Document ID: EPA-HQ-SFUND-1990-0010-0061
Agency: epa
Document Type: Proposed Rule
Title: National Oil and Hazardous Substances Pollution Contingency Plan; National Priorities List: Partial Deletion of the Townsend Saw Chain Co. Superfund Site
Posted Date: 2019-07-22T04:00Z

[Federal Register Volume 84, Number 140 (Monday, July 22, 2019)]
[Proposed Rules]
[Pages 35054-35059]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-15419]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 300

[EPA-HQ-SFUND-1990-0010; FRL-9996-76-Region 4]

National Oil and Hazardous Substances Pollution Contingency Plan; 
National Priorities List: Partial Deletion of the Townsend Saw Chain 
Co. Superfund Site

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule; notice of intent.

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SUMMARY: The Environmental Protection Agency (EPA) Region 4 is issuing 
a Notice of Intent to Delete the soil, sediment, surface water, 
surficial aquifer, and the intermediate aquifer of this Site with the 
exception of a limited area (5,000-8,000 square feet) of the 
intermediate aquifer below the 1C clay in the vicinity of monitoring 
wells IMW-01B, MW-128, and OW-143 of the Townsend Saw Chain Co. 
Superfund Site (Site) located in Pontiac, South Carolina, from the 
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 South Carolina, through the South Carolina Department of 
Health and Environmental Control (SC DHEC), have determined that all 
appropriate response actions at these identified media and/or parcels 
under CERCLA except for five-year reviews, operations and maintenance 
and monitoring have been completed. However, this deletion does not 
preclude future actions under Superfund. All Site areas and media will 
be included in this partial deletion except for the groundwater in the 
intermediate aquifer as specified above which will remain on the NPL 
and are not being considered for deletion as part of this action.

DATES: Comments must be received by August 21, 2019.

[[Page 35055]]

ADDRESSES: Submit your comments, identified by Docket ID no. EPA-HQ-
SFUND-1990-0010, by one of the following methods:
     http://www.regulations.gov. Follow the 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 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 http://www2.epa.gov/dockets/commenting-epa-dockets.
     Email: Joydeb Majumder, Remedial Project Manager, 
majumder.joydeb@epa.gov.
     Mail: Joydeb Majumder, Remedial Project Manager, Superfund 
and Emergency Management Division, Superfund Restoration and 
Sustainability Branch, U.S. Environmental Protection Agency, Region 4, 
61 Forsyth Street SW, Atlanta, Georgia 30303-8960.
     Hand delivery: USEPA Region 4 Superfund Record Center, 
Attention: Tina Terrell, Records Center, Superfund and Emergency 
Management Division, Superfund Enforcement Branch, U.S. Environmental 
Protection Agency, Region 4, 61 Forsyth Street SW, Atlanta, Georgia 
30303-8960. Monday to Friday 7:30 a.m. to 4:30 p.m.; Phone: 404-562-
9121.
    Instructions: Direct your comments to Docket ID no. EPA-HQ-SFUND-
1990-0010. EPA policy is that all comments received will be included in 
the public docket without change and may be made available online at 
http://www.regulations.gov, including any personal information 
provided, unless the comment includes information claimed to be 
Confidential Business Information (CBI) or other information whose 
disclosure is restricted by statute. Do not submit information that you 
consider to be CBI or otherwise protected through http://www.regulations.gov or email. The http://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 http://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 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 http://www.regulations.gov index. Although listed in the index, some 
information is not publicly available, e.g., CBI or other information 
whose disclosure is restricted by statute. Certain other material, such 
as copyrighted material, will be publicly available only in the hard 
copy. Publicly available docket materials are available either 
electronically in http://www.regulations.gov or in hard copy at:
    (1) USEPA Region 4, 61 Forsyth Street SW, Atlanta, Georgia 30303-
8960, Monday-Friday 7:30 a.m.-4:30 p.m., Contact Tina Terrell 404-562-
8835; and
    (2) Northeast Regional Library, 7490 Parklane Road, Columbia, South 
Carolina, Monday--Thursday: 9:00 a.m.-9:00 p.m., and Friday-Saturday: 
9:00 a.m.-6:00 p.m., Phone: (803) 736-6575.

