Libby Asbestos Superfund Site
QU2 - Former Screening Plant
U.S. EPA, Region 8 - Denver, Colorado
September 2009
Proposed Plan for Public Comment
Introduction
The public is invited to review and comment on
this Proposed Plan to address environmental
cleanup at Operable Unit 2 (OU2) of the Libby
Asbestos Superfund Site in Libby, Montana. OU2
is the former Screening Plant and is located on
the banks of the Kootenai River about five miles
northeast of Libby, Montana. OU2 is one of eight
OUs at the site (Exhibit 1). The investigation and
cleanup are being done by the U.S.
Environmental Protection Agency (EPA), in
consultation with the Montana Department of
Environmental Quality (DEQ) under the
Superfund law. This Proposed Plan provides an
overview of the site history, site contamination,
and risk; summarizes the remedial alternatives
EPA is considering; and details EPA's preferred
remedial alternative and supporting rationale.
Exhibit 1. Libby Asbestos Superfund Site OUs
ou#
1
2
3
4
5
6
7
8
Name
Former Export Plant
Former Screening Plant and nearby areas
Former Vermiculite Mine
Libby, MT (Residential, commercial, industrial,
and public properties)
Former Stimson Lumber parcel
Burlington Northern and Santa Fe Railroad
Troy, MT
State Highways
Issuance of this plan starts the public comment
period (September 16 to October 16 2009). At the
end of that period, EPA will review and consider
all comments provided.
Based on that consideration, EPA may select the
preferred cleanup alternative, modify it, select
another response action, or develop other
alternatives if public comment warrants or if new
material is presented.
Information on how to provide your comments
or questions to EPA is provided on page 12,
along with details on where you can get more
information and attend a public meeting. To help
you better understand the plan, page 13 provides
a list of commonly used environmental terms
that appear in BOLD thought this Proposed Plan.
This Proposed Plan focuses on OU2. For
additional information on the Libby Asbestos Site
as a whole, please contact the EPA Information
Center in Libby or visit EPA's web site (page 12).
Understanding the
Superfund Process
Issuance of the Proposed Plan is part of a detailed
process that includes everything from site
discovery through cleanup (Exhibit 2). EPA will
continue to work with local residents on this
process over the coming months.
The remedial investigation (RI) and feasibility
study (FS) for OU2 were completed in July and
August 2009 using the data collected since 1999.
These documents are conducted concurrently, as
data collected in the RI influence development of
remedial alternatives in the FS. The RI
characterizes the site conditions, determines the
nature of the waste, and assesses risk to human
health and the environment. The FS identifies,
develops, screens, and evaluates remedial
alternatives to address risks to human health and
the environment from soil contaminated with
Libby Amphibole (LA) asbestos.
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The general FS process follows the steps
summarized in the following bullets:
Identify remedial action objectives (RAOs)
Identify and screen potential remedial
technologies that will satisfy these RAOs
Assemble remedial alternatives that can
provide protection of human health and the
environment from the retained remedial
technologies
Screen the alternatives based on
effectiveness, implementability, and cost
For alternatives that make it through the
screening process, conduct a detailed
analysis against seven of nine evaluation
criteria (the two threshold criteria and the
five primary balancing criteria) and a
comparison between alternatives
After the FS is finalized, a preferred alternative
for the site is presented to the public in a
Proposed Plan (this document). The Proposed
Plan briefly summarizes the alternatives studied
in the detailed analysis phase of the Rl/FS and,
highlights the key factors that led to identifying
the preferred alternative. The public comment
period allows the State of Montana (through
DEQ) and the community to provide comment
on the preferred alternative.
The final phase of the Rl/FS process is to prepare
a Record of Decision (ROD). Following the
receipt and evaluation of public comments and
any final comments from DEQ, EPA selects and
documents the remedy for the site in a ROD.
Exhibit 2. The Superfund Process
The Superfund Process
"The Road to the ROD"
_____________».
Site
Inspection
National
Priority
List(NPL)
Remedial Investigation (Rl)
Public
Comment
Remedial
Action (RA)
Remedial
Design (RD)
*
Feasibility
Study (FS)
/
Record of
Decision and
Responsiveness
Summary
You Are
Here
Operation and Maintenance (O&M)
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Site Characteristics
OU2 is mostly undeveloped and contains only
two buildings. With the exception of the
riverbank, the majority of the Former Screening
Plant and Flyway properties are fenced to
prevent access from Highway 37 and the River
Runs through It subdivision (south of the OU).
OU2 is divided into four subareas:
Subarea 1 - Former Screening Plant. This 21-
acre subarea has a privately owned
garage/shed/apartment that is accessed
periodically by the owners. This property is
used for residential purposes, and it is
anticipated that future use will continue to be
residential and/or commercial. Rip-rap was
also placed along the river banks in this
subarea to protect against flooding and bank
erosion. Due to the LA contamination
associated with vermiculite from the Libby
Mine, the subarea has undergone extensive
investigation and removals since 1999, when
EPA began emergency response activities in
Libby.
