[Federal Register Volume 84, Number 141 (Tuesday, July 23, 2019)]
[Rules and Regulations]
[Pages 35324-35334]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-15633]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 300

[EPA-HQ-SFUND-1983-0002 FRL-9996-98-Region 5]


National Oil and Hazardous Substances Pollution Contingency Plan; 
National Priorities List: Partial Deletion of the New Brighton/Arden 
Hills/Twin Cities Army Ammunition Plant (TCAAP) Superfund Site

AGENCY: Environmental Protection Agency (EPA).

ACTION: Direct final rule.

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SUMMARY: The Environmental Protection Agency (EPA) Region 5 is 
publishing a direct final Notice of Partial Deletion of all soil and 
five aquatic sites in Operable Unit 2 (OU2) of the New Brighton/Arden 
Hills/TCAAP Superfund Site in Minnesota from the National Priorities 
List (NPL). The NPL, promulgated pursuant to Section 105 of the 
Comprehensive Environmental Response, Compensation, and Liability Act 
(CERCLA) of 1980, as amended, is an appendix of the National Oil and 
Hazardous Substances Pollution Contingency Plan (NCP). This direct 
final partial deletion is being published by EPA with the concurrence 
of the State of Minnesota, through the Minnesota Pollution Control 
Agency, because all appropriate response actions for soil and these 
five aquatic sites under CERCLA, other than maintenance, monitoring and 
five-year reviews, have been completed. However, this partial deletion 
does not preclude future actions under Superfund.

DATES: This direct final partial deletion is effective September 23, 
2019 unless EPA receives adverse comments by August 22, 2019. If 
adverse comments are received, EPA will publish a timely withdrawal of 
the direct final partial deletion in the Federal Register informing the 
public that the partial deletion will not take effect.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-
SFUND-1983-0002 by one of the following methods:
    https://www.regulations.gov. Follow the on-line instructions for 
submitting comments. Once submitted, comments cannot be edited or 
removed from Regulations.gov. The EPA may publish any comment received 
to its public docket. Do not submit electronically any information you 
consider to be Confidential Business Information (CBI) or other 
information whose disclosure is restricted by statute. Multimedia 
submissions (audio, video, etc.) must be accompanied by a written 
comment. The written comment is considered the official comment and 
should include discussion of all points you wish to make. The EPA will 
generally not consider comments or comment contents located outside of 
the primary submission (i.e., on the web, cloud, or other file sharing 
system). For additional submission methods, the full EPA public comment 
policy, information about CBI or multimedia submissions, and general 
guidance on making effective comments, please visit https://www2.epa.gov/dockets/commenting-epa-dockets.
    Email: [email protected].
    Mail: Randolph Cano, NPL Deletion Coordinator, U.S. Environmental 
Protection Agency Region 5 (ST-6J), 77 West Jackson Boulevard, Chicago, 
IL 60604, (312) 886-6036.
    Hand deliver: Superfund Records Center, U.S. Environmental 
Protection Agency Region 5, 77 West Jackson Boulevard, 7th Floor South, 
Chicago, IL 60604, Phone: (312) 886-0900. Such deliveries are only 
accepted during the Docket's normal hours of operation, and special 
arrangements should be made for deliveries of boxed information. The 
normal business hours are Monday through Friday, 8 a.m. to 4 p.m., 
excluding Federal holidays.
    Instructions: Direct your comments to Docket ID no. EPA-HQ-SFUND-
1983-0002. EPA's policy is that all comments received will be included 
in the public docket without change and may be made available online at 
https://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 https://www.regulations.gov or email. The https://www.regulations.gov website 
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 email comment directly to EPA without 
going through https://www.regulations.gov, your email 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

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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 https://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 hard copy. 
Publicly available docket materials are available either electronically 
at https://www.regulations.gov or electronically or in hard copy at:
    U.S. Environmental Protection Agency, Region 5, Superfund Records 
Center, 77 West Jackson Boulevard, 7th Floor South, Chicago, IL 60604, 
Phone: (312) 886-0900, Hours: Monday through Friday, 8 a.m. to 4 p.m., 
excluding Federal holidays.
    Minnesota National Guard, 4761 Hamline Avenue North, Arden Hills, 
MN 55112, Contact: Mary Lee, Arden Hills Army Training Site, Phone: 
(651) 282-4420. Hours: Monday through Friday, 8 a.m. to 3:30 p.m., 
excluding State holidays.

FOR FURTHER INFORMATION CONTACT: Randolph Cano, NPL Deletion 
Coordinator, U.S. Environmental Protection Agency Region 5 (ST-6J), 77 
West Jackson Boulevard, Chicago, IL 60604, Phone: (312) 886-6036, or 
via email at [email protected].

SUPPLEMENTARY INFORMATION:

Table of Contents

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

I. Introduction

    EPA Region 5 is publishing this direct final Notice of Partial 
Deletion for the New Brighton/Arden Hills/Twin Cities Army Ammunition 
Plant Site (NB/AH/TCAAP Site), from the NPL. This partial deletion 
pertains to all soil (shallow and deep) located within the boundary of 
OU2 of the NB/AH/TCAAP Site and to the surface water and sediment (not 
groundwater) of the five aquatic sites located within the OU2 boundary: 
Rice Creek, Sunfish Lake, Marsden Lake North, Marsden Lake South and 
Pond G (see Figures 2-2 and 11-1 in the Docket). The remaining areas at 
the NB/AH/TCAAP Site, including OU1, OU3, groundwater in OU2 and a 
sixth aquatic site, Round Lake located southwest of the OU2 boundary, 
will remain on the NPL and are not being considered for deletion as 
part of this action.
    The NPL constitutes Appendix B of the NCP, which EPA promulgated 
pursuant to CERCLA. EPA maintains the NPL as the list of sites that 
appear to present a significant risk to public health, welfare, or the 
environment. Sites on the NPL may be the subject of remedial actions 
financed by the Hazardous Substance Superfund (Fund). This partial 
deletion of the NB/AH/TCAAP Site is proposed in accordance with 40 CFR 
300.425(e) and is consistent with the 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) of the NCP, a 
portion of a site deleted from the NPL remains eligible for Fund-
financed remedial actions if future conditions warrant such actions.
    Section II of this document explains the criteria for deleting 
sites from the NPL. Section III discusses procedures that EPA is using 
for this action. Section IV discusses the shallow and deep soil and the 
five aquatic sites located within OU2 of the NB/AH/TCAAP Site and 
demonstrates how they meet the deletion criteria. Section V discusses 
EPA's action to partially delete the soil and five aquatic sites 
located within the OU2 boundary of the NB/AH/TCAAP Site from the NPL 
unless adverse comments are received during the public comment period.

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, or portions 
thereof, may be deleted from the NPL where no further response is 
appropriate. 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:
    i. Responsible parties or other persons have implemented all 
appropriate response actions required;
    ii. all appropriate Fund-financed response under CERCLA has been 
implemented, and no further response action by responsible parties is 
appropriate; or
    iii. the remedial investigation has shown that the release poses no 
significant threat to public health or the environment and, therefore, 
the taking of remedial measures is not appropriate.
    Pursuant to CERCLA Section 121(c) and the NCP, EPA conducts five-
year reviews to ensure the continued protectiveness of remedial actions 
where hazardous substances, pollutants, or contaminants remain at a 
site above levels that allow for unlimited use and unrestricted 
exposure. EPA conducts such five-year reviews even if a site or a 
portion of a site is deleted from the NPL. EPA may initiate further 
action to ensure continued protectiveness at a deleted site if new 
information becomes available that indicates it is appropriate. 
Whenever there is a significant release from a site deleted from the 
NPL, the deleted site may be restored to the NPL without application of 
the hazard ranking system.

