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National Oil and Hazardous Substances Pollution Contingency Plan; National Priorities List
Note: EPA no longer updates this information, but it may be useful as a reference or resource.
[Federal Register: June 28, 2006 (Volume 71, Number 124)]
[Proposed Rules]
[Page 36736-36741]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr28jn06-37]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 300
[EPA-HQ-SFUND-1990-0011; FRL-8188-9]
National Oil and Hazardous Substances Pollution Contingency Plan;
National Priorities List
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice of intent for partial deletion of the Ellsworth Air
Force Base Site from the National Priorities List.
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SUMMARY: The Environmental Protection Agency, Region 8 (EPA) announces
its intent to delete portions of the Ellsworth Air Force Base (AFB)
Site located in Meade and Pennington Counties, South Dakota, from the
National Priorities List (NPL) and requests public comment on this
action. The NPL constitutes Appendix B to the National Oil and
Hazardous Substances Pollution Contingency Plan (NCP), 40 CFR Part 300,
which EPA promulgated pursuant to Section 105 of the Comprehensive
Environmental Response, Compensation, and Liability Act (CERCLA).
The EPA has determined, with the concurrence of the State of South
Dakota through the Department of Environment and Natural Resources
(SDDENR) that for the parcels proposed for deletion, all appropriate
actions under CERCLA have been implemented to protect human health,
welfare and the environment and no further response action by
responsible parties is appropriate. This partial deletion pertains to
surface soil, unsaturated subsurface soil, surface water, and sediments
at Operable Units 2, 3, 4, 5, 6, 7, 8, 9, 10 and 12, and excludes the
ground water medium at these parcels. The ground water medium at the
Ellsworth AFB Site (OU-11, Basewide Ground Water), and the soil medium
(surface and unsaturated subsurface soils) at OU-1, Fire Protection
Training Area, will remain on the NPL and response activities will
continue for those OUs. Two additional areas not associated with an
operable unit, the Gateway Lake Ash Study Area and the Pride Hangar
Study Area, are currently under investigation and are also not part of
this partial deletion.
DATES: Comments concerning this proposed partial deletion may be
submitted on or before July 28, 2006.
ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-
SFUND-1990-0011, by one of the following methods:
? http://www.regulations.gov: 
Follow the on-line
instructions for submitting comments.
? E-mail: dalton.john@epamail.epa.gov.
? Fax: 303-312-6961.
? Mail: Mr. John Dalton, Community Involvement Coordinator
(8OC), U.S. EPA, Region 8, 999 18th Street, Suite 300, Denver, CO
80202-2466.
? Hand Delivery: 999 18th Street, Suite 300, Denver, CO 80202-2466.
Instructions: Direct your comments to Docket ID No. EPA-HQ-SFUND-
1990-0011. EPA's policy is that all comments received will be included
in the public docket without change and may be made available online at
http://www.regulations.gov, including any personal information
provided, unless the comment includes information claimed to be
Confidential Business Information (CBI) or other information whose
disclosure is restricted by statute. Do not submit information that you
consider to be CBI or otherwise protected through http://www.regulations.gov
or e-mail. The http://www.regulations.gov Web site
is an ``anonymous access'' system, which means EPA will not know your
identity or contact information unless you provide it in the body of
your comment. If you send an e-mail comment directly to EPA without
going through http://www.regulations.gov, your e-mail address
will be automatically captured and included as part of the comment that is
placed in the public docket and made available on the Internet. If you
submit an electronic comment, EPA recommends that you include your name
and other contact information in the body of your comment and with any
disk or CD-ROM you submit. If EPA cannot read your comment due to
technical difficulties and cannot contact you for clarification, EPA
may not be able to consider your comment. Electronic files should avoid
the use of special characters, any form of encryption, and be free of
any defects or viruses.
Docket: All documents in the docket are listed in the
http://www.regulations.gov index. Although listed in the index,
some information is not publicly available, e.g., CBI or other
[[Page 36737]]
information whose disclosure is restricted by statute. Certain other
material, such as copyrighted material, will be publicly available only
in hard copy. Publicly available docket materials are available either
electronically in http://www.regulations.gov or in hard copy
at the EAFB Information Repository located at the Rapid City Public Library
and at the Ellsworth AFB Holbrook Library. The Rapid City Library is
located at 610 Quincy Street, Rapid City, SD 57701. For hours of
operation, call (605) 394-4171. Holbrook Library is located at 2650
Doolittle Dr. Ellsworth AFB, SD 57706, between the Base commissary and
the Base Theater. For hours of operation, call (605) 385-1686.
