Federal Register, Volume 85 Issue 141 (Wednesday, July 22, 2020)

[Federal Register Volume 85, Number 141 (Wednesday, July 22, 2020)]
[Proposed Rules]
[Pages 44259-44265]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-14429]

-----------------------------------------------------------------------

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 300

[EPA-HQ-SFUND-1994-0009; FRL-10009-99-Region 4]

National Oil and Hazardous Substances Pollution Contingency Plan;
National Priorities List: Partial Deletion of the Redstone Arsenal
(USARMY/NASA) Superfund Site

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule; notice of intent.

-----------------------------------------------------------------------

SUMMARY: The U.S. Environmental Protection Agency (EPA) Region 4 is
issuing a Notice of Intent to Partially Delete Operable Unit (OU)-09
(OU-20 for Redstone Arsenal) and OU-12 (OU-21 for Redstone Arsenal),
which are located on the George C. Marshall Space Flight Center (MSFC)
within the Redstone Arsenal (USARMY/NASA) Superfund Site (Site), in
Huntsville, Madison County, Alabama, from the

[[Page 44260]]

National Priorities List (NPL) and requests public comments on this
proposed action. 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). The EPA and the
State of Alabama, through the Alabama Department of Environmental
Management (ADEM), have determined that all appropriate response
actions at OU-09 and OU-12 have been completed under CERCLA. However,
this deletion does not preclude future response actions under CERCLA at
the Redstone Arsenal (USARMY/NASA) Superfund Site which includes the
MSFC.

DATES: Comments must be received by August 21, 2020.

ADDRESSES: Submit your comments by one of the following methods:
https://www.regulations.gov. Follow online 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 for which disclosure is restricted by statute. Multimedia
submissions, such as audio or video, must be accompanied by a written
comment. The written comment is considered the official comment and
should include a discussion of all points you wish to make. In general,
the EPA will not consider comments or comment content located outside
the primary submission, such as 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.
Following Centers for Disease Control and Prevention (CDC)
and Office of Policy Management (OPM) guidance and specific state
guidelines impacting our regional offices, the EPA's workforce has been
authorized to telework to help prevent transmission of the coronavirus
[COVID-19]. As a result, there is a temporary shutdown of the EPA's
Docket Center and the EPA Regional Records Centers. While in this
workforce telework status, there are practical limitations on the
ability of staff to collect, and for Agency personnel to respond to,
``hard copy'' mailed queries sent directly to Agency office locations.
Therefore, until the workforce is able to return to office locations,
the EPA recommends that, to the extent feasible, any correspondence
mailed to the Agency should also be sent via email.
For question on this Notice and submission of comments
please contact--Brad Jackson, Remedial Project Manager, U.S.
Environmental Protection Agency, Region 4, 61 Forsyth Street SW--
MS9T25, Atlanta, GA 30303, (404) 562-8925, jackson.brad@epa.gov or Ron
Tolliver, Community Involvement Coordinator, at tolliver.ron@epa.gov.
Instructions: Direct your comments to Docket ID No. EPA-HQ-SFUND-
1994-0009. The 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 CBI or other information for which 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 the 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 the 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, the 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 the EPA cannot read your comment due to technical
difficulties and cannot contact you for clarification, the 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
for which 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 are available
electronically in https://www.regulations.gov.
The EPA is temporarily suspending its Docket Center and Regional
Records Centers for public visitors to reduce the risk of transmitting
COVID-19. In addition, many site information repositories are closed
and information in these repositories, including the deletion docket,
has not been updated with hardcopy or electronic media. For further
information and updates on the EPA Docket Center services, please visit
us online at https://www.epa.gov/dockets.
The EPA continues to carefully and continuously monitor information
from the Centers for Disease Control and Prevention (CDC), local area
health departments, and our Federal partners so that we can respond
rapidly as conditions change regarding COVID -19. The EPA is committed
to continuing our critical work on behalf of the American public while
also safeguarding the health and safety of the public and the families
of the EPA employees by taking responsible measures to help prevent
transmission of the coronavirus. Thank you for your cooperation and
understanding.
More information on the Site's Superfund Cleanup Program is
available on the Web at: https://eemo.msfc.nasa.gov/eemo/.

FOR FURTHER INFORMATION CONTACT: Brad Jackson, Remedial Project
Manager, U.S. Environmental Protection Agency, Region 4, 61 Forsyth
Street SW, Atlanta, GA 30303, (404) 622-2876, email:
jackson.brad@epa.gov.