III. Deletion Procedures

    The following procedures apply to the deletion of the soil portion 
of OU2 and to the five aquatic sites located within the OU2 boundary of 
the NB/AH/TCAAP Site:
    (1) EPA consulted with the State of Minnesota prior to developing 
this direct final Notice of Partial Deletion and the Notice of Intent 
for Partial Deletion co-published today in the ``Proposed Rules'' 
section of the Federal Register.
    (2) EPA has provided the State 30 working days for review of this 
notice and the parallel Notice of Intent for Partial Deletion prior to 
their publication today, and the State, through the MPCA, has concurred 
on the partial deletion of the NB/AH/TCAAP Site from the NPL.
    (3) Concurrent with the publication of this direct final Notice of 
Partial Deletion, an announcement of the availability of the parallel 
Notice of Intent for Partial Deletion is being published in three major 
local newspapers, the Minneapolis Star Tribune, The Mounds View/New 
Brighton Sun Focus and the Shoreview Press. The newspaper notices 
announce the 30-day public comment period concerning the Notice of 
Intent for Partial Deletion of the NB/AH/TCAAP Site from the NPL.
    (4) The EPA placed copies of documents supporting the partial 
deletion in the deletion docket and made these items available for 
public inspection and copying at the NB/AH/TCAAP Site information 
repositories identified above.
    (5) If adverse comments are received within the 30-day public 
comment period on this partial deletion action, EPA will publish a 
timely notice of withdrawal of this direct final Notice of Partial 
Deletion before its effective date and will prepare a response to 
comments and continue with the deletion process on the basis of the

[[Page 35326]]

Notice of Intent for Partial Deletion and the comments already 
received.
    Deletion of a portion of a site from the NPL does not itself 
create, alter, or revoke any individual's rights or obligations. 
Deletion of a portion of a site from the NPL does not in any way alter 
EPA's right to take enforcement actions, as appropriate. The NPL is 
designed primarily for informational purposes and to assist EPA 
management. Section 300.425(e)(3) of the NCP states that the deletion 
of a site from the NPL does not preclude eligibility for further 
response actions, should future conditions warrant such actions.

IV. Basis for Partial Site Deletion

    The following information provides EPA's rationale for deleting the 
soil portion of OU2 and the five aquatic sites located within the OU2 
boundary (Rice Creek, Sunfish Lake, Marsden Lake North, Marsden Lake 
South and Pond G) of the NB/AH/TCAAP Site from the NPL:

Site Background and History

    The NB/AH/TCAAP Site (CERCLIS ID: MN7213820908) consists of a 25-
square mile area located in Ramsey County, Minnesota. The NB/AH/TCAAP 
Site includes the 4-square mile area of the original TCAAP facility 
(about 2,370 acres) operated by the U.S Army (Army), located east of 
U.S. Interstate Highway 35W and north of Ramsey County Highway 96 at 
the time of NPL listing in 1983 (OU2) and portions of seven nearby 
communities with Site-related groundwater contamination (OU1 and OU3). 
These communities include: New Brighton, Arden Hills, St. Anthony, 
Shoreview, Mounds View, Columbia Heights and Minneapolis. See Figure 2-
1 in in the Docket.
    The TCAAP facility manufactured, stored and tested small-caliber 
ammunition and related materials for the United States military and 
handled and stored strategic and critical materials for other 
government agencies from 1941 to 2005. Between 1941 and 1981, the 
facility disposed of waste materials including volatile organic 
compounds (VOCs), heavy metals, corrosive materials and explosives at 
several locations on the TCAAP property. Alliant Techsystems Inc. 
(Alliant) was the Army's installation services contractor for TCAAP and 
also operated manufacturing facilities at the TCAAP property.
    The U.S. Army Toxic Hazardous Materials Agency issued a report on 
waste disposal activities at TCAAP in 1978. In 1981, MPCA and the 
Minnesota Department of Health (MDH) began sampling water supply wells 
in the TCAAP area. The sampling found that municipal and private 
drinking water wells near the TCAAP facility and wells at TCAAP were 
contaminated with VOCs.
    Due to the contamination, the City of New Brighton shut down six 
municipal wells, deepened two municipal wells and constructed three new 
municipal wells from 1982 to 1984. One of the City of St. Anthony's 
municipal wells was also contaminated and this well was closed.
    In 1983 EPA installed carbon treatment filters on two of the City 
of New Brighton wells that were reopened to meet summertime peak 
demand. EPA also provided New Brighton with an additional deep well and 
carbon treatment for two of St. Anthony's municipal wells in the late 
1980s.
    In 1983, MPCA connected several private well users adjacent to the 
TCAAP facility to New Brighton's and Arden Hills' water mains. In 1984, 
MPCA constructed a temporary water connection from the City of St. 
Anthony to the City of Roseville to alleviate a water shortage due to 
the shutdown of one of St. Anthony's wells.
    EPA proposed the NB/AH/TCAAP Site to the NPL on December 30, 1982 
(47 FR 58476). EPA finalized the NB/AH/TCAAP Site on the NPL on 
September 8, 1983 (48 FR 40658).
    The Army began a Phase I investigation at the TCAAP facility in 
1981. The Army installed and sampled a significant number of monitoring 
wells at TCAAP to identify the overall contribution of the facility to 
the groundwater contamination identified by MPCA and MDH.
    Site records and investigations conducted at TCAAP subsequent to 
the Army's 1978 waste disposal report identified 14 source areas of 
contamination at TCAAP. These areas were used for the burial or open-
burning of waste or were industrial sources of contamination. The Army 
designated the source areas as Sites A, B, C, D, E, F, G, H, I, J, K, 
129-3, 129-5 and 129-15. See Figure 3 in the Docket.
    The Army entered into a Federal Facilities Agreement (FFA) with EPA 
and the State of Minnesota in 1987. The FFA establishes the framework, 
schedule and requirements for the Army to conduct a remedial 
investigation (RI) and feasibility study (FS) at the TCAAP facility and 
to implement the selected cleanup actions.
    The Army implemented several interim remedial actions (IRAs) at the 
TCAAP facility (i.e., OU2 of the NB/AH/TCAAP Site) under the Army's 
Installation Restoration Program (IRP). The Army conducted the IRAs in 
the 1980s and 1990s before an overall remedy was selected for OU2 in 
the OU2 Record of Decision (ROD) in 1997. These actions included 
unilateral actions by the Army, actions with EPA and State concurrence, 
and other actions initiated by the Army/Alliant. The IRAs were 
coordinated with the State and Federal regulatory agencies.
    The Army implemented unilateral removal actions at TCAAP using its 
own delegated removal authorities under CERCLA Section 104. These 
actions included installing in-situ soil vapor extraction (SVE) systems 
at Sites D and G to remediate VOC-contaminated soils in 1986 and 
installing groundwater pump-and-treat systems at Sites A and K to treat 
VOC-contaminated groundwater in 1988.
    Army IRAs at TCAAP undertaken with EPA and State concurrence 
included: (1) Installing a Boundary Groundwater Recovery System (BGRS) 
in 1987 to prevent additional groundwater contaminants from flowing off 
of the TCAAP property pursuant to a 1987 ROD; (2) expanding the BGRS 
into the TCAAP Groundwater Recovery System (TGRS) with source control 
wells installed downgradient of Sites D, G and I; (3) thermally 
treating 1,400 cubic yards of soil contaminated with polychlorinated 
biphenyls (PCBs) at Site D in 1989 pursuant to a 1989 ROD on Removal 
Action for PCB-Contaminated Soils Near Site D; (4) remediating heavy 
metal soil contamination through soil washing/leaching technologies at 
Site F from 1993-1997 under the Resource Conservation and Recovery Act 
(RCRA); and (5) modifying the Site A groundwater remediation system 
installed in 1983 to include eight boundary extraction wells in 1994.
    Other IRAs the Army implemented at TCAAP included: Cleaning of the 
sanitary sewer system lines (Site J) from 1984 to 1986 and closing Site 
J in accordance with the EPA and MPCA-approved Final Site J Closure 
Report issued in 1994; and excavation by Alliant of the PCB-
contaminated soils around Building 502 in 1985 and disposing of the 
soils at a permitted off-site facility in 1996.
    Several property ownership transfers and reassignments of control 
have occurred at the TCAAP property since the NB/AH/TCCAP Site was 
listed on the NPL. See Figure 4 in the Docket. Since 1983, control of 
over 1,500 acres of TCAAP has been reassigned to the National Guard 
Bureau which licenses the use of the property to the Minnesota Army 
National Guard for the operation of the Arden Hills Army Training Site 
(AHATS) and to the U.S. Army Reserve.

