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Site 1 – Former Drum Marshalling Area
Site 1 – Former Drum Marshalling Area was first identified in the 1986 Initial Assessment Study (IAS). Site 1 is relatively flat with a 6-foot high vegetated windrow located along the east-central portion of the former NWIRP Bethpage, on the 9-acre leased parcel retained by the Navy . The site slopes to the south and west. The site is enclosed by a facility perimeter fence along the east and interior facility fences along the north, south, and west. The interior fence was installed in 1998 as an interim measure to restrict exposure of facility personnel to areas with residual soil contamination. Site 1 covers approximately 5.5 acres.
The drum marshalling areas and extent of the leach field were the original boundary of Site 1. Site 1 was expanded in 2005 to include adjacent Areas of Concern (AOCs) consisting of:
Dry Well/AOC 34-07 and Dry Well/AOC 20-08 (part of stormwater management system to discharge stormwater into soil),
AOC 23 – Former Aboveground Storage Tanks (6 aboveground storage tanks to store waste oil),
AOC 30 – Various Storage Sheds (3 former storage sheds for storage of pesticides and petroleum), and
AOC 35 – Former Sludge Drying Beds (received sludge from septic system and were closed and backfilled in 1980).
Site 1 – Former Drum Marshalling Area originally consisted of two former drum marshalling pads that were used to store drums containing waste materials from operations at Plant No. 3 and potentially other sources at the facility. According to the 1986 IAS, the waste drums reportedly contained chlorinated and non-chlorinated solvents, and liquid cadmium and chromium wastes. Transformers and polychlorinated biphenyl (PCB)-filled autoclaves were also stored at the site into the 1990s. In addition, underlying most of Site 1 is an abandoned septic system that was in use from the early 1950s to 1978. The system consisted of approximately 120 abandoned cesspools that were designed to discharge sanitary waste waters from Plant No. 3. It may have discharged non-sanitary wastes since volatile organic compounds (VOCs) and PCBs were widely distributed within the cesspools. These cesspools were filled with soil sometime between 1978 and 1986.
Previous Environmental Investigations and Remedial Actions
In 1986, Site 1 was identified in the IAS.
In 1992, the Phase 1 Remedial Investigation (RI) revealed soils that contained sufficient residual volatile organic contamination to confirm the source of groundwater contamination as being near or at the former drum marshaling areas.
In 1992 a Baseline Human Health Risk Assessment (HHRA) was conducted. The risk assessment found that potential risk to onsite workers and offsite residents were within the USEPA target risk range of 1 X 10-4 to 1 X 10-6. The groundwater at NWIRP Bethpage, if used as a potable water source, would be expected to result in significant carcinogenic and noncarcinogenic risks to residents and employees.
In 1993, PCB contamination was discovered in the surface soils at Site 1. An interim cover of approximately 6 inches of soil was placed over the contaminated soils to protect site workers at that time from contact with PCB-contaminated surface soil.
In 1994, a Feasibility Study (FS) was conducted to identify potential cleanup options for addressing soils and groundwater.
The preferred remedy from the FS was chosen by the Navy and NYSDEC for remediating contaminated soils that included fixation of metals, incineration of soils containing PCBs at concentrations greater than or equal to 500 parts per million (ppm), land filling of soils containing PCBs at concentrations between 10 and 500 ppm, and in-situ vapor extraction of VOCs for on-site soils (OU1 Soils ROD). The depth of PCB contamination was believed to be limited to approximately 7 feet. The selected remedy was documented in a ROD signed in May 1995.
Between 1995 and 1996, soil sampling was conducted as part of the Remedial Design. Volatile Organic Compounds (VOCs) (1,1,1-trichloroethane [TCA], trichloroethene [TCE] and tetrachloroethane [PCE]), PCBs and metals (cadmium) were detected in the soil. The results of the pre-excavation sampling at Site 1 indicated that the volume and depth of contaminated soil was greater than the original estimate.
