

[Federal Register: March 13, 2007 (Volume 72, Number 48)]
[Proposed Rules]               
[Page 11313-11319]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr13mr07-15]                         

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 300

[EPA-HQ-SFUND-1989-0011; FRL-8286-7]

 
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 Flats Plant 
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 Peripheral Operable Unit (OU) and Operable 
Unit 3 (OU 3), also referred to as the Offsite Areas, encompassing 
approximately 25,413 acres, of the Department of Energy (DOE) Rocky 
Flats Plant 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). Rocky Flats Plant means the property owned 
by the United States Government, also known as Rocky Flats, Rocky Flats 
Site, or Rocky Flats Environmental Technology Site (RFETS), as 
identified in Figure 1. The Rocky Flats Plant is divided into the 
Central and Peripheral Operable Units (Figure 2) which contain 1,308 
and 4,933 acres, respectively, and OU 3 (Figure 3) which contains 
approximately 20,480 acres. The 3 referenced figures are available as

[[Page 11314]]

described below in the section entitled Docket.
    EPA bases its proposal to delete the Peripheral OU and OU 3 of the 
Rocky Flats Plant 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 media (soil, surface 
water, sediment) and subsurface media, including groundwater, within 
the Peripheral OU and OU 3 of the Rocky Flats Plant. The Central OU 
will remain on the NPL and is not being considered for deletion as part 
of this action.

DATES: Comments must be received on or before April 12, 2007.

ADDRESSES: Submit your comments, identified by Docket ID no. EPA-HQ-
SFUND-1989-0011, by one of the following methods:
     http://www.regulations.gov. Follow on-line instructions 

for submitting comments.
     E-mail: henneke.rob@epa.gov.
     Fax: 303-312-6961.
     Mail: Rob Henneke, Community Involvement Coordinator 
(8OC), U.S. Environmental Protection Agency Region 8, 1595 Wynkoop 
Street, Denver, Colorado 80202-1129.
     Hand delivery: Rob Henneke, 1595 Wynkoop Street, Denver, 
Colorado 80202-1129. Such deliveries are only accepted during normal 
business hours from 8 a.m.--4 p.m., Monday through Friday, excluding 
legal holidays. Special arrangements should be made for deliveries of 
boxed information.
    Instructions: Direct your comments to Docket ID no. EPA-HQ-SFUND-
1989-0011. 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, not 
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 and referenced figures 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 
information whose disclosure is restricted by statute. Certain other 
material, such as copyrighted material, will be publicly available only 
in the hard copy. Publicly available docket materials may be accessed 
at the following locations during specified hours of operation. The 
U.S. EPA Region 8 Docket Facility, EPA Technical Library, 1595 Wynkoop 
Street, Denver, Colorado 80202-1129, is open from 8 a.m. to 4 p.m. by 
appointment, Monday through Friday, excluding legal holidays. The EPA 
Docket telephone number is 303-312-6734. The DOE Rocky Flats Plant 
Docket Facility is located at Front Range Community College, 3705 112 
Avenue, Westminster, Colorado, 80030. The Rocky Flats Plant Docket 
Facility is open from 9 a.m. to 5 p.m., Monday through Thursday and 10 
a.m. to 5 p.m., Friday, excluding legal holidays.

FOR FURTHER INFORMATION CONTACT: Rob Henneke, Community Involvement 
Coordinator (8OC), U.S. Environmental Protection Agency Region 8, 1595 
Wynkoop Street, Denver, CO 80202-1129; telephone number: 1-800-227-8917 
or (303) 312-6734; fax number: 303-312-7150; e-mail address: 
henneke.rob@epa.gov.


