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IR Site 1 – Railroad Spur – Response Complete; Restricted to Industrial/Commercial Uses IR Site 1 is an approximately 2.2-acre area located along the entire eastern edge of NBPL OT. When the NBPL OT facility was operating as an aircraft manufacturing facility, the railroad spur was used for shipping and receiving a variety of raw material and finished products. IR Site 1 was first documented in a 1994 environmental assessment report for inclusion in the Navy’s ERP. The report speculated that waste products and cleaning wastes from past operations were discharged into the area along the railroad tracks because the site is at a low elevation, is not covered by asphalt, and is located next to the manufacturing buildings. The railroad spur was designated as IR Site 1.
A 2000 field investigation first characterized site contamination at IR Site 1. In 2009, a comprehensive work plan for IR Sites 1, 2, 3, 4, 5, 7, and 9 presented all the data collected at each IR site. Further investigation at IR Site 1 was recommended to provide data necessary to complete a human health risk assessment. A 2010 remedial investigation confirmed the presence of Aroclor-1260, a polychlorinated biphenyl compound, in shallow soil at IR Site 1. The impacted area was estimated to be approximately 0.06 acres. A 2010 focused feasibility study evaluated remedial alternatives that would mitigate risks to human health at the site. Rail lines on the spur and ties within the nearby Atchison Topeka, and Santa Fe right-of-way at the IR Site 1 spur were removed in June 2011. The 2014 record of decision identified soil excavation and off-site disposal as the preferred remedial action at IR Site 1.
In 2016, excavation and off-site disposal of approximately 2,000 square feet of polychlorinated biphenyls-impacted railroad spur soil, or 0.05 acres, were completed. The soil removal depths varied from one to eight feet, with most of the areas requiring removal at deeper depths located along the western half of the excavation. Confirmation soil samples were collected following the excavation to evaluate the effectiveness of the remedial action. In areas where the confirmation samples showed results greater than those established by remediation goals, an additional 1-foot of soil was excavated, and a new confirmation sample was collected. Based on the results of post-remedial action groundwater sampling, there was no impact to groundwater at the site. In 2019, the Navy received letters from state regulators concurring on completion of the remedial action, with the condition that land use at the site be restricted to industrial and commercial purposes.
In March 2021, the Navy issued a post-Record of Decision revision to the remedy for IR Site 1 in a memorandum to the Administrative Record file. The memorandum documented land use controls as the remedy, which includes restrictions on residential use and requirements for soil management at IR Site 1. The land use control remedy will also require annual inspections and remedy evaluations and reviews at five-year intervals because concentrations of chemicals in soil will remain above levels acceptable for unlimited use and unrestricted exposure at IR Site 1. In November 2021, the Navy finalized the land use control remedial design document for IR Site 1 that provides the details of the land use controls and requirements.
The Navy continues to manage land use controls (restrictions on residential use and requirements for soil management), annual inspections, and five-year reviews at IR Site 1.
IR Site 2 – Exposed Pipe – Closed IR Site 2 is an exposed 10-inch diameter pipe located east of Building 8, near the Atchison, Topeka, and Santa Fe railroad right-of-way. Building 8, constructed in 1940, was a fabrication facility consisting of sheet metal works including mills, presses, routers, and lathes used in WWII aircraft manufacturing. IR Site 2 was first documented in a 1994 environmental assessment report for inclusion in the Navy’s ERP because the exposed pipe was suspected to be part of a broken pipeline. Pipe tracing was subsequently performed, resulting in a determination that the exposed pipe was debris and apparently not connected to any potential source of contamination at the NBPL OT facility.
A 2000 removal site evaluation report characterized site contamination at IR Site 2. A 2008 comprehensive work plan for IR Sites 1, 2, 3, 4, 5, 7, and 9 presented the data collected at each IR site. Site closure with no further action was recommended for IR Site 2 based on the conclusions of previous investigations. In 2009, the Navy received concurrence letters from state regulators agreeing no further investigation was required under the condition that land use at the site be restricted to industrial and commercial purposes.
In March 2022, the Navy and regulatory agencies re-evaluated IR Sites 2, 3, 4, 5, and 7 in a Site Inspection Addendum. The Site Inspection Addendum recommended site closure for IR Site 2 and the regulatory agencies concurred.