SUPPLEMENTARY INFORMATION:

Table of Contents

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

I. Introduction

The EPA Region 4 announces its intent to delete the surface water,
sediment, soil and groundwater of OU-09 and the soil (including
sediment) of OU-12 of the George C. Marshall Space Flight Center (MSFC)
portion of the Redstone Arsenal (USARMY/NASA) Superfund site from the
National Priorities List (NPL) and requests public comment on this
proposed action. Groundwater beneath OU-12 is being addressed under
CERCLA as part of the Site-wide Groundwater Operable Unit, OU-03 under
the MSFC Federal Facility Agreement (FFA) between NASA, EPA Region 4,
and ADEM (effective September 17, 2001). OU-09 and OU-12 are located on
the MSFC portion of the NPL Superfund site managed by NASA

[[Page 44261]]

and are identified by the Army and the EPA as Redstone OU-20 and OU-21,
respectively. All other media and OUs which are part of the Redstone
Arsenal (USARMY/NASA) Superfund Site are not being considered for
deletion as part of this action and will remain on the NPL. The NPL
constitutes Appendix B of 40 CFR part 300 which is the National Oil and
Hazardous Substances Pollution Contingency Plan (NCP), which the EPA
promulgated pursuant to Section 105 of the Comprehensive Environmental
Response, Compensation and Liability Act (CERCLA) of 1980, as amended.
The EPA maintains on the NPL those 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 surface
water, sediment, soil and groundwater at OU-09 (OU-20 for Redstone
Arsenal) and soil an OU-12 (OU-21 for Redstone Arsenal) from the Site
is proposed in accordance with 40 CFR Section 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 [November 1,
1995]). As described in Section 300.425(e)(3) of the NCP, a portion of
a site deleted from the NPL remains eligible for Fund-financed remedial
action if future conditions warrant such actions.
The EPA will accept comments on the proposal to partially delete
this Site for 30 days after publication of this document in the Federal
Register.
The criteria for deleting sites from the NPL are explained in
Section II and the procedures for this action are discussed in Section
III. In Section IV, OU-09 (OU-20 for Redstone Arsenal) and OU-12 (OU-21
for Redstone Arsenal) of the MSFC portion of the Redstone Arsenal
(USARMY/NASA) Superfund Site are described, along with how they meet
the criteria for partial deletions.

II. NPL Deletion Criteria

The NCP establishes the criteria that the EPA uses to delete sites
from the NPL. In accordance with 40 CFR Section 300.425(e), sites may
be deleted from the NPL where no further response is appropriate. In
making a determination pursuant to 40 CFR Section 300.425(e), the EPA
will consider, in consultation with the State of Alabama, 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.

III. Deletion Procedures

The following procedures apply to the deletion of soil and
groundwater at OU-09 (OU-20 for Redstone Arsenal) and soil (including
sediments) at OU-12 (OU-21 for Redstone Arsenal) of the Site:
(1) The EPA consulted with the State before developing this Notice
of Intent for Partial Deletion;
(2) The EPA has provided the State 30 working days for review of
this action prior to publication of it today;
(3) In accordance with the criteria discussed above, the EPA has
determined that no further response is appropriate;
(4) On August 30, 2019, the State of Alabama through the Alabama
Department of Environmental Management (ADEM) concurred with the
deletion from the NPL MSFC portions of the Redstone Arsenal (USARMY/
NASA) Superfund Site designated as OU-09 and OU-12;
(5) Concurrently with publication of this Notice of Intent for
Partial Deletion in the Federal Register, a notice is being published
in a major local newspaper, The Huntsville Times. The newspaper
announces the 30-day public comment period concerning the Notice of
Intent for Partial Deletion of the Site from the NPL; and
(6) The EPA placed copies of documents supporting the proposed
partial deletion in the deletion docket, made these items available for
public inspection, and copying at the Site information repositories
identified above.
If comments on this document are received within the 30-day comment
period, the EPA will evaluate and respond accordingly to the comments
before making a final decision to delete OU-09 (identified as OU-20 for
Redstone Arsenal) and OU-12 (identified as OU-21 for Redstone Arsenal)
from the Superfund Site. If necessary, the EPA will prepare a
Responsiveness Summary to address any significant public comments
received. After the public comment period, if the EPA determines it is
still appropriate to delete OU-09 and OU-12 located in MSFC portion of
the Redstone Arsenal (USARMY/NASA) Superfund Site, the Regional
Administrator will publish a final Notice of Partial Deletion in the
Federal Register. Public notices, public submissions, and copies of the
Responsiveness Summary, if prepared, will be made available to
interested parties and included in the site information repositories
listed above.
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
the EPA's right to take enforcement actions, as appropriate. The NPL is
designed primarily for informational purposes and to assist the 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 future
response actions, should future conditions warrant such actions.