Subarea 2 - Flyway. This 19-acre subarea
(currently owned by a subsidiary of Grace)
housed a pump that conveyed water from
the Kootenai River to the mine during
mining operations. The pump house has
been abandoned and cleaned, and the
structure was left on-site for possible future
use. The subarea includes the adjacent
Highway 37 right-of-way. The subarea is
currently vacant, undeveloped land, and
there are no plans for development. Portions
of the subarea have shore line that could be
accessible by boat. This subarea was found to
contain several vermiculite piles and
vermiculite-containing material was also
used as fill. The majority of the subarea was
remediated between 2001 and 2005 by EPA
and Grace.
Subarea 3 - Private Property. This 1-acre
parcel includes the Highway 37 right-of-way
adjacent to it. The property is currently
vacant, undeveloped land, and there are
currently no plans for development. In the
past, the property was used for mining
related activities such as decontamination,
storage, and staging area. The subarea was
remediated in 2005 by EPA.
sample 1-03000 with
isolated contamination
Exhibit 3. Locations of Subareas in OU2
Subarea 4 - Rainey Creek Road Frontage.
This 45,000 square foot subarea is privately
owned and was used to store trees for use
during restoration at the former Screening
Plant. It is currently vacant, undeveloped
land, and it is expected to remain
undeveloped. The subarea was remediated
by EPA between 2004 and 2006.
Rainey Creek flows through Subarea 1. It is a
perennial stream that discharges to the Kootenai
River. The lower reach of Rainey Creek that
flows through OU2 is owned by the State of
Montana. However, the adjacent riparian lands
are privately owned. This reach was restored
with several step pools to facilitate fish
migration. It is expected that Rainey Creek will
continue to sustain a viable fish population;
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however, it is unknown whether public access to
the lower reach will be allowed in the future.
Site Background
Contamination at OU2 is primarily linked to
operations at the nearby vermiculite mine, most
recently owned and operated by the W. R. Grace
Company (Grace). LA is a naturally occurring
contaminant in the vermiculite deposits at the
mine. Ore was transported from the mine to the
former Screening Plant and then to local and
nationwide processing facilities. The ore was
processed by heat expansion and was then
exported to market via truck or rail.
Historic uses of these four subareas are:
Subarea 1. Grace used the former Screening
Plant from 1975 to 1990 to screen mined
vermiculite by size and grade. The ore was
sorted, stored, and loaded onto a conveyor
for transport across the Kootenai River. It
was then trucked to the local Export Plant
(OU1) for processing or transported by rail to
expansion plants outside of Libby. From 1993
to 1999, it operated as Raintree Nursery.
Subarea 2. The Flyway is currently owned by
Kootenai Development Corporation (a Grace
subsidiary). In 1999, it was found to contain
vermiculite piles, and vermiculite-containing
fill was also suspected to have been used to
level drainages.
Subarea 3. The Private Property was likely
used by Grace for vermiculite mining-related
activities (e.g., storage or equipment staging).
More recently, it was used for equipment
decontamination during remediation of
Areas 1 and 2.
Subarea 4. The Rainey Creek Road frontage
areas were used for a short period to store
trees for use in restoration of Subarea 1.
In November 1999, in cooperation with the
Agency for Toxic Substances and Disease
Registry and DEQ, EPA began an emergency
response action to protect public health. The
Libby Asbestos Site was subsequently listed on
the NFL in October 2002. Due to LA
contamination associated with vermiculite from
the Libby mine, OU2 has undergone extensive
investigation and response actions under EPA's
emergency response authorities.
The investigations conducted at OU2 since 1999
to determine the nature and extent of LA
contamination have included sampling of soil,
dust, air, and bulk materials, as well as activity-
based sampling. They are detailed in the RI and
are briefly summarized in Exhibit 4.
Exhibit 4 - Summary of Investigations at OU2
Year
Event
Summary
Screening Plant (Subarea 1)
1 999, Dec
2000,
March/
Aug
2001,
April - May
2003,
March
Soil
sampling
Soil, dust,
and
scenario-
based
personal
air
sampling
Soil
sampling
Soil and
bulk
material
sampling
Baseline evaluation of LA soil
contamination on-site.
Soil sampling to supplement 1999
investigation.
Dust sampling to determine if
contamination was present.
Scenario-based sampling to
determine concentrations of LA from
building maintenance activities.
Soil sample event to supplement the
1999 investigation and better
characterize site soils.
Sampling to determine if soil
contained in the root mass of trees
removed from the OU was
contaminated with LA.
Flyway (Subarea 2)
2000,
March
2000, Sept
2001,
March
2001 , May
and July
2003, July
2005, June
2007, Aug
2008, June
Soil
sampling
Ambient
air
sampling
Baseline evaluation of LA soil
contamination on-site.
Sampling from test pits to document
possible exposure during an
archaeological investigation.
Trenching to determine vertical
extent of LA contamination in soil not
previously investigated.
Soil sample event to supplement the
2000 investigation and better
characterize site soils.
Sampling to supplement 2000
investigation, including portions of
the Highway 37 right-of-way.
Soil sampling activities to determine
the extent of soil requiring removal
along the Highway 37 right-of-way.
Outdoor ambient air samples
collected
Private Property (Subarea 3)
2000, April
Soil
sampling
Sampling of vermiculite stockpiles
and soil areas.