SUPPLEMENTARY INFORMATION: 

Table of Contents

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

I. Introduction

    EPA Region 8 announces its intent to delete the Peripheral OU and 
OU 3 of the Rocky Flats Plant, Jefferson and Boulder Counties, 
Colorado, from the NPL and requests comment on this proposed action. 
The NPL constitutes Appendix B of the NCP, 40 CFR Part 300, which EPA 
promulgated pursuant to Section 105 of 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 NPL (60 FR 55466 
(November 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 Rocky Flats Plant for 30 days after publication of this notice 
in the Federal Register (FR).
    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 
Peripheral OU and OU 3 of the Rocky Flats Plant 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 
40 CFR 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;
     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 of 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

[[Page 11315]]

or impede agency efforts to recover costs associated with response 
efforts. DOE 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 Peripheral OU and OU 3 of the Rocky Flats 
Plant from the NPL:
    (1) DOE has requested the partial deletion and has prepared the 
relevant documents.
    (2) The State of Colorado, through 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 30 
day public comment period on the deletion package, which ends on April 
12, 2007, 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 30 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 repositories 
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 Peripheral OU and OU 3 of the 
Rocky Flats Plant 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 repositories listed above after a final 
document has been published in the Federal Register.

IV. Basis for Intended Partial Deletion

    The following provides EPA's rationale for deletion from the NPL of 
the Rocky Flats Plant Peripheral OU and OU 3 and EPA's finding that the 
criteria in 40 CFR 300.425(e) are satisfied.

Site Background and History

    The Rocky Flats Plant is a DOE facility owned by the United States. 
Rocky Flats is located in the Denver metropolitan area, approximately 
sixteen miles northwest of Denver, Colorado, and ten miles south of 
Boulder, Colorado. Nearby communities include the Cities of Arvada, 
Broomfield, and Westminster, Colorado. The majority of the Site is 
located in Jefferson County, with a small portion located in Boulder 
County, Colorado.
    Rocky Flats Plant was proposed by EPA for inclusion on the CERCLA 
NPL in 1984, and was added to the CERCLA NPL on September 21, 1989 (54 
FR 41015, October 4, 1989). The EPA Superfund Identification Number for 
Rocky Flats Plant is CO7890010526. The Site was proposed for listing 
because activities at Rocky Flats resulted in the release of materials 
defined by CERCLA as hazardous substances, contaminants, and 
pollutants, as well as hazardous wastes and hazardous waste 
constituents as defined by the Resource Conservation Recovery Act 
(RCRA) and Colorado Hazardous Waste Act (CHWA). Contaminants released 
to the environment from the activities at Rocky Flats have included, 
but were not limited to: Radionuclides (such as plutonium, americium, 
and various uranium isotopes), organic solvents (such as 
trichloroethene, tetrachloroethene, and carbon tetrachloride), metals 
(such as chromium), and nitrates. Apart from the activities of DOE and 
its contractors at the Site, there are no other known, significant, 
human-caused sources of contamination at Rocky Flats.
    Two Operable Units (OUs) are present within the boundaries of the 
Site: the Peripheral OU and the Central OU. The Central OU consolidated 
all areas of the Site that required remedial actions, while also 
considering practicalities of future land management. The Central OU is 
not included within this proposed partial deletion action. The 
Peripheral OU includes the majority of the Buffer Zone and was left 
undisturbed. This land provided a security and safety buffer area 
around the former manufacturing areas of the Site. Portions of the 
Buffer Zone have been co-managed by the U.S. Fish and Wildlife Service 
for ecological resources since 1999. Based upon the RCRA Facility 
Investigation--Remedial Investigation/Corrective Measures Study--
Feasibility Study Report for the Rocky Flats Environmental Technology 
Site (RI/FS) Report, which included both a Human Health and Ecological 
Risk Assessment, DOE (as the Lead Agency under CERCLA) determined that 
no action was necessary to protect public health, welfare or the 
environment for the Peripheral OU. That decision was supported and 
documented in the Rocky Flats Environmental Technology Site Corrective 
Action Decision/Record of Decision (CAD/ROD) signed by DOE, CDPHE and 
EPA, Region 8 on September 29, 2006.
    OU 3 encompasses an area north, south, and primarily east of the 
Peripheral and Central OUs. OU 3 was addressed under a separate CAD/
ROD, Corrective Action Decision/Record of Decision Operable Unit 3, The 
Offsite Areas Rocky Flats Environmental Technology Site dated April 
1997. The OU 3 CAD/ROD was signed by DOE, CDPHE and EPA, Region 8 on 
June 3, 1997 and determined that no action was necessary to protect 
public health, welfare or the environment.
A. Peripheral Operable Unit
    The RI/FS Report was prepared in accordance with the Interim Final 
Guidance for Conducting Remedial Investigations and Feasibility Studies 
under CERCLA. Because remedial activities at RFETS were conducted under 
RCRA and CHWA, this RI/FS Report also met RCRA/CHWA requirements for an 
RCRA Facility Investigation/Corrective Measures Study (RFI/CMS) Report. 
References to CERCLA requirements were also intended to encompass RCRA/
CHWA requirements. For simplicity, the report is hereinafter referred 
to as the RI/FS Report. The RI/FS Report, approved by EPA and CDPHE on 
July 5, 2006, was the basis for development of the Rocky Flats 
Environmental Technology Site Proposed Plan that described the 
preferred remedy. The Proposed Plan was the basis for the Final CAD/
ROD.
A.1 Description of the Peripheral OU Remedial Investigation
    DOE began more than 20 years ago to develop an extensive body of 
documentation about the use of hazardous substances and the known or 
suspected release of hazardous substances at Rocky Flats. Information 
was gathered from an extensive review