All CERCLA and Environmental Restoration Program (ERP) documents,
including those not kept at the Information Repositories, and the
Docket for this proposed partial deletion are kept in the
Administrative Record. The Administrative Record is available for
public viewing at the Base Environmental Management Flight, 2103 Scott
Drive, Ellsworth AFB, SD 57706. To schedule an appointment or for Base
access call (605) 385-2680.
FOR FURTHER INFORMATION CONTACT: Mr. John Dalton, Community Involvement
Coordinator (8OC), U.S. EPA, Region 8, 999 18th Street, Suite 300,
Denver, CO 80202-2466, Phone: (303) 312-6633.
Table of Contents
I. Introduction
II. NPL Deletion Criteria
III. Deletion Procedures
IV. Basis for Intended Partial Site Deletion
V. Deletion Action
I. Introduction
The EPA announces its intent to delete portions of the Ellsworth
AFB Site (CERCLIS ID #SD2571924644), from the NPL and requests
comments on this proposed action. The NPL constitutes Appendix B to the
NCP, 40 CFR part 300, which EPA promulgated pursuant to Section 105 of
CERCLA as amended, 42 U.S.C. 9605. The NPL is a list of facilities
which EPA determined may pose a significant threat to public health,
welfare, or the environment. 40 CFR 300.425(e) authorizes deletion of
facilities, or portions of facilities, from the NPL provided that
facility meets certain criteria. Deletion from the NPL does not
necessarily preclude further remedial action. If a significant release
occurs at a facility deleted from the NPL, that facility is restored to
the NPL without application of the Hazard Ranking System. Federal
facilities are not eligible for Superfund-financed remedial action.
However, all Federal facilities, whether listed on the NPL or not, have
a continuing statutory duty to conduct further remediation, if
required, even after the Federal property is transferred to non-Federal
owners. When a release attributable to a Federal facility's historical
activities is discovered after a property transfer, CERCLA section
120(b)(3)(A)(i) requires the federal entity to conduct further
remediation if necessary for the protection of human health and the
environment.
An environmental assessment was conducted at Ellsworth AFB on the
parcels proposed for deletion. All media were sampled. Results of the
sampling were reported in Remedial Investigation (RI) reports which
were used to conduct Risk Assessments. Feasibility Studies (FS) were
generated which evaluated potential remedies required to address the
contamination. The remedies were summarized in a public notice
soliciting comments on the remedies. All public comments received
during the public comment periods were considered by the Air Force and
EPA before the final remedy was selected.
The parcels proposed for deletion are described in more detail
later in this document. EPA proposes deleting these parcels from the
NPL because no further CERCLA response is appropriate. The remaining
portions of the property comprising the Ellsworth AFB Site will remain
on the NPL. This notice will be published in the Federal Register to
solicit public comments on the proposed partial deletion. The public
comment period is thirty (30) days beginning on the date of publication.
Section II of this action explains the criteria for the partial
deletion of sites from the NPL. Section III discusses the procedures
that EPA is using for this action. Section IV discusses the history of
the Ellsworth AFB Site and explains how the portions of the Site
proposed for deletion meet deletion criteria. Section V states EPA's
intention to delete the portions of the Site from the NPL unless
dissenting comments are received during the comment period.
II. NPL Deletion Criteria
The NCP establishes the criteria that are used to delete sites from
the NPL. In accordance with 40 CFR 300.425(e), sites may be deleted
from the NPL where no further response is appropriate to protect human
health or the environment. In making such a determination pursuant to
40 CFR 300.425(e), EPA will consider, in consultation with the State,
whether any of the following have been met:
(1) Section 300.425(e)(1)(i). Responsible parties or other persons
have implemented all appropriate response actions required; or
(2) Section 300.425(e)(1)(ii). All appropriate Fund-financed
response under CERCLA has been implemented, and no further response
action by responsible parties is appropriate; or
(3) Section 300.425(e)(1)(iii). The remedial investigation has
shown that the release poses no significant threat to human health or
the environment and, therefore, taking of remedial measures is not
appropriate.