Rainey Creek Road Frontage (Subarea 4)
2003, May
2003, Nov
Soil
sampling
Soil
sampling
Baseline evaluation of LA soil
contamination.
Confirmation samples of
decontamination run-off water.
In addition to the investigations, a variety of past
response actions have been performed at OU2.
These include the removal of vermiculite
contaminated dust, soil, and debris. These actions
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Exhibit 5 - Summary of Past Response Actions at OU2
Year
Material Removed
Summary of Response Actions
Former Screening Plant (Subarea 1)
2000, August
through October
2001 , August
through November
2002, August
through October
2002, October
2003, April
2003, September
2004, August
2005, July
2006, May
Building demolition materials,
vermiculite contaminated soil, and
debris
Building demolition materials,
vermiculite contaminated soil, and
debris
Vermiculite contaminated soil,
debris, trees, and vegetative
material
Vermiculite contaminated soil,
granular pad
Vermiculite contaminated soil
Vermiculite contaminated soil
Demolition of all buildings except the long shed. Removal of miscellaneous
metal debris, vegetative covering, and excavation of contaminated soil. All
debris and soil was stockpiled for future disposal at the Former Libby
Vermiculite Mine.
Demolition of the long shed. Continued excavation and disposal of
contaminated soil at the Former Libby Vermiculite Mine.
Removal of decontamination pad and surrounding soil. Excavation along the
banks of Rainey Creek, including removal of trees and vegetation and
disposal of contaminated soil at the Former Libby Vermiculite Mine.
Removal of vermiculite contaminated soil and granular pad during installation
of potable water well.
Excavation within the Highway 37 right-of-way and disposal of contaminated
soil at the Former Libby Vermiculite Mine.
Removal of vermiculite contaminated soil and granular pad during installation
of potable water well.
Flyway (Subarea 2)
2001, September
2004, July through
November
2005, June
Vermiculite contaminated soil
Vermiculite contaminated soil
Vermiculite contaminated soil
Excavation and disposal of vermiculite contaminated soil at the Former Libby
Vermiculite Mine site.
Continued excavation and disposal of vermiculite contaminated soil at the
Former Libby Vermiculite Mine.
Excavation within the Highway 37 right-of-way adjacent to the Flyway and
disposal of contaminated soil at the Former Libby Vermiculite Mine.
Private Property (Subarea 3)
2005, June
Vermiculite contaminated soil
Excavation in conjunction with removal activities along Hwy 37 right-of-way
and disposal of contaminated soil at the Former Libby Vermiculite Mine.
Rainey Creek Road Frontage (Subarea 4)
2004, August
through October
2006, August
Vermiculite contaminated soil
Vermiculite contaminated soil,
repairs to damaged water line
Excavation along the North and South frontages and disposal of vermiculite
contaminated soil at the Former Libby Vermiculite Mine site.
Excavation to locate and repair a damaged water line and disposal of
vermiculite contaminated soil at the Former Libby Vermiculite Mine site.
were taken to reduce the volume of LA and
reduce further exposure to source material.
Response activities completed between 2000 and
2006 are summarized in Exhibit 5.
Nature and Extent of
Contamination
The RI summarizes the nature and extent of
contamination. Over the years, LA has been
observed in all the media sampled (indoor air,
indoor dust, outdoor ambient air, outdoor air
near disturbed soil, and soil). However, all
complete exposure pathways have either been
broken through past response actions or
investigation has found them to be below levels
of concern. The possible exception is outdoor air
near disturbed soil in an isolated portion of the
Highway 37 right-of-way and the area
surrounding sample location 1-03000. Both of
these locations are within the Flyway (Subarea 2).
In summary:
There is an isolated area with concentrations
of LA of greater than 1 percent at less than 1
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foot within the Flyway portion of the
Highway 37 right-of-way.
There is an area surrounding sample location
1-03000 with concentrations of LA at less
than 1 percent within the Flyway.
unacceptable risks. LA is the dominant
environmental concern at the site. The CSM for
OU2 includes current and future receptors and is
depicted pictorially in Exhibit 6 (next page).
Ambient air concentrations indicate an
acceptable risk range of between 5E-08 and
1E-07. For the layman, a risk of 5E-08 means
that, over a lifetime, the contamination is
expected to have a risk of 5 additional cancer
deaths per 100 million people.
There is vermiculite-containing soil in the
subsurface below engineered caps.
The majority of residual contamination is
present at depths greater than or equal to 4
feet. In several isolated areas in Subarea 1, it
is present at depths less than 4 feet.
The majority of the excavated areas in
Subarea 2 met EPA's clearance criteria (less
than 1 percent LA at depth) at depths
varying from less than 1 foot to greater than
4 feet. However, LA concentrations greater
than 1 percent have been detected in
confirmation soil samples from the eastern
boundary of the Flyway within the Highway
37 right-of-way at depths less than 1 foot up
to 2 feet. LA was also seen in surface soil in
one other location (surrounding sample 1-
03000, which was not previously remediated)
at concentrations less than 1 percent.
The majority of Subarea 3 does not contain
residual contamination; however, one
confirmation soil sample collected along the
north portion of the property contained less
than 1 percent LA at a depth of 1 foot.