[[Page 11316]]

of Rocky Flats operating records and contemporaneous documents. In 
addition, interviews were conducted of persons with knowledge of Rocky 
Flats operations and of events that did release or were suspected of 
releasing hazardous substances. The information collected is organized 
in the Rocky Flats Historical Release Report (HRR), originally 
published in 1992, which has been periodically updated as investigation 
and cleanup of the Site progressed. The final version of the HRR is 
provided as Appendix B of the RI/FS report entitled FY2005 FINAL 
Historical Release Report dated October 2005.
    Sampling and analysis of surface and subsurface soil, groundwater, 
and surface water were extensively used to locate and measure hazardous 
substance contamination at historical release locations and guide the 
conduct and completion of remediation activities. Environmental 
monitoring was performed under the auspices of a site-wide integrated 
monitoring plan. Additional monitoring was conducted pursuant to 
environmental permits, including the National Pollutant Discharge 
Elimination System permit and the State of Colorado Air Quality 
Operating Permit, issued to DOE and its contractors.
    Environmental data for Rocky Flats were collected in accordance 
with agency-approved Sampling and Analysis Plans (SAPs) and 
standardized contract-required analytical procedures. Approved Work 
Plans and SAPs specified the use of EPA-approved sampling procedures 
and analytical methods, data quality requirements, and data management 
processes, and specified the appropriate data quality objectives. 
Documented releases of hazardous substances at Rocky Flats include 
radionuclides, volatile organic compounds (VOCs), and semivolatile 
organic compounds (SVOCs), inorganic compounds, and metals.
    Known or suspected release locations (primarily soil) were 
delineated by 183 Individual Hazardous Substance Sites (IHSSs), 146 
Potential Areas of Concern (PACs), 31 Under Building Contamination 
(UBC) Sites, and 61 Potential Incidents of Concern (PICs) (totaling 421 
areas). The IHSSs, PACs, UBC Sites, and PICs were thoroughly 
investigated and characterized, as appropriate, and accelerated 
actions, including non-time critical removals, triggered by 
contamination levels have been confirmed as completed and met response 
goals.
    The nature and extent of contamination evaluations considered the 
following environmental media: soil, groundwater, surface water, 
sediment, and air. These evaluations were conducted to show the types 
of analytes of interest (AOIs) remaining in the environmental media and 
their extent at Rocky Flats following the completion of accelerated 
actions. The purpose of identifying AOIs was to focus the nature and 
extent evaluation on constituents that were detected at concentrations 
that may contribute to the risk to future receptors and to show the 
overall spatial and temporal trends of those constituents on a sitewide 
basis. These evaluations identified 14 AOIs for surface soil, 14 AOIs 
for subsurface soil, 19 AOIs for groundwater, 18 AOIs for surface 
water, 5 AOIs for sediment, and 5 AOIs for air. The contaminant fate 
and transport evaluation used information about the Site physical 
characteristics, contaminant source characteristics, and contaminant 
distribution across the Site to develop a conceptual understanding of 
the dominant transport processes that affect the migration of different 
contaminants in various Rocky Flats environmental media. The primary 
focus was evaluating the potential for contaminants from any medium to 
impact surface water quality. Evaluation of a contaminant's fate and 
transport was based upon two criteria: (1) Does a complete migration 