As explained below, portions of the Ellsworth AFB Site meet the
NCP's deletion criteria listed above. Therefore, partial deletion is
being proposed.
III. Deletion Procedures
Upon determination that at least one of the criteria described in
40 CFR 300.425(e) of the NCP has been met, EPA may formally begin
deletion procedures. The following procedures were used for the
proposed partial deletion of portions of Ellsworth AFB:
(1) All appropriate responses under CERCLA have been implemented
and no further action is appropriate for the identified areas;
(2) The State of South Dakota through the Department of Environment
and Natural Resources concurred with this proposed partial deletion
decision via a letter dated February 10, 2006;
(3) Concurrent with this Notice of Intent for Partial Deletion,
notice has been published in the Rapid City Journal (the newspaper of
record) and has been distributed to appropriate Federal, State, and
local officials, and other interested parties. These notices announce a
thirty (30) day public comment period on the deletion package, which
commences on the date of publication of this notice in the Federal
Register and the Rapid City Journal; and
(4) All relevant documents have been made available for public
review at the local information repositories listed previously.
Upon completion of the 30-day comment period, EPA will evaluate all
comments received before issuing the final decision on partial
deletion. If appropriate, EPA will prepare and issue a Responsiveness
Summary for comments received during the public comment period and will
address concerns presented in the comments. The Responsiveness Summary
will be made available to the public at the information repositories.
Members of the public are encouraged to contact EPA to obtain a copy of
the Responsiveness Summary. If, after review of all public comments,
EPA determines that the partial deletion from
[[Page 36738]]
the NPL is appropriate, EPA will publish a Final Notice of Partial
Deletion in the Federal Register. As stated in 40 CFR 300.425, a site,
or portion of a site, deleted from the NPL, remains eligible for future
response actions if conditions warrant.
IV. Basis for Intended Partial Site Deletion
The following site summary provides EPA's rationale for the
proposed partial deletion. It also includes information demonstrating
satisfaction of the deletion criteria specified under 40 CFR 300.425(e).
Background
Ellsworth AFB is a U.S. Air Force Air Combat Command (ACC)
installation located 12 miles east of Rapid City, South Dakota, and
adjacent to the small community of Box Elder. The main Air Base covers
approximately 4,858 acres within Meade and Pennington counties and
includes runways, airfield operations, industrial areas, housing, and
recreational facilities. The site was officially activated in July 1942
as the Rapid City Army Air Base, a training facility for B-17 bomber
crews. Ellsworth AFB has been the headquarters of operations for a
variety of aircraft, the Titan I Intercontinental Ballistic Missile
system and the Minuteman I and Minuteman II Missile systems. The Base
has historically provided support, fueling, training, maintenance, and/
or testing facilities. Operations at Ellsworth AFB over the years
generated a variety of waste materials including municipal solid waste,
wastewater treatment plant sludge, industrial wastes including waste
oils, solvents, paints, spilled fuels, waste pesticides, shop waste,
metal remains from ordnance disposal (shell casings and bomb fragments
but not unexploded ordnance) and radiological wastes. Contaminants of
concern at Ellsworth AFB include chlorinated solvents, waste fuels and
metals.
Ellsworth AFB is located within the following Sections, Townships,
and Ranges, in Pennington and Meade Counties, South Dakota:
Sections 35 and 36, Township 3 North, Range 8 East, Meade County;
Section 31, Township 3 North, Range 9 East, Meade County;
Sections 1, 2, 11, 12, 13, Township 2 North, Range 8 East,
Pennington and Meade Counties; and
Sections 5, 6, 7, 8, 17, 18, 19, Township 2 North, Range 9 East,
Pennington and Meade Counties.
Ellsworth AFB was placed on the NPL August 30, 1990 (55 FR 35509)
and is therefore subject to the provisions of Section 120 of CERCLA, 42
U.S.C. 9620. At that time the entire base, approximately 4,858 acres,
was included in the listing (``fence line to fence line''). The
Department of Defense, EPA and the State of South Dakota entered into a
Federal Facilities Agreement (FFA) which formalizes the process for
environmental response actions and the relative roles of the Air Force,
the EPA and the State of South Dakota under CERCLA and the Installation
Restoration Program (IRP). The FFA was signed by the Air Force, the
EPA, and the State of South Dakota in January, 1992 and became
effective on April 1, 1992.
