[Federal Register Volume 68, Number 144 (Monday, July 28, 2003)]
[Proposed Rules]
[Pages 44265-44269]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-18740]



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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 300

[FRL-7534-7]


National Oil and Hazardous Substances Pollution Contingency Plan; 
National Priorities List

AGENCY: Environmental Protection Agency.

ACTION: Notice of intent for partial deletion of the Rocky Mountain 
Arsenal National Priorities List Site from the National Priorities 
List; request for comments.

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SUMMARY: The Environmental Protection Agency (EPA) Region 8 announces 
its intent to delete the Surface Deletion Area (SDA), which includes 
the surface and structures media only within 123 acres of the Rocky 
Mountain Arsenal National Priorities List Site (RMA/NPL Site) On-Post 
Operable Unit (OU), from the National Priorities List (NPL) and 
requests public comment on this proposed action. The NPL constitutes 
Appendix B of 40 CFR part 300, which is the National Oil and Hazardous 
Substances Pollution Contingency Plan (NCP), which EPA promulgated 
pursuant to section 105 of the Comprehensive Environmental Response, 
Compensation, and Liability Act (CERCLA).
    EPA bases its proposal to delete the SDA of the RMA/NPL Site on the 
determination by EPA and the State of Colorado, through the Colorado 
Department of Public Health and Environment (CDPHE), that all 
appropriate actions under CERCLA have been implemented to protect human 
health, welfare and the environment and that no further response action 
by responsible parties is appropriate.
    This partial deletion pertains to the surface (soil, surface water, 
sediment) and structures media only and excludes the groundwater media 
of the Surface Deletion Area of the On-Post OU of the RMA/NPL Site. The 
Selected Perimeter Area of the On-Post OU RMA/NPL Site, composed of the 
surface, structures, and groundwater media within an additional 4,930 
acres, also is being proposed as a separate partial deletion during the 
same public comment period. The rest of the On-Post OU and the Off-Post 
OU will remain on the NPL and response activities will continue at 
those OUs.

DATES: Comments concerning this proposed partial deletion may be 
submitted on or before August 26, 2003.

ADDRESSES: Comments may be mailed to: Catherine Roberts, Community 
Involvement Coordinator (8OC), U.S. EPA, Region 8, 999 18th Street, 
Suite 300, Denver, Colorado, 80202-2466, 1-800-227-8917 or (303) 312-
6025.
    Comprehensive information on the RMA/NPL Site, as well as 
information specific to this proposed partial deletion, is available 
through EPA's Region 8 Superfund Records Center in Denver, Colorado. 
Documents are available for viewing by appointment from 8 a.m. to 4 
p.m., Monday through Friday excluding holidays, by calling (303) 312-
6473. The Administrative Record for the RMA/NPL Site and the Deletion 
Docket for this partial deletion are maintained at the Joint 
Administrative Records Document Facility, Rocky Mountain Arsenal, 
Building 129, Room 2024, Commerce City, Colorado 80022-1748, (303) 289-
0362. Documents are available for viewing from 12 p.m. to 4 p.m., 
Monday through Friday, or by appointment.

FOR FURTHER INFORMATION CONTACT: Ms. Laura Williams, Remedial Project 
Manager (8EPR-F), U.S. EPA, Region 8, 999 18th Street, Suite 300, 
Denver, Colorado, 80202-2466, (303) 312-6660.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Introduction
II. NPL Deletion Criteria
III. Deletion Procedures
IV. Basis for Intended Partial Deletion

I. Introduction

    The Environmental Protection Agency (EPA) Region 8 announces its 
intent to delete the Surface Deletion Area (SDA) of the Rocky Mountain 
Arsenal/National Priorities List (RMA/NPL) Site, Commerce City, 
Colorado, from the National Priorities List (NPL) and requests comment 
on this proposed action. The NPL constitutes appendix B of the National 
Oil and Hazardous Substances Pollution Contingency Plan (NCP), 40 CFR 
part 300, which EPA promulgated pursuant to section 105 of 
Comprehensive Environmental Response, Compensation and Liability Act 
(CERCLA), 42 U.S.C. 9605. EPA identifies sites that appear to present a 
significant risk to public health or the environment and maintains the 
NPL as the list of those sites. Sites on the NPL may be the subject of 
remedial actions financed by the Hazardous Substance Superfund (Fund). 
This partial deletion of the Site is proposed in accordance with 40 CFR 
300.425(e) and Notice of Policy Change: Partial Deletion of Sites 
Listed on the National Priorities List (60 FR 55466 (Nov. 1, 1995)). As 
described in 40 CFR 300.425(e)(3), portions of a site deleted from the 
NPL remain eligible for further remedial actions if warranted by future 
conditions.
    EPA will accept comments concerning its intent for partial deletion 
of the RMA/NPL Site for thirty days after publication of this notice in 
the Federal Register.
    Section II of this document explains the criteria for deleting 
sites from the NPL. Section III discusses the procedures that EPA is 
using for this proposed partial deletion. Section IV discusses the 
Surface Deletion Area of the RMA/NPL Site and explains how it meets the 
deletion criteria.