pathway to a potential receptor exist based on an evaluation of 
contaminant transport in each environmental medium; and (2) is there a 
potential impact to surface water quality based on an evaluation of 
data at representative groundwater and surface water monitoring 
locations in the creek drainages.
    The RI included a Comprehensive Risk Assessment (CRA). The CRA 
consisted of two parts: Human Health Risk Assessment (HHRA) and 
Ecological Risk Assessment (ERA). The CRA was designed to provide 
information to decision makers to help determine the effectiveness of 
the accelerated actions and select a final remedy that is protective of 
human health and the environment. The CRA evaluated the risks posed by 
conditions at the Site to the anticipated future users (wildlife 
workers and visitors) and anticipated future land use. The CRA did not 
evaluate an unrestricted use scenario, but did consider an indoor air 
pathway, if occupied structures were to be present at the Site in the 
future.
    The Peripheral OU was determined to be unimpacted by hazardous 
substances, pollutants or contaminants with the exceptions subsequently 
discussed. A small portion of the Peripheral OU was impacted by Site 
activities from a radiological perspective. For example, plutonium 
exists above background in surface soil in small areas within the 
Peripheral OU. A few sampling locations for plutonium within the 
Peripheral OU exceed a level of 9.8 picocuries per gram (pCi/g), which 
corresponds to a 1 x 10-6 risk level for a wildlife refuge 
worker. Of these few sampling locations, the highest result is 
approximately 20 pCi/g. If that highest concentration of 20 pCi/g was 
considered the average concentration over an appropriate exposure unit, 
it would correspond to a risk of approximately 1 x 10-5 for 
a resident, which would be in the middle of the CERCLA risk range 
(10-6 to 10-4). These levels of radioactivity are 
also far below the 231 pCi/g activity level for an adult rural 
resident, which equates to the 25-millirem per year dose criterion 
specified in the Colorado Standards for Protection Against Radiation.
A.2 Declaration Statement for the Peripheral OU CAD/ROD
    Based upon the RI/FS Report, which included both a Human Health and 
Ecological Risk Assessment, DOE (as the Lead Agency under CERCLA) 
determined that no action was necessary to protect public health or 
welfare or the environment for the Peripheral OU.
    The RI/FS Report concluded that the Peripheral OU was in a state 
protective of human health and the environment. The NCP provides for 
the selection of a no action remedy when an OU is in such a protective 
state and therefore, no remedial action for the Peripheral OU was 
warranted. The selected remedy for the Peripheral OU was no action.
A.3 Peripheral OU Conclusions
    The selected remedy for the Peripheral OU meets the requirements of 
CERCLA Section 121, and to the extent practicable, the NCP. The 
selected remedy for the Peripheral OU is protective of human health and 
the environment, complies with Federal and State requirements, and is 
cost-effective. The selected remedy complies with applicable 
requirements of the CHWA. No accelerated actions were taken in the 
Peripheral OU, and no remedial action alternatives other than the no 
action alternative were required to be evaluated for the Peripheral OU. 
Because no hazardous substances, pollutants, or contaminants occur in 
the Peripheral OU above levels that allow for unlimited use and 
unrestricted exposure, no five-year review is required for this remedy.
B. Operable Unit 3 (Offsite Areas)
    The OU 3 CAD/ROD was prepared by DOE, Rocky Flats Field Office, 
Golden,