Upon listing, the facility began identifying sites where activities
involving hazardous substances may have occurred. The sites requiring
further investigations were grouped into Operable Units (OUs). Twelve
OUs have been identified at Ellsworth AFB. The OUs include: OU-1, Fire
Protection Training Area; OU-2, Landfills Nos. 1 and 6; OU-3, Landfill
No. 2; OU-4, Landfill No. 3; OU-5, Landfill No. 4; OU-6, Landfill No.
5; OU-7, Weapons Storage Area; OU-8, Explosive Ordnance Disposal Area;
OU-9, Old Auto Hobby Shop Area; OU-10, North Hangar Complex; OU-11,
Basewide Ground Water; and OU-12, Hardfill No. 1. Records of Decision
(RODs) have been finalized for all of these OUs. Appropriate response
actions for soil media have been completed per ROD decisions at the 10
OUs proposed for deletion. The RI/FS process did not identify any
unacceptable risks for surface water and sediment at these OUs.
Therefore, remedial actions were not required for surface water and
sediment. Remedial activities for areas where there has been a release
or disposal of petroleum products have been deferred to action under
the SDDENR petroleum release program.
The portions of the Ellsworth AFB Site to be deleted from the NPL
include surface soil, unsaturated subsurface soil, surface water and
sediment media at OU-2, OU-3, OU-4, OU-5, OU-6, OU-7, OU-8, OU-9, OU-10
and OU-12 (approximately 542 acres) and the surface soil, unsaturated
subsurface soil, surface water and sediment media of an additional
4,300 acres which are not associated with an operable unit and are not
identified as posing a risk to human health or the environment.
Of the approximately 4,858 acres originally included in the
Ellsworth AFB site NPL listing in 1990, there are four areas that are
not being deleted. These areas are:
? OU-1 (all media) [generally described by the following
coordinates: N667749.88/E1242611.11; N667496.84/E1242812.29;
N667330.75/E1242852.01; N666933.49/E1242558.40; N667158.53/E1242265.75;
N667787.47/E1242276.80; N667749.88/E1242611.11]
? OU-11 (Basewide Ground Water) [including all ground water
plumes located within the Base boundary (described earlier) and those
described as emanating from the Base]
? Gateway Lake Ash Study Area [generally described by the
following coordinates: N667944.01/E1248056.74; N667694.15/E1248058.87;
N667695.57/E1247811.84; N667947.55/E1247834.49; N667944.01/E1248056.74]
? Pride Hanger Study Area [generally described by the
following coordinates: N673538.32/E1243066.96; N673267.45 /E1243270.27;
N673228.21/E1243223.95; N673113.04/E1243308.87; N673021.04/E1243204.65;
N673409.00/E1242911.91; N673538.32/E1243066.96]
Maps identifying all areas are available for review in the partial
deletion docket.
Operable Unit 2
The OU-2 study area consists of Landfill No. 1, Landfill No. 6, the
drainage channel in the western portion of Landfill No. 1, and the
drainage channel near Landfill No. 6, which includes Pond 002.
Landfill No. 1 is approximately 21.5 acres in size and is located
at the southern boundary of Ellsworth AFB. The landfill was active from
the early 1940s to 1964 and was used to dispose of a variety of wastes
including Base refuse, incinerator ash, sludge, oil, and possibly
liquid industrial wastes. Hardfill debris was also disposed of at
Landfill No. 1.
Landfill No. 6 is approximately 0.5 acres in size and is located
northeast of Landfill No. 1 on the north side of Kenney Road. Landfill
No. 6 was used from 1962 to 1965 and primarily received general Base
refuse. Waste oil, fuel, and solvents may also have been disposed of at
this location. However, no direct physical evidence of these chemicals
was found at Landfill No. 6 during the 1993/1994 remedial investigation
field activities.