IV. Basis for Partial Site Deletion

The following information provides the EPA's rationale for deleting
OU-09 (identified as OU-20 for Redstone Arsenal) and OU-12 (identified
as OU-21 for Redstone Arsenal) located in the MSFC portion of the
Redstone Arsenal (USARMY/NASA) Superfund Site from the NPL.

Site Background and History

The Redstone Arsenal (USARMY/NASA) Superfund Site (CERCLIS ID:
AL7210020742) is located on the active Redstone Arsenal Army
Installation that encompasses 38,300 acres of land southwest of
Huntsville, Alabama. Since opening in the early-1940s, development
within the Arsenal has largely revolved around the historical need to
produce, and later dispose of, conventional and chemical munitions.
From 1942 to 1945, the Army's operations were used to manufacture raw
materials for toxic agents and incendiary materials and to assemble,
store, and ship the final products. Onsite waste disposal activities
included the disposal of construction debris, drums, and chemical
munitions, as well as the open burning of combustible materials.
After WWII, Redstone Arsenal became a center for the receipt,
storage, and demilitarization of Allied and German chemical agents. In
1949, the Arsenal's mission changed to research and development of
rocketry and guided missile systems. In 1960, civilian rocketry and
missile activities were transferred to the NASA, George C. Marshall
Space Flight Center (MSFC), which is located on 1,841 acres within the
central portion of the Arsenal.
Since then, the area known as MSFC has been used to develop, test,
and manufacture space vehicles and

[[Page 44262]]

components. MSFC is NASA's principal propulsion development center.
NASA uses a state-of-the-art propulsion laboratory for developing and
testing the newest propulsion system innovations at MSFC. Its
scientists, engineers, and support personnel also play a significant
role in managing experiments conducted on the International Space
Station and managing and developing the Space Launch System.
The EPA proposed the Redstone Arsenal (USARMY/NASA) site to the NPL
on June 23, 1993 (58 FR 34018) and listed the site as final on the NPL
on May 31, 1994 (59 FR 27989). MSFC is part of the ``fence-to-fence''
listing of the Redstone Arsenal (USARMY/NASA) site on the NPL but is
managed by NASA. The Army and NASA cleanup programs are separately
funded and operated. They coordinate on common programmatic needs such
as data sharing, consistent cleanup, and technical issues.
In 2001, the EPA, NASA, and ADEM signed a Federal Facilities
Agreement (FFA) under CERCLA Section 120 for the MSFC portion of the
site. The FFA integrates both NASA's Resource Conservation and Recovery
Act (RCRA) and CERCLA requirements. The FFA requires that NASA will
fully investigate environmental impacts associated with past and
present activities and take the appropriate cleanup actions. The Site
Management Plan required by the FFA establishes schedules, priorities,
and enforceable milestones for cleanup activities at the MSFC. To date
there has not been an FFA signed between the EPA, the Army, and ADEM
for the Redstone Arsenal portion of the Superfund Site.
The MSFC portion of the Superfund Site includes over 80 areas with
surface media (e.g., soil, surface water, and sediment) contamination,
five groundwater plumes, and 17 subsurface groundwater source areas.
Proposed for deletion is OU-09 that addresses former surface water,
sediment, soil, and groundwater contamination. Also proposed for
deletion is OU-12 which addresses former soil (including sediment)
contamination. The docket contains a map depicting these areas.