[[Page 11317]]

Colorado, in April 1997, and was signed by DOE, CDPHE, and EPA Region 8 
on June 3, 1997. The following is the basis for deleting OU3 and is a 
part of the deletion docket.
    OU 3 was investigated and a remedy was selected in compliance with 
the Federal Facility Agreement and Consent Order--Interagency Agreement 
(IAG), signed by DOE, CDPHE, and EPA on January 22, 1991. The selected 
remedy is also consistent with the Federal Facility Agreement and 
Consent Order--Rocky Flats Cleanup Agreement (RFCA), signed by DOE, 
CDPHE, and EPA on July 19, 1996.
    OU 3 is one of sixteen OUs at Rocky Flats identified in the 1991 
IAG, and is the only one not located within the RFETS boundaries. The 
1996 RFCA consolidated the original sixteen OUs into three OUs, but OU 
3 remained separate, owing both to its unique geographic location and 
to the fact that investigations and administrative activity for OU 3 
were nearly completed when the 1996 RFCA was signed. OU 3 is comprised 
of four Individual Hazardous Substance Sites (IHSSs): Contamination of 
the Land's Surface (IHSS 199), Great Western Reservoir (IHSS 200), 
Standley Lake (IHSS 201) and Mower Reservoir (IHSS 202). IHSSs are 
specific locations where hazardous substances, solid wastes, 
pollutants, contaminants, hazardous wastes or hazardous constituents 
may have been disposed of or released to the environment from Rocky 
Flats at any time in the past.
B.1 Description of the OU 3 Remedial Investigation
    The selected remedy for OU 3 was no action. A Baseline Risk 
Assessment (BRA), including an HHRA and an ERA, was conducted as part 
of the OU 3 Resource Conservation and Recovery Act (RCRA) Facility 
Investigation. The RCRA Facility Investigation/CERCLA Remedial 
Investigation (RFI/RI) Report was completed in accordance with 
requirements presented in the Interagency Agreement and specifically 
identified in the OU3 RFI/RI Work Plan and addenda. The RFI/RI Report 
evaluated human health risks based upon exposure to identified 
Contaminants of Concern (COCs) and was reported as the probability of 
an individual developing cancer as a result of exposure to OU 3 
contamination under recreational and residential exposure scenarios. 
Assumptions regarding future land use provided the basis to calculate 
human health risks for both IHSS 199 and for IHSS 200. No COCs were 
identified in surface water samples collected from Standley Lake, Great 
Western Reservoir, and Mower Reservoir.
    For IHSS 199, risks from both plutonium and americium were 
calculated and were assumed to be additive. For IHSS 200, only the 
risks associated with plutonium were calculated, as plutonium was the 
only COC there. In both IHSSs, the highest contaminant concentration 
was used in risk calculations. The RFI/RI Report also calculated 
radiation doses that would be expected as a result of the recreational 
and residential scenarios described in the OU 3 CAD/ROD.
    Excess lifetime cancer risk (that is, the incremental additional 
cancer risk that is incurred through exposure to COCs at OU 3 or any 
other contaminated site) is calculated by multiplying the average daily 
chemical intake over a lifetime of exposure by the contaminant's 
individual slope factor. For radionuclides, slope factors are the 
average risk per unit intake or exposure for an individual in a 
stationary population with mortality rates typical of those in the 
United States in 1970. EPA guidelines indicate that excess lifetime 
cancer risks which are within or below the one in ten thousand (1 x 
10-4) to one in one million (1 x 10-6) range are 
considered protective of human health.
    For IHSS 199, the highest calculated excess cancer risk, assuming 