FOR FURTHER INFORMATION CONTACT: Joydeb Majumder, Remedial Project 
Manager, Superfund Restoration and Sustainability Branch, Superfund and 
Emergency Management Division, U.S. Environmental Protection Agency, 
Region 4, 61 Forsyth Street SW, Atlanta, Georgia 30303-8960, phone 404-
562-9121, email: majumder.joydeb@epa.gov

SUPPLEMENTARY INFORMATION:

Table of Contents

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

I. Introduction

    EPA Region 4 announces its intent to delete the soil, sediment, 
surface water, surficial aquifer, and the intermediate aquifer with the 
exception of a limited area (5000-8000 square feet) of the intermediate 
aquifer below the 1C clay in the vicinity of monitoring wells IMW-01B, 
MW-128, and OW-143 of the Townsend Saw Chain Co. Superfund Site (Site), 
from the National Priorities List (NPL) and requests public comment on 
this proposed action. The NPL constitutes Appendix B of 40 CFR part 300 
which is the National Oil and Hazardous Substances Pollution 
Contingency Plan (NCP), which EPA promulgated pursuant to Section 105 
of the Comprehensive Environmental Response, Compensation and Liability 
Act (CERCLA) of 1980, as amended. EPA maintains the NPL as the list of 
Site 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 Townsend Saw Chain Co. Superfund 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 
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.
    EPA will accept comments on the proposal to partially delete this 
Site for thirty (30) days after publication of this document in the 
Federal Register.
    Section II of this document explains the criteria for deleting 
Sites from the NPL. Section III discusses procedures that the EPA is 
using for this action. Section IV discusses the soil, sediment, surface 
water, surficial aquifer, and the intermediate aquifer with the 
exception of the intermediate aquifer below the 1C clay in the vicinity 
of monitoring wells IMW-01B, MW-128, and OW-143 of the Townsend Saw 
Chain Co. Superfund Site and demonstrates how it meets the deletion 
criteria.

II. NPL Deletion Criteria

    The NCP establishes the criteria that the EPA uses to delete Sites 
from the NPL. In accordance with 40 CFR 300.425(e), Sites may be 
deleted from the NPL where no further response is appropriate. 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;

[[Page 35056]]

    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. The EPA conducts such five-year reviews even if a Site is 
deleted from the NPL. The 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 deletion of the soil, sediment, 
surface water, surficial aquifer, and the intermediate aquifer with the 
exception of the intermediate aquifer below the 1C clay in the vicinity 
of monitoring wells IMW-01B, MW-128, and OW-143 of the Site:
    (1) The EPA consulted with the State of South Carolina before 
developing this Notice of Intent for Partial Deletion.
    (2) The EPA has provided the state 30 working days for review of 
this notice 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) The State of South Carolina, through the SC DHEC, has concurred 
with the deletion of the soil, sediment, surface water, surficial 
aquifer, and the intermediate aquifer with the exception of the 
intermediate aquifer below the 1C clay in the vicinity of monitoring 
wells IMW-01B, MW-128, and OW-143 of the Townsend Saw Chain Co. 
Superfund Site, from the NPL.
    (5) Concurrently, with the publication of this Notice of Intent for 
Partial Deletion in the Federal Register, a notice is being published 
in a major local newspaper, the Greenville News. The newspaper 
announces the 30-day public comment period concerning the Notice of 
Intent for Partial Deletion of the Site from the NPL.
    (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 are received within the 30-day comment period on this 
document, EPA will evaluate and respond accordingly to the comments 
before making a final decision to partially delete the soil, sediment, 
surface water, surficial aquifer, and the intermediate aquifer with the 
exception of the intermediate aquifer below the 1C clay in the vicinity 
of monitoring wells IMW-01B, MW-128, and OW-143 of the Townsend Saw 
Chain Co. Superfund Site. If necessary, the EPA will prepare a 
Responsiveness Summary to address any significant public comments 
received. After the public comment period, if EPA determines it is 
still appropriate to delete the soil, sediment, surface water, 
surficial aquifer, and the intermediate aquifer with the exception of 
the intermediate aquifer below the 1C clay in the vicinity of 
monitoring wells IMW-01B, MW-128, and OW-143 of the Townsend Saw Chain 
Co. 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 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 Intended Partial Site Deletion