Description of OU-09 (Recorded by Army as OU-20 for Redstone Arsenal)

OU-9 is the Former Industrial Waste Treatment Facility (IWTF). The
first phase of the IWTF was constructed in the 1960s. This phase
included only the Industrial Waste Treatment Basin, which received
flows from the industrial sewer. The second phase of the IWTF was
constructed in the late-1960s or early-1970s. This phase included the
remainder of the IWTF (ultimate lagoons, hydrostatic dump lagoon,
concentrate receiving tank, caustic storage tank, transfer tank, and
mix tank). This portion of the IWTF was constructed to treat the
plating waste from Building 4760. The IWTF operated into the 1980s.
The Former IWTF consists of the following eight components:
1. Industrial Waste Treatment Basin (MSFC-044);
2. Concentrate Receiving Tank (MSFC-045);
3. Transfer Tank (MSFC-046);
4. Hydrostatic Dump Lagoon (MSFC-047);
5. Mix Tank (MSFC-048);
6. East Ultimate Lagoon (MSFC-049);
7. West Ultimate Lagoon (MSFC-050); and
8. Caustic Storage Tank (MSFC-A).
The IWTF or OU-9 (OU-20 for Redstone Arsenal) is shown on Figure 1.

Description of OU-12 (Recorded by Army as OU-21 for Redstone Arsenal)

OU-12 is the location of the former Stauffer Chemical Plant, which
produced chlorine gas for the manufacture of mustard gas during the
1940s. These sites are adjacent to each other in the northern portion
of MSFC near the Center's eastern border. OU-12 is bounded by Digney
Road on the south, Morris Road on the east, Neal Street on the north,
and Building 4207 on the west.
The sites in OU-12 consist of a former building, a nearby drainage
ditch, a satellite waste accumulation area, and a product storage area.
OU-12 comprises the following individual RCRA solid waste management
units (SWMUs):
1. Satellite Waste Accumulation Area for Buildings 4241 and 4244
(MSFC-022);
2. Portion of Industrial Sewer North of MSFC-034 (MSFC-052a);
3. Site of the Former Stauffer Chemical Company Plant (MSFC-055);
4. Building 4241 Surface Drainage (MSFC-065);
5. Containment Area for Tanks 4234A, B, and C (MSFC-D); and
6. Buildings 4241 and 4244 Product Storage Area (MSFC-E).
OU-12 (OU-21 for Redstone Arsenal) is shown as Figure 2.

Remedial Investigation at OU-09 (Recorded by Army as OU-20 for Redstone
Arsenal)

Three SWMUs (MSFC-044, MSFC-049, and MSFC-050) were closed under
RCRA regulations and certified by ADEM in January 1990. A soil
investigation at the remaining five units (MSFC-045, MSFC-046, MSFC-
047, MSFC-048, and MSFC-A) was conducted by NASA in May 1996 to provide
data for confirmation sampling. A soil investigation at the three RCRA-
closed units (MSFC-044, MSFC-049, and MSFC-050) was conducted in May
1997 to provide data for the CERCLA remedial investigation (RI). These
data were combined and presented in the MSFC OU-9 RI Report.
The 1999 RI evaluated the eight sites of OU-09 (former IWTF) to
determine if a contaminant release had occurred at the site. Surface
and subsurface soil samples were collected from borings installed
around the remaining five sites (MSFC-045, MSFC-046, MSFC-047, MSFC-
048, and MSFC-A), which are concrete structures, and within the sites
that are surface impoundments lined with clay. Subsurface soil samples
were collected from the natural soil beneath the locations where the
RCRA-closed sites (MSFC-044, MSFC-049, and MSFC-050) were placed.
Groundwater at OU-09 was evaluated through RCRA-required quarterly
sampling for the closed units. The 1999 RI included a baseline risk
assessment for soil and groundwater.
Soil and groundwater associated with OU-09 were proposed for no
further action (NFA) in the OU-09 RI Report. Based on information
provided in the report, it was concluded that further investigation of
the soil and groundwater, monitoring of the groundwater under RCRA, and
remedial action for soils were not necessary to ensure the protection
of human health and the environment.

Remedial Investigation and Feasibility Study at OU-12 (Recorded by Army
as OU-21 for Redstone Arsenal)

The 2008 OU-12 RI Report addressed the surface media at the OU-12
sites, including contaminated surface soil, subsurface soil, and
sediment. Groundwater at the NASA-administered MSFC property is
addressed in the FFA as OU-03 Site-wide Groundwater Operable Unit. The
OU-12 RI included human health and ecological risk assessments for soil
(including sediment), which are discussed in the OU-12 RI report, along
with an evaluation of options for implementing non-time-critical
removal actions.
Chemicals of concern (COCs) identified for OU-12 as a whole
included polynuclear aromatic hydrocarbons (PAHs) (benzo(a)anthracene,
benzo(a)pyrene, benzo(b)fluoranthene, dibenz(a,h)anthracene,
benzo(k)fluoranthene, chrysene, and indeno(1,2,3-cd)pyrene),
polychlorinated biphenyls or PCBs

