[Federal Register: July 31, 2006 (Volume 71, Number 146)]
[Rules and Regulations]
[Page 43071-43073]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr31jy06-13]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 300
[EPA-HQ-SFUND-1987-0002; FRL-8204-2]
National Oil and Hazardous Substances Pollution Contingency Plan;
National Priorities List
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice of partial deletion of the Rocky Mountain Arsenal
National Priorities List Site from the National Priorities List.
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SUMMARY: The Environmental Protection Agency (EPA) Region 8 announces
the deletion of the Internal Parcel of the Rocky Mountain Arsenal
National Priorities List (RMA/NPL) Site from the National Priorities
List (NPL). All areas originally proposed for deletion (71 FR 24627),
except for a three-acre area which encompasses the Rail Yard Treatment
System, are being deleted (see map). The Rail Yard Treatment System is
excluded from the Internal Parcel due to a delay in developing the
Interim Construction Completion Report. With the Rail Yard area
excluded, the Internal Parcel consists of 7,396 acres (11.5 square
miles) of the On-Post Operable Unit of RMA. 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), as amended. EPA and the State
of Colorado, through the Colorado Department of Public Health and
Environment (CDPHE), have determined that the Internal Parcel of the
RMA/NPL Site poses no significant threat to public health or the
environment and, therefore, no further remedial measures pursuant to
CERCLA are appropriate.
This partial deletion pertains to the surface media (soil, surface
water, sediment), structures, and groundwater of the Internal Parcel of
the On-Post OU of the RMA/NPL Site. The Internal Parcel includes
groundwater that is east of E Street with the exception of a small area
in the northwest corner of Section 6. The Rail Yard Treatment System
and the rest of the On-Post OU, including groundwater below RMA that is
west of E Street and the small area in the northwest corner of Section
6, as well as the Off-Post OU will remain on the NPL. This partial
deletion of the Internal Parcel will not change Appendix B of 40 CFR
part 300, which was previously amended in January 2003 (68 FR 2699) to
reflect that a partial deletion of 1.5 square miles from the RMA/NPL
Site had occurred.
DATES: This partial deletion of the Internal Parcel is effective on
July 31, 2006.
FOR FURTHER INFORMATION CONTACT: Ms. Jennifer Chergo, Community
Involvement Coordinator (8OC), U.S. Environmental Protection Agency,
Region 8, 999 18th Street, Suite 300, Denver, Colorado 80202-2466;
[[Page 43072]]
telephone number: 1-800-227-8917 or (303) 312-6601; fax number: 303-
312-6961; e-mail address: chergo.jennifer@epa.gov.
SUPPLEMENTARY INFORMATION: The Rocky Mountain Arsenal National
Priorities List (RMA/NPL) Site is located in southern Adams County,
Colorado and is comprised of two operable units (OU), the On-Post and
Off-Post. The On-Post OU of the RMA/NPL Site encompasses 17.2 square
miles (11,007 acres) approximately eight miles northeast of downtown
Denver, Colorado. The Off-Post OU addresses contamination north and
northwest of the RMA proper boundaries. The Internal Parcel consists of
approximately 11.5 square miles (7,396 acres) of the On-Post OU of RMA
in Commerce City, Colorado.
This partial deletion pertains to the surface media (soil, surface
water, sediment), structures, and groundwater of the Internal Parcel of
the On-Post OU of the RMA/NPL Site. The Internal Parcel includes
groundwater that is east of E Street with the exception of a small area
in the northwest corner of Section 6. The rest of the On-Post OU,
including groundwater below RMA that is west of E Street and the small
area in the northwest corner of Section 6, and the Off-Post OU will
remain on the NPL.
On April 26, 2006, EPA published a Notice of Intent for Partial
Deletion (NOIDp) in the Federal Register (71 FR 24627) and local
newspapers which proposed to delete the Internal Parcel from the RMA/
NPL Site. EPA received comment letters from ninety-four organizations/
entities and individuals. Authors of six letters were opposed to the
proposed partial deletion of the Internal Parcel. One of these letters
requested postponement of the deletion stating that the 60-day review
time was insufficient to review and resolve questions regarding
characterization of the eastern portion of the Internal Parcel and
their perception of unnecessary risk posed by deletion of the western
portion of the Internal Parcel. Several commenters also questioned the
``piece-meal'' approach to the Internal Parcel deletion.