    The following information provides the EPA's rationale for deleting 
the soil, sediment, surface water, surficial aquifer, and the 
intermediate aquifer with the exception of the intermediate aquifer 
below the 1C clay in the vicinity of monitoring wells IMW-01B, MW-128, 
and OW-143 of the Site:

Site Background and History

    Due to contaminated soils, sediments, groundwater, and surface 
water, the EPA, EPA proposed listing the Site on the National 
Priorities List (EPA ID: SCD980558050) on June 24, 1988 (53 FR 23988), 
and finalized the listing on February 21, 1990, (55 FR 6154), under 
CERCLA, 42 U.S.C. 9601. The 50-acre Site located in Pontiac, Richland 
County, South Carolina was a small manufacturing facility located 
approximately two miles south of Pontiac, South Carolina. Starting in 
1971, Textron Inc., began utilizing the facility for manufacturing the 
saw chain component of chain saws. Between 1964 and 1981, under the 
Townsend Division of Textron, Inc. and a previous owner, Dictaphone 
Inc., waste rinse waters from on-site plating and parts-assembly 
processes were discharged to the ground surface in a low-lying area 
adjacent to the facility. These discharges are the origin of the 
groundwater and soil contamination. There is one sitewide operable unit 
that includes soils, sediments, and groundwater associated with the 
waste water rinse releases from the previous operation.
    The Site consists of a 50-acre area associated with a former metal 
products Manufacturing facility and is referred to as ``the Site'' in 
this report. The leading edge of the contaminated groundwater plume has 
also migrated to a 350-acre parcel of undeveloped land located to the 
northeast across Spears Creek Church Road, which includes a 113-acre 
Conservation Easement through the Congaree Land Trust. This 350-acre 
parcel is referred to as the ``off-Site area.'' While the off-Site area 
is technically part of the Superfund site, for ease of understanding, 
the 50 acre parcel is referred to as ``off-Site'' to distinguish from 
the 50-acre area. The Site has 2 underlying aquifers.
    The portion of the Site being proposed for deletion in today's 
action are soil, sediment, surface water, surficial aquifer, and the 
intermediate aquifer with the exception of the intermediate aquifer 
below the 1C clay in the vicinity of monitoring wells IMW-01B, MW-128, 
and OW-143, for a limited area (5000-8000 square feet) in the vicinity 
of the three wells. Since June 2016, all of the contaminated 
groundwater plume has been remediated to levels below the Safe Drinking 
Water Act Maximum Contaminant Levels (MCLs) except for a limited area 
(5000-8000 square feet) in the vicinity of three wells located in the 
on-site area (IMW-01B, MW-128, OW-143).

[[Page 35057]]

    Site-specific geological and stratigraphic information was 
developed during the installation of test borings and monitoring well 
boring. Soils underlying the Site can be divided into three units; Unit 
I exposed at the surface and consists of alternating layers of sand, 
silty or clayey sand, and silt or clay lenses. These various layers 
appear to be hydraulically connected. Perched water zones occur within 
the upper part of Unit I. Unit II is a low-permeability confining unit 
consisting of hard, dry, kaolinitic silty clays or clayey silt. Unit II 
appears to be laterally continuous on the Site property. Unit III 
consists of slightly silty, fine-to medium-grained sand. Because only a 
few Site well borings have penetrated into Unit III, its hydrogeologic 
and stratigraphic characteristics are not as well known. Units II and 
III and the lower portion of Unit I are part of the Middendorf 
Formation. Sand strata within the Middendorf are productive aquifers, 
and the formation serves as a major aquifer in South Carolina.
    There is potential redevelopment of the western portion of the Site 
west of Spears Creek Church Road to commercial property including 
retail and other commercial uses. AMBAC Intermodal (formerly American 
Bosch), a manufacturer and supplier of fuel injection equipment 
operates on approximately five acres of the fifty-acre Site. The 
remaining portion of the Site east of Spears Creek Church Road has been 
redeveloped to various commercial uses.