[[Page 35327]]

The National Guard Bureau and Army Reserve property is still federally-
owned and is controlled by the Army, but it is no longer controlled by 
TCAAP, which reports to a different division.
    Prior to 2010, the Army also transferred more than 270 acres of 
TCAAP that did not require land or groundwater use restrictions to 
Ramsey County and the City of Arden. This property consists of: Parcels 
093023320001 and 093023240003 owned by Ramsey County (the unlabeled OU2 
area in the northwest corner of OU2 on Figure 4 in the Docket); Parcel 
153023340001 located at 1425 Paul Kirkwold Drive owned by Ramsey 
County; and Parcel ID 153023430001 located at 1245 Highway 96W owned by 
the City of Arden Hills (shown as the unlabeled OU2 areas along the 
southern boundary of OU2 on Figure 4).
    In 2013, the Army transferred another 397 acres of TCAAP to Ramsey 
County and leased another 30 acres of TCAAP to the County. In 2017, the 
Army transferred the ownership of the 30 acres Ramsey County was 
leasing from the Army to Ramsey County.
    Forty-seven of the 427 acres of property the Army transferred and 
leased to Ramsey County in 2013 did not require land or groundwater use 
restrictions (see the Operation and Maintenance section of this 
notice). The other 380 acres were restricted by land use controls 
(LUCs) for soil and groundwater.
    Ramsey County conducted an additional soil investigation at the 380 
acres of restricted property they owned or were leasing in 2014. Ramsey 
County remediated the areas of remaining soil contamination, including 
the soil contamination at Sites I and K located within the 380-acre 
area.
    Following the additional cleanup, MPCA and EPA approved the soil in 
the 380-acre area to be suitable for unlimited use/unrestricted 
exposure (UU/UE). The Army removed the soil LUCs on the 380 acres in 
Revision 4 of the OU2 Land Use Control Remedial Design (LUCRD) dated 
August 2016. This property, however, is still subject to the 
groundwater LUCs (see Figure 5, Area with Groundwater LUCs, in the 
Docket).
    The Army determined that the remaining 160 acres of the TCAAP 
property are surplus to the needs of the Federal government. This 
property is in the process of being transferred out of Federal 
ownership. These 160 acres are controlled by the Base Realignment and 
Closure (BRAC) Division of the Army, the organization to which TCAAP 
currently reports.
    Ramsey County identified 108 acres of the remaining 160-acre TCAAP 
property (Parcels A through D) for use as part of the Rice Creek 
Regional Trail Corridor (RCRTC) (see Attachment B, Site Boundary--Rice 
Creek Regional Trail Parcels A-D in the Docket). Ramsey County 
completed an additional soil investigation and cleanup on the 108 acres 
to levels that are suitable for recreational use. The Army removed the 
soil LUCs on the 108-acre property in Revision 5 of the OU2 Land Use 
Control Remedial Design (LUCRD) dated March 2018.
    The Army will transfer title to Parcels A, B, and D of the 108-acre 
property to Ramsey County. Parcel C will remain under Federal 
ownership, but the government intends to grant Ramsey County a 
perpetual easement to Parcel C for its use as part of the RCRTC.
    This partial deletion pertains to all soil (shallow and deep) 
located within the OU2 boundary of the NB/AH/TCAAP Site (see Figure 2-2 
in the Docket). This partial deletion also pertains to surface water 
and sediment (not groundwater) in the five aquatic sites located within 
the OU2 boundary of the NB/AH TCAAP Site: Rice Creek, Sunfish Lake, 
Marsden Lake North, Marsden Lake South and Pond G (see Figure 11-1 in 
the Docket).
    The remaining areas at the NB/AH/TCAAP Site, including OU1, OU3, 
groundwater in OU2 and a sixth aquatic site, Round Lake located 
southwest of the OU2 boundary, will remain on the NPL and are not being 
considered for deletion as part of this action.

Remedial Investigation (RI) and Feasibility Study (FS)

    The Army conducted a RI at the TCAPP portion of the NB/AH/TCAAP 
Site (OU2) from 1988 to 1991. The purpose of the RI was to characterize 
the nature and extent of soil, sediment, surface water and groundwater 
contamination within the OU2 boundary. The FS developed and evaluated 
cleanup alternatives to address the unacceptable risks identified at 
OU2.
    The Army completed the OU2 RI and conducted an OU2 Terrestrial 
Ecological Risk Assessment in 1991. The Army conducted a Tier II 
Ecological Risk Assessment for the OU2 aquatic sites in 2004. Due to 
EPA and MPCA concerns, the Army conducted additional sampling at 
Marsden Lake and Pond G in 2008. The Army issued a separate FS for the 
five aquatic sites located within the OU2 site boundary in 2011. The 
Army is addressing Round Lake, which is still considered part of OU2 
but is located outside of the OU2 site boundary, southwest of OU2, 
separately.
    EPA completed a Human Health Risk Assessment (HHRA) addressing OU1, 
OU2 and OU3 of the NB/AH/TCAAP Site in 1991. In 1992, the Army 
collected additional data as part of the FS development process to 
further characterize the nature and extent of OU2. The Army completed 
the OU2 FS in 1997. The OU2 FS included an updated list of additional 
contaminants of concern (COCs) and cleanup levels.
    The Agency for Toxic Substances and Disease Registry (ATSDR) 
completed a Public Health Assessment of the NB/AH portion of the NB/AH/
TCAAP Site (OU1 and OU3) in 1994. Based on the assessment, ATSDR 
considered the NB/AH portion of the NB/AH/TCAAP Site to be a ``public 
health hazard'' because people were exposed to past groundwater 
contaminants from TCAAP at concentrations that could result in adverse 
health effects.
    The Army's RI identified all known or suspected sources of 
contamination at OU2 of the NB/AH/TCAAP Site. The RI separated the OU2 
contamination into four categories: Shallow soil sites, with soil 
contamination less than 12 ft-bgs (Sites A, C, E, H, 129-3 and 129-5); 
deep soil sites, with soil contamination greater than 12 ft-bgs, down 
to depths between 50 and 170 feet (Sites D and G); shallow (Unit 1) 
groundwater contamination (Sites A, I and K); and deep (Units 3 and 4) 
groundwater contamination (groundwater underlying the southwestern 
portion of OU2, originating primarily from Sites D, G and I). Although 
Sites D and G were considered deep soil sites, shallow soil 
contaminants were also present at Site D, and Site G also contains a 
dump.
    The Army addressed Sites F (RCRA) and J (sewer line cleaning) 
separately and did not include these areas in the OU2 RI. Also, the 
Army did not find any contamination in Site B other than part of a dump 
(Site B-3) that would require additional investigation.
    The RI and additional FS sampling indicated that the shallow soil 
sites (Sites A, C, E, H, 129-3 and 129-5) were contaminated by heavy 
metals, VOCs, polynuclear aromatic hydrocarbons (PAHs) and PCBs. The 
contamination was generally present in the upper five to 10 feet of 
soil. Contaminated soil volumes ranged from as little as 15 cubic yards 
(CY) at Site 129-5 to as much as 2,600 CY at Site C.
    Unpermitted landfills or dumps also existed within the boundaries 
of shallow soil Sites A, E and H. The estimated material in these dumps 
ranged from 4,400 CY at Site A to 12,200 CY at Site E. The RI 
identified