In 1997, an AS/SVE system Pilot Study was installed to address the VOCs in groundwater. The full scale AS/SVE system was installed in 1998 and operated until 2002. A total of 2,948 pounds of VOCs had been removed. In 2003, a Close-Out Report for the AS/SVE system was completed that showed a greater than 95% reduction in VOC in groundwater.
In 1998, PCB-contaminated soils identified in two dry wells (34-07 and 20-08) were removed under the USEPA Underground Injection Control program (Note that this removal did not address all of the PCB-contaminated soil).
In 2007, a five-year review was conducted to evaluate the implementation and performance of the remedies at the sites to determine whether the remedies were protective of human health and the environment. The report concluded that the remedy at the Site 1 - Former Drum Marshalling Area is currently protective of human health and the environment. Access to the site is currently restricted through fencing and security, contaminant migration via groundwater is being monitored and contained.
In 2008, a soil vapor investigation was conducted to determine if vapors were present near the facility boundary. Soil gas samples collected along the eastern border of Site 1 exceeded NYSDOH criteria for the sub-slab areas for TCE and PCE of 250 micrograms per cubic meter (µg/m3) and 1,000 µg/m3, respectively. Chemical concentrations in soil gas samples collected along the southern edge of Site 2 and the northeast corner of Site 1 were much lower than concentrations detected along the central and southeast corner of Site 1 but exceeded NYSDOH criteria for the sub-slab areas for TCE.
In May 2009, under a time-critical removal action, a Soil Vapor Investigation was conducted along the Town of Oyster Bay rights-of-ways adjacent to the NWIRP. Based on the evaluation, sub-slab vapor and indoor air sampling was conducted in the residential homes. Due to the concentrations detected, 14 APU’s and 6 SSD systems were placed in the residential homes.
In December 2009, the SVE containment system was installed and started. It is currently operating to prevent further off-site migration of contaminated soil vapor and to the extent practical and remediate contaminated soil vapor located off site. Indoor air monitoring continued in the residential homes until approval was received by NYSDEC to remove the systems. In January 2012 the APUs and the SSDs were removed from the residential homes.
In December 2010, under a non-time critical removal action, a fence line Soil Vapor Extraction (SVE) Containment System was installed on Navy property. Operation of this system reduced the levels of VOCs in off-property soil vapor and ultimately allowed the removal of the in-home purification and SSD units. The SVE Containment System remains in operation.
In 2012, at the request of the current property lessee (Steel Equities) to allow additional parking for facility tenants, the southern Site 1 fence was moved to the north approximately 100 feet, and the western fence was moved to the east approximately 30 feet. This new parking area was covered with gravel and asphalt in accordance with the OU1 ROD.
In April 2012, the current property lessee, Steel Equities, uncovered two intact underground storage tanks (USTs) that were found to contain residual solvent impacted water and sediment. The USTs and contents were removed in September 2012 and post-removal soil samples were collected. The maximum concentration of PCE in the underlying soil was 1,200 µg/kg.
In 2015, an RI Addendum was conducted to define the boundaries of a much later volume of PCB-contaminated soil, as well as other soil contamination not identified in the 1995 OU1 ROD.
After the RI Addendum in 2015, remedial plans for Site 1 were defined in the 2018 OU4 ROD. The select impacted media and pathways addressed in the 2018 OU4 ROD consist of deep PCB-contaminated soil, PCB- and metal-contaminated groundwater, and VOC-contaminated soil vapor at Site 1.
From 2019 through August of 2020, PCB-contaminated soils with concentrations greater than 10 mg/kg to a depth of 10 feet bgs and PCB-contaminated soils with concentrations greater than 50 mg/kg to a depth of 20 feet bgs at Site 1, were excavated from the site and disposed of offsite. At Dry Well 20-08, soils with concentrations of PCBs of greater than 50 mg/kg, were excavated to a depth of 30 feet bgs and disposed of offsite. A reduced permeability cover was placed in areas over soils where the residual PCBs and other COCs were greater than the cleanup levels.