Remedial Investigation and Feasibility Study (RI/FS)

    In August 1991, the EPA entered into an Administrative Order on 
Consent with Homelite Division of Textron, Inc. to perform a Remedial 
Investigation/Feasibility Study (RI/FS). Investigation results 
indicated that hazardous substances, including chromium and volatile 
organic compounds (VOC) were present in soil and groundwater at the 
Site and groundwater and surface water in the off-Site area.
    A Baseline Risk Assessment (BRA) was conducted in 1993. The BRA 
concluded that, under the industrial land use scenario that existed at 
the Site in 1993, the Site did not present any unacceptable human 
health risks via any medium. However, under the anticipated future land 
use scenario, which assumed residential and commercial land uses in the 
off-Site area and continued industrial land uses on the Site, excess 
human health risks existed through contact with contaminated ground 
water (e.g. ingestion, inhalation, and dermal exposure).
    The Feasibility Study, completed on August 19, 1996, considered 
remedial options including a Resource Conservation and Recovery Act 
(RCRA) cap, solidification/stabilization, in-situ chemical treatment, 
and excavation/offsite disposal as alternatives to address contaminated 
soils. The FS considered groundwater use restrictions/institutional 
controls, groundwater extraction/treatment/spray field discharge, 
groundwater extraction/treatment/publicly-owned treatment works (POTW) 
discharge, and in-situ chemical treatment to address contaminated 
groundwater.

Selected Remedy

    On December 22, 1993, an Interim Record of Decision (IROD) was 
issued for the Site. The interim remedy selected in the IROD was 
intended to prevent the continued off-Site migration of the chromium-
contaminated groundwater plume. The interim action consisted of the 
following remedial components:
    (1) Planning and execution of a hydrogeologic investigation that 
would support the remedial design of an Interim Action Pump and Treat 
System (IAPTS). This system would, at a minimum, prevent further off-
Site migration and enlargement of the contaminant plume; and
    (2) Expeditious design and construction of such a system and 
initiation of ground water pump-and-treat operations.
    The EPA issued the ROD for the Site on December 19, 1996. Based on 
the results of the RI/FS and the Baseline Risk Assessment, the EPA 
determined that remediation of soils, groundwater, and sediments would 
be required for the protection of human health and the environment.
    The remedial action objectives includes:
Soils
    Prevent the leaching of contamination into groundwater, which can 
contribute to human health risk via groundwater;
Groundwater
    (1) Prevent exposure to chemicals of concern in groundwater which 
pose an unacceptable human health risk;
    (2) Reduce concentrations of chemicals of concern, thereby 
restoring potential use of the aquifer as a potable water source; and
    (3) Prevent or reduce the continued discharge of contaminated 
groundwater to surface water, such that surface water quality standards 
are not exceeded.
Surface Water
    (1) Reduce contamination to levels which (a) cannot pose ecological 
risk to tributary flora and fauna, and (b) are incapable of 
recontaminating tributary sediment;
    (2) Prevent exposure of the tributary ecosystem to chemicals of 
concern, and/or reduce the concentrations of chemicals of concern such 
that no unacceptable ecological risks are present. The selected remedy, 
as stated in the ROD, included several major components and a 
contingency remedy. The selected remedy includes:
Soil Treatment
    (1) Excavation and removal of the uppermost highly contaminated 
soils, and treatment of surficial soils through in-situ chemical 
treatment.
Groundwater Remediation
    (1) In-situ chemical treatment of ground water;
    (2) Continued operation of IAPTS; and
    (3) Sediment removal action at the off-Site area seep (to be 
performed upon completion of the chromium ground water cleanup.
Site Monitoring
    (1) Continued quarterly sampling/analysis of Site ground water.
    (2) Additional quarterly sampling of surface water in the unnamed 
off-Site tributary. and
    (3) Periodic sampling of treated Site soils.