Within OU-2, soils contained chlorinated volatile organic compounds
(VOCs), benzene, toluene, ethyl benzene, xylenes (BTEX), pesticides,
inorganic compounds, and polynuclear aromatic hydrocarbons (PAHs). The
concentrations of several inorganic compounds exceed background
concentrations. This is believed to be a combination of landfill
activities and variations in the concentrations of
[[Page 36739]]
naturally-occurring compounds in the soil. Jet fuel contamination
caused by a leak in a fuel line was identified along the southern
boundary of OU-2. This jet fuel contamination has been remediated under
the SDDENR petroleum release program. Sediment samples collected at OU-
2 contained semi-volatile organic compounds (SVOCs), primarily PAHs,
pesticides and inorganic compounds. Low concentrations of three SVOCs
were detected in surface water samples at OU-2, as well as numerous
inorganic compounds. The concentrations of several inorganic compounds
exceeded State and Federal water quality standards. However, the
results of the risk assessment indicated that risk due to exposure to
contaminants in sediments at OU-2 was within the acceptable risk range,
and that surface water was not a media of current concern. Therefore,
it was determined that remedial action was not warranted for surface
water or sediment.
Two removal actions were completed at this OU. A site in the
southwest corner of Landfill 1 identified during RI geophysical
investigations was excavated in 1997. This location contained low-level
radioactive waste material. A second removal action was completed for
remnants of chemical weapons training materials located in the same
general area. The identified materials were excavated and moved off
Site for disposal at a licensed waste disposal facility.
The ROD was signed in May of 1996. The selected alternative for
Landfill No. 1 was a vegetated soil cover and institutional controls.
This alternative includes institutional controls, storm-water channel
realignment and lining, in conjunction with physical modification of
the OU to reduce potential risk. The selected alternative for Landfill
No. 6 was institutional controls. This alternative uses access
restriction, monitoring, and other controls to reduce potential risk.
Construction for the storm-water channel was completed in October 1996.
The landfill cover was completed in May 1997. Ground water remediation
and monitoring are part of OU-11.
Operable Unit 3
OU-3, located in the northeast portion of Ellsworth AFB, consists
of Landfill 2, (approximately one acre), the four identified trenches
to the north and two disturbed soil areas in the southeast and
southwest corners. The landfill was active for approximately one year
(1964-1965). Combustible trash, described as shop wastes, was burned
daily in a burn pit. Four trenches located north of the fill area were
used for the disposal of metal and industrial and household refuse. A
sign located within the boundary of OU-3 indicates a missile disposal/
burial site. The missile disposal site contains scrap metal salvaged
from a test flight. Contaminants identified in soil at this OU include,
VOCs, jet fuel, numerous SVOCs, pesticides and inorganic compounds. The
concentrations of several inorganic compounds exceed background
concentrations.
The ROD was signed in June of 1996. The selected remedial action
was a vegetated soil cover. This alternative includes institutional
controls in conjunction with physical modification of the OU to reduce
potential risk. The landfill cover was completed in May 1997. Ground
water monitoring is part of OU-11.
Operable Unit 4
OU-4 (Landfill No. 3) is approximately 40 acres in size and is
located in the southwestern corner of Ellsworth AFB. The landfill was
active between 1965 and 1976 as a trench and fill operation. The
landfill was also used for disposal of construction demolition debris
during the mid-1980s, digested wastewater treatment plant biomass, shop
wastes (liquids and paints), industrial sewer sludge and oils, soil
containing Pramitol and sodium chromate, and miscellaneous refuse. The
contents of approximately 100 55-gallon drums containing waste oil and
fuel were placed in a waste-oil pit on site. OU-4 was also used as a
staging area for 55-gallon drums containing waste oil and fuel. In
addition, the southwest corner of OU-4 was used to stage asphalt
rubble. Contaminants in soil at the OU include VOCs, PAHs, jet fuel,
pesticides, polychlorinated biphenyls (PCBs), inorganic compounds,
dioxins and furans. The concentrations of several inorganic compounds
exceed background concentrations. Contaminants in sediment include
acetone, PAHs, pesticides, and inorganic compounds. However, it was
determined in the risk assessment that those levels of contaminants
fell within the acceptable risk range and therefore, no remedial action
was warranted for sediment.
The ROD was signed in May of 1996. The selected remedial action was
a vegetated soil cover for the landfill, and extraction and treatment
for ground water. This alternative includes institutional controls in
conjunction with physical modification of the OU to reduce potential
risk. The landfill cover was completed in December 1996. Ground water
remediation and monitoring are part of OU-11.
Operable Unit 5
OU-5 (Landfill No. 4) is a 10-acre site located adjacent to the
north perimeter of Ellsworth AFB. From the 1940s through 1990, the
landfill was used primarily for the disposal of construction demolition
and hardfill materials, general refuse and drums. Contaminants in soil
at OU-5 include PAHs, pesticides, inorganic compounds, and jet fuel.