[[Page 44263]]

(Aroclor-1260 and Aroclor-1254), dieldrin, iron, and lead. Individual
RCRA SWMUs located within OU-12 generally exhibited a subset of the
COCs.
The results of the risk assessments indicated that response actions
for contaminated soil and sediment were necessary to protect the public
health and welfare or the environment from actual or threatened
releases of hazardous substances into the environment.
NASA identified the following six remedial action alternatives in a
Feasibility Study (FS) Report for consideration at OU-1-2:
(1) No action;
(2) Institutional Controls with Monitoring;
(3) Capping;
(4) Removal and offsite disposal to meet the residential risk
criteria;
(5) Removal and offsite disposal to meet the industrial risk
criteria; and
(6) Treatment.
At the conclusion of the remedial action alternative evaluation
process, the recommended remedial action alternative for OU-12 provided
in the Proposed Plan was removal of contaminated soil (including
sediment) and offsite disposal to meet the residential risk criteria.
Because of this method's effectiveness in reducing the risk associated
with soil (including sediments) contamination to acceptable residential
risk levels there was no need for land use controls (LUCs) to prevent
exposure at the OU-12 Area. The Final Proposed Plan: Remedial Action at
OU-12 (June 2010) sought public comments on the Preferred Alternative.
NASA received no comments on the Proposed Plan during the 30-day public
comment period.

Selected Remedy for OU-09 (Recorded by Army as OU-20 for Redstone
Arsenal)

The Record of Decision (ROD) for OU-09, which recommended no
further action (NFA), was signed by the EPA and NASA in 2000, along
with concurrence by the State. The 2000 ROD documents that no CERCLA
response action was necessary for OU-09 in order to protect human
health and the environment and five-year reviews under CERCLA Section
121(c) would not be necessary for the soil or groundwater at OU-09.
Two years after the ROD was signed, ADEM requested that NASA
prepare and submit a Clean Closure Equivalency Demonstration (CCED) for
the three former RCRA units (MSFC-044, MSFC-049, and MSFC-050) within
OU-09. The CCED presented the data, information, and risk assessment in
a similar manner as the 1999 OU-09 RI Report. In addition, a revised
screening level human health risk evaluation was conducted for the
eight SWMUs to demonstrate that no further remedial action under CERCLA
is warranted. The 1999 risk evaluation was revised to incorporate more
current toxicity values, as well as to incorporate new site
characterization data to fills data gaps identified by the regulatory
agencies during their review of the CCED and the 2000 ROD, which was
issued by the EPA for OU-09 (NASA, 2000a). The results are integrated
into the 2006 Final CCED. The residential risk assessment for the CCED
demonstrated that site surface and subsurface soil do not pose a
significant risk; sitewide NASA groundwater and sediment issues
remaining are being managed under the sitewide OU-03 Groundwater
Operable Unit.

Selected Remedy for OU-12 (Recorded by Army as OU-21 for Redstone
Arsenal)

NASA identified five areas of OU-12 that required the removal and
disposal of contaminated soil (including sediment) to meet the
residential risk criteria, as well as the removal and disposal of the
entire length of industrial sewer pipeline within OU-12. Additionally,
abandonment of select manholes by removing sediment and filling the
manholes with grout to 1-foot below ground surface (bgs) was included
in the selected remedy. The selected remedy was presented in the OU-12
ROD, which was signed by the EPA and NASA in 2012, along with State
concurrence.
The remedial action objectives (RAOs) for the OU-12 remedial action
were as follows:
Prevent unacceptable human exposures (dermal contact,
ingestion, inhalation) to contaminated surface soil, subsurface soil,
and sediment by removing contaminated soil and sediment so that the
concentrations of contamination are below the EPA Region 9 industrial
and/or residential preliminary remediation goal (PRG) levels or
applicable background levels (inorganic parameters only);
Prevent the migration of contaminated soil (including
sediment) offsite via stormwater runoff in ditches; and
Clean up to a level that allows for unrestricted use and
unlimited exposure at OU-12.
The 2012 ROD also documented significant changes to the preferred
remedial alternative presented in the Proposed Plan (PP). In accordance
with the 2009 action memorandum for the time-critical removal action
(TCRA) for OU-12, approximately 350 feet of the 10-inch-diameter,
vitrified clay pipeline on either side of manhole MHI-136 and
associated with MSFC-052a (beneath the potential sodium hydroxide area
of OU-12) were removed and disposed in an off-site landfill in 2010.
The removal of this portion of pipeline is discussed in the 2018 OU-12
Removal Action Completion Report (RACR). The section of the industrial
sewer pipeline removed during of the TCRA is part of MSFC-052a, the
rest of which was removed as part of the 2012 ROD selected remedy.
Additionally, because soils and sediment at OU-12 were cleaned to
unlimited use/unrestricted exposure (UU/UE) levels, the 2012 ROD
documented a non-significant change. At the EPA's request, the remedial
action alternative of institutional controls (ICs) with monitoring was
removed from the ROD as an independent alternative since ICs with
monitoring is part of other remedial alternatives. This was documented
as a change to the Administrative Record for the selected remedy for
OU-12.