Response Actions

    The Remedial Design and Remedial Action were implemented by 
Textron, Inc. through two Unilateral Administrative Orders. The Site's 
principal exposure pathway of concern was ingestion of groundwater.
    Therefore, the soil cleanup goal was based upon leachability to 
groundwater. Although not prescribed in the Site's Interim Record of 
Decision, approximately 75 tons of soils from hotspot areas 
contaminated with chromium, lead, and several other heavy metals, were 
excavated and disposed of properly in 1995 and 1996. The excavations 
were located near the northeast and northwest corners of the 
manufacturing facility. Soils with contamination above the cleanup goal 
for hexavalent chromium had been removed and no further soil 
remediation was required based on currently available data. Between 
June and December 1995, a five-well IAPTS was constructed and new 
treatment equipment installed for the wastewater treatment system. The 
system consisted

[[Page 35058]]

of the three original recovery wells located along Spears Creek Church 
Road, and two new recovery wells located in the off-Site area. The 
IAPTS began operating in December 1995. Groundwater from these wells 
was pumped to a treatment facility at the manufacturing facility and 
treated in electrochemical precipitation cells. Treated groundwater was 
then discharged to an on-Site, South Carolina DHEC-permitted spray 
field.
    Remedial design work for the in-situ chemical treatment technology 
began in May 1997 and was completed in September 1999. Injection lines 
of wells on 40-foot centers were used to place a ferrous sulfate 
solution in contact with chromium contaminated groundwater. The 
solution converted the main contaminant, hexavalent chromium, into an 
inert and harmless type of chromium mineral, which remains safely in 
the subsurface. The 2001 ESD established an updated chromium soil 
cleanup number. Based upon this ESD, no additional soil cleanup was 
necessary.
    In April 2002, the IAPTS was shut down as a trial measure because 
it was thought to be affecting groundwater flow pathways and 
potentially affecting chemical treatment activities. The system has 
remained shut down since this time. While in operation, the IAPTS 
recovered over 550 pounds of chromium from groundwater. During 2000-
2003, the in-situ treatment was implemented along successive injection 
well lines, proceeding northeastward across Spears Creek Church Road 
and into the off-Site area. Since 2002, the off-Site area was largely 
the focus of treatment; however, spot treatments have been performed on 
small resistant areas within the former plume area onsite. In September 
to October 2004, seven additional monitoring wells were installed in 
four locations in the off-Site area. The wells were installed to better 
characterize groundwater flow direction both above and below the 1C 
clay.
    The Explanation of Significant Difference (ESD) issued in April 
2007, was to add two remedy components to the original remedy to 
enhance remedy performance and to place the IAPTS into stand-by mode. 
The two new remedy components were institutional controls (ICs) over 
the 39.79 acres portion of the Site on the western side of Spears Creek 
Church Road including parcel 28800-01-03 and a portion of parcel 28800-
01-22 and installation of a Permeable Reactive Barrier (PRB) in the 
off-Site area to prevent discharge of TCE and chromium contaminated 
groundwater to surface water. The objectives for ICs were to (1) 
restrict the use of ground water as a drinking water source until MCLs 
are met for the Site and off-Site area; (2) restrict the use of the 
Site (property associated with original facility operations) to 
commercial, industrial, or light industrial land uses only; and (3) 
restrict the use of the off-Site area in order to protect the future 
PRB from damage. The IAPTS would remain in stand-by mode until 
determined that it needed to be reactivated or dismantled.
    To enhance groundwater cleanup, a bio-stimulation approach and a 
pilot test of a combination of fatty acids and ferrous sulfate 
injection system (creating a BioBarrier) was conducted in 2009. Based 
on the results of the pilot study, construction of the BioBarrier by 
injection was initiated in 2010 in lieu of the PRB proposed in the 2007 
ESD. The initial BioBarrier consisted of twelve new wells for injection 
of the carbon source substrate that were installed along the top of the 
slope (upgradient area) and three new injection wells in the 
downgradient area in late 2011.
    As of 2012, the BioBarrier had reduced chromium concentrations in 
the leading edge of the plume to below MCLs. A second round of Phase 2 
ferrous sulfate injections were conducted in 2012 and completed by 
April 2013. By mid-2013, the combination of the BioBarrier and 
upgradient ferrous sulfate injections, the overall plume area had been 
reduced to 53,400 square feet from an original size of 400,250 square 
feet. Since that time, remedial activities at the Site have largely 
consisted of installation of injection wells and injection of the 
carbon source amendment to address residual areas of the plume. Since 
June 2016, all of the plume has been remediated to levels below the MCL 
except for a limited area (5000-8000 square feet) in the vicinity of 
three wells located in the ``on-Site area'' (IMW-01B, MW-128, OW-143).
    In 2013, fourteen new injection wells were installed. Seven 
injection wells were installed in the perched groundwater table in the 
western area of the Site and seven injection wells were installed in 
the BioBarrier area to augment existing injection wells.