Residual contamination is present along the
Rainey Creek Road Frontages at depths of
between 1 and 2 feet.
Conceptual Site Model
The conceptual site model (CSM) is a basic
description of how contaminants enter the
environment, how they are transported, and
what routes of exposure to organisms and
humans occur. It also provides a framework for
assessing risks from contaminants, developing
remedial strategies, determining source control
requirements, and methods to address
Sources of Vermiculite
Vermiculite and/or vermiculite concentrate was
transported to OU2 from the mine for screening
prior to shipment to the various export plants. It
is also believed that vermiculite materials were
used to fill in low lying areas of the site. Potential
contaminated media of concern evaluated for
OU2 include: outdoor air near highways, indoor
air, dust in air of vehicles, outdoor air near
disturbed soil, general (ambient) outdoor air, and
dust in air from disturbance of outdoor surfaces.
Exposure Pathways
Current potential human receptors at OU2
include commercial workers, tradespersons,
recreational visitors, and future residents. The
exposure route of chief concern for these
receptors is inhalation (breathing) of LA fibers in
air. The original CSM was prepared before the
past response actions and additional sampling
had been conducted. It predicted that people at
OU2 may have been exposed to LA in air via four
main exposure pathways:
Inhalation of fibers released during activities
that disturb soil
Inhalation of fibers in indoor air
Inhalation of fibers in outdoor (ambient) air
Inhalation of fibers from dust on Highway 37
A summary of results of past response actions and
additional monitoring on exposure pathways at
OU2 is shown below and in Exhibit 6.
Disturbance of Soil. The potential exposure
resulting from active soil disturbance is
believed to be the most significant pathway.
However, the majority of LA contamination
in soil is present at depths between 1 to 4 feet
and is below an engineered cover. The two
exceptions are: the area around sample
location 1-03000 where surface soil has not
been remediated and an isolated portion of
the Highway 37 right-of-way where LA was
found at concentrations greater than 1
percent at less than 1 foot.
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Indoor Air. The potential exposure resulting
from inhalation of LA fibers in indoor air has
been eliminated through a response action
that cleaned the interior of the buildings.
Outdoor (Ambient) Air. Investigation results
indicate this pathway is no longer a concern.
at Superfund sites, including recent guidance
that has been specifically developed to support
evaluations of exposure and risk from asbestos.
Detailed explanations of the steps used to
conduct the risk assessment are provided in the
RI report, including background information on
asbestos, the basis for concern, the exposure
model, a toxicity assessment, quantification of
exposure and risk, and a listing of uncertainties.
Exhibit 6. Summary of Current Status of Exposure Pathways after Past Response Actions
LA exposure to workers,
tradespersons, recreational
visitors, and future residents
from general ambient air
Investigation shows the
pathway is not a concern
LA exposure to workers,
tradespersons, recreational
visitors, and future residents
from outdoor air near the
highway
LA exposure to workers,
tradespersons, and future
residents from contaminated
soil tracked inside buildings
Pathway eliminated by past
response actions
D
4*4
LA exposure to workers,
tradespersons, recreational
visitors, and future residents from
disturbed contaminated soil
Pathway partially eliminated by
past response actions
Dust on Highway 37. This pathway has been
largely eliminated through the response
actions. The exception is an isolated portion
of shallow contaminated soil on the Highway
37 right-of-way, adjacent to the Flyway
(approximately 2,000 feet north of the
highway turn off to the Flyway gate).
Summary of Site Risks
The RI report contains a baseline human health
risk assessment for OU2. The risk assessment
uses available data to estimate the health risks to
people who may breathe asbestos in air while
working in or visiting OU2, either now or in the
future, based on current conditions. Methods
used to evaluate human health risk are in basic
accord with EPA guidelines for evaluating risks
This Proposed Plan provides a brief summary of
the conclusions of the risk assessment. Methods
for quantification of cancer and non-cancer risk
from inhalation exposure to asbestos are still
under development. However, risk predictions
based on the best methods and data currently
available indicate the following:
Results of a 2-year study on ambient air
concentrations in and around Libby indicate
that lifetime excess cancer risks to area
residents and workers from LA were below
EPA's level of concern (less than one in one
million [<1E-06]).
Most surface soils in OU2 have been
remediated, and there are no complete
exposure pathways of concern at present in
those areas.
7
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Two locations remain in the Flyway subarea
where surface soil is known to be
contaminated (west embankments of
Highway 37 and the area surrounding
sample location 1-03000). Also, residual
vermiculite and LA remain in subsurface soil
in many locations. If contaminated
subsurface soil were brought to the surface,
human exposure could become a concern at
many locations across the OU.
No data exist to support a quantitative
evaluation of potential risks to humans who
might disturb contaminated surface soil.
However, air sampling data (prior to and
during cleanup) at the site indicate that
human health risks might be unacceptable if
contamination in soil became sufficiently
extensive and human exposure was chronic.
EPA is working to develop a reference
concentration that will allow non-cancer
exposure risk for inhalation exposure to LA to be
quantified. Therefore, the risk assessment does
not include an evaluation of non-cancer risk.