In late 2021, six additional SVE wells were installed. These wells are expected to be incorporated into the existing SVE Containment System in 2022.
In late 2021, new monitoring wells for monitoring groundwater at Site 1 were installed. Existing and new groundwater monitoring wells are being monitored for PCBs and metals.
Nature and Extent
The 1995 OU1 ROD identified the following soil Chemicals of Concern (COCs) for Site 1:
VOCs: Trichloroethene (TCE), Tetrachloroethene (PCE), and 1,1,1-Trichloroethane (1,1,1-TCA)
Pesticides: Chlordane only
Semi-volatile organic compounds (SVOCs): Seven Polynuclear Aromatic Hydrocarbons (PAHs)
Metals: Arsenic and Manganese
The 2018 OU4 ROD identified the following soil COCs for Site 1:
VOCs: TCE, PCE, and 1,1,1-TCA
Pesticides: Chlordane only
Metals: Arsenic, cadmium, and chromium (hexavalent)
The 2018 OU4 208 ROD identified the following groundwater COCs for Site 1:
The 2018 OU4 ROD identified the following soil vapor COCs for Site 1:
Current Site Conditions
An interior facility fence was originally used to isolates portions of the site that do not have a Record of Decision (ROD)-required cover including AOC 23, AOC 30 and AOC 35 along the north, south, and west. This fence was reinstalled after construction was complete, pending establishment of vegetation. Remediation of the PCB-and metal-contaminated portions of the OU4 ROD was completed in 2020, with the removal and offsite disposal of the majority of the site waste. The site is covered by a minimum of 24 inches of clean soil. A geosynthetic clay liner is present at depth at the site to reduce precipitation drainage through areas with residual deep PCB-contaminated soil. This cap is located at a depth of 5 to 10 feet below ground surface. A soil vapor extraction containment system is in place along the eastern edge of the site to control vapor migration off the facility. The blower and GAC system for the extracted vapors are located at Site 4. A soil vapor extraction system is being constructed in late 2021 to remediate residual VOCs in soil at Site 1. Operations at the site are currently limited to parking, environmental investigations and remediation, control of vegetation, and fence repair. Groundwater will be monitored for PCBs, cadmium, and chromium contamination.
An air sparging/soil vapor extraction (AS/SVE) system was operated to treat chlorinated solvents in site soils and shallow groundwater to eliminate an impact to the regional groundwater. Contaminants, including metals and PCBs, in site soils remain and will require remediation. In January 2009, an off-site soil vapor intrusion investigation was initiated. Between February and May 2009, 18 homes were evaluated and 14 air purification units (APUs) and 6 sub-slab depressurization (SSD) systems were installed in offsite residential homes. Between October and December 2009, a fence-line soil vapor containment system was installed. Operation of the system started in late December 2009 and continues to operate. Based on an evaluation of the offsite soil gas and successful operation of the containment system, the APUs and the SSDs were removed from the residential homes in January 2012.
Natural flushing of VOCs in soil and shallow groundwater is ongoing, and no further investigation is warranted at Site 1. The performance of the natural flushing component is evaluated via sampling of monitoring wells downgradient of Site 1 as part of the OU2 remedy.
Groundwater samples will be collected annually from select monitoring wells to be analyzed for metals and PCBs.
Quarterly collection of vapor samples and vapor pressure measurements at the existing fence line SVE wells, quarterly measurements of the vapor pressure at the offsite soil vapor pressure monitoring points (SVMPs), and collection of process vapor samples for the SVE Containment System is being conducted. Vapor samples also being collected annually at the offsite SVMPs. Vapor samples are being collected from the source area SVE wells.
Operation and maintenance (O&M) activities of SVE Containment System in accordance with the O&M Plan continues to occur. O&M activities are performed on a weekly basis include general site inspections, collection of operational data, adjustment of system equipment, preventative maintenance, and collection/disposal of condensate. Operation is expected to continue through 2025. SVE Containment System operations and performance are documented in annual reports.