Cleanup Levels

    The Remedial Design for the Soil/Sediment remedy began in 1995 and 
was completed in 1997 by the PRP with EPA oversight. Soil cleanup 
levels for chromium were attained by soil removals conducted in 1996. 
As of April 2017, all groundwater monitoring wells with the exception 
of IMW-01B, MW-128, and OW-143 in the intermediate aquifer below the 1C 
clay had attained and maintained the groundwater cleanup goals for a 
period of at least eight separate and distinct sampling rounds pursuant 
to the February 24, 2015, Textron Verification Monitoring Strategy.
    Semi-annual sampling of surface water and sediments in the 
tributary to Spears Creek have demonstrated a declining trend in 
(contaminant or chromium) concentrations over the past eight years as 
groundwater remediation progressed. The ESD did not establish a 
chromium cleanup goal for sediment. The 2010 Five-Year review 
referenced the Ecotox threshold of 81 mg/kg for total chromium. 
Chromium concentrations are below screening values in 11 of 12 samples 
analyzed at 4 locations and any sporadic exceedances do not present 
significant risks to ecological receptors. No additional response 
action for chromium in sediments was required.
    The Ambient Water Quality Criteria (AWQC) for surface water for 
ecological protection for hexavalent chromium is 11 ug/L and the AWQC 
for trivalent chromium is 74 ug/L which are typically adjusted for 
hardness. The 2001 ESD set the stream cleanup goal as 40 ug/L which was 
retained in the 2010 and 2015 five-year reviews. As of July 2016, 
surface water sampling results for total and hexavalent chromium had 
been well below that level for eight sampling events and below 
detection levels for six sampling events.

Operation and Maintenance

    EPA approved an Operations, Maintenance, and Performance Monitoring 
Plan for the Site in August 2001. This plan encompasses the operation 
and maintenance of both the in-situ chemical injection treatment and 
pump-and-treat systems. The Plan was revised in March 2002, to shut 
down the IAPTS as a trial measure. The Site's 2007 ESD further 
stipulated that the IAPTS should be maintained in a stand-by condition 
for reactivation, if needed. The 2010 five-year review listed as one 
recommendation the evaluation of the need to continue holding the lAPTS 
in stand-by condition at the Site due to the improved performance of 
the in-situ treatment. The November 22, 2010, semiannual groundwater 
results demonstrated two years of consecutive reduction in the 
contaminant plume size and contaminant concentrations.
    In 2012, an assessment of historic and recent volatile organic 
chemical concentration data at the Site was conducted for the three 
chlorinated VOCs that had been detected over time (perchloroethylene, 
trichloroethylene, and 1,1 dichloroethylene). The data

[[Page 35059]]

evaluation determined that the initially low concentrations observed at 
the Site had declined over time due to attenuation and the in-situ 
reductive processes employed in the remediation. Groundwater MCLs for 
the 3 VOCs are met. The potential for vapor intrusion issues was also 
evaluated using the most conservative (95th percentile) and median 
attenuation factors for soil types. Allowable groundwater 
concentrations were back-calculated from USEPA indoor air Regional 
Screening Levels, the indicated attenuation factors, and Henry's Law 
Constants. All detections of perchloroethylene and 1,1 DCE in the most 
recent data were below the allowable groundwater concentrations 
calculated using the most conservative attenuation factors. The most 
recent TCE groundwater concentrations were an order of magnitude below 
with the allowable concentrations derived from the median attenuation 
factors for depths of greater than 5 meters which corresponds with Site 
groundwater depths (approximately 30 ft bgs). Additionally, all VOC 
detections were from wells screened below the middle clay layer which 
provides a barrier to vertical vapor migration or adjacent to the 
Congaree Land Trust where development would be prohibited. There is no 
vapor intrusion pathway of concern at the Site.
    The monitoring wells located on and around the Site are regularly 
sampled at designated quarterly or semi-annual intervals. Groundwater 
sampling at monitoring wells will continue until all the remedial goals 
for all contaminants are achieved at the three remaining monitoring 
wells that have not yet attained Site cleanup standards. Future 
groundwater restoration activities may include additional subsurface 
injections of ferrous sulfate and a blend of fatty acids to address 
chromium MCL exceedances in the intermediate aquifer below the 1C clay 
in the vicinity of monitoring wells IMW-01B, MW-128, and OW-143.