IR Site 3 – Building 8 Hydraulic Press Vaults – Ongoing Investigation IR Site 3, located within Building 8, included one large and two small underground press vaults approximately 12 feet below ground surface. Constructed in 1940, Building 8 was a sheet metal works used for WWII aircraft manufacturing. IR Site 3 was first documented in a 1994 environmental assessment report for inclusion in the Navy’s ERP. IR Site 3 was identified because hydraulic presses housed in the vaults formerly used in a variety of metal stretching and molding operations contained hydraulic fluids. The hydraulic presses were removed in 1995, cleaned, filled with clean soil to grade in 2005, and covered with concrete in 2007.
A 2000 removal site evaluation report characterized site contamination at IR Site 3. A 2003 and 2004 extended site investigation at NBPL OT included sampling for metals, volatile and semi-volatile chemicals, pesticides, polychlorinated biphenyls, and petroleum hydrocarbons in soil and groundwater, the potential contaminants of concern at IR Site 3. A 2008 comprehensive work plan for IR Sites 1, 2, 3, 4, 5, 7, and 9 presented the data collected at each IR site and included the collection of additional groundwater data. Site closure with no further action was recommended for IR Site 3 based on the conclusions of previous investigations. In 2009, the Navy received concurrence letters from state regulators agreeing no further investigation was required under the condition that land use at the site be restricted to industrial and commercial purposes.
In March 2022, the Navy and regulatory agencies re-evaluated IR Sites 2, 3, 4, 5, and 7 in a site inspection addendum resulting in a recommendation that a feasibility study be completed for IR Site 3 to evaluate land use controls as a remedy for potential human health risk from exposure to contaminants remaining in soil and groundwater above levels acceptable for unlimited use and unrestricted exposure. The regulatory agencies concurred with the recommendation. The Navy finalized the Focus Feasibility Study for IR Site 3 in February 2024 and the Draft Proposed Plan is being reviewed by regulatory agencies. The Draft Proposed Plan describes the preferred remedial alternative of land use controls. Although the site remedy has not been formally selected in a Record of Decision yet, the Navy continues to ensure land use at the site is restricted to industrial and commercial purposes and soil and groundwater are managed appropriately during any subsurface work at the site.
IR Site 4 – Building 1 Hydraulic Press Vaults – Ongoing Investigation IR Site 4, located within in Building 1, consists of a former hydraulic press pit, two pipeline corridors, and an eight-foot deep hydraulic fluid tank pit in an underground press vault approximately 15 feet below ground surface. Constructed in 1940, Building 1 was a production facility for WWII aircraft manufacturing. It was later used by moving and storage companies for warehousing purposes. IR Site 4 was first documented in a 1994 environmental assessment report for inclusion in the Navy’s ERP because the hydraulic press used for metal-stretching and molding operations contained hydraulic fluids. The hydraulic presses were removed in 1995. The vault was cleaned and filled with clean soil to grade in 2005 and covered with concrete in 2007.
A preliminary assessment and site investigation were conducted at IR Site 4 in 1996. A 2003 and 2004 extended site investigation at NBPL OT included sampling soil and groundwater for metals, volatile and semi-volatile chemicals, pesticides, polychlorinated biphenyls, and petroleum hydrocarbons, the potential contaminants of concern at IR Site 4. A 2008 comprehensive work plan for IR Sites 1, 2, 3, 4, 5, 7, and 9 presented the data collected at each IR site and included the collection of additional groundwater data. Site closure with no further action was recommended for IR Site 4 based on the conclusions of previous investigations. In 2009, the Navy received concurrence letters from state regulators agreeing no further investigation was required under the condition that land use at the site be restricted to industrial and commercial purposes.
In March 2022, the Navy and regulatory agencies re-evaluated IR Sites 2, 3, 4, 5, and 7 in a site inspection addendum resulting in a recommendation that a feasibility study be completed for IR Site 4, with an expanded boundary to that included the adjacent IR Site 5, to evaluate land use controls as a remedy for potential human health risk from exposure to contaminants remaining in soil and groundwater above levels acceptable for unlimited use and unrestricted exposure. The regulatory agencies concurred with the recommendation. The Navy finalized the Focus Feasibility Study for IR Site 4 in February 2024 and the Draft Proposed Plan is being reviewed by regulatory agencies. The Draft Proposed Plan describes the preferred remedial alternative of land use controls. Although the site remedy has not been formally selected in a Record of Decision yet, the Navy continues to ensure the land use at the site is restricted to industrial and commercial purposes and groundwater is managed appropriately if encountered during subsurface work at the site.
