and the Environment
Alternative S10, the "No Action" alternative, does not provide adequate protection because it
does not address the risks to human health and the environment identified in the HHERA.
Therefore, Alternative S10 is not discussed below, although the evaluation of the other criteria in
relation to Alternative S10 is shown in Table 10. All of the other alternatives would provide
adequate protection of human health and the environment by eliminating, reducing, or
controlling risk through excavation, cover, engineering controls and ICs.
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9.1.2 Compliance with ARARs
Alternative SI 1 does not meet all potential ARARs because it does not prevent exposure to soil
that exceeds the 10 ppt cleanup level for dioxin specified in HSCA. Therefore, Alternative SI 1 is
not discussed below, although the evaluation of the other criteria in relation to Alternative SI 1 is
shown in Table 10. Alternatives S12 through S15 all comply with all ARARs. Alternatives S12,
S13 and S14 achieve the HSCA dioxin cleanup level by means of a combination of excavation
and a soil cover; Alternative S15 achieves HSCA cleanup levels by excavation of contaminated
soil that exceeds the HSCA dioxin clean up level.
9.1.3 Long-term Effectiveness and Permanence
Unremediated soil in OU1 and OU2 will remain at the end of the remedial action for OU7, so
until these OUs are remediated, there is the potential for recontamination by deposition of soil
carried by wind or surface water runoff. However, follow-up sampling of the soil in OU7
properties until the adjacent OUs are remediated will provide assurance that the OU7 properties
remain under PRGs.
Both a clean soil cover and excavation can permanently reduce exposure to soil contamination.
Excavation removes contaminated soil permanently, while use of a clean soil cover requires ICs
and ongoing monitoring and maintenance of the soil cover to prevent exposure. Monitoring the
integrity of the clean soil cover compliance with ICs and is not difficult, as disturbed soil is easy
to identify and remedy. Factors in the evaluation of the long-term effectiveness of the soil cover
include the number of property owners of the area subject to ICs, the current and reasonably-
anticipated future uses of the properties, and the property owners' intended future uses of their
property and stated interest in implementing ICs.
In OU7, the anticipated future use of all property is residential. Alternative S12 would require
many different property owners to comply with ICs on many properties in OU7, while
Alternative S13 reduces this number by excavating all soil that exceeds Level 1 PRGs on
properties with a current resident or habitable residence. Alternative S14 would only require the
RP to comply with ICs. The RP would be required by an enforcement agreement with EPA to
place ICs on their property, and has unmediated access to these properties, so there is a high
degree of long-term effectiveness for soil cover as specified in Alternatives SI4, as well as the
excavation specified in Alternative SI5.
Off-site Disposal and On-site Soil Containment
The on-site disposal options rely on monitoring and maintenance activities to ensure that the
excavated and re-emplaced soil is properly contained. The on-site containment area is on
property owned by an RP, so access would be available to perform the ongoing monitoring and
maintenance.
A small percentage of excavated soil may contain high concentrations of mobile contaminants,
or present a potential leaching threat, and would not be placed in the containment area. The
containment area would be above the water table and would present the same conditions (redox,
pH, etc.) which currently characterizes the soil. Therefore, on-site management of the soil would
be very unlikely to increase the mobility of the contaminants.
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9.1.4 Reduction of Toxicity, Mobility, or Volume of Contaminants through Treatment
None of the proposed alternatives reduce the toxicity, mobility, or volume of the soil
contaminants through treatment. The large volume soils with residual levels of dioxin that is
being addressed in this remedy does not lend itself to treatment.
9.1.5 Short-term Effectiveness
Short-term effectiveness considers the amount of time until remedy completion and the potential
adverse effects to the community, workers, and the environment during remedy implementation.
Table 5 compares the estimated construction time of the alternatives. A minimum of two years is
estimated for Alternatives S12 through S14 due to the relatively short construction season in
northern Minnesota, and an additional year is required for Alternative SI5.