II. NPL Deletion Criteria

    The NCP establishes the criteria that EPA uses 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 public 
health or the environment. In making such a determination pursuant to 
section 300.425(e), EPA will consider, in consultation with the State, 
whether any of the following criteria have been met:
    Section 300.425(e)(1)(i). Responsible parties or other persons have 
implemented all appropriate response actions required; or
    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
    Section 300.425(e)(1)(iii). The remedial investigation has shown 
that the release poses no significant threat to public health or the 
environment and, therefore, taking remedial measures is not 
appropriate.
    A partial deletion of a site from the NPL does not affect or impede 
EPA's ability to conduct CERCLA response activities for portions not 
deleted from the NPL. In addition, deletion of a portion of a site from 
the NPL does not affect the liability of responsible parties or impede 
agency efforts to recover costs associated with response efforts. The 
U.S. Army and Shell Oil Company will be responsible for all future 
remedial actions required at the area deleted if future site conditions 
warrant such actions.

III. Deletion Procedures

    Upon determination that at least one of the criteria described in 
Section 300.425(e) of the NCP has been met, EPA may formally begin 
deletion procedures. The following procedures were used for this 
proposed deletion of the SDA of the RMA/NPL Site:
    (1) EPA has recommended the partial deletion and has prepared the 
relevant documents.

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    (2) The State of Colorado, through the CDPHE, has concurred with 
publication of this notice of intent for partial deletion.
    (3) Concurrent with this national Notice of Intent for Partial 
Deletion, a local notice has been published in a 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 
ends on August 26, 2003, based upon publication of this notice in the 
Federal Register and a local newspaper of record.
    (4) EPA has made all relevant documents available at the 
information repositories listed previously for public inspection and 
copying.
    Upon completion of the thirty calendar day public comment period, 
EPA Region 8 will evaluate each significant comment and any significant 
new data received before issuing a final decision concerning the 
proposed partial deletion. EPA will prepare a responsiveness summary 
for each significant comment and any significant new data received 
during the public comment period and will address concerns presented in 
such comments and data. The responsiveness summary will be made 
available to the public at the EPA Region 8 office and the information 
repository listed above and will be included in the final deletion 
package. Members of the public are encouraged to contact EPA Region 8 
to obtain a copy of the responsiveness summary. If, after review of all 
such comments and data, EPA determines that the partial deletion from 
the NPL is appropriate, EPA will publish a final notice of partial 
deletion in the Federal Register. Deletion of the Surface Deletion Area 
of the RMA/NPL Site does not actually occur until a final notice of 
partial deletion is published in the Federal Register. A copy of the 
final partial deletion package will be placed at the EPA Region 8 
office and the information repository listed above after a final 
document has been published in the Federal Register.

IV. Basis for Intended Partial Deletion

    The following information provides EPA's rationale for deletion of 
the SDA of the RMA/NPL Site from the NPL and EPA's finding that the 
proposed final deletion satisfies 40 CFR 300.425(e) requirements:

RMA/NPL Site Background

    The Rocky Mountain Arsenal was established in 1942 by the U.S. 
Army, and was used to manufacture chemical warfare agents and 
incendiary munitions for use in World War II. Prior to this, the area 
was largely undeveloped ranch and farmland. Following the war and 
through the early 1980s, the facilities continued to be used by the 
Army. Beginning in 1946, some facilities were leased to private 
companies to manufacture industrial and agricultural chemicals. Shell 
Oil Company, the principal lessee, primarily manufactured pesticides 
from 1952 to 1982. After 1982, the only activities at the Arsenal 
involved remediation.
    Complaints of groundwater pollution north of the RMA/NPL Site began 
to surface in 1954. Common industrial and waste disposal practices used 
during these years resulted in contamination of structures, soil, 
surface water, and groundwater. As a result of this contamination, the 
RMA was proposed for inclusion on the NPL on October 15, 1984. The 
listing of RMA on the NPL, excluding Basin F, was finalized on July 22, 
1987. Basin F was added to the RMA/NPL Site listing on March 13, 1989. 
On February 17, 1989, an interagency agreement--referred to as a 
Federal Facility Agreement (FFA)--formalizing the process framework for 
selection and implementation of cleanup remedies at the RMA/NPL Site, 
became effective. The FFA was signed by the Army, Shell Oil Company, 
EPA, U.S. Department of the Interior, U.S. Department of Justice, and 
the Agency for Toxic Substances and Disease Registry.
    Prior to the selection of remedial alternatives, a remedial 
investigation/endangerment assessment/feasibility study (RI/EA/FS) was 
conducted for the On-Post OU to provide information on the type and 
extent of contamination, human and ecological risks, and feasibility of 
remedial actions suitable for application at RMA. The remedial 
investigation (RI) completed in January 1992 studied each of the five 
environmental media at the RMA/NPL Site, including soils, water, 
structures, air, and biota. The feasibility study (FS) was finalized in 
October 1995, and a proposed remedial action plan was prepared and 
presented to the public in October 1995.
    On June 11, 1996, the Army, EPA, and the State of Colorado signed 
the Record of Decision (ROD) for the On-Post Operable Unit. The ROD, 
which formally establishes the cleanup approach to be taken for the On-
Post OU, specified the remedial actions to be implemented for soil, 
structures, and groundwater for the On-Post OU of RMA.
    The On-Post OU of the RMA/NPL Site (see map, RMA Surface Deletion 
Area) encompasses 25.5 square miles in southern Adams County, Colorado, 
approximately 8 miles northeast of downtown Denver.

Surface Deletion Area of the On-Post OU

    The SDA is an area of approximately 123 acres ( 0.2 square miles) 
on the northern and southern perimeter of the RMA/NPL Site. The SDA 
consists of a 250-foot-wide strip along the northern RMA boundary in 
Sections 23 and 24, and 62.6 acres adjacent to Lake Ladora and 
including Lake Mary in Section 2 (see map). Below the SDA area, the 
groundwater contaminant concentrations remain above remedial action 
levels. Therefore, only the surface and structures media are included 
as part of the SDA. The groundwater media below the SDA will remain as 
part of the RMA/NPL Site.
    A remedial investigation (RI) for the On-Post OU, completed in 
January 1992, studied each of the environmental media at the RMA/NPL 
Site including soil, sediment, structures, water, air, and biota. Based 
upon evidence gathered during the RI, one soil project was identified 
within the SDA. The Miscellaneous Southern Tier Soil project located 
near the south lakes included eight contamination areas; one located 
partially within the SDA in Section 2, contaminated with pesticides 
(aldrin and dieldrin) which presented a risk to human health and biota. 
A structures survey identified three structures within the SDA. One of 
these structures has no history of contamination and is designated for 
future use. The contaminants identified within the other two structures 
include asbestos, polychlorinated biphenyls (PCBs), pesticides, 
herbicides and heavy metals.
    One groundwater plume below the northern portion of the SDA 
primarily contains chloroform, benzene, atrazine, dieldrin, DIMP (a 
byproduct of nerve agent production), trichloroethylene, 
dibromochloropropane, and DDT. A second groundwater plume flows beneath 
the southern portion of the SDA and primarily contains dieldrin and 
chloroform.
    A feasibility study (FS) was finalized in October 1995, and a 
proposed plan prepared and presented to the public in October 1995. On 
June 11, 1996, the On-Post Record of Decision (ROD) was signed by the 
Army, EPA, and the State of Colorado. The ROD required the excavation 
and consolidation of soil presenting a risk to human health, as well as 
munition debris, in a state-of-the-art hazardous waste landfill to be 
built within the On-Post OU; and