IR Site 5 – Air Compressor Pipes and Catch Basin – Closed IR Site 5 consisted of three metal pipes that originate within Building 1 and feed into a six-inch diameter drain on the ground surface outside the building. The pipes were traced to an unused boiler tank inside the building. The pipes conveyed any water or steam from the boiler to the asphalt surface outside the building, which then drained to a catch basin. Constructed in 1940, Building 1 was a production facility for WWII aircraft manufacturing. It was later used by moving and storage companies for warehousing purposes.
IR Site 5 was first documented in a 1994 environmental assessment report for inclusion in the Navy’s ERP. IR Site 5 was identified because of unspecified concern that the pipe and drain may have been used for product or waste disposal. The pipes were subsequently determined to not be connected to any potential sources of contamination originating from operations or other potential disposal activities at IR Site 5.
A 2000 removal site evaluation report characterized site contamination at IR Site 5, identifying metals and volatile chemicals as potential contaminants of concern in soil. A 2008 comprehensive work plan for IR Sites 1, 2, 3, 4, 5, 7, and 9 presented the data collected at each IR site. Site closure with no further action was recommended for IR Site 5 based on the conclusions of previous investigations. In 2009, the Navy received concurrence letters from state regulators agreeing no further investigation was required under the condition that land use at the site be restricted to industrial and commercial purposes.
In March 2022, the Navy and regulatory agencies re-evaluated IR Sites 2, 3, 4, 5, and 7 in a site inspection addendum, resulting in a recommendation that the IR Site 4 boundary be expanded to include the IR Site 5 area and a feasibility study be completed to evaluate land use controls as a remedy for potential human health risk from exposure to contaminants remaining in soil and groundwater above levels acceptable for unlimited use and unrestricted exposure. Since IR Site 4 remediation would encompass IR Site 5, IR Site 5 would be closed. The regulatory agencies concurred with the recommendation.
IR Site 6 - Old Transformer Pad Outside Building 1 – Closed IR Site 6 was eliminated from the Navy’s ERP during the preliminary assessment phase in the mid-1990s.
IR Site 7 – Outdoor Eyewash Station Catch Basin – Ongoing Investigation IR Site 7 consists of a small diameter pipe exiting the southeastern portion of Building 2 and a catch basin approximately 5 feet southeast of the pipe. Constructed in 1940, Building 2 was used for painting, etching, deoxidizing, machining, steam cleaning, and degreasing during WWII aircraft manufacturing. Information regarding historical use of the outdoor catch basin is unknown.
IR Site 7 was first documented in a 1994 environmental assessment report for inclusion in the Navy’s ERP because the pipe was directly connected to an eyewash station inside the building and, when in use, potable water from the station flowed from the pipe and discharged onto the asphalt pavement. The catch basin that the pipe drained into was a concrete vault approximately 3-feet by 3-feet by 2-feet deep.
A 2000 removal site evaluation report characterized site contamination, identifying metals and polycyclic aromatic hydrocarbons as potential contaminants of concern in soil at IR Site 7. A 2003 and 2004 extended site investigation at NBPL OT included sampling at IR Site 7, although the catch basin was filled-in prior to the investigation. A 2008 comprehensive work plan for IR Sites 1, 2, 3, 4, 5, 7, and 9 presented the data collected at each IR site. Site closure with no further action was recommended for IR Site 7 based on the conclusions of previous investigations. In 2009, the Navy received concurrence letters from state regulators agreeing no further investigation was required under the condition that land use at the site be restricted to industrial and commercial purposes.
In March 2022, the Navy and regulatory agencies re-evaluated IR Sites 2, 3, 4, 5, and 7 in a site inspection addendum resulting in a recommendation that a feasibility study be completed to evaluate land use controls as a remedy for potential human health risk from exposure to contaminants remaining in soil above levels acceptable for unlimited use and unrestricted exposure. The regulatory agencies concurred with the recommendation. The Navy finalized the Focus Feasibility Study for IR Site 7 in February 2024 and the Draft Proposed Plan is being reviewed by regulatory agencies. The Draft Proposed Plan describes the preferred remedial alternative of land use controls. Although the site remedy has not been formally selected in a Record of Decision yet, the Navy continues to ensure the land use at the site is restricted to industrial and commercial purposes and soil is managed appropriately during any subsurface work at the site.