reasonable maximum exposures (RME) under a residential exposure was 
three in one million (3 x 10-6). Using central tendency, the 
risk under a residential scenario was two in ten million (2 x 
10-7). For the recreational exposure, the excess cancer risk 
was five in one hundred million (5 x 10-8) using the RME, 
and three in one billion (3 x 10-9) using central tendency.
    For IHSS 200, the highest calculated excess cancer risk employing 
RME and the residential exposure was nine in ten million (9 x 
10-7); the corresponding risk using central tendency was six 
in one hundred million (6 x 10-8). Using the recreational 
scenario, the highest risk using RME was one in one hundred million (1 
x 10-8), and the risk using central tendency was eight in 
ten billion (8 x 10-10).
    The highest calculated radiation dose for IHSSs 199 and 200 
occurred using the RME, assuming a residential exposure scenario. The 
highest Total Effective Dose Equivalent (TEDE, which incorporates both 
internal and external radiation dose) for IHSS 199 for an adult was 
0.12 millirem per year (mrem/yr); the corresponding TEDE for IHSS 200 
is 0.0065 mrem/yr. The average radiation dose in the U.S. is estimated 
to be about 300 mrem/year, while the average dose in Colorado may be as 
much as 700 mrem/year, owing to the state's higher altitude and 
relative abundance of naturally occurring radionuclides.
    These levels of radioactivity are also far below the 231 pCi/g 
activity level for an adult rural resident that equates to the 25 mrem/
year dose criterion specified in the Colorado Standards for Protection 
Against Radiation. Based on these results, the Peripheral OU is 
determined to be acceptable for all uses from a radiological 
perspective.
    The RFI/RI Report evaluated health risks and radiation dose from 
surface water. Surface water was sampled for plutonium and americium. 
The maximum and mean concentrations of plutonium and americium detected 
in surface water from the reservoirs were well below the CDPHE 
standards, the National Drinking Water Standards, and the Rocky Flats 
Site specific standards for plutonium and americium.
    DOE submitted the RFI/RI Report to the Agency for Toxic Substances 
and Disease Registry (ATSDR), a part of the federal Center for Disease 
Control, for the purpose of obtaining a Health Consultation. The 
purpose of the Health Consultation was to obtain an independent 
evaluation as to whether COCs had been adequately identified in OU 3, 
the risks to human health posed by releases of hazardous substances in 
OU 3 adequately analyzed, and whether the proposal for no remedial 
action in OU 3 was appropriate considering these risks. The ATSDR 
concluded that the COC selection process was based on reasonable 
assumptions, and that none of the constituents present in OU 3 posed 
public health concerns. Further, the ATSDR Health Consultation stated 
that no additional activities were needed in OU 3 in order to ensure 
the public's health.
    Based upon the BRA and the ERA contained in the RFI/RI Report, DOE, 
the lead agency under CERCLA for OU 3, concluded that no action was 
appropriate for OU 3. The RFI/RI Report concluded that all IHSSs within 
OU 3 are already protective of human health and the environment. Field 
and laboratory work showed no indications of adverse effects from 
plutonium or americium on the ecology of OU 3. The NCP provides for the 
selection of a no action remedy when an OU is in such a protective 
state. Therefore, no remedial action regarding OU 3 or any of its 
constituent IHSSs was warranted.
B.2 Declaration Statement for Offsite Areas OU CAD/ROD
    DOE in consultation with CDPHE and EPA, determined that no remedial 
action was necessary for OU 3 to be