The concentrations of several inorganic compounds exceed background
concentrations. One surface water and one sediment sample were
collected at OU-5 from an ephemeral surface water source. These samples
contained VOCs, SVOCs, and inorganic compounds. However, it was
determined in the risk assessment that those levels of contaminants
fell within the acceptable risk range and therefore, no remedial action
was warranted for surface water or sediment.
The ROD was signed in June of 1996. The selected remedial action
was a vegetated soil cover. This alternative includes institutional
controls in conjunction with physical modification of the OU to reduce
potential risk. The landfill cover was completed in May 1997. Ground
water monitoring is part of OU-11.
Operable Unit 6
OU-6 (Landfill No. 5) is a 7-acre site located in the southeastern
corner of Ellsworth AFB. From 1960 to 1980, demolition debris and
hardfill materials were placed in the landfill along with miscellaneous
refuse, dried sewage sludge, and possibly shop wastes. Construction and
demolition debris was initially placed along the rail line to stabilize
erosion, and was later expanded to the east. OU-6 was used for
stockpiling wastewater treatment plant sludge. Contaminants in soil at
OU-6 include PAHs, pesticides, and inorganic compounds. The
concentrations of several inorganic compounds exceed background
concentrations. Contaminants in surface water and sediment include
VOCs, SVOCs, pesticides and inorganic compounds. However, it was
determined in the risk assessment that those levels of contaminants
fell within the acceptable risk range and therefore, no remedial action
was warranted for surface water or sediment.
The ROD was signed in October of 1995. The selected remedial action
was a vegetated soil cover, and long-term surface water and sediment
sampling. This alternative includes institutional controls in
conjunction with physical modification of the OU to reduce potential
risk. The landfill cover was
[[Page 36740]]
completed in July 1996. Ground water monitoring is part of OU-11.
Operable Unit 7
OU-7 (Low-Level Radioactive Waste Burial Site) is located in the
Munitions Storage Area (MSA), formerly identified as the Weapons
Storage Area (WSA), at the northernmost end of Ellsworth AFB. The MSA
covers approximately 65 acres. Radioactive wastes were generated at
Ellsworth AFB between 1952 and 1962. During that time the WSA was under
the control of the Atomic Energy Commission (AEC). After 1962, control
of the WSA was transferred to the Air Force. Contaminants in soil at
OU-7 include VOCs and inorganic compounds. Contaminants in surface
water and sediment include VOCs and inorganic compounds. The
concentrations of several inorganic compounds in soil and sediment
exceed background concentrations. Radionuclides detected in all media
were within the normal background range due to natural variations in
soil types and geological characteristics. The results of the risk
assessment indicated that risk due to exposure to contaminants in
surface water and sediments at OU-7 was within the acceptable risk
range. Therefore, it was determined that remedial action was not
warranted for surface water or sediment.
The ROD was signed in June of 1996. The selected remedial action
was application of institutional controls for soil and ground water,
completion of detailed records searches and long term ground water
monitoring. Ground water monitoring is part of OU-11.
Operable Unit 8
OU-8 (Explosive Ordnance Disposal Area) is located in the
northeastern portion of Ellsworth AFB. OU-8 consists of two distinct
areas, the Explosive Ordnance Disposal (EOD) Area and the Debris Burial
Area. The EOD Area is approximately 600 feet by 1,350 feet, and the
Debris Burial Area is approximately 300 feet by 150 feet. The EOD Area
includes: A Pramitol (an herbicide) spill area, a burn pit area, a burn
furnace area, and a detonation site. This detonation area was formerly
used for the detonation of active explosives. The Debris Burial Area
was used for the burial of debris generated from detonation of
explosives at the demolition area. Contamination in soil at this OU
includes VOCs, SVOCs (primarily PAHs), jet fuel, pesticides, dioxins/
furans, and inorganic compounds. The concentrations of several
inorganic compounds in soil and sediment exceed background
concentrations. One pesticide was detected in sediment samples.
However, it was determined in the risk assessment that those levels of
contaminants fell within the acceptable risk range and therefore, no
remedial action was warranted for sediment.
The ROD was signed in June of 1996. The selected remedial action
was installation of vegetated soil covers, application of institutional
controls and long term sediment sampling. The soil covers over the EOD
Area and the Debris Burial Area were completed in June 1997. Ground
water monitoring is part of OU-11.