Table 5: Comparison of Estimated Construction Time, Time to Meet RAOs, and Soil
Excavation Volume
Alternative
Sll
S12
S13
S14
S15
Estimated Construction Time
1 year
2 years
3 yrs
Estimated time to meet RAOs
1 year
2 years
3 yrs
Estimated Soil Excavation
Volume (cubic yards)
36,800
36,800
24,900
67,400
111,100
Greater volumes of soil excavation, stockpiling, off-site transport, and import of clean soil for
cover increase the potential for adverse effects to the community and workers. Two of these
impacts are the potential to impact air quality from the temporary stockpiling of contaminated
soil and the potential risk to workers from earth-moving activities. Table 5 shows the estimated
volume of soil to be excavated for each alternative, which is an indication of the potential for
these adverse effects.
For all excavation alternatives, it is assumed that a small percentage of excavated soil will be
classified as hazardous waste and will have to be trucked to an incinerator in Texas,
approximately 1400 miles from Cass Lake. For the "A" alternatives, the remainder of the
excavated soil would be transported to a RCRA Subtitle D disposal facility in Buffalo,
Minnesota, approximately 150 miles from Cass Lake. For all cover alternatives, clean fill and top
soil that would be imported to the site would be trucked in from an assumed distance of 20 miles.
Table 6 shows the number of truck trips associated with those alternatives that have the most off-
site disposal (the "A" alternatives) and those with the least off-site disposal (the "B"
alternatives).
The most significant adverse potential impact to the public is the potential for traffic accidents
and deaths due to additional truck traffic. Alternatives with greater amounts of excavation, off-
site disposal, and clean soil import are associated with greater truck traffic.
The total distance trucks would have to travel for a given alternative may be correlated with the
risk of traffic fatalities by multiplying the total miles driven by the fatality risk per mile. Table 7
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presents the estimated fatality risk range from the truck traffic associated with each OU7
alternative. The low end of each range is calculated using the 2013 Minnesota Department of
Public Health mortality per mile statistic1, while the high end of each range is calculated using
the U.S. Department of Transportation fatality statistic for large trucks and buses2. For nearly all
alternatives, the risk of traffic fatality to a member of the public is greater than the risk posed by
unremediated surface soil at the St. Regis Site. Alternative S15-A for OU7 is associated with the
highest risk of traffic fatality, while Alternatives S13-B and S14-B are associated with the
lowest.
Table 6: Comparison of Estimated Truck Trips and Estimated Increased Fatality Risk
from Truck Traffic
Alternative
Truck Trips (at 15
cy/truck)
Range of Estimated Fatality Risk from Truck
Traffic
Sll
A
4,900
7.2 x 10"3 to 1.8 x 10"2
B
670
1.8 x 10"3 to 4.7 x 10"3
S12
A
6,700
7.7 x 10"3 to 2.0 x 10"2
B
1,800
2.2 x 10"3 to 5.5 x 10"3
S13
A
5,200
4.7 x 10"3 to 1.2 x 10"2
B
1,400
4.7 x 10"4 to 1.9 x 10"3
S14
A
10,000
1.2 x 10"2 to 3.1 x 10"2
B
1,500
2.1 x 10"3 to 5.3 x 10"3
S15
A
14,800
1.9 x 10"2 to 4.9 x 10"2
B
7,500
4.2 x 10"3 to 1.1 x 10"2
9.1.6 Implementability
All of the alternatives can be implemented. Implementation would be more difficult with larger
amounts of soil for off-site disposal due to the limited amount of appropriate landfill space
available in Minnesota. However, a larger number of property owners who must agree to
implement ICs on their properties would also increase the difficulty of implementation.