[[Page 11318]]

protective of human health, welfare and the environment. No hazardous 
substances, pollutants or contaminants remain within the boundaries of 
OU3 above levels that allow for unlimited use and unrestricted 
exposure, as these levels have been calculated in the OU 3 RFI/RI 
Report.
B.3 Evaluation of OU3 CAD/ROD Data in First Five-Year Review
    A five-year review of the OU 3 CAD/ROD was conducted to assess the 
continued protectiveness of the remedy. The OU 3 CAD/ROD concluded that 
transport by wind and water was the primary means by which plutonium 
and americium were carried to OU 3. Therefore, available air and water 
monitoring data collected after the OU 3 CAD/ROD was signed were 
reviewed to determine if environmental conditions at OU 3 have changed 
since the BRA was completed. The air monitoring data from the RFETS 
perimeter air monitoring network were analyzed and the conclusion was 
that the amounts of plutonium and americium that have been measured at 
the RFETS perimeter since 1997 have been environmentally insignificant. 
These amounts of plutonium and americium would not have caused 
contaminant levels in OU 3 to change significantly since the OU 3 CAD/
ROD was signed. Water monitoring data from the RFCA Points of 
Compliance on Woman Creek and Walnut Creek at Indiana Street, and data 
collected by the City of Broomfield for Great Western Reservoir, were 
analyzed. Samples of water leaving RFETS showed consistent compliance 
with RFCA surface water standards, and water samples from Great Western 
Reservoir were consistently at or below detection limits for plutonium 
and americium. The report also included a Protectiveness Statement as 
required by EPA guidance. Pursuant to the Protectiveness Statement, 
DOE's ongoing custody and control of RFETS, ongoing monitoring 
programs, and restriction of public access serve to adequately control 
risks posed by contamination at RFETS. The no action decision for OU 3 
was determined to be adequately protective.
    Review of air monitoring data and water quality data at the Points 
of Compliance since the first five-year review also indicate there have 
not been significant amounts of plutonium or americium that have 
entered OU 3 through the air or water pathways. Therefore, 
environmental conditions at OU 3 have not changed significantly since 
the OU 3 CAD/ROD was signed.
B.4 OU 3 Conclusions
    Conditions in OU 3 pose no unacceptable or significant risks to 
human health or the environment; future unacceptable or significant 
exposures will not occur there as a result of past contamination. DOE 
concluded that no action was necessary in OU 3 for the protection of 
human health or the environment. Reviews following the OU 3 CAD/ROD 
have concluded that environmental conditions at OU 3 have not changed 
significantly since the OU 3 CAD/ROD was signed.

Community Involvement

    Public Participation activities for the cleanup of the Peripheral 
OU and OU 3 were conducted as required under CERCLA Section 113(k), 42 
U.S.C. 9613(k) and Section 117, 42 U.S.C. 9617. Public review included 
the following activities:
A. Community Involvement for the Peripheral OU
    The Draft RI/FS Report for the RFETS was released for public review 
and information in October 2005, and was available at that time in the 
Rocky Flats public reading rooms and online. Several informational 
public meetings on the draft RI/FS were held, at which representatives 
from DOE and its contractor, EPA and CDPHE were present to answer 
questions. These meetings included a discussion at the Rocky Flats 
Citizens Advisory Board meeting on November 3, 2005. The final RI/FS 
report was approved by EPA and CDPHE on July 5, 2006. Copies of the 
final RI/FS report were placed at seven information centers in the 
Denver metropolitan area on July 14, 2005. In addition, the RI/FS 
report was available on line at http://www.rfets.gov, and copies on 

compact disc were available at the public information meetings during 
the comment period for the Proposed Plan. DOE, EPA and CDPHE held a 
pre-release informational meeting for the Proposed Plan on May 30, 
2006, to explain changes that were made to the draft RI/FS report, and 
to describe the major components of the Proposed Plan. The Proposed 
Plan was released for formal public comment on July 14, 2006. Notice of 
the public comment period appeared in The Rocky Mountain News and The 
Denver Post from May 22 through May 28, 2006, and was also provided at 
the informational public meeting. DOE sent out community and media 
advisories prior to the release of the Proposed Plan, and prior to each 
informational meeting and the public hearing. The Proposed Plan was 
placed in seven information centers in the Denver metropolitan area, 
was available at the informational meetings held during the comment 
period, and was available on line at http://www.rfets.gov. The Proposed 

Plan included discussions on future land use and use of groundwater at 
Rocky Flats. The Rocky Flats administrative record file was available 
for public review at the Front Range Community College reading room in 
Westminster, Colorado, as well as on line at http://www.rfets.gov.