In our Responsiveness Summary, EPA described the CERCLA
investigation process and how various areas of the Internal Parcel,
including the eastern portion which includes the groundwater aquifer
below a demolition range, were characterized. This process included
file searches, ``desktop'' information (e.g., aerial photographs)
searches, site reconnaissance, and collection of both soil and
groundwater samples during the Remedial Investigation (RI). Soil
samples were collected from burn pits and ordnance disposal areas,
specific areas of concern to the commenters, during the RI. Explosive
residue and Toxicity Characteristic Leaching Procedure (TCLP)-metals
were addressed during pre-design studies for the Burial Trenches and
Munitions (Testing) Soil Remediation Project. These studies showed that
explosive residue and TCLP-metal concentrations were below risk-based
regulatory levels. Considering these studies, the geology of the area,
as well as the history of the disposal areas, there is no evidence of
explosive or TCLP-metal soil contamination that could act as a source
of groundwater contamination. The discovery of limited additional
contamination at one area subsequent to the original excavation being
completed demonstrates the multiple, sometimes overlapping, elements of
the selected remedy that protect human health and the environment.
These elements include excavation of known contaminated soil, further
evaluation of ecological risks, and collection of confirmatory samples.
EPA ensures that human health is protected from on-going remedial
activities on the remaining NPL areas through effective control of
project emissions, restricting visitor access, and implementation of
the Site-Wide Air Quality Monitoring Program Plan, including monitoring
of air emissions. There are two major project areas that involve
disturbance of contaminated soil remaining in the NPL area. Visitors to
the Refuge are restricted to areas located approximately one mile from
the Lime Basin slurry wall project and approximately two miles from the
Basin F projects. Air emissions are measured at the current fenceline
and near the Visitor Center to verify that potential risks to visitors
and the nearby communities are minimized. These requirements to protect
human health will remain in place irrespective of the deletion of the
Internal Parcel.
EPA's responsiveness summary further explained how only areas which
met the criteria of ``Responsible parties or other persons have
implemented all appropriate response actions required'' (40 CFR
300.425(e)(1)(i)) were considered for deletion. EPA's Partial Deletions
Rule, published November 1, 1995, was intended to allow portions of a
site or an OU that have been cleaned up to be available for productive
use, especially where total site cleanup may take many years. This
description accurately reflects the ongoing cleanup at the RMA/NPL
Site, which is over 50 percent complete, i.e., ten years of the
fifteen-year schedule have passed and 16 of the 31 remedy projects have
been completed. Partial deletion of the Internal Parcel communicates to
the public the successful implementation of the remedy and progress
toward final cleanup. In addition, it helps the Army achieve its goal
of transferring property and furthers the purposes of the RMA National
Wildlife Refuge Act (1992). The Internal Parcel deletion, though
described as ``piece-meal'' by the commenters, is consistent with other
partial deletions that leave islands of an NPL site surrounded or
abutted by deleted lands, e.g., Cecil Field, (68 FR 27746).
The remaining eighty-eight letters supported proceeding with the
Internal Parcel deletion based upon their confidence in the
thoroughness of the cleanup activities conducted by the Department of
the Army (Army) and Shell Oil Company (Shell). EPA agrees that
completion of the remedy requirements as well as recent, site-wide
studies adequately demonstrate that the Internal Parcel does not
present a threat to the environment or human health and deletion of the
Internal Parcel from the RMA/NPL Site is appropriate.
EPA identifies sites that appear to present a significant risk to
public health, welfare, or the environment and maintains the NPL as the
list of those sites. Any site deleted from the NPL remains eligible for
Fund-financed actions in the unlikely event that conditions at the site
warrant such action. Section 300.425(e)(3) of the NCP states that Fund-
financed actions may be taken at sites deleted from the NPL. Deletion
of a site from the NPL does not affect responsible party liability or
impede Agency efforts to recover costs associated with response
efforts.
BILLING CODE 6560-50-P
[[Page 43073]]
[GRAPHIC] [TIFF OMITTED] TR31JY06.000
List of Subjects in 40 CFR Part 300
Environmental protection, Air pollution control, Chemicals,
Hazardous substances, Hazardous waste, Intergovernmental relations,
Penalties, Reporting and recordkeeping requirements, Superfund, Water
pollution control, Water supply.
Dated: July 24, 2006.
Robert E. Roberts,
Regional Administrator, Region 8.
[FR Doc. 06-6572 Filed 7-28-06; 8:45 am]
BILLING CODE 6560-50-C