OU7 has multiple property owners who would need to place ICs on their properties in
Alternatives S12 and S13. For Alternative S14, only one property owner, who is a RP and would
be required by an enforcement agreement with EPA to place ICs on their property, would need to
do so. Alternative S15 does not require ICs of any property owners, but the greater volume of
soil to be excavated in Alternative S15 increases the difficulty of implementation of the "A"
alternative.
1 https://dps.mn.gov/divisions/ots/reports-statistics/Documents/2013-crash-facts.pdf
2 U.S. DOT, 2014, Large Truck and Bus Crash Facts 2012, U.S. DOT Analysis Division, Federal Motor Carrier
Safety Administration, June 2014.
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9.1.7 Cost
Table summarizes the total estimated costs of Alternatives S12 through S15 for OU7.
Alternative S15-A is the most costly at $30.2 million, while alternative S12-B is the least
expensive alternative at $10.0 million.
Table 7: Comparison of Estimated Total Costs1
Cost (Millions)
Alternative
A
B
S12
$14.3
$10.0
S13
$13.6
$10.3
S14
$22.5
$15.4
S15
$30.0
$18.5
9.1.8 Tribal/State Acceptance
EPA conducted government-to-government consultation with LLBO in June and July 2015 on
several Site issues, including concerns with the SFS Report and EPA's preliminary selection of
its preferred alternative for OU7. LLBO has not clearly expressed either agreement or
disagreement with EPA's preferred alternative, S15-B. LLBO supports excavation of all soil that
exceeds HSCA cleanup levels and disposal of the excavated soil off of the Leech Lake
Reservation; this is consistent with Alternative S15-A. LLBO believes that EPA does not have
adequate information to make the proposed decision on soil in OU7 because LLBO believes: 1)
the Site is inadequately characterized, and 2) the SFS Report is of poor quality and does not
consider leaching threats to groundwater. LLBO has noted in communications to EPA that
alternatives that involve a cover (Alternatives SI2, SI3, and SI4) are not consistent with the
intent of HSCA. LLBO also noted concerns regarding their potential future acquisition and use
of site properties that have residual contamination and require the placement of ICs. LLBO
believes that selection and implementation of alternatives that involve a cover directly
compromise potential future options to make full use of its reservation lands and place them in
trust. However, at the conclusion of formal government-to-government consultation in July
2015, LLBO expressed cautious optimism that the EPA's preferred S15-B remedy for OU7 was
acceptable with the understanding that EPA is committed to further studying and addressing the
remaining soil contamination issues in OU1 and OU2, as well as following up on the
groundwater contamination issues at the Site-as later noted in EPA's 2015 Five year Review
Report.
While LLBO has identified numerous potential ARARs for the St. Regis Site as a whole, EPA is
addressing only those potential standards which pertain to our proposed soils remedy for OU7.
LLBO has notified EPA of three Leech Lake Reservation Business Committee Resolutions
amending or relating to HSCA that may be potential ARARs for this remedial action: No. 05-16
1 Costs may differ slightly from those presented in the SFS Report due to differences in rounding. The cost for S15B
assumes use of onsite soil borrowing.
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(July 15, 2004), No 2009-11 (July 9, 2008), and No. 2015-27 (August 7, 2014). EPA does not
consider these Resolutions on their own or in the context of HSCA to be either "applicable" or
"relevant and appropriate." Resolution 05-16 requests that EPA comply with the Land
Acquisition Policy when cleaning up the St. Regis site. Resolution 2009-11 states the Tribal
Council's position that EPA should conduct further site characterization activities at the St. Regis
Site in support of LLBO's Land Acquisition Policy. The "Letter Health consultation," adopted
by Resolution 2015-27, provides a location-specific sampling protocol for residential properties
within the St. Regis Site. Because each of these resolutions pertain specifically to the St. Regis
Site, EPA cannot determine that either Resolution is a statute of general applicability.