[[Page 35328]]

two additional dumps in OU2. Dump Site B-3 was estimated to contain 
12,400 CY of material. The other dump is Site 129-15 and is estimated 
to be 53,000 CY.
    The RI did not investigate the material at Site B-3 or Site 129-15. 
The RI indicated that additional characterization would be required 
before response actions could be selected for these areas. There was no 
clear indication, however, that either dump was contaminating the 
groundwater.
    The Army updated EPA's 1991 HHRA in the 1997 OU2 FS to incorporate 
the results of the additional sampling. The updated risk assessment in 
the FS indicated that the surface soil and debris at Sites A, C, H and 
129-3 posed an unacceptable cancer and/or noncancer risk to on-site 
workers under a current industrial exposure scenario. Subsurface soil 
and debris at Sites A, C, H and 129-3 and at Sites D, E, G and 129-5 
also posed an unacceptable cancer and/or noncancer risk to future 
construction workers in these areas. The risks were primarily due to 
the incidental ingestion of and dermal contact with surface and/or 
subsurface soil and debris.
    According to the updated HHRA, surface soil and debris at Sites A, 
C, E, H and 129-3 posed an unacceptable cancer and/or noncancer risk to 
potential future residents living in these areas under a future 
residential exposure scenario. These risks were primarily due to the 
incidental ingestion of and dermal contact with surface soil and debris 
and to the ingestion of home-grown fruits and vegetables.
    The Army developed remedial action objectives (RAOs) for the OU2 
cleanup in the FS based on the current and most probable future land 
use for the property, which was industrial. The FS then developed 
numerical remediation goals for the cleanup based on applicable or 
relevant and appropriate requirements (ARARs), health-based risk 
values, background concentrations of metals, contaminant migration 
potential and technological limitations.
    The health-based risk values developed for surface soil were based 
on the lower of either an excess lifetime cancer risk equal to one in a 
million or a noncancer hazard of one, adjusted for exposure to multiple 
contaminants. The industrial values were calculated based on the 
primary routes of exposure which were ingestion and dermal contact. The 
cleanup levels for the deep soil Sites D and G were based primarily on 
leaching-based goals that are protective of the underlying groundwater 
for use as residential drinking water. For Site 129-15, a one-time 
commercial, industrial or utility construction scenario was utilized. 
The construction scenario assumed that construction workers would be 
exposed to excavated soils for 40 days (i.e., a two-month construction 
period) a year for two years. See the Cleanup Levels section below for 
additional information. The FS developed general response actions for 
the OU2 cleanup based on the technical applicability and the 
contaminant characteristics of each individual site within OU2. After 
initial screening, the FS retained a set of final cleanup alternatives 
for full evaluation. The alternatives evaluated for the shallow soil 
Sites A, C, E, H, 129-3 and 129-5 were: No action, in-situ fixation/
capping, soil washing/soil leaching and excavation/stabilization with 
off-site disposal. The alternatives evaluated for the deep soil Sites D 
and G were: No action, continue shallow SVE, or expand the SVE systems 
vertically.
    The only alternative the FS evaluated for the unpermitted landfills 
in Sites A, E and H was excavation and off-site disposal. The FS 
indicated that the landfills in Site B and Site 129-15 would require 
further characterization.

Selected Remedy

    EPA, MPCA and the Army selected an industrial cleanup remedy for 
the OU2 shallow soil sites, dumps and deep soil sites in a 1997 OU2 
ROD. The agencies also selected remedies for the five aquatic sites 
located within the OU2 boundary in OU2 ROD Amendment #4 (Rice Creek, 
Sunfish Lake, Marsden Lake North, Marsden Lake South and Pond G).
    The selected remedy for the shallow soil Sites A, C, E, H, 129-3 
and 129-5 and for the dumps within Sites A, E and H in the 1997 OU2 ROD 
included the following remedial components (see the 1997 ROD for 
information about the groundwater components of the OU2 remedy):
    (1) Identification/characterization of contaminated soil 
boundaries, surface and subsurface debris and dump contents;
    (2) Excavation and sorting of hazardous and nonhazardous dump 
materials, debris and ordnance;
    (3) Removal and disposal of ordnance, debris and oversized 
material;
    (4) On-site stabilization of hazardous and contaminated soils from 
Sites A, E, H, 129-3 and 129-5;
    (5) Off-site disposal of stabilized materials from Sites A, E, H, 
129-3 and 129-5;
    (6) Off-site transport, incineration and disposal of soils 
containing low levels of dioxin-furans from Site C (if required);
    (7) Backfill/regrade excavations;
    (8) Restrict site access and use during remedy implementation; and
    (9) A limited period of monitoring to verify remedy effectiveness.
    The selected remedy for the dumps at shallow soil Sites B and 129-
15 was characterization to determine the contents of the dumps. If the 
contents were found to be toxic, hazardous or contaminated, then a 
remedy for the landfill would be documented through a ROD Amendment. If 
the contents were not toxic, hazardous or contaminated then a no 
further action remedy will be selected.
    The selected remedy for the shallow and deep soil contamination at 
Site D and for the deep soil contamination and dump at Site G was to 
expand the SVE systems vertically. The remedy included:
    (1) Groundwater monitoring;
    (2) Access and use restrictions;
    (3) Installation and operation of deep SVE systems with modified 
shallow SVE systems, as appropriate;
    (4) Evaluation and potential use of enhancements to the SVE 
systems;
    (5) Maintenance of existing soil caps and surface drainage 
controls; and
    (6) Characterization of shallow soils at Site D and the dump at 
Site G following cessation of SVE system operation to determine 
appropriate action.
    The remedy in the 1997 OU2 ROD also included the characterization 
of the unsaturated Unit 1 soil at Site K as part of the Site K shallow 
groundwater remedy.
    The 1997 OU2 ROD clarified that Site F, a former disposal area 
within OU2, was being closed under RCRA and was not addressed in the 
OU2 ROD. The 1997 OU2 ROD also confirmed that the 1994 Final Site J 
Closure Report for the sanitary sewer cleaning was approved by the 
regulatory agencies, documented the absence of contaminants above 
background levels and recommended no further action for this area.
    Between 2007 and 2014, EPA, MPCA and the Army issued five ROD 
Amendments and an Explanation of Significant Differences (ESD) 
modifying various components of the selected remedies for the shallow 
soil sites, dumps and deep soil sites in the 1997 OU2 ROD and selecting 
remedies for the five aquatic sites located within the OU2 boundary.
    OU2 ROD Amendment #1, issued in 2007, modified the requirements for 
Site C-2 shallow soil and sediment contamination discovered in 2004 in 
two Site C-2 ditches. Because the depth to groundwater is shallow at 
Site C-2, it was not feasible to remove all of the contaminated soil 
and sediment from

[[Page 35329]]