However, studies in Libby reveal that the
incidence of asbestos-related, non-cancer effects
(e.g., pleural calcification, pleural thickening and
opacities) is increased in workers and residents.
These findings emphasize that, despite the
present inability to provide a quantitative
calculation, non-cancer effects are a significant
human health concern in the community. Thus, it
should not be presumed that cancer risk is the
"risk driver" at OU2 or other parts of the site.
Ecological risk has not yet been addressed for
OU2. EPA will be conducting a comprehensive
assessment of ecological risks as part of the OU3
work (the mine site) that will address ecological
risk for OU2.
Remedial Action
Objectives
Remedial Action Objectives (RAOs) are goals
developed by EPA to protect human health and
the environment at the Libby Asbestos Site.
These are the overarching goals that all cleanup
activities selected for OU2 should strive to meet
(Exhibit 7). EPA considers current and future use
of the site when determining RAOs.
Within OU2, Subareas 2, 3, and 4 are currently
undeveloped with no plans for future
development. Subarea 1 is being used as
residential property. Future land use for the
entire OU2 is assumed to be residential and/or
commercial.
In evaluating potential future activities at the site,
the final condition of the remediated area must
be considered. For each of the alternatives
evaluated, institutional controls (ICs) and
engineered controls would be implemented to
provide continued protection to human health
and the environment. ICs are actions, such as
restrictive covenants, zoning ordinances,
easements, deed restrictions, and building
permits, that help minimize the potential for
human exposure to contamination by ensuring
appropriate land or resource use. Engineered
controls are physical controls, such as fencing
and signs. Both types of controls are used to help
preserve the integrity of the remedy.
Exhibit 7. RAOs for OU2
RAOs for OU2
1. Mitigate the potential for inhalation exposures
to asbestos fibers that would result in risks
that exceed the target cancer risk range
specified by EPA of 1E-06 to 1E-04 (one in
one million to one in ten thousand).
2. Control erosion of contaminated soil by wind
and water from source locations to prevent
the spread of contamination to unimpacted
locations and media.
3. Implement controls to prevent site uses that
could pose unacceptable risks to human
health or the environment or compromise the
remedy.
EPA's goal is to protect public health or welfare
or the environment from exposure to LA in a
way that is consistent with the intended use of
the property. EPA will perform cleanup to
provide protection to the public and the
environment, but will not otherwise create
improvements to the property. The RAOs for
OU2 are based on anticipated future use.
Summary of Remedial
Action Alternatives
A number of proven, remedial technologies and
process options were used to develop remedial
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Exhibit 8. Remedy Components Used in Site
Remedial Alternatives
Remedy
Component Used
In-Place Containment of
Contaminated Soil
Removal of
Contaminated Soil
Offsite Disposal at the
Former Libby
Vermiculite Mine
Offsite Thermo-
Chemical Treatment
and Reuse of Treated
Material
ICs and Engineered
Controls with
Monitoring
5-year Review
Remedial Alternative
1
2
3a
3b
4
5
The shaded alternatives were eliminated from
consideration prior to detailed analysis
alternatives for cleanup. The five remedial
alternatives that were screened during the FS
consisted of varying combinations of those
technologies and process options (Exhibit 8). As
can be seen from the exhibit, the main differences
between alternatives relate to the following:
Is contaminated surface soil across the OU
left alone (Alternative 2), capped in place
(Alternatives 3a and 3b), or removed
(Alternatives 3b, 4, and 5)?
Is removed soil disposed at the former mine
(Alternatives 3b and 4) or is the soil treated
and returned to the site (Alternative 5)?
Each of the five alternatives was evaluated in the
FS to determine its ability to provide protection
to human health and the environment through
overall effectiveness, implementability, and cost.
Alternatives deemed to have lower than
moderate effectiveness or implementability
and/or high cost were eliminated from further
consideration. Alternative 4 was eliminated on
the basis of implementability as removal of
contaminated soil from highway embankments
might jeopardize pavement stability and cause
significant disruption of the highway. Alternative
5 was eliminated for the above reason and
because of issues related to the availability of the
technology and applicability to this medium.
Further information on those determinations can
be found in the FS.
Four remedial alternatives were retained for
detailed analysis and are discussed below. Their
costs are presented for purposes of comparing
one alternative to another and are not developed
with the level of detail necessary to be estimated
completion costs. Typically, costs developed for
FS purposes are as much as 30 percent lower to
50 percent higher than actual completion costs.
ICs would be used for all alternatives except
Alternative 1. Specific ICs would be chosen in the
remedial design phase in consultations with EPA,
Montana DEQ, and the property owner(s).
Alternative 1
No Action
Est. Total Capital Costs: None
Est. Total Five-year Review Costs (first 30
years): $288,000
Est. Construction Timeframe: None
Est. Total Alternative Cost (Present Value [PV]):
$104,000
Superfund requires that EPA retain a no-action
alternative as a baseline for comparison to other
alternatives. This alternative would require that
current site operations be suspended. The only
actions that would be implemented for
Alternative 1 are completion of five-year site
reviews and monitoring (e.g., non-intrusive
visual inspections) needed to support
conclusions made in the reviews. Non-intrusive
visual surface inspections performed in support
of five-year reviews would be made on the entire
OU. Alternative 1 is not protective of human
health or the environment and does not comply
with RAOs.