    DOE held two informational meetings during the public comment 
period, at which agency representatives presented the scope and purpose 
of the Proposed Plan, discussed opportunities to provide input on the 
Proposed Plan, and responded to questions from the public. The first 
informational meeting was held on July 19, 2006 in Golden, Colorado, 
and the second informational meeting took place in Westminster, 
Colorado on August 8, 2006. Prior notice of each meeting was provided 
through advertisements in the aforementioned newspapers, running from 
July 13 through July 19, 2006, and again from August 2 through August 
8, 2006. A public hearing for the Proposed Plan took place on August 
31, 2006 in Arvada, Colorado; separate sessions were held in the 
afternoon and in the evening on that date to accommodate as many 
members of the public as possible. Prior notice of the public hearing 
was accomplished through advertisements in the aforementioned 
newspapers that ran from August 25 through August 31, 2006, with a 
display ad posted in both papers on August 29, 2006. Both written and 
oral public comments were accepted at the public hearing. A transcript 
of the public hearing has been made available to the public and placed 
in the Rocky Flats administrative record file.
    The public comment period for the Proposed Plan extended from July 
14 through September 13, 2006. No requests for extension of the public 
comment period were received. DOE's responses to public comments 
received during the comment period are included in the Responsiveness 
Summary section of the RFETS CAD/ROD.
B. Community Involvement for OU 3
    DOE submitted the final RFI/RI Report for OU 3 to EPA on July 11, 
1996 following resolution of final comments by EPA, CDPHE, the City of 
Broomfield, and the City of Westminster. Regulatory approval to release 
the OU 3 Proposed Plan for public comment was granted on August 7, 
1996.
    The Proposed Plan was released for public comment on August 7, 
1996. A

[[Page 11319]]

public hearing on the OU 3 Proposed Plan was held on September 18, 1996 
at the Arvada Center for the Performing Arts and Humanities in Arvada, 
Colorado. Citizen comments received at the public hearing were recorded 
and responses to those comments were included in a Responsiveness 
Summary. The public comment period for the OU 3 Proposed Plan ended on 
October 11, 1996. Written comments on the Proposed Plan were received 
from the Cities of Westminster and Broomfield. Responses to those 
written comments were also included in the Responsiveness Summary.

Current Status

    The RFETS RI/FS Report concluded that the Peripheral OU was already 
in a state protective of human health and the environment, therefore 
the selected remedy in the RFETS CAD/ROD for the Peripheral OU was no 
action. No accelerated actions were taken in the Peripheral OU, and no 
remedial action alternatives were evaluated for the Peripheral OU. 
Because no hazardous substances, pollutants, or contaminants occur in 
the Peripheral OU above levels that allow for unlimited use and 
unrestricted exposure, a five-year review was not required for this 
remedy. This documentation provides the technical justification for 
deletion of the Peripheral Operable Unit, Rocky Flats Plant from the 
NPL.
    For the OU 3 (Offsite Areas) conditions were determined to be 
protective of human health and the environment at the time the OU 3 
CAD/ROD was signed in 1997, and again during the first five-year review 
finalized in September 2002. Since then, summary data for OU 3 has been 
reviewed and indicate that conditions have not changed to alter 
conclusions of earlier OU 3 assessments. This documentation provides 
the technical justification for deletion of OU 3 (Offsite Areas), Rocky 
Flats Plant from the NPL.
    EPA, with concurrence from CDPHE, has determined that all 
appropriate CERCLA response actions have been completed within the 
Peripheral OU and OU 3 to protect public health and the environment and 
that no further response action by responsible parties is required. 
Therefore, EPA proposes to delete the Peripheral OU and OU 3 of the 
Rocky Flats Plant from the NPL.

    Dated: March 1, 2007.
Robert E. Roberts,
Regional Administrator, Region 8.
 [FR Doc. E7-4449 Filed 3-12-07; 8:45 am]

BILLING CODE 6560-50-P