Response Action for OU-09 (Recorded by Army as OU-20 for Redstone
Arsenal)

As described above, a CERCLA response action was not required at
OU-09 since conditions at the site did not pose an unacceptable risk to
human health and the environment as verified with several
investigations under both RCRA and CERCLA.

Response Action for OU-12 (Recorded by Army as OU-21 for Redstone
Arsenal)

The selected response action was summarized in the Proposed Plan
issued for public comment in 2010. The final approved remedial actions
are documented in the ROD issued in 2012 and implemented through the
2012 Remedial Design (RD).
The selected remedy for the OU-12 remedial action included the
removal of soil (including sediment) and offsite disposal to meet the
residential risk criteria for surface soil, subsurface soil, and
sediment contamination. For the former industrial sewer (MSFC-052a),
NASA proposed to remove and dispose of each pipeline section and
abandon each manhole by cutting them down approximately 1-foot below
grade and filling each with cement and bentonite grout. The selected
remedy accomplished the RAOs and met the CERCLA requirements for
implementing remedial actions. The selected remedy

[[Page 44264]]

achieved residential cleanup levels so that the site was suitable for
unlimited use and unrestricted exposure (UU/UE) and eliminated the need
for statutory five-year reviews per CERCLA Section 121(c) and land use
controls (LUCs) which include use or activity restrictions to prevent
unacceptable exposure to contamination left in place. No further
monitoring and maintenance are required at OU-12.
Additional information led NASA to prepare an addendum to the RD in
2014 and an ESD in 2015. These documents provide the basis for the
following changes to the scope of the OU-12 remedial action:
Based on confirmation samples collected during the MSFC-D
area excavation, an additional 2,200 cubic yards (yd\3\) of impacted
soil requiring remediation were identified and incorporated into
Remedial Area (RA) 4;
Two segments of industrial sewer pipeline could not be
removed as originally planned. A segment within, and south of, RA-8
could not be removed because of the presence of an adjacent active
sanitary sewer line made of fragile vitrified clay. The northern
segment (near Buildings 4241 and 4244) could not be removed because of
the potential to damage the foundation of Building 4241. These segments
of the industrial sewer were abandoned in place;
To improve excavation efficiency, staging piles instead of
roll-off boxes were used for temporary storage of excavated soil during
excavations in 2015. The soil in the staging piles was characterized,
and nonhazardous contaminated material was loaded into dump trucks for
waste disposal at an approved off-site RCRA permitted solid waste
landfill. Soil considered RCRA hazardous waste was disposed in approved
off-site RCRA permitted Subtitle C hazardous waste landfill; and
As documented in the 2014 OU-12 RD Addendum, the names of
several excavation areas within MSFC-D were revised and included within
RA-4, as the areas fell within or near the revised RA excavation area
boundary. In addition to the changes detailed in the 2014 OU-12 RD
Addendum. The following additional changes were made, which are
summarized in the 2018 Remedial Action Completion Report (RACR):
--During preparation for pressure-washing and grouting of the sewer
lines near Building 4244, it was determined that no portion of the
industrial sewer was connected to Building 4244 and that a previously
unknown portion of the industrial sewer was present that extended
parallel to, and connected with, the north side of Building 4241. These
pipelines were disconnected from Building 4244 and plugged at an
unknown time;
--During the site preparation phase, it also was discovered that
the amount of industrial sewer south of RA-8 that would need to be
grouted in place was underestimated in the 2014 OU-12 RD Addendum,
because the active, fragile, vitreous clay sanitary sewer was adjacent
to the industrial sewer line for a greater distance than had previously
been thought. Therefore, the amount of sewer line abandoned in place
increased;
--It was determined that no excavation would occur within 5 feet of
the high value fiber optic communication line that was exposed in Ditch
B, south of the intersection of Ditch B and Ditch C, due to the
potential catastrophic consequences of any damage to this utility. This
cable was contained in a terra cotta tile at the ditch crossing, which
may have been damaged or broken during a heavy rain event prior to the
OU-12 remedial action;
--The northern end of Ditch B was not excavated as originally
designed. A relatively large concrete apron was identified as existing
in this area. A historical RI sample (SX12-009) was collected atop this