Alternative 2
ICs and Engineered Controls w/Monitoring
Est. Total Capital Costs: $261,000
Est. Total Operations and Maintenance (O&M)
and Five-Year Site Review (first 30 years):
$984,000
Est. Construction Timeframe: less than one
construction season (May-Oct)
Est. Total Alternative Cost (PV): $623,000
Alternative 2 provides protection of human
health through ICs (administrative controls)
coupled with engineered controls (physical
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controls) to restrict access and use of areas
containing contaminated soil, including
subsurface soils covered under previous response
actions. Monitoring would be used to ensure
these controls are protective.
ICs would help ensure remedy effectiveness and
could consist of a combination of governmental,
proprietary, legal, or information devices. A
comprehensive ICs plan would be required.
Engineered controls (e.g., chain-link fencing and
warning signs) would prevent access to
seasonally flooded areas in the Flyway where the
presence or absence of LA is unknown. Long-
term O&M would maintain the integrity of
engineered controls and effectiveness of ICs.
Alternative 3a
In-Place Containment of Contaminated Soil
in the Flyway Subarea (Highway 37
Embankments and Soil Surrounding
Sample Location 1-03000)
ICs and Engineered Controls w/Monitoring
Est. Total Capital Costs: $323,000
Est. Total O&M and 5-Year Review Costs (first
30 years): $984,000
Est. Construction Timeframe: less than one
construction season (May to October)
Est. Total Alternative Cost (PV): $681,000
Alternative 3a provides protection of human
health through in-place containment (protective
covers) to address risks to human receptors from
contaminated soil within two isolated locations of
the Flyway subarea. These two locations include
the west embankment of Flighway 37 and the
area surrounding sample location 1-03000. The
contaminated surface soil in these two isolated
locations would be covered with 12 inches of
clean soil cover and 6 inches of topsoil. Clean soil
would be brought in from a source outside of the
valley. Water or chemicals would be used during
construction to prevent asbestos fibers from
becoming airborne.
Covers would be seeded to minimize erosion.
Long-term O&M would be required to maintain
the integrity of the engineered controls and
covers, including covers placed during previous
response actions and as part of this alternative.
ICs and engineered controls would be used as
described under Alternative 2. Inspections and
five-year reviews would be performed, and
monitoring would continue to evaluate
protectiveness of the remedy.
Alternative 3b
In-Place Containment of Contaminated Soil
in the Flyway Subarea (Highway 37
Embankments)
Removal of Contaminated Soil within
Flyway Subarea (Soil Surrounding Sample
Location 1-03000)
Off site Disposal of Removed Soil at the
Former Libby Vermiculite Mine
ICs and Engineered Controls w/Monitoring
Est. Total Capital Costs: $338,000
Est. Total O&M and 5-Year Review Costs (first
30 years): $984,000
Est. Construction Timeframe: less than one
construction season (May-Oct)
Est. Total Alternative Cost (PV): $695,000
Alternative 3b provides protection of human
health through in-place containment (protective
covers) as well as removal and offsite disposal to
address risks to human receptors from
contaminated soil within two isolated locations of
the Flyway. These two locations include the west
embankment of Highway 37 and the area
surrounding sample location 1-03000. The
location within the west embankment of
Highway 37 would be contained in-place using
protective covers and the location surrounding
sample location 1-03000 would be excavated
along with offsite disposal of contaminated soil.
The contaminated surface soil in the west
embankment of Highway 37 would be covered as
discussed for Alternative 3a.
Limited removal (excavation) of contaminated
soil within the area surrounding sample 1-03000
would be conducted to an assumed depth of 12
inches and to then backfilled using clean soil.
Specialized trucks (with covered tops) would be
used to transport removed contaminated soil to
the Former Libby Vermiculite Mine. This mine is
been currently used for disposal of contaminated
soil generated during ongoing cleanup activities
performed in other OUs within the Libby
Asbestos Superfund Site. Water or chemicals
would be used during removal and construction
of the covers and engineered controls to prevent
asbestos fibers from becoming airborne.
Covers would be seeded to minimize erosion.
Long-term O&M would be required to maintain
10
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the integrity of the engineered controls,
backfilled areas, and covers, including covers
placed during previous response actions and as
part of this alternative.
ICs and engineered controls would be used as
described under Alternative 2. Inspections and
five-year reviews would be performed.
Monitoring would continue to evaluate
protectiveness of the remedy.
Evaluation of Remedial
Alternatives
The alternatives that survived the initial
screening process (Alternatives 1, 2, 3a, and 3b)
were evaluated in detail with respect to seven of
the nine evaluation criteria. The nine criteria fall
into three groups: Threshold, Primary Balancing,
and Modifying. Each alternative (except no-
action) must meet the threshold criteria. The
primary balancing criteria are used to weigh
major trade-offs among alternatives, and the
modifying criteria may be fully considered only
after State and public comment is received on the
Proposed Plan. Exhibit 9 presents the
comparative analysis of alternatives against these
criteria. The FS provides a detailed summary of
how the comparison of alternatives was made.