Institutional Controls (ICs)

    The 2007 ESD required ICs over the 39.79 acres portion of the Site 
on the western side of Spears Creek Church Road including parcel 28800-
01-03 and a portion of parcel 28800-01-22. The restrictions limit soil 
and groundwater use and restrict the property use to commercial, 
industrial or light industrial uses. Groundwater use is prohibited for 
potable, irrigation or other uses except with express written consent 
of Textron, Inc. This was implemented in a Declaration of Covenants and 
Restrictions recorded on Deeds recorded at the Richland County Register 
of Deeds on February 9, 2007 in Instrument #2007011804. The ICs are 
recorded on the deed, are transmitted to successors, and are verified 
during the five-year Review process.

Five-Year Review

    Previous five-year reviews were conducted because hazardous 
substances remained on Site above levels which allowed for Unlimited 
Use/Unrestricted Exposure and the Site groundwater had not attained all 
cleanup levels contemplated in the Record of Decision (ROD) and 
subsequent Explanation of Significant Difference (ESD). Five year 
Reviews will no longer be conducted at the portions of the Site deleted 
from the NPL which achieved Unrestricted Use/Unlimited Exposure (UU/
UV). Five-year reviews will continue to be conducted for that portion 
of the Site designated for industrial and commercial uses. A 39.79-acre 
portion of the Site including parcel 28800-01-03 and a portion of 
parcel 28800-01-22 meets clean up criteria, but has Institutional 
Controls, requires five-year reviews and does not meet Unlimited Use/
Unrestricted Exposure criteria. Five-year reviews will continue for 
that portion of the groundwater of the Site still on the NPL. The last 
five-year Review was completed in July 2015 and found the remedy 
protective of human health and the environment. There were no Issues or 
Recommendations in the Five-Year Review. The next Five-Year Review is 
scheduled to be completed in July 2020.

Community Involvement

    On June 12, 1991, April 14, 1992, August 23, 2001, and June 6, 
2006, EPA, SC DHEC, and Textron representatives conducted public 
availability sessions for RI/FS kickoff, the interim groundwater remedy 
ROD, and two Explanation of Significant Difference proposals addressing 
groundwater. On August 31, 1993 and September 17, 1996, EPA, DHEC, and 
Textron representatives conducted proposed plan meetings. EPA conducted 
community interviews during December 10-13, 1991, prior to the Site 
National Priority Listing. EPA and DHEC conducted community interviews 
for the three Five-Year reviews in 2005, 2010, and 2015.

Determination That the Criteria for Deletion Have Been Met

    The EPA has followed procedures required by 40 CFR 300.425(e) 
regarding requirements for deletions. EPA consulted with the State of 
South Carolina through the SC DHEC. South Carolina issued a May 12, 
2017, concurrence letter indicating its agreement with today's proposed 
action.
    The implemented remedy achieves the degree of cleanup or protection 
specified in the ROD and ESD for the areas proposed for deletion. The 
selected remedial and removal action objectives and associated cleanup 
levels for the areas proposed for deletion are consistent with agency 
policy and guidance. No further Superfund response in the areas 
proposed for deletion are needed to protect human health and the 
environment.

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. 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.

    Dated: June 19, 2019.
Mary S. Walker,
Regional Administrator, Region 4.
[FR Doc. 2019-15419 Filed 7-19-19; 8:45 am]
 BILLING CODE 6560-50-P