this area. The OU2 ROD Amendment #1 modified the remedy to allow the 
placement of a 4-foot thick soil cover over the Site C-2 areas where 
the contamination remains in-place above the cleanup levels instead of 
excavating the material. The OU2 ROD Amendment #1 also specified LUCs 
to maintain the integrity of the soil cover, prohibit unauthorized 
disturbance to the underlying soil and sediment and to restrict the 
Site C area outside the soil cover to site-specific industrial use. The 
OU2 ROD Amendment #1 also included the creation of a new wetland within 
the TCAAP facility to replace the loss of existing wetland.
    OU2 ROD Amendment #3 was issued in 2009 and modified the remedies 
for the shallow soil and dump sites as follows:
    (1) Documented, as a final remedy, the additional actions performed 
for shallow soil at Site D (soil cover for residual PCB-contaminated 
soil following the 1985 interim remedial action and 1989 thermal 
treatment selected in the 1989 ROD for Removal Action for PCB-
Contaminated Soils Near Site D, and excavation, stabilization and off-
site disposal of other contaminated Site D soil) after completing the 
deep soil cleanup at Site D.
    (2) Documented, as a final remedy, the additional action (capping) 
implemented for the dump at Site G after completing the Site G deep 
soil cleanup.
    (3) Documented the use of soil covers as part of the final 
remedies, in addition to excavation and off-site disposal, at Sites E 
and H and as the primary remedy for the dump at Site 129-15.
    (4) Documented that three OU2 areas not addressed in the 1997 OU2 
ROD were acceptable for unrestricted use: 135 Primer/Tracer Area (PTA) 
Stormwater Ditch, Trap Range Site and Water Tower Area. The OU2 ROD 
Amendment #3 determined that the previous soil removals at the 135 PTA 
Stormwater Ditch in 2005 and at the Water Tower Area in 1993 reduced 
soil contamination to levels that allow for unrestricted use. ROD 
Amendment #3 also determined that, based on the 1999 preliminary 
assessment of the Trap Range Site, that the Trap Range Site is 
acceptable for unrestricted use.
    (5) Documented the final remedies for two OU2 areas not addressed 
in the 1997 ROD: Grenade Range and Outdoor Firing Range. The OU2 ROD 
Amendment #3 determined that the 1993 and 1999 soil and unexploded 
ordnance removal actions at the Grenade Range and at the Outdoor Firing 
Range, and the construction of a soil cover at the Outdoor Firing Range 
in 2003-2004, cleaned up these areas to levels that are acceptable for 
industrial use.
    (6) Requires long-term LUCs as an additional remedy component for 
shallow soil and dump Sites: D, E, G, H, 129-15, Grenade Range, and 
Outdoor Firing Range. The LUCs restrict these areas to site-specific 
industrial use, require the integrity of the soil covers to be 
maintained, and prohibit the unauthorized disturbance of materials 
underlying the soil covers. The exact details of the LUCs were to be 
specified and maintained in accordance with a LUCRD document approved 
by EPA and MPCA. ROD Amendment #3 concluded that LUCs are not needed 
for the 135 PTA Stormwater Ditch or Trap Range because contamination 
levels in these areas are suitable for UU/UE. The Amendment also 
concluded the Water Tower Area is suitable for UU/UE; however, it is 
located within the area of ``blanket LUCs'' the Army implemented as 
specified in the 2010 LUCRD so it is restricted.
    ESD #2, issued in 2009, modified the 1997 OU2 ROD by requiring 
long-term LUCs as an additional remedy component for Sites A, C-1, 129-
3 and 129-5 restricting these areas to industrial use. ESD #2 also 
documented that based on an additional investigation, the Site B dump 
is cleared for unrestricted use and no further action is the final 
remedy for Site B.
    OU2 ROD Amendment #4 was signed in 2012. The OU2 ROD Amendment #4 
documented remedy decisions for the five aquatic sites located within 
the OU2 boundary and the 535 PTA Site, which were not addressed in the 
1997 OU2 ROD. OU2 ROD Amendment #4 also documented the remedy decision 
for the Site K unsaturated Unit 1 soil characterized as part of the 
Site K shallow groundwater remedy.
    OU2 ROD Amendment #4 determined:
    (1) No action is needed for Rice Creek, Sunfish Lake, Marsden Lake 
North or Marsden Lake South. The 2011 FS, which the Army prepared 
following the 2004 Tier II Ecological Risk Assessment, documented that 
there are no human health risks associated with these areas and that 
the ecological risks are considered to be acceptable. These aquatic 
areas are acceptable for unrestricted use.
    (2) In-situ treatment to raise hardness is the selected cleanup 
remedy for Pond G. No human health risks were associated with Pond G, 
however, Pond G surface water contains lead above the State water 
quality standard and may not be protective of the entire aquatic 
ecosystem. Pond G surface water was to be chemically altered and 
monitored to verify that the adjusted level of hardness increases to 
the minimum required level to comply with the Class 2Bd Minnesota 
chronic surface water quality standard for lead.
    (3) The 2009 removal actions at the 535 PTA Site and for the VOC-
contaminated soil at Site K, which involved the excavation and off-site 
disposal of contaminated soil, cleaned up the soils for unrestricted 
use. No further action is necessary for the soil in these areas and 
LUCs are not required.
    OU2 ROD Amendment #5 was signed in 2014. The OU2 ROD Amendment #5 
documented remedy decisions for three additional areas of soil 
contamination not addressed in the 1997 OU2 ROD. The Army remediated 
these areas as a 2013 removal action and addressed: (1) Additional 
metal contamination at Site A, (2) PAH-contamination at Site 135 PTA, 
and (3) PAH and/or metals contamination discovered in two areas during 
an environmental baseline survey (EBS Areas) conducted by the Minnesota 
National Guard before the property was transferred to the National 
Guard Bureau.
    The 2013 soil removal action involved excavating the soil that was 
contaminated above industrial use cleanup levels in these areas and 
disposing of the contaminated materials off-site. OU2 ROD Amendment #5 
documented that the completed 2013 removal action constitutes the final 
remedy for these soil areas of concern. OU2 ROD Amendment #5 also added 
the requirement that these areas be covered by a LUC restricting the 
areas to industrial use.
    Decision documents that address the groundwater components of the 
OU2 remedy (groundwater not included in this partial deletion) include: 
OU2 ROD (1997), OU2 ROD Amendment #2 (2009), OU2 ESD #1 (2009), OU2 ROD 
Amendment #4 (2012) and OU2 ROD Amendment #6 (2017).

Response Actions

    The Army constructed a corrective action management unit (CAMU) to 
aid in the OU2 cleanup and initiated shallow soil site remediation in 
1998 beginning with Site A. The CAMU was a bermed, asphalt pad with 
lined ponds to store rainwater runoff from the pad. The CAMU was to be 
a central staging area where soils from each site would be brought for 
treatment before loading for off-site disposal at a permitted landfill. 
In 1999, however, the Army discovered asbestos-containing material 
(ACM) at the shallow soil sites which made further use of the CAMU 
impractical. The safeguards needed to control the

[[Page 35330]]

asbestos during handling defeated the cost savings of the central 
processing pad. The Army determined that it was more convenient and 
cost-effective to treat the soil at each site instead of moving the 
contaminated material to a central location for treatment.
    The Army removed the CAMU in 2002. The Army decontaminated and 
removed the storage and storm water holding ponds, tested for 
contamination under the pad and ponds, and monitored the groundwater. 
EPA and MPCA approved the Army's CAMU Closeout Report in 2004. The CAMU 
Closeout Report states that there were no adverse impacts to soil or 
groundwater due to CAMU operations and that no LUCs are required for 
this area.
    The Army completed the remedial actions at the shallow soil Sites 
A, C, E, H, 129-3, 129-5 and the Outdoor Firing Range from 1999 to 
2010. The Army excavated debris and contaminated soil above industrial 
cleanup levels, stabilized the material and disposed of it at an off-
site landfill. The Army excavated approximately: 16,300 CY from Site A; 
21,450 CY from Site C; 20,900 CY from Site E; 8,620 CY from Site H; 
3,470 CY from Site 129-3; 100 CY from Site 129-5 and 100 CY from the 
Outdoor Firing Range.
    The Army also constructed a 2-foot thick protective soil cover over 
a portion of Site E and a 30-inch thick soil cover over a portion of 
Site H where ACM remains in-place; a 4-foot thick soil cover over 
portions of Site C where metals-contaminated soils and sediment from 
the former ditches remain in-place; and a 2-foot thick soil cover at 
the 1900 Yard Range of the Outdoor Firing Range where PAH-contaminated 
soils remain in place.
    The Army investigated the Site 129-5 dump then constructed a 
protective soil cover over the materials. The Army also constructed a 
new wetland at Site C to replace the loss of existing wetlands when the 
Site C ditches were backfilled.
    The Army completed the remediation work (shallow and deep soils) at 
the deep soil Sites D and G in 2004. The Army dismantled the SVE 
systems in 2000 after the deep soil cleanups were complete. At Site D, 
the Army then excavated 1,300 CY of shallow soils contaminated with 
non-VOCs and disposed of them at an off-site landfill. The Army also 
constructed a four to six foot soil cover over residual PCB-
contaminated soils remaining at Site D after the 1985 interim remedial 
action. At Site G, the Army characterized the dump then constructed a 
2-foot thick protective soil cover over the material.
    The Army conducted five years of groundwater monitoring at the 
shallow soil sites and Site D from 2003 through 2007. The Army 
conducted three years of groundwater monitoring at the Grenade Range 
from 1999 to 2004. The Army conducted the monitoring to verify that the 
groundwater beneath these areas was not impacted by remediation 
activities.
    The Army conducted the groundwater monitoring in accordance with 
groundwater monitoring plans that were reviewed and updated annually as 
part of the Army's Annual Performance Report (APR). Based on the 
monitoring data, the Army extended the monitoring at Site H. The 
groundwater sampling is now complete at all shallow soils sites and 
confirms that there are no adverse remedy impacts to groundwater in 
these areas. Groundwater monitoring for VOCs, however, continues as 
part of OU2 deep groundwater monitoring in the vicinity of Sites D and 
G.
    The Army treated the Pond G surface water in 2012 in accordance 
with the Pond G RD/RA Work Plan. The Army monitored the Pond G surface 
water in 2012 and 2013. The monitoring results verified that the 
surface water in Pond G was in compliance with the surface water 
standard for lead. Since the Pond G remedy does not result in hazardous 
substances remaining in the Pond above levels that allow for UU/UE, 
long-term maintenance, monitoring, and LUCs are not required.
    Reports documenting the completion of remedial activities for the 
shallow soil Sites A, C, E, H, 129-3, 129-5, 129-15, the shallow and 
deep soil in deep soil Site D and the deep soil and dump in deep soil 
Site G are in the Docket in the following reports: Final Remedial 
Action Completion and Shallow Soil Sites Close Out, Volumes I through 
VIII; Final Site 129-15 Dump Investigation, Characterization and 
Remedial Action Completion and Close Out Report; Final Site D Shallow 
and Deep Soil Volatile Organic Compound Investigation and Close Out 
Report; Final Site G Volatile Organic Compound Investigation and Dump 
Close Out Report; and Outdoor Firing Range 1900 Yard Range Cover 
Construction: Addendum to the Final Close Out Report, Outdoor Firing 
Range and #150 Reservoir Site Removal. The completed Pond G remedial 
action work and surface water monitoring results are documented in the 
2013 Remedial Action Completion and Close Out Report, Pond G.
    No action or no further action (other than LUCs) was required for 
shallow soil Site B, Site J, the Unit 1 soil in Site K, Grenade Range, 
Site 135 PTA, Site 135 PTA Stormwater Ditch, Site 535 PTA, the EBS 
areas, Water Tower Area, the Trap Range Site, Former Building 576, Rice 
Creek, Sunfish Lake, Marsden Lake North or Marsden Lake South. Also, 
Site F was closed under RCRA. Additional information about these areas 
is documented in the 1997 OU2 ROD, 2009 OU2 ROD Amendment #3, 2009 ESD 
#2, 2012 OU2 ROD Amendment #4 and 2014 ROD Amendment #5 and the 
following reports in the Docket: Final Site B Dump Investigation, 
Characterization, and Close Out Report; Final Close Out Report, Outdoor 
Firing Range and #150 Reservoir Site Soil Removal Action, Completion of 
Soil Removal; Remedial Action Report, Site K; Lead-Impacted Soil 
Cleanup documentation, TCAAP Former Building 576; Close Out Report: 
Removal of Contaminated Sediment at the 135 Primer/Tracer Area 
Stormwater Outfall; Removal Action Completion Report, Site K; Final 
Close Out Report for Soil Removal Action at 535 Primer/Tracer Area; and 
Removal Action Completion Report for Soil Areas of Concern--Site A, 135 
Primer/Tracer Area, EBS Areas.