Alternatives 2, 3a, and 3b are expected to comply
with the chemical-, location, and action-specific
applicable or relevant and appropriate
requirements (ARARs) identified in the FS. No
key ARARs that significantly differ between
these alternatives were identified. In addition,
these alternatives are not expected to require
ARAR waivers pursuant to NCP 300.430(f)2(iv).
Exhibit 9. Detailed Evaluation of the Retained Remedial Alternatives
o>
(0
dial Alter
I
1
2
3a
3b
Description
No Action
ICs and Engineered Controls with
Monitoring
In-Place Containment of
Contaminated Soil within the Flyway
Subarea, ICs and Engineered
Controls with Monitoring
In-Place Containment and Removal
of Contaminated Soil within the
Flyway Subarea, Offsite Disposal at
the Former Libby Vermiculite Mine,
ICs and Engineered Controls with
Monitoring
Threshold
Criteria
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$
$104,000
$623,000
$681 ,000
$695,000
1. Numerical designations for the qualitative ratings are used to illustrate a range of compliance with that criterion.
2. Detailed cost spreadsheets for each alternative are presented in the FS (within a -30 to +50 percent range).
Threshold and Balancing Criteria (Excluding Cost)
© None
O Low
© Low to Moderate
© Moderate
O Moderate to High
© High
Balancing Criteria (Present Value Cost in Dollars)
$
11$$$$$
None ($0)
Low ($0 through $250K)
Low to Moderate ($250K through $500K)
Moderate ($500K through $1M)
Moderate to High ($1M through $1.5M)
High (Greater than $1.5M)
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EPA's Preferred Alternative
EPA's preferred alternative for cleanup of contamination at
OU2 is: Alternative 3b, In-Place Containment and Removal of
Contaminated Soil within the Flyway Subarea, Offsite Disposal
at the Former Libby Vermiculite Mine, ICs and Engineered
Controls with Monitoring.
As discussed earlier, Alternative 3b provides protection of human
health by addressing two isolated areas of contaminated soil in
the Flyway and by maintaining and protecting remedies put in
place under past response actions. In-place containment
(protective covers) will be used in a small area of the Highway 37
embankment and removal and offsite disposal will be used in the
area surrounding sample location 1-03000. ICs (administrative)
coupled with engineered controls (physical) would be used to
restrict access and use of areas containing contaminated soil,
including subsurface soils covered under previous response
actions and seasonally flooded areas in the Flyway where
presence or absence of LA contamination is unknown.
Covers would be seeded to minimize erosion. Long-term O&M
would be required to maintain the integrity of the engineered
controls, backfilled areas and covers, including covers placed
during previous response actions and as part of this alternative.
Monitoring would be used to ensure these controls are protective.
Est. Total Capital Costs: $338,000
Est. Total O&M and 5-Year Review Costs (first 30 years):
$984,000
Est. Construction Timeframe: less than one construction
season (May to October)
Est. Total Alternative Cost (PV): $695,000
Approximate quantities of materials were used in the
evaluation of the remedial alternatives in the FS process and
approximately include: 5000 square feet of surface area for
covers, 10000 square feet of surface area for removal, 400 loose
cubic yards (cy) of common fill for covers and excavations, and
300 loose cy of topsoil for covers, 3300 feet of fencing, and 11
warning signs. Final quantities will be determined in the design
process and may vary significantly.
Details of Implementation for
Alternative 3b
A soil cover would be used because of
ease of installation, availability of borrow
soil resources, and affordability compared
to other types of covers (e.g., geosynthetic
or concrete/ asphalt).
Offsite subsoil and topsoil sources outside
of the Libby valley (used for the ongoing
Libby cleanup efforts) would also be used.
The cover thickness and materials used
will be refined in the remedial design
process (e.g., 12 inches of subsoil and 6
inches of topsoil).
A visible marker layer would be placed at
the bottom of the covers and excavations
to denote the extent of the cleanup
During construction, water-based dust
suppression (using water from the pump
house) would likely be used to prevent
asbestos fibers from becoming airborne.
Chemicals could be used as an alternative
to water, if necessary.
ICs and monitoring (inspections) would be
used.
Engineered controls would be used to
prevent access to seasonally flooded
areas in Area 2. They would likely consist
of fencing and warning signs. Signs would
be installed at all entrances and at
appropriate intervals along the fence
perimeter.
The community would be kept informed
during remedy implementation and five-
year site reviews. Reviews are required
because contaminated soil left in place
below covers prevents unrestricted use.
As seen in Exhibit 9, Alternative 3b is preferred because it performs better than Alternative 2 or 3a without
a significant increase in cost.
Overall protection of human health and the environment
Compliance with ARARs
Long-term effectiveness and permanence
Reduction of toxicity, mobility, or volume through treatment
Short-term effectiveness
Implementability
Cost
© Moderate
O Moderate to High
© Moderate to High
© None
©Moderate
©Moderate
$$$ Moderate
12
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Opportunities for Public Involvement
Public Meeting
EPA will provide a short presentation about the proposed
plans for both OU1 and OU2 at a public meeting in
September 2009. It's a great opportunity to learn more about
the details.