apron; when the remedial action for the Ditch B area began, most
sediment and/or soil deposits were washed from this apron. It is likely
that the remediation of Ditch D, Ditch E, Ditch F, and Ditch G (mostly
brush clearing activities) resulted in elevated surface water flow
during storm events, which aided in removing the soil atop this
concrete apron. Remedial actions were not required in this area of
Ditch B, and field personnel were unable to collect agency-requested
sample SS12-263;
Additional minor deviations from the 2012 OU-12 RD Report
occurred that were driven by field conditions, such as minor shifts to
the outline of the excavation areas, increasing the depth of
excavation, and adjusting the work zones;
Site conditions impacted the remedial plans for RA-8B. The
proposed excavation plan (5-feet by 5-feet by 5-feet) changed into an
elongated, trench-like excavation when a concrete-lined basin/slab was
encountered. Soil was excavated to the horizontal and vertical walls of
this area. Although the deepest confirmation sample results from
station SB12-110B showed elevated concentrations of lead, impacted soil
from this area was removed and the risk was mitigated.
The RACR documents the remedial action conducted at OU-12. A
residual risk evaluation was also included in the RACR to assess the
residual risk associated with the remaining sewer sections and exposure
to potential contamination at the unexcavated area south of the
intersection of Ditch B and Ditch C.
The potential risks associated with exposure to the limited volume
of sediment, if present, in the remaining sections of sewer pipeline at
MSFC-052a are expected to be within acceptable levels for ecological
receptors, as well as for industrial receptors and hypothetical future
residents. Therefore, no additional investigations or LUCs were
recommended for the areas within the remaining sewer sections.
The estimated carcinogenic risks associated with the unexcavated
ditch areas for all scenarios were less than ADEM's target risk level
of 1 x 10^-5 and the estimated noncarcinogenic hazard indexes
for all scenarios were less than the target hazard index of 1. The
estimated carcinogenic risks were within the EPA's Superfund Program
target risk range (1 x 10^-6 to 1 x 10^-4) for
location SX12-012 and for the combined data from the upgradient
locations SX12-012, and SS12-232. The estimated carcinogenic risks for
location SS12-232 met the EPA's target risk range, specifically the
point of departure level of 1 x 10^-6. Therefore, the
potential risks associated with exposures to the unexcavated soil are
within acceptable levels for an unrestricted land use scenario and no
additional investigations or LUCs are recommended for soil at this
area.
Soil and sediment removal activities at OU-12 began in September
2012 and were completed in May 2015, and site restoration activities
were completed September 2015. Approximately 16,895 yds\3\ cubic yards
of contaminated soil (including sediment) were removed and disposed of
offsite in approved RCRA permitted landfills. A total of 868 linear
feet of industrial sewer pipeline was removed and a total of 187 yds\3\
of grout was used to fill the portions of the industrial sewer that
could not be excavated.

Cleanup Levels for OU-09

Remedial cleanup levels were not developed for OU-09 because
remedial actions were not required at OU-09 since site conditions were
determined to not present an unacceptable risk to human health and the
environment.

[[Page 44265]]

Cleanup Levels for OU-12

Cleanup levels were developed for soil COCs (PAHs, PCBs, dieldrin,
iron, and lead) at OU-21 on the basis of the EPA Region 9 PRGs listed
for industrial and residential scenarios or on the basis of a
background value for a particular parameter (iron), and therefore, the
final remedy cleaned up OU-12 to residential standards suitable for UU/
UE. The following are the cleanup levels for COCs at OU-12:
PAH (as benzo(a)pyrene equivalent)--60 micrograms per
kilogram ([mu]g/kg) (residential) or 210 [micro]g/kg (industrial);
PCBs--220 [mu]g/kg (residential) or 740 [mu]g/kg
(industrial);
Dieldrin--30 [mu]g/kg (residential) or 110 [mu]g/kg
(industrial);
Lead--400 milligrams per kilogram (mg/kg) (residential) or
800 mg/kg (industrial); and
Iron--66,400 mg/kg.
The cleanup level for iron is the subsurface soil background value,
as referenced in the OU-12 RI Report (NASA, OU-12, 2008). The iron
background value was used instead of the EPA Region 9 PRG despite that
the background value is one order of magnitude higher than the PRG.,
the EPA policy does not require CERCLA cleaning up to below background
levels in soils provided the levels are protective of human health and
the environment. This cleanup level was obtained at OU-12.