IR Site 8 - Old Machinery Pad Outside Building 2 – Closed IR Site 8 was eliminated from the Navy’s ERP during the preliminary assessment phase in the mid-1990s.
IR Site 9 – Building 2 Compressed Air Vaults – Closed IR Site 9 runs along the western side of the interior of Building 2. It includes 22 unpaved floor vaults that measure approximately 1.5- by 2.5-feet and are approximately 3-feet deep. The vaults provide access to subsurface deactivated compressed air lines. Two unrelated interior floor drains are also included in IR Site 9. Constructed in 1940, Building 2 was used for painting, etching, deoxidizing, machining, steam cleaning, and degreasing during WWII aircraft manufacturing. The vaults may have collected hazardous materials, including waste oil, paint sludge, spent acids, and plating materials.
IR Site 9 was first documented in a 1994 environmental assessment report for inclusion in the Navy’s ERP. IR Site 9 was identified because the floor vaults could have potentially intercepted liquid wastes that may have been spilled in the building work areas, although it was subsequently determined that any potential spills were not significant enough to have a major impact on the subsurface beneath the site. Since the 1997 removal site evaluation at NBPL OT, the floor vaults have been sealed with steel plates welded flush with the surface.
A 2000 removal site evaluation characterized site contamination at IR Site 9, identifying metals as a potential contaminant of concern in soil. A 2009 comprehensive work plan for IR Sites 1, 2, 3, 4, 5, 7, and 9 presented the data collected at each IR site. Further investigation at IR Site 9 was recommended to satisfy data gaps and complete a human health risk assessment. A 2010 remedial investigation included groundwater monitoring and soil vapor sampling at IR Site 9 and recommended no further action based on the results confirming that no CERCLA release had occurred. The remedial investigation also concluded that any concerns or issues relating to soil gas detected outside of the IR Site 9 boundary should be addressed in planned future investigation activities for IR Site 11, which appears to be the primary source of volatile organic compounds in soil gas. In 2010, state regulators concurred that IR Site 9 does not pose unacceptable risk to human health or the environment, and that no further action under CERCLA was appropriate for IR Site 9. Site closure with no further action was documented in the Navy’s 2014 Record of Decision for IR Site 9.
IR Site 10 – Former Building 33 – Closed IR Site 10 is the site of former Building 33, a belowground, reinforced concrete bunker that extended 8 feet below grade, with a roofline 2 feet above ground surface. Building 33 was demolished and backfilled in 2003 and the area is currently used as a parking lot. Constructed in 1940 and closed in the 1980s, the bunker was used for the storage of pyrotechnics and munitions. A one-foot by one-foot sump and pump were reportedly present in the southwest corner of the bunker. IR Site 10 was first designated in a 1994 environmental assessment report for inclusion in the Navy’s ERP because at that time sludge appeared to be seeping through cracks in the concrete floor.
Environmental studies beginning in the 1990s identified groundwater and soil vapor impacted with volatile organic compounds, such as tetrachloroethylene, trichloroethylene (TCE), and vinyl chloride at IR Site 10. Investigations conducted through 2009 characterized site contamination at IR Site 10 and the adjacent IR Site 11. Based on close proximity and similar contaminants in groundwater and soil vapor, the remedial actions for IR Sites 10 and 11 were combined.
A two-phase remedial investigation at IR Sites 10 and 11 was conducted in 2010 and 2014. The remedial investigation report recommended a remediation pilot study that would test options for protecting future human health, control the plume contaminant source, provide additional characterization information, and support selection and design of a final remedy.
From 2012 through 2013, the remediation pilot study was conducted and confirmed the effectiveness of soil vapor extraction and in-situ enhanced anaerobic bioremediation processes in successfully reducing contaminant concentrations. As a result, the 2015 Record of Decision for IR sites 10 and 11 selected soil vapor extraction and enhanced anaerobic bioremediation as the remedy for both sites to address the contamination of volatile organic compounds in soil and groundwater. Enhanced anaerobic bioremediation injections were performed in 2015, and the soil vapor extraction system was implemented that same year and continues to operate.
Data from quarterly and semiannual monitoring of remediation progress since 2015 indicated that the remediation goals for groundwater and soil vapor were being achieved in most monitoring locations, with the exception of some elevated volatile organic compound concentrations remaining in the parking lot north of Building 3.