Libby Asbestos Superfund Site
Public Comment Meeting
Monday, Sept. 28, 2009
7:00 to 9:00 pm
Little Theater
724 Louisiana Ave.
(School Administration Building)
Libby, MT
If you like, you can provide your comment orally at the public
meeting, and the meeting stenographer will record it.
Contacts
If you have questions or need additional
help, please feel free to contact the following
representatives:
Rebecca Thomas, Project Manager
U.S. EPA, Region 8
1595 Wynkoop Street
Denver, Colorado 80202
(303)312-6552
1-800-227-8917, ext. 6552
Thomas.rebecca@epa.gov
Ted Linnert, Community Involvement
Coordinator
U.S. EPA, Region 8-8 OC
1595 Wynkoop Street
Denver, Colorado 80202
(303)312-6119
1-800-227-8917, ext. 6119
linnert.ted@epa.gov
Dick Sloan, Project Officer
Montana DEQ
P.O. Box 200901
Helena, MT 59601
(406) 841-5046
rsloan@mt.gov
Written Comments and Extensions
The public comment period for the Proposed Plan runs from
September 16 to October 16, 2009, and may be extended 30
days with a formal request to EPA. You can submit a
comment in writing (by mail, email, or at the public meeting).
The mailing address for written comments is:
Ted Linnert
Office of Communications & Public Involvement
U.S. EPA, Region 8-8 OC
1595 Wynkoop Street
Denver, Colorado 80202
Email: linnert.ted@epa.gov
Documents
All public project reports and documents
are available for viewing at EPA's web
site or at one of the document
repositories. These are also excellent
sources for all sorts of project
information (fact sheets, brochures,
etc.).
www.epa.gov/libby
EPA Superfund Records Center
1595 Wynkoop Street
Denver, CO 80202
(303)312-6473
EPA Information Center
108E. 9th Street
Libby, MT
(406)293-6194
13
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Useful Terms
Understanding environmental cleanup can be daunting for the average person. The following are
definitions of commonly used terms at the Libby Asbestos Site to aid your understanding of this document.
Applicable or relevant and appropriate requirements (ARARs). Any state or federal statute that
pertains to protection of human life and the environment in addressing specific conditions or use of a
particular cleanup technology at a Superfund site.
Exposure. The amount of pollutant present in a given environment that represents a potential health
threat to living organisms.
Exposure Pathway. The path from sources of pollutants via, soil, water, or food to man and other
species or settings.
Feasibility Study (FS). The FS is the mechanism for the development, screening, and detailed
evaluation of alternative remedial actions. It is conducted concurrently with the RI.
Five-Year Review. Remedial actions that result in hazardous substances, pollutants, or contaminants
remaining at a site above levels that allow for unlimited use and unrestricted exposure are required to
be reviewed every five years to ensure protection of human health and the environment.
ICs and Engineered Controls. ICs are actions, such as restrictive covenants, zoning ordinances,
easements, deed restrictions, and building permits, that help minimize the potential for human
exposure to contamination by ensuring appropriate land or resource use. Engineered controls are
physical controls, such as fencing. Both types of controls are used to help preserve the integrity of the
remedy.
Libby Amphibole Asbestos (LA). The term used to differentiate asbestos fibers originating from the
W.R. Grace Mine from other types of asbestos. LA fibers have no odor, smell, or taste. They are not
flammable. They do not evaporate in air, dissolve in water, or breakdown in dirt.
National Priorities List (NPL). EPA's list of the most serious uncontrolled or abandoned hazardous
waste sites identified for possible long-term remedial action under Superfund. A site must be on the
NPL to receive money for remedial action.
Operable Unit (OU). A designation based on geography or other characteristics that defines a specific
area of a site and enables the Superfund process to move forward in different areas at different times,
speeding up the overall cleanup process at the site.
Operation and Maintenance (O&M). Activities conducted after a Superfund site action is completed
to ensure that the action is effective for the long-term.
Present Value (PV). The present value (of a sum payable in the future) calculated by deducting interest
that will accrue between the current and future date.
Remedial Investigation (RI). The investigation phase of the Superfund process that determines the
nature and extent of contamination and assesses the risk to human health and the environment.
Remedial Action (RA). The actual construction or implementation phase of a Superfund site cleanup
that follows remedial design. The remedial design is the design phase of a Superfund site cleanup that
follows the signing of the ROD and precedes the RA.
Record of Decision (ROD). A public document that explains which cleanup alternative(s) will be used
at NPL sites.
Superfund. The program that funds and carries out EPA solid waste emergency and long-term
removal and remedial activities. These activities include establishing the NPL, investigating sites for
inclusion, determining priority, and conducting and/or supervising cleanup and other actions.
14
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15
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US Environmental Protection Agency PPSRT STD
Region 8 8 OC Postage and Fees
1595 WynKoop Street EJ2
Denver, Colorado 80202 Helena, MT
Attn: Ted Linnert
See inside for details on the
Proposed Plan
for cleanup of OU2 - the Former Screening
Plant and nearby areas
Libby Asbestos Superfund Site
The public comment period begins on September 16, 2009
The public meeting is on September 28, 2009
(You should have already received the Proposed Plan for OU1 last week)
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