Land use controls (LUCs) consist of restrictions on land uses and the use of groundwater at Site 1.
The Navy retains ownership of Site 1 and leases the property to Nassau County, who subleases it to Steel Equities.
Administrative controls include a restriction in the Deed of Transfer to Nassau County, New York, stating that the county and its transferees and lessees cannot excavate or otherwise disturb subsurface soils at the site without submitting a written request to NYSDEC for review and approval, and restricts the use of groundwater underlying the site.
LUCs also require evaluation of the site to identify the need to control potential vapor intrusion exposure for any newly constructed structures on the site.
Annual LUC inspections are conducted to ensure compliance with restrictions and maintenance of the fencing and cover. Cover/fencing to be repaired as needed.
Site 1 will be included in Five-Year Reviews.
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Site 2 – Recharge Basins
Site 2 – Recharge Basins is located on the 96-acre parcel that was transferred to Nassau County, in the northeast corner of the Navy’s former property – north of OU1, Site 1 – Former Drum Marshalling Area Site 2 is enclosed by a facility perimeter fence along the north, east and south and an interior facility fence along the west. Except for three recharge basins, the site is relatively flat. The three recharge basins currently receive storm water from catch basins located on current and former Navy property and former Northrop Grumman Corporation (NGC) property to the north. Site 2 covers approximately 16 acres.
Site 2 consists of three recharge basins and former sludge drying beds. Historically, the recharge basins were used primarily for disposal of storm water and single pass non-contact cooling water for air conditioning units that was derived from onsite production wells. Recharge basins also received rinse waters from NG’s operations. Former sludge drying beds have been filled since prior to 1991. The former sludge drying beds were located in the northwest portion of the site. Sludge from the Plant 02 industrial waste treatment facility was dewatered in these beds before being disposed offsite. From 1995 to 1996, polychlorinated biphenyls (PCB)-contaminated soils were excavated and a soil and gravel cover was installed to meet the cleanup goals. In 2008, the Site was transfer to Nassau County.
Previous Environmental Investigations/Interim Action
Site 2 was originally identified in the Initial Assessment Study (IAS) in 1986 (Rogers, Golden, and Halpern, 1986).
In 1992, a Remedial Investigation (RI) was conducted that confirmed the presence of PCBs in the soil and chlorinated solvents (trichloroethene, tetrachloroethane and toluene) in the groundwater. The concentrations of volatile organic compounds (VOCs) in groundwater were consistent with the facility State Pollutant Discharge Elimination Discharge (SPDES) permit. As part of the RI, a Baseline Human Health Risk Assessment (HHRA) was conducted. The risk assessment found that potential risk to onsite workers and offsite residents were within the United States Environmental Protection Agency (USEPA) target risk range of 1 X 10-4 to 1 X10-6. The groundwater at NWIRP Bethpage, if used as a potable water source, would be expected to result in significant carcinogenic and non-carcinogenic risks to residents and employees.
A Feasibility Study and a Record of Decision (ROD) for OU1 Soils were prepared in 1994 and in 1995. The ROD presented the selected remedial action for soil. The selected remedy consisted of removing 2,600 cubic yards of PCB-contaminated soil with concentrations between 10 parts per million (ppm) and 500 ppm for offsite disposal and the placement of a 6-inch soil/gravel cover over residual contaminated soils at the site.
In 1996, 7,239 tons of PCB-contaminated soil was removed that had concentrations in excess of 10 ppm and the soil and gravel cover was completed in 2001 to most of the areas surrounding the basins. Contaminated soil was disposed at the Grayback Mountain hazardous waste landfill in Clive, Utah.
In 2007, a five-year review was conducted to evaluate the implementation and performance of the remedies at the sites to determine whether the remedies are protective of human health and the environment. The remedy at Site 2 – Recharge Basins was deemed protective of human health and the environment.
In 2008, Site 2 was conveyed as part of the 96-acre transfer to Nassau County. Land use controls requiring cap maintenance and limiting future uses of the site were included in the transfer document.