The Navy’s ERP conducted field investigations at IR Site 10 from late 2019 through the spring of 2020, to determine if the Navy’s CERCLA response was complete or what may be necessary to optimize the current remedy-in-place. The 2019 and 2020 data demonstrated that there was no hazardous substance release from IR Site 10 and that residual volatile organic compound concentrations in groundwater in the vicinity of IR Site 10 were attributable to IR Site 11, which are being addressed by the remedy at IR Site 11.
Because there is no evidence of a hazardous substance or petroleum release to soil or groundwater at IR Site 10, the Navy recommended site closure. The California Department of Toxic Substances Control and San Diego Regional Water Quality Control Board concurred with this recommendation and the site was closed.
IR Site 11 – Building 3 – Ongoing Remediation IR Site 11 was historically identified as the site of a sanitary sewer line break in the northeast portion of Building 3, the main manufacturing and assembly building. Constructed in 1940, Building 3 was a production facility for World War II aircraft manufacturing. It was later used by moving and storage companies for warehousing purposes. Since 1951, the facility has been used to produce aircraft, rockets, and missiles. Processes within Building 3 may have generated metal cleaning solvents, paint sludge, waste oil, spent acids, plating materials, degreasing solvents, and Oakite cleaners. In addition, wastewater from plant processes, including metal plating, photography, and x-rays, may have been discharged to the sanitary sewer prior to and at the time of the sewer line break. IR Site 11 was first designated in a 1994 environmental assessment report for inclusion in the Navy’s ERP because of a sanitary sewer line break that was observed in this area.
Environmental studies beginning in the 1990s identified groundwater and soil vapor impacted with volatile organic compounds, such as tetrachloroethylene, trichloroethylene (TCE), and vinyl chloride at IR Site 11. Investigations conducted through 2009 characterized site contamination at IR Site 11 and the adjacent IR Site 10. Based on close proximity and similar contaminants in groundwater and soil vapor, the remedial actions for IR Sites 10 and 11 were combined.
A two-phase remedial investigation at IR Sites 10 and 11 was conducted in 2010 and 2014. The volatile organic compound TCE was reported in soil vapor beneath the slab and in indoor air in Building 3 at IR Site 11. The remedial investigation report recommended a remediation pilot study that would test options to protect future human health, control the plume contaminant source, provide additional characterization information, and support selection and design of a final remedy.
From 2012 through 2013 the remediation pilot study evaluated the effectiveness of the soil vapor extraction and in-situ enhanced anaerobic bioremediation processes. Contaminant concentrations were successfully reduced using a combination of both methods during the pilot study. As a result, the 2015 Record of Decision for IR sites 10 and 11 selected soil vapor extraction and enhanced anaerobic bioremediation as the remedy for both sites to address the contamination of volatile organic compounds in soil and groundwater.
The Navy performed enhanced anaerobic bioremediation injections in 2015 which consisted of the injection of microorganisms into the groundwater to facilitate degradation of contaminants in groundwater. The Navy also implemented the soil vapor extraction system that same year which continues to operate and remediate contaminants in soil vapor. To address the indoor air at Building 3, mitigation included infrastructure repairs to the concrete floor, enhanced air exchange management, and installation and continuous operation of a sub-floor ventilation system.
Data from quarterly and semiannual monitoring of remediation progress since 2015 indicated that the remediation goals for groundwater and soil vapor were being achieved in most monitoring locations, except for some elevated volatile organic compound concentrations remaining in the parking lot north of Building 3. TCE concentrations in indoor air in Building 3 have remained below regulatory action levels.
The Navy’s ERP conducted field investigations at IR Site 11 from late 2019 through the spring of 2020, to determine if the Navy’s CERCLA response was complete or what may be necessary to optimize the current remedy-in-place.