EPA also consulted with the State of Minnesota, both prior to and during the development of the
December 2015 SFS. The State of Minnesota conditionally supports Alternative S15-B because
it will meet or exceed PRGs established for residential property for this project for all of OU7,
and because no ICs would be required on the residential properties post-remediation. The State
conditions its support on assurances of timely future remedial actions at the other OUs to prevent
recontamination of remediated OU7 properties.
LLBO's and MPCA's comments on the SFS Report and PP, and EPA's responses to those
comments, are contained within the Administrative Record for this decision.
9.1.9 Community Acceptance
Community Acceptance will be evaluated after the public comment period ends. EPA will
address public comments in the Responsiveness Summary of the ROD for OU7.
9.2 EPA's Preferred Alternative: Alternative S15B
Under Superfund law, the selected remedy must meet the threshold criteria of Overall Protection
of Human Health and the Environment, and Compliance with ARARs. The preferred alternative
meets these threshold criteria by excavating all soil contamination in OU7 above ARAR-based
(HSCA) limits, which will protect to a 2 x 10"6 ELCR, and consolidating those soils in a
managed area. There will be no need for ICs in OU7. Soil sampling will be conducted after
remedy implementation to insure that contaminated soil from nearby OUs is not re-
contaminating the residential properties. This remedy is protective and meets applicable ARARs.
In addition to meeting the two threshold criteria, the selected remedy must be evaluated by
assessing: Long-term Effectiveness and Permanence; Reduction of Toxicity, Mobility or Volume
through Treatment; Short-Term Effectiveness; Implementability; and Cost. The preferred
alternative provides long-term and permanent protection against exposure to site-related
contaminants by soil excavation. On-site management of excavated soil significantly reduces the
short-term impacts due to increased truck traffic that would be required to dispose of soil offsite.
None of the alternatives reduce toxicity, mobility or volume of the contamination through
treatment because effective alternative treatment technologies or resource recovery technologies
are not practical for large quantities of soil containing low levels of dioxin contamination. The
preferred alternative is implementable. Finally, Alternative S15-B meets the evaluation criteria at
a much lower cost than alternatives that dispose of soil off-site.
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Figure 3 shows how Alternative S15B would be applied in OU7; green regions denote
excavation while yellow regions already meet Level 1 PRGs and do not need remedial action.
Uncolored properties will be sampled during the remedial design or remedial action phase of the
project as necessary to determine whether they need to be excavated.
9.3 Next Steps
EPA will evaluate public reaction to the preferred cleanup alternative during the public comment
period before deciding on a final cleanup alternative. Based on new information or public
comments, EPA may modify its preferred alternative or choose another that is discussed in this
PP. EPA encourages the public to review and comment on the cleanup alternatives.
EPA will respond in writing to all significant comments in a Responsiveness Summary which is
part of the final decision document called the Record of Decision. EPA will announce the
selected cleanup alternative in local newspaper advertisements and will place a copy of the
Record of Decision in the local information repositories.
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Table 8: Comparison of OU7 Cleanup Options with the Nine Superfund Remedy Selection Criteria
Evaluation Criteria
S10
Sll
SI
L2
S13
SI
L4
SI
L5
A
B
A
B
A
B
A
B
A
Overall protection of human health and
the environment
o
Compliance with ARARs
o
O
O
Long-term effectiveness and
permanence
o
ฎ
ฎ
ฎ
ฎ
ฎ
ฎ
Reduction of toxicity, mobility, or
volume through treatment
o
O
O
O
O
O
O
O
O
O
O
Short-term effectiveness
ฎ
ฎ
ฎ
ฎ
ฎ
Implementability
Cost (Millions)
$0
$12.1
$8.0
$14.3
$10.0
$13.6
$10.3
$22.5
$15.4
$30.0
$18.5
Tribal and State Acceptance
LLBO and MPCA conditionally support S15B.
Community Acceptance
Will be evaluated after the public comment period ends.
Fully meets criterion ฎ Partially meets criterion O Does not meet criterion
** EPA's preferred alternative
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