Cleanup Levels

    The cleanup levels for shallow soils in the 1997 OU2 ROD were 
derived specifically for each shallow soil site because MPCA did not 
have published rules or guidance values for soil at the time. The ROD 
selected cleanup levels for shallow soils based on background levels, 
ARARs and the more stringent of either the site-specific industrial 
health-based value or leaching-based goal (see Table 8 in the 1997 OU2 
ROD in the Docket). The health-based values were the lower of either an 
excess lifetime cancer risk equal to one in a million or a noncancer 
hazard of one, adjusted for exposure to multiple contaminants. The 
cleanup levels for the deep soil Sites D and G were based primarily on 
leaching-based goals that are protective of the underlying groundwater.
    The site-specific health-based values calculated for the shallow 
soils sites assumed that adult industrial workers at TCAAP would be 
exposed to contaminated soil through dermal contact and ingestion for 
250 days a year for 25 years. The calculations assumed an adult body 
weight of 70 kilograms, a soil ingestion rate of 50 milligrams/day and 
a dermal exposure over 0.31 square meters of body surface.
    For Site 129-15, a one-time commercial, industrial or utility 
construction scenario was utilized. The construction scenario assumed 
that construction workers would be exposed to excavated soils for 40 
days (i.e., a two-month construction period) a year

[[Page 35331]]

for two years. The construction exposure assumes that the excavated 
soils are managed to eliminate or greatly reduce exposure to fugitive 
dusts; all other parameters were assumed to be the same as the 
industrial exposure scenario.
    The leaching-based goals for shallow and deep soils were calculated 
by MPCA using a soil model for chemicals that were found at the site in 
groundwater above drinking water or health-based standards. The 
industrial soil cleanup level for lead of 1,200 milligrams per kilogram 
(mg/Kg) was calculated by EPA using the Exposure Model for Assessing 
Risks Associated with Adult Exposure to Lead in Soil. Additional 
information concerning the soil cleanup standards is in Appendix C of 
the 1997 OU2 ROD.
    Additional soil cleanup standards were later added based on 
subsequent investigations for Site A (tetrachloroethene and TCE), Site 
D (antimony, lead, and nitroglycerine) and Site 129-15 (lead). PCBs 
were not specifically listed as COCs for Site D in the OU2 ROD; 
however, the PCBs that were ``secured in-place'' exist at 
concentrations that exceed the ARAR of 10 mg/Kg cited in the OU2 ROD, 
so the cleanup standard for PCBs is considered to be 10 mg/Kg. 
Nitroglycerine was listed as a COC for Site 129-3 in the OU2 ROD; 
however, no cleanup level was established. The current cleanup level 
for nitroglycerine was calculated at the time of soil remediation work 
at Site 129-3.
    In 1999, the background number for arsenic in the TCAAP soils 
increased from 4 mg/Kg to 10 mg/Kg, as documented in a June 14, 1999 
MPCA letter to the Army. This resulted in the cleanup level for arsenic 
increasing to 10 mg/Kg at Sites C and H. At Site 129-15 the highest 
arsenic concentration detected in soils was 5 mg/Kg and arsenic was 
dropped as a COC.
    In 2002, the soil cleanup level for TCE at Site G increased to 36.1 
mg/Kg. This revised cleanup standard is based on an updated soil 
leaching analysis that specifically accounted for the lower 
permeability of the Site G cover. EPA and MPCA agreed with this change 
on July 24, 2002. For cleanup levels that were established subsequent 
to the OU2 ROD, the health risk calculations are noted to be based on 
the same methodology and input parameters that were documented in 
Appendix C of the OU2 ROD.
    The current cleanup standards for the OU2 shallow and deep soils 
sites are provided in Table 1 of the 2018 LUCRD Revision 5. A copy of 
Table 1 and the complete 2018 LUCRD document are available in the 
Docket.
    The cleanup level for lead in Pond G is the Minnesota Class 2Bd 
surface water quality standard for lead, as promulgated in Minnesota 
Rule 7050.0222. The lead standard is calculated based on the hardness 
value of the surface water. At Pond G, the calculated lead standard 
ranged from a concentration of 11.4 micrograms per liter ([mu]g/L) 
after initial treatment with lime and calcium to 1.6 to 2.0 [mu]g/L 
approximately one year later.
    The Army confirmed that the soil cleanup levels were attained at 
each of the shallow and deep soils sites through extensive soil 
verification sampling around each of the excavated areas, and by soil 
sampling below the shallow and deep vents at the SVE systems at Sites D 
and G. The Army conducted the verification sampling at the shallow soil 
Sites A, C, E, H, 129-3, 129-5, 129-15, the shallow soil at deep soil 
Site D and the dump at deep soil Site G through field and laboratory 
sampling and analysis at gridded locations in accordance with the 2000 
Final Comprehensive Work Plan, Final Sampling and Analysis Plan and 
Final Site Safety and Health Plan, Shallow Soil Sites RD/RA Activities 
and associated Work Plan Clarifications. The Army conducted the 
verification sampling for deep soil at deep soil Sites D and G in 
accordance with the 1997 Final Work Plan, Sites D and G Pilot Study and 
the 1999 Addendum 1, Final Work Plan Sites D and G Pilot Study. The 
Army conducted the verification sampling at the other sites in 
accordance with the Removal Action Work Plan or other work plan for 
each area.
    The Army confirmed that the cleanup level for lead in the Pond G 
surface water was met through four rounds of post-treatment monitoring. 
The Army detected lead during the second monitoring event at an average 
concentration of 0.61 [mu]g/L. This concentration was well below the 
calculated standard for lead of 10.6 [mu]g/L based on the average 
surface water hardness of 255 mg/L for that event. The Army did not 
detect lead in any of the other rounds of post-treatment monitoring.
    Complete documentation of the verification of the cleanup levels 
for Pond G and the shallow and deep OU2 soils is available in the 
Remedial Action Completion Reports, Removal Action Completion Reports 
and Final Close Out Reports referenced in the Response Actions section 
above which are available in the Docket.