The 2019 and 2020 data demonstrated that a TCE source existing as free product remains in the subsurface at IR Site 11. The Navy conducted a second round of bioremediation injections in 2021 and additional investigations in 2021 and 2022 to determine the extent of the free product. Modeling results showed that approximately 3,000 to 6,000 gallons of free product are present under the site. In December 2023, the Navy completed a pilot test to evaluate technologies for reducing the TCE source in the groundwater. The pilot test utilized high vacuum technology to remove the TCE source and groundwater from strategically placed extraction wells. The Navy is testing the vacuum technology because the TCE source is present as a separate liquid phase with a higher density than water. The pilot test was successful and removed approximately 23 gallons of the TCE source along with 6,000 gallons of groundwater. Based on preliminary results, the Navy will be conducting a second phase of the pilot test in summer 2024. For this second phase, the pilot test will be optimized with more robust design/equipment so that a larger volume of the TCE source can be removed more efficiently. The Navy’s ongoing remediation, mitigation activities, and periodic monitoring continue to demonstrate protectiveness of human health.
IR Site 12 – Between Building 2 and 3 – Ongoing Investigation The Navy confirmed evidence of a past release and contamination beneath the roadway between Buildings 2 and 3 at NBPL OT during the late 2019 through spring of 2020 IR Site 11 field investigation program. Preliminary sampling results found concentrations of trichloroethylene (TCE) above IR Site 11 remedial goals in soil vapor and groundwater, but also showed that the contamination did not originate from the source at IR Site 11. A new ERP site, designated as IR Site 12 was established in 2020 by the Navy at NBPL OT in order to initiate additional investigations and remediation in this area in accordance with the regulatory process.
The Navy completed site inspection fieldwork at IR Site 12 in 2022. Preliminary sampling results received in May 2022 showed elevated TCE concentrations beneath the concrete slab in the southern portion of Building 3. Although previous indoor air samples collected in Building 3 south between 2011 and 2022 did not show TCE present at concentrations above the response action level, the Navy expedited indoor air sampling to verify indoor air concentrations and collected 56 additional indoor air samples between June 3 and 10 of 2022. TCE was detected in two rooms at concentrations above the USEPA’s response action level of 8 micrograms per cubic meter. To mitigate potential migration of the TCE from beneath Building 3 and into indoor air, a temporary subfloor ventilation system was installed in Building 3 south by the Navy on June 17, 2022. Two follow-on sampling events on June 22 and July 22 of 2022 confirmed that the mitigation system had reduced TCE concentrations in the two rooms to below the response action level. The Site Inspection Report was finalized in March 2023 and recommended the site move forward to the remedial investigation and feasibility study phase (RI/FS).
As part of evaluating remedial alternatives in the RI/FS, the Navy installed a dual-purpose vapor extraction system in Building 3 south in May 2023 and replaced the temporary mitigation system. The system continuously extracts vapors from the void spaces beneath the concrete slab and extracts vapor contaminants from the soil below. Vapor extraction prevents vapors from accumulating and moving through the slab into the building and impacting indoor air quality. The system continues to operate effectively and the Navy’s monitoring verifies that TCE concentrations remain below response action levels and are protective of human health in buildings at IR site 12. The Navy completed Remedial Investigation field work in November 2023 and is drafting the Remedial Investigation/Feasibility Study Report.
IR Site 13 – South of Building 7 – Ongoing Investigation During 2019 environmental field investigations conducted in support of Naval Information Warfare Systems Command Center (NAVWAR) Revitalization, a redevelopment program at NBPL OT that considers NAVWAR’s plans for a new facility to support its cyber security mission, the Navy discovered evidence of a past release and contamination beneath the parking lot south of Building 7. Preliminary sampling results at that time showed concentrations of volatile organic compounds above regulatory screening levels in soil vapor and groundwater. Indoor air sample results were less than response action levels. The Navy established IR Site 13 in 2020, a new ERP site at NBPL OT, to initiate additional investigations and remediation in this area in accordance with the regulatory process.
2022 site inspection data received for IR Site 13 verified the presence of trichloroethylene (TCE) and other solvent related contaminants in groundwater and soil vapor beneath IR Site 13 and that no immediate action is needed at the site because indoor air sample results continue to be below response action levels. In addition, contaminant concentrations in sub-slab air, soil vapor, and groundwater were significantly less than those detected at IR Sites 11 and 12 at NBPL OT. The Navy and regulatory agencies finalized the Site Inspection Report in May 2023 and recommended the site move forward to the remedial investigation and feasibility study phase. The pilot tests conducted at IR Site 12 to evaluate potential remedial alternatives will provide data and other information that will inform remedial decisions for IR Site 13. Periodic air monitoring will continue to verify that TCE concentrations remain below response action levels and are protective of human health in buildings at IR Site 13.
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