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excavation of debris and soil presenting a risk to biota and placement 
of those soils in the Basin A consolidation area which is located in 
the central portion of the RMA/NPL Site. The excavated human health 
exceedence areas were to be backfilled with on-post borrow material and 
revegetated. Unexploded ordnance was to be transported off-site for 
detonation or other demilitarization process, unless the unexploded 
ordnance was unstable and must be detonated on-site.
    The remedy for structures included the demolition of two of the 
three structures identified in the SDA. The selected groundwater remedy 
consisted of continued operation of the groundwater treatment systems, 
including the North Boundary Containment System to treat the 
groundwater plume in the northern portion of the SDA and the Northwest 
Boundary Containment System to treat the groundwater plume originating 
in the southern portion of the SDA. Lake levels were to be maintained 
to prevent the groundwater plume from entering the South Lakes, 
including Lake Mary. Additionally, wells which had the potential to 
provide a cross-contamination pathway from the contaminated, upper 
groundwater aquifer to the deeper, confined aquifer were to be closed. 
The ROD also required continued use restrictions for the property.

Community Involvement

    Since 1988, each of the parties involved with the Arsenal cleanup 
has made extensive efforts to ensure that the public is kept informed 
on all aspects of the cleanup program. More than 100 fact sheets about 
topics ranging from historical information to site remediation have 
been developed and made available to the public. Following the release 
and distribution of the draft Detailed Analysis of Alternatives report 
(a second phase of the FS), the Army held an open house for about 1,000 
community members. The open house provided opportunity for individual 
discussion and understanding of the various technologies being 
evaluated for cleanup of the RMA/NPL Site.
    The Proposed Plan for the On-Post OU was released for public review 
on October 16, 1995. On November 18, 1995, a public meeting was held, 
attended by approximately 50 members of the public, to obtain public 
comment of the Proposed Plan. As a result of requests at this meeting, 
the period for submitting written comments on the plan was extended one 
month, concluding on January 19, 1996. Minimal comments were received 
on the alternatives presented for the projects in the SDA of the On-
Post OU. Specifically, the comments requested that the health and 
safety of nearby communities be protected from air emissions during 
excavation and demolition activities, that additional treatment 
capabilities or modification of the existing water treatment systems be 
considered, and that potential dioxin contamination of the entire RMA/
NPL Site be evaluated.
    The design for the Miscellaneous Southern Tier Soils, Miscellaneous 
RMA Structure Demolition, Phase I, and Confined Flow System Well 
Closure projects were provided to the public for a thirty calendar day 
review and comment period at both the 30 percent and 95 percent design 
completion stages (six separate public comment periods). Each design 
was also presented at the monthly meeting of the RMA Restoration 
Advisory Board, composed of community stakeholders, regulatory 
agencies, the Army, Shell Oil Company, and USFWS. No comments regarding 
the excavation/demolition approach or the proposed health and safety 
controls for each project were received.
    Upon completion of the thirty calendar day public comment period 
for this NOIDp, EPA Region 8 in consultation with the State and the 
Army, will evaluate each comment and any significant new data received 
before issuing a final decision concerning the proposed partial 
deletion.

Current Status

    The Miscellaneous Southern Tier Soil project, completed in 2000, 
remediated eight areas including one partially located in the SDA. A 
total of 1,054 bank cubic yards (bcy) of soil presenting a risk to 
human health was disposed in the hazardous waste landfill. Another 134 
bcy of soil presenting a risk to biota was disposed in the Basin A 
consolidation area. The Miscellaneous Structures Demolition and Removal 
Project Design, Phase I required the demolition of the structures and 
foundations; removal and disposal of the structures and foundations, 
substations, debris piles, roads and parking areas; removal and 
disposal or recycling of underground storage tanks, structural steel 
and other metal components; backfilling and grading; and revegetation 
of the excavated areas. During the design process, the two structures 
in the SDA slated for demolition were determined to have been 
previously demolished.
    The North and Northwest Boundary Containment Systems will continue 
to operate long-term to treat the groundwater below the SDA which 
continues to have contaminants above regulatory standards. Monitoring 
of the groundwater aquifer for the North and Northwest Boundary 
Containment Systems has been incorporated into the sitewide monitoring 
program, as required by the ROD.
    The Confined Flow System Well Closure project was completed in 
2000. A total of 51 wells, one in the SDA, which extended into the 
deeper, confined flow aquifer were closed. Closure was accomplished by 
overdrilling the well casing and installing a grout plug. An additional 
32 monitoring wells within the SDA are part of the long-term, site-wide 
monitoring plan. Four wells located within a 100-foot strip of land in 
the northern part of the SDA to be transferred to local government will 
be closed. Substitute wells will be used to monitor inside the new RMA 
boundary.
    In 2001, an evaluation of existing water quality data below Lake 
Mary identified naturally occurring conditions that have prevented the 
South Plants contaminated groundwater plume from entering the lake. 
Therefore, there is no need to artificially maintain the water level in 
Lake Mary. This minor change to the ROD was documented in the Lake Mary 
Fact Sheet (2003).
    Use of the groundwater below the SDA and surface water for potable 
drinking purposes is prohibited by the FFA, Public Law 102-402, and the 
ROD; and will continue to be prohibited even after the SDA is 
transferred to the U.S. Department of Interior or units of local 
government. Additional prohibitions imposed by the FFA, Public Law 102-
402, and the ROD include the use of the SDA for residential, 
industrial, and agricultural purposes, and for hunting or fishing for 
consumptive purposes.
    The Army is responsible for ongoing monitoring and maintenance 
associated with groundwater wells located on land to be transferred to 
the Department of Interior within the SPA. The conduct of long-term 
groundwater monitoring required by the ROD is delineated in the Final 
Interim Rocky Mountain Arsenal Institutional Control Plan.