Operation and Maintenance

    Operation and maintenance (O&M) for the soil portion of OU2 
(shallow and deep) is limited to inspecting and maintaining the 
cautionary warning signs and the thicknesses of the soil covers at 
Sites C, D, E, G, H, 129-15 and the Outdoor Firing Range; annually 
removing woody vegetation from the Site G soil cover to prevent deep 
rooting that could cause increased infiltration by any VOCs remaining 
below the cover; and to maintain, monitor and enforce the ESD and ROD 
Amendment-required LUCs, which are in the form of the Army's OU2 LUCRD 
document approved by EPA and MPCA. No O&M or LUCs are required for the 
five aquatic sites within the OU2 boundary: Rice Creek, Sunfish Lake, 
Marsden Lake North, Marsden Lake South or Pond G.
    The Army issued the initial EPA and MPCA-approved OU2 LUCRD 
(Revision 1) in 2010. The Army updated the LUCRD in 2011, 2015, 2016 
and 2018 as portions of OU2 were further characterized, remediated as 
needed, and transferred for reuse and redevelopment. The current LUCRD 
is LUCRD Revision 5 issued in 2018.
    The LUCRD documents that since 1997, the working presumption is 
that the OU2 property outside of the individual areas of concern (i.e., 
the OU2 property beyond Site A, Site C, Site D, etc.) does not have 
soil contamination above the typical ``industrial use'' cleanup levels 
derived for the areas of contamination within OU2. Ongoing and future 
uses of the OU2 property outside of the areas of concern would be 
compatible with past uses. Land used for manufacturing could continue 
to be used for manufacturing; open space could continue to be used for 
open space. As such, the mostly open space along Rice Creek and the 
former OU2 staff housing area the Army previously transferred to Ramsey 
County and other OU2 property the Army transferred to the City of Arden 
Hills without any use restrictions (approximately 270 acres total) 
would remain acceptable for UU/UE.
    LUCRD Revision 1 and subsequent revisions formalize the Army's 
decision to implement ``blanket LUCs'' limiting the OU2 property to 
industrial land use and restricting groundwater use across the 
remaining federally-owned OU2 property at the time LUCRD Revision 1 was 
issued in 2010 (except for Site F which the Army cleaned up to 
unrestricted use under RCRA). A map showing the initial federally-owned 
property with LUCs at the time of the 2010 LUCRD is in the September 
2010 Figure 4 in the Docket.

[[Page 35332]]

    The ``blanket LUCs'' resolved the outstanding LUC issues for the 
OU2 property outside of the individual areas of concern (i.e., OU2 
property beyond Site A, Site C, Site D, etc.,) because the remedy-
required LUCs in the OU2 ESDs and ROD Amendments only apply to each 
individual area of concern, not to the OU2 property outside of those 
areas. The Army's ``blanket LUCs'' also address the uncertainty 
associated with not having soil data to characterize the entire OU2 
property outside of the areas of concern. The 2010 LUCRD and subsequent 
revisions include additional restrictions for OU2 areas with soil 
covers and components of the OU2 groundwater extraction and treatment 
systems to protect the integrity of these remedies.
    The 2010 LUCRD and subsequent revisions allow and formalize a 
process for the Army to demonstrate to EPA and MPCA that less 
restrictive uses of OU2 property are acceptable in anticipation of 
future redevelopment and property transfers at the NB/AH/TCAAP site.
    The Army issued Revisions 2, 3, 4 and 5 to the LUCRD from 2011 to 
2018. These revisions: (1) Cleared the Watchable Wildlife Area of AHATS 
for unrestricted public use and revised the LUCs for a portion of the 
AHATS Cantonment Area to allow uses compatible with a restricted 
commercial exposure scenario (Revision 2, 2011); (2) revised the LUCs 
for the remainder of the Cantonment Area and the Army Reserve Center to 
restricted commercial use and documented the transfer/lease of 427 
acres of Army/BRAC controlled property to Ramsey County (Revision 3, 
2015); (3) revised the LUCs to eliminate soil LUCs from the 380-acre 
``California-Shaped Area'' of the 427 acres transferred to Ramsey 
County in 2013 following the County's additional investigation and soil 
cleanup to levels consistent with UU/UE (Revision 4, 2016); and (4) 
revised the LUCs to allow recreational use on 108 acres in the western 
portion of OU2 to be used as part of the Rice Creek Regional Trail 
Corridor (Revision 5, 2018).
    The specific details of the current OU2 soil and groundwater use 
restrictions and the provisions for long-term stewardship of the LUCs 
are contained in the 2018 OU2 LUCRD Revision 5 which is available in 
the Docket. The technical basis and supporting documentation for the 
LUC revisions are included in Appendices B through E of LUCRD Revision 
5. Maps showing the areas covered by the current soil and groundwater 
LUCs for OU2 are in Figures 4 and 5 in the Docket.
    The Army is the lead agency for the NB/AH/TAACP Site and is 
responsible for conducting routine inspections to ensure that the LUCs 
are maintained and enforced. The Army is responsible for reporting the 
results of the inspections and any breach of the LUCs to the MPCA and 
EPA.

Five-Year Review

    The Army is required to conduct statutory five-year reviews (FYR) 
at the NB/AH/TCAAP Site because hazardous substances, pollutants, or 
contaminants remain at the Site above levels that allow for UU/UE. The 
Army completed the last FYR of the NB/AH/TCAAP Site in 2014. The FYR 
was approved by MPCA and by EPA on August 19, 2014.
    The Army's 2014 FYR concluded that the remedy has been completed 
for the OU2 soils sites: Sites A, C, D, E, G, H, 129-3, 129-5, 129-15, 
the Grenade Range and the Outdoor Firing Range. The FYR also determined 
that the protective soil covers at Sites C, D, E, G, H, 129-15 and the 
Outdoor Firing Range, in conjunction with the implemented LUCs, 
effectively prevent exposure to contaminated soils/debris remaining at 
OU2 above industrial exposure levels. The protective soil cover at Site 
G also minimizes infiltration and reduces the leaching of any remaining 
VOCs below the cover.
    The 2014 FYR concluded that OU2 has been restored for industrial 
use. The Army also reviewed the toxicity data that the 1991 and 1997 
health risk assessments for the soil sites were based on and determined 
that no changes have occurred that could potentially affect the 
protectiveness of the soil remedies. The 2014 FYR did not identify any 
issues or recommendations for the OU2 soils sites.
    For OU2 groundwater, the FYR concluded that the OU2 groundwater 
remedies are protective in the short term. The groundwater containment 
systems are meeting the containment objectives and the treatment 
systems are meeting their discharge requirements. The alternate water 
supply and well abandonment program, along with Ramsey County's Special 
Well Construction Area permitting system, mitigate potential risks 
associated with private wells. At Site A, monitored natural attenuation 
is adequately controlling plume migration and water quality trends 
indicate that aquifer restoration continues to occur in both shallow 
and deep groundwater. A vapor intrusion investigation the Army 
conducted north of County Road I in 2014 indicates that there are no 
significant soil vapor risks and no further vapor intrusion 
investigation work is warranted (see the 2014 Site A Vapor Intrusion 
Investigation Report in the Docket).
    The Army must complete the next FYR of the NB/AH/TCAAP Site and 
have it approved by EPA and MPCA on or before August 19, 2019.