Operation and Maintenance, If Applicable

Neither OU-09 nor OU-12 require any operation and maintenance (O&M)
activities. All cleanup objectives in the RODs were met, and no further
remedial action or O&M is required.

Five-Year Review, If Applicable

NASA conducted a statutory Five-Rear Review (FYR) of the MSFC Site
in 2013 and 2018 in accordance with CERCLA Section 121(c). The 2018 FYR
confirmed that soil and groundwater at OU-09 and soil (including
sediment) at OU-12 met UU/UE criteria and further reviews are not
required for either OU-09 and OU-12 (OU-20 or OU-21, respectively for
Redstone Arsenal).
The soil media at OU-09 was recommended for NFA in the final 2000
ROD. To address the EPA and ADEM comments with respect to a residential
risk evaluation, NASA collected additional soil samples at OU-09 and
submitted a 2016 CCED. The FFA parties determined that the site met
residential exposure levels and no further action required.
Remedial actions are complete for soil (including sediment) at OU-
12 and any residual risks for that media are considered to be
protective of human health and the environment for future unrestricted
residential use and therefore does not require LUCs.

Community Involvement

The EPA and ADEM satisfied public participation activities as
required in CERCLA Section 113(k), 42 United States Code (U.S.C.) 9613.
The EPA published notifications in The Huntsville Times announcing the
FYR and inviting the public to comment and express their concerns about
the Site at the start of the 2013 and 2018 FYRs as well as offer public
comment for proposed plans for all of the EPA Site decision documents
and this proposed NPL partial deletion. The Administrative Record file
contains the documentation NASA considered in selecting the CERCLA
response actions for both OU-09 and OU-12 in accordance with the NCP
requirements.

Determination That the Criteria for Deletion Have Been Met

OU-09 (including surface water, sediment, soil, and groundwater)
and OU-12 (soil including sediment) meet all of the site completion
requirements as specified in Office of Solid Waste and Emergency
Response Directive 9320.2-22, Close Out Procedures for National
Priorities List Sites. The EPA has followed NPL deletion procedures
required by NCP at 40 CFR 300.425(e).
Soil and groundwater associated with OU-09 were proposed for NFA in
the CERCLA 1999 OU-09 RI Report. The 2000 ROD selected NFA for OU-09.
MSFC, ADEM, and the EPA concurred that additional remedial actions are
not required at OU-09 to protect of human health and the environment
and approved the ROD.
All cleanup actions specified in the OU-12 ROD have been
implemented, and the Site has achieved the degree of cleanup or
protection specified in the ROD and met ROD remedial action objectives.
The soil (including sediment) area proposed for partial deletion has
been cleaned up to residential risk levels for soil exposure pathways.
The RAOs and associated cleanup goals are consistent with agency policy
and guidance. Groundwater beneath OU-12 (OU-21 for Redstone Arsenal) is
being investigated by NASA under the FFA as part of OU-3 Site-wide
Groundwater and, therefore, is not included in this proposed deletion
action.
The EPA has determined that no further Superfund response is
necessary at OU-09 and OU-12 -to protect human health and the
environment and supports the partial deletion of these operable units
from the MSFC portion of the Redstone Arsenal (USARMY/NASA) Superfund
Site.
The NCP (40 CFR Section 300.425(e)) states that a site may be
deleted from the NPL when no further response action is appropriate.
The EPA, in consultation with the State of Alabama, has determined that
all required response actions have been implemented and no further
response action by the responsible parties is appropriate for these
identified OUs at the MSFC.

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.

Authority: 33 U.S.C. 1251et seq.

Dated: June 26, 2020.
Mary Walker,
Regional Administrator EPA R4.
[FR Doc. 2020-14429 Filed 7-21-20; 8:45 am]
BILLING CODE 6560-50-P