National Oil and Hazardous Substances Pollution Contingency Plan; National Priorities List: Partial Deletion of the Redstone Arsenal (USARMY/NASA) Superfund Site, 44259-44265 [2020-14429]

Agencies

• ENVIRONMENTAL PROTECTION AGENCY

[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]


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 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.

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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, [email protected] or Ron 
Tolliver, Community Involvement Coordinator, at [email protected].
    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: 
[email protected].

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

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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

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(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