Community Involvement

    The Army satisfied public participation activities for the NB/AH/
TCAAP Site as required by Sections 113(k)(2)(B)(i-v) and 117 of CERCLA, 
42 U.S.C. 9613(k)(2)(B)(i-v) and 9617. The communities near the NB/AH/
TCAAP Site have been involved in NB/AH/TCAAP Site activities since the 
environmental problems were initially identified. The Army developed a 
Community Involvement Plan for the NB/AH/TCAAP Site in 1991 to 
establish processes for sharing knowledge and encouraging community 
participation concerning the hazardous waste remediation activities 
underway and planned at the NB/AH/TCAAP Site. The Community Relations 
Plan outlines specific community relations strategies for addressing 
these goals and for updating the plan as needed to adjust to evolving 
community needs and concerns. The Army updated the Community 
Involvement Plan in 1997.
    Over the years the Army has prepared and distributed numerous fact 
sheets to a large number of local and interested residents to keep the 
community apprised of the remedial activities at the NB/AH/TCAAP Site. 
The Army sponsored tours of the facility and accompanying wildlife 
areas, in addition to providing monthly Technical Review Committee 
(TRC) meetings open to the public to review the status of restoration 
activities at the NB/AH/TCAAP Site.
    The TCAAP Restoration Advisory Board (RAB) was established in 1996 
to provide citizen input into the cleanup of the NB/AH/TCAAP Site. The 
RAB provides an opportunity for community representatives to review and 
analyze issues concerning the contamination and remediation of the NB/
AH/TCAAP soils and groundwater; provide comments and recommendations 
regarding the remediation of contaminated areas at the site; and to 
provide advice on decisions that affect the quality of the environment 
of the communities that are impacted by the contamination.
    The Army met the public participation requirements for selecting 
cleanup remedies and the amended cleanup remedies for the NB/AH/TCAAP 
Site required by CERCLA Sections 113(k)(a)(B)(i-v) and 117. The Army 
met these requirements by issuing

[[Page 35333]]

fact sheets and Proposed Plans, notifying the public of the 
availability of the Proposed Plans in newspaper advertisements, holding 
public meetings and holding 30-day public comment periods.
    The Army involves project stakeholders in the FYR process by 
notifying them at the start of each FYR. Project stakeholders notified 
at the start of the 2014 FYR include EPA, MPCA, Alliant Techsystems, 
Army National Guard, U.S. Army Environmental Command, U.S. Army Corp of 
Engineers, City of New Brighton, and the RAB.
    The Army published a notice indicating that the 2014 FYR for the 
NB/AH/TCAAP Site was starting during the week of November 18, 2013 in 
the following newspapers: Minneapolis Star Tribune, Mounds View/New 
Brighton Sun Focus, and the Shoreview Press. The notice invited anyone 
interested in the FYR process to contact the Army TCAAP representative. 
The City of New Brighton was interested in participating in the FYR 
process.
    The Army published a notice indicating that the FYR was complete 
and included contact information and the location of the public 
repository for the report (470 West Hwy. 96, Suite 100, Shoreview, MN 
55126) in the newspapers after the FYR was finalized.
    EPA has satisfied public participation activities for this partial 
deletion of the NB/AH/TCAAP Site as required by CERCLA section 113(k), 
42 U.S.C. 9613(k), and CERCLA section 117, 42 U.S.C. 9617. EPA arranged 
to publish advertisements announcing this proposed direct final Partial 
Deletion and the 30-day public comment period in the Minneapolis Star 
Tribune, the Mounds View/New Brighton Sun Focus, and the Shoreview 
Press concurrent with publishing this partial deletion in the Federal 
Register. Documents in the deletion docket, which EPA relied on for 
recommending the partial deletion of the NB/AH/TCAAP Site from the NPL, 
are available to the public in the information repositories and at 
https://www.regulations.gov. Documents in the Docket include maps which 
identify the NB/AH/TCAAP Site, the locations of the OU2 areas of 
contamination/sites, the OU2 area included with this proposed direct 
final Partial Deletion, and the LUCs implemented for OU2.

Determination That the Criteria for Partial Deletion Have Been Met

    The soil (shallow and deep) portion of OU2 and the five aquatic 
sites located within the OU2 boundary of the NB/AH/TCAAP Site: Rice 
Creek, Sunfish Lake, Marsden Lake North, Marsden Lake South and Pond G, 
meet all of the site completion requirements specified in Office of 
Solid Waste and Emergency Response (OSWER) Directive 9320.2-22, Close-
Out Procedures for National Priorities List Sites. All cleanup actions 
and remedial action objectives for OU2 shallow and deep soil and these 
five aquatic sites set forth in the 1997 ROD, 2007 ROD Amendment #1, 
2009 ROD Amendment #3, 2009 ESD #2, 2012 ROD Amendment #4 and 2014 ROD 
Amendment #5 have been implemented for all pathways of exposure. The 
selected remedial actions, RAOs, and associated cleanup levels for OU2 
soil and the five aquatic sites located within the OU2 boundary are 
consistent with EPA policy and guidance. No further Superfund response 
is necessary to protect human health or the environment from the soil 
portion of OU2 (shallow and deep) or from the five aquatic sites 
located within the OU2 boundary.
    Section 300.425(e) of the NCP states that a Superfund site or a 
portion of a site may be deleted from the NPL when no further response 
action is appropriate. EPA, in consultation with the State of 
Minnesota, has determined that all required response actions have been 
implemented for all soil (shallow and deep) located within the OU2 
boundary of the NB/AH/TCAAP Site and for the five aquatic sites located 
within the OU2 boundary: Rice Creek, Sunfish Lake, Marsden Lake North, 
Marsden Lake South and Pond G, and that no further response action by 
the Army is appropriate for these media/areas.

V. Deletion Action

    EPA, with concurrence of the State of Minnesota, through the MPCA, 
has determined that all appropriate response actions under CERCLA, 
other than maintenance, monitoring and five-year reviews, have been 
completed for all soil (shallow and deep) located within the OU2 
boundary and for the five aquatic sites located within the OU2 
boundary: Rice Creek, Sunfish Lake, Marsden Lake North, Marsden Lake 
South and Pond G. Therefore, EPA is deleting all soil (shallow and 
deep) located within OU2 and these five aquatic sites located within 
the OU2 boundary from the NPL.
    Because EPA considers this action to be noncontroversial and 
routine, EPA is taking it without prior publication. This action will 
be effective September 23, 2019 unless EPA receives adverse comments by 
August 22, 2019. If adverse comments are received within the 30-day 
public comment period, EPA will publish a timely notice of withdrawal 
of this direct final Notice of Partial Deletion before its effective 
date and the partial deletion will not take effect. EPA will prepare a 
response to comments and continue with the deletion process on the 
basis of the notice of intent to partially delete and the comments 
already received. There will be no additional opportunity to comment.

List of Subjects in 40 CFR Part 300

    Environmental protection, Air pollution control, Chemicals, 
Hazardous waste, Hazardous substances, Intergovernmental relations, 
Penalties, Reporting and recordkeeping requirements, Superfund, Water 
pollution control, Water supply.

    Dated: July 8, 2019.
 Cathy Stepp,
Regional Administrator, Region 5.

    For the reasons set out in this document, 40 CFR part 300 is 
amended as follows:

PART 300--NATIONAL OIL AND HAZARDOUS SUBSTANCES POLLUTION 
CONTINGENCY PLAN

0
1. The authority citation for part 300 continues to read as follows:

    Authority:  33 U.S.C. 1321(d); 42 U.S.C. 9601-9657; E.O. 13626, 
77 FR 56749, 3 CFR, 2013 Comp., p. 306; E.O. 12777, 56 FR 54757, 3 
CFR, 1991 Comp., p. 351; E.O. 12580, 52 FR 2923, 3 CFR, 1987 Comp., 
p. 193.


0
2. Table 2 of Appendix B to part 300 is amended by revising the entry 
for ``MN, New Brighton/Arden Hills/Twin Cities Army Ammunition Plant, 
New Brighton'' to read as follows:

Appendix B to Part 300--[Amended]

                                       Table 2--General Superfund Section
----------------------------------------------------------------------------------------------------------------
             State                      Site name                  City/county                   Notes \a\
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
MN.............................  New Brighton/Arden      New Brighton...................  P
                                  Hills/TCAAP (USARMY).

[[Page 35334]]

 
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------
\a\ * * *
* P = Sites with partial deletion(s).

[FR Doc. 2019-15633 Filed 7-22-19; 8:45 am]
 BILLING CODE 6560-50-P