Post-ROD Investigations

    In addition to the 2001 evaluation for Lake Mary, four studies have 
been conducted since the signing of the ROD on June 11, 1996, that are 
relevant to the deletion of the SDA. The Summary and Evaluation of 
Potential Ordnance/Explosives and Recovered Chemical Warfare Materiel 
Hazards at the Rocky Mountain Arsenal (2002) was conducted in response 
to the unexpected discovery of six M139 bomblets as part of the

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Miscellaneous Structure Demolition and Removal, Phase I project in the 
Section 36 Boneyard (central portion of the RMA/NPL Site). Using state-
of-the-art computer imaging, mapping technology, and software 
capability which had not existed previously, a comprehensive RMA-wide 
evaluation for the potential presence of ordnance and explosives as 
well as recovered chemical warfare materiel hazards was completed. The 
evaluation identified six additional areas for remedial action (none in 
the SDA) and concluded that the future discovery of additional sites 
with ordnance/explosives or recovered chemical warfare materiel hazards 
is highly unlikely.
    In 2001, EPA conducted a four-part Denver Front Range Dioxin Study 
which determined that the concentration of dioxins at most of the RMA/
NPL Site, including the SDA, is not statistically different from values 
observed in open space and agricultural areas within the Denver Front 
Range area. Therefore there is no significant health risk from dioxin 
in soil to future Refuge workers, volunteers, or visitors.
    As required by the ROD, a Terrestrial Residual Ecological Risk 
Assessment was completed in 2002. This report concluded that no 
significant excess terrestrial residual risks will remain after the 
ROD-required cleanup actions for soil, including additional areas of 
excavation and tilling identified as part of remedial design refinement 
as required by the ROD, are completed. In addition, an aquatic residual 
risk assessment was conducted for the South Lakes, including Lake Mary. 
This report estimated risks for the great blue heron, shorebird, and 
waterbird and concluded that no remediation of lake sediments is 
required to protect aquatic receptors. Long-term terrestrial and 
aquatic biomonitoring will be conducted as part of the USFWS 
Biomonitoring Program.
    Based on the extensive investigations and risk assessment performed 
for the SDA of the RMA/NPL Site, there are no further response actions 
planned or scheduled for this area. Currently, no hazardous substances 
remain at the SDA above health-based levels with respect to anticipated 
uses of and access to the site, which are limited under the FFA, Public 
Law 102-402, and the ROD. Because the SDA is subject to these 
restrictions on land and water use, it will be included in the RMA-wide 
five-year reviews. There are no operation and maintenance requirements 
for the remedies implemented at the SDA. All completion requirements 
for the SDA of the On-Post OU have been achieved as outlined in OSWER 
Directive 9320.2-09A-P.
    EPA, with concurrence from the State of Colorado, has determined 
that all appropriate CERCLA response actions have been completed within 
the SDA of the RMA/NPL Site to protect public health and the 
environment and that no further response action by responsible parties 
is required. Therefore, EPA proposes to delete the SDA of the On-Post 
OU of the RMA/NPL Site from the NPL.

    Dated: July 16, 2003.
Kerrigan G. Clough,
Acting Regional Administrator, Region 8.
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[FR Doc. 03-18740 Filed 7-25-03; 8:45 am]
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