Operable Unit 9
OU-9 encompasses 90 acres surrounding the Old Auto Hobby Shop. The
types of potential contaminant source areas at OU-9 include: Building
Operations, underground storage tanks, the former Quartermaster
Gasoline Dispensing Area, the former fuel transfer line, industrial
waste lines, jet engine test facilities and upgradient source areas.
There is no known documentation of major spills or releases at OU-9.
Small volumes of fuels, oils, and solvents may have been released to
the environment over time through incidental spills, leaks, and/or poor
waste handling and disposal practices. Contaminants in soil at this OU
include VOCs (primarily BTEX), SVOCs (primarily PAHs), jet fuel, and
inorganic compounds. Several inorganic compounds were detected in
surface water and sediment samples. PAHs were also reported in sediment
samples.
It was determined that OU-9 did not pose a threat to human health
or the environment. In May 1996, a ROD was signed for no further
action. Remediation of soils contaminated by petroleum will be
performed under the SDDENR petroleum release program. Ground water
remediation was deferred to OU-11.
Operable Unit 10
OU-10 is the North Hangar Complex, a 75-acre site located in the
central portion of Ellsworth AFB, northeast of the primary instrument
runway. The North Hangar complex was constructed in the 1950s and is
composed of five rows of aircraft repair and maintenance hangars. Most
of OU-10 is paved with concrete with some grassy areas between the
hanger rows. OU-10 contains a system of underground jet fuel hydrant
lines that deliver fuel to docked aircraft, and underground industrial
waste lines associated with aircraft maintenance. It was reported that
waste products used for aircraft maintenance may have been washed down
floor drains in the maintenance buildings. Contaminants at this OU included
VOCs, SVOCs and jet fuel. The predominant VOCs were BTEX compounds.
It was determined that OU-10 did not pose a threat to human health
or the environment. In May 1996, a ROD was signed for no further
action. Remediation of soils contaminated by petroleum will be
performed under the SDDENR petroleum release program. Ground water
remediation was deferred to OU-11.
Operable Unit 12
OU-12 (Hardfill No. 1) is located in the southern half of Ellsworth
AFB and is approximately 14 acres in size. OU-12 was identified as a
hardfill, rather than a landfill, because disposal records indicated
that it only received construction debris such as wood, metal,
concrete, and asphalt. The remedial investigation identified the
presence of VOCs, SVOCs, jet fuel and pesticides, but through site
characterization it was found that these contaminants were related to
flightline runoff rather than landfill disposal practices.
The ROD was signed in May of 1996. The selected remedial action was
a vegetated soil cover. This alternative includes institutional
controls in conjunction with physical modification of the OU to reduce
potential risk. The soil cover was completed in May 1997. Ground water
monitoring is part of OU-11.
Five-Year Review
The initial five-year review for Ellsworth AFB base was completed
in September 2000. The second five-year review was completed in
September 2005. The reviews focused on the final remedial activities at
each OU. Discussions and recommendations were included for the long-
term ground water actions at the OUs and for Operation and Maintenance
issues with landfill covers.
V. Deletion Action
EPA, with the State of South Dakota's concurrence, has determined
that no additional response is necessary at Ellsworth AFB for surface
soil, unsaturated subsurface soil, surface water and sediment media at
OU-2, OU-3, OU-4, OU-5, OU-6, OU-7, OU-8, OU-9, OU-10 and OU-12
(approximately 542 acres) and the surface soil, unsaturated subsurface
soil, surface water and sediment media of an additional 4,300 acres
which are not associated with an operable unit and are
[[Page 36741]]
not identified as posing a risk to human health or the environment.
No further CERCLA response is appropriate or necessary to provide
protection of human health and the environment other than the ongoing
inspection, maintenance and monitoring activities. Therefore EPA is
deleting these portions of the Ellsworth AFB Site. OU-1, OU-11, the
Pride Hanger Study Area and the Gateway Lake Ash Study Area will remain
on the NPL.
Dated: June 8, 2006.
Kerrigan G. Clough,
Acting Regional Administrator, U.S. Environmental Protection Agency,
Region 8.
[FR Doc. E6-10105 Filed 6-27-06; 8:45 am]
BILLING CODE 6560-50-P