Nature and Extent
The COCs listed in the 1995 OU1 ROD included:
VOCs: TCE only
Semi-volatile organic compounds (SVOCs): primarily polycyclic aromatic hydrocarbons (PAHs)
Polychlorinated biphenyls (PCBs)
Metals: Arsenic and Beryllium/
Current Site Conditions
Site 2 is enclosed by a facility perimeter fence along the north and east. It is a relatively flat area, with the exception of the three recharge basins. Recharge basins currently receive storm water from catch basins located on current and former Navy property and former NG property to the north. They also receive treated groundwater from the Bethpage Park Groundwater Containment System (BPGWCS). Former sludge drying bed area has been re-developed as a paved parking area associated with the FedEx hub located to the west of the site.
Land use controls (LUCs) consist of restrictions on land uses at Site 2. Administrative controls include a restriction in the Deed of Transfer to Nassau County, New York, stating that the county and its transferees and lessees cannot excavate or otherwise disturb subsurface soils at the site without submitting a written request to NYSDEC for review and approval, and restricts the use of groundwater underlying the site.
Annual LUC inspections are conducted to ensure compliance with restrictions and maintenance of cover. Cover to be repaired as needed.
Site 2 will be included in Five-Year Reviews.
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Site 3 – Salvage Storage Area
Site 3 – Salvage Storage Area is a relatively flat area located north of Plant No. 3 and west of Site 2. The site covers approximately 9 acres and is located on the 96-acre parcel that was transferred to Nassau County. The site consists of a parking area, office space, salvage storage area, and three warehouses.
From the 1950s through 1969, fixtures, tools, and metallic wastes were stored at the Site prior to recycling. Stored materials included aluminum and titanium scraps and shavings. While in storage, cutting oils dripped from some of this metal. From the early 1950s to 1969, drum marshalling also occurred in this area. Waste oils as well as waste halogenated and non-halogenated solvents were also stored during this time frame. In 1998, as part of Northrop Grumman Corporation’s agreement to leave the NWIRP Bethpage property, surface soils were scrapped and disposed offsite. Based on subsequent sampling, surface soils were determined to meet cleanup goals and did not require a cover prior to being transferred to Nassau County.
Previous Environmental Investigations/Interim Actions
Site 3 was originally identified in the Initial Assessment Study (IAS) in 1986 (Rogers, Golden & Halpern, 1986).
In 1992, a Phase I Remedial Investigation (RI) was conducted and only low concentrations of volatile organics were detected in the soils at Site 3. As part of the RI, a Baseline Human Health Risk Assessment (HHRA) was conducted. The risk assessment found that potential risk to onsite worker and offsite residents were within the United States Environmental Protection Agency (USEPA) target risk range of 1 X 10-4 to 1 X10-6.
In 1993, a Phase II RI was conducted and a subsequent Feasibility Study and Record of Decision (ROD) for Operable Unit 1 Soils were prepared in 1994 and in 1995. The OU1 ROD presented the selected remedial action for soil which consisted of placing a 6-inch soil/gravel cover over residual contaminated soils at the site. The OU1 ROD for Site 3 soil was signed in 1995.
In 1998, a general cleanup of the facility by NG occurred as part of it exiting the NWIRP. A 2-inch permeable clean soil cover was placed over residual contaminated soils and corresponding deed restrictions were put in place. Residual soil contamination consists of metals, VOCs, and PAHs.
In 2007, a five-year review was conducted to evaluate the implementation and performance of the remedies at the sites to determine whether the remedies are protective of human health and the environment. The remedy at Site 3 was deemed protective of human health and the environment. Access to the site is currently restricted through fencing and security.
In 2008, Site 3 was conveyed as part of the 96-acre transfer to Nassau County. Land use controls (LUCs) limiting future uses of the site were included in the transfer document.
The existing site cover of asphalt and soil was altered in October 2018, during construction of the FedEx hub. The existing asphalt was removed, and the soil cover was re-graded to accommodate construction. The soil cover remains in place and the FedEx hub serves as an additional barrier to exposure to site soils (i.e., concrete building slab, sidewalks and paved parking lots covering the site soils).
Nature and Extent
The COCs listed in the 1995 ROD included:
VOCs: tetrachloroethene (PCE) only
SVOCs: primarily polycyclic aromatic hydrocarbons (PAHs)
Metals: arsenic, beryllium and manganese
Current Site Conditions
A hub for FedEx was constructed in the area of Site 3 in 2018/2019. The site currently contains a large building surrounded by paved parking areas and a few small grassy areas.
LUCs consist of restrictions on land uses at Site 3. Administrative controls include a restriction in the Deed of Transfer to Nassau County, New York, stating that the county and its transferees and lessees cannot excavate or otherwise disturb subsurface soils at the site without submitting a written request to NYSDEC for review and approval, and restricts the use of groundwater underlying the site.
Annual LUC inspections are conducted to ensure compliance with restrictions and maintenance of cover. Cover to be repaired as needed.
Site 3 will be included in Five-Year Reviews.
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Site 4 – Former Underground Storage Tanks
Site 4 – Former Underground Storage Tanks (USTs) is a relatively flat, paved area located south of Plant No. 3 and west of Site 1. Site 4 is also referred to as Area of Concern (AOC) 22. USTs were reportedly removed sometime between 1980 and 1984. The site covers approximately 0.14 acres.
This area consists of former USTs which reportedly stored Nos. 4 and 6 Fuel Oils. The USTs were used to fire several boilers inside of Plant 03 in order to generate steam. This practice occurred from 1941 until 1966 when a new Central Steam Plant became operational. Since the boilers were no longer required, these tanks were then used to store reserve quantities of No. 4 fuel oil until the tanks were removed between 1980 and 1984. Site 4 is addressed under Environmental Restoration (ER) and the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) because the site chemicals of concern (COCs) are comingled with TCE and other chlorinated VOCs.
Previous Environmental Investigations/Interim Actions
The removal of USTs occurred between 1980 and 1984.
In 1997, the Environmental Baseline Survey (EBS) found evidence of petroleum in the soils from near the bottom of the former USTs to depths near the water table.
Groundwater monitoring wells were installed in 1999, and a free product layer (petroleum) was identified on the groundwater table at a maximum thickness of 0.02 feet. Based on field observations, petroleum-contaminated soils were observed from 20 feet below ground surface to the water table near the former USTs. However, at distances greater than 60 feet, there was no evidence of petroleum-contaminated soils.
In 2003, a Resource Conservation and Recovery Act (RCRA) Facility Assessment (RFA)/Focused Feasibility Study (FFS) was prepared that evaluated remedial alternatives including a permanent cap (cover) with deed restrictions, groundwater monitoring, excavation/offsite disposal, and in-situ treatment options of bioremediation, chemical oxidation, and thermally enhanced soil vapor extraction. Petroleum-contaminated soil and semi-solid petroleum product were identified above and below the water table which is approximately 50 feet below ground surface (bgs) at the site. Uncontaminated soil was confirmed at 73 feet bgs. Chlorinated and non-chlorinated volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs) and several metals were also detected in groundwater at this site at concentrations greater than New York State Department of Health (NYSDOH) Maximum Contaminant Levels (MCLs) and United States Environmental Protection Agency (USEPA) Regional Screening Levels (RSLs). Since site history does not indicate the use or disposal of chlorinated solvents at this site, chlorinated VOCs may be the result of another nearby source area.
In 2004, the Navy conducted a closed-loop bioreactor (CLB) pilot-scale system study that combined in-situ and ex-situ bioremediation. The CLB system features no discharge of soil vapors and adds pure oxygen for biodegradation. The system was shut down in the spring of 2006.
From 2006 through 2007, the Navy conducted a post-operation soil sampling event of the CLB system. Four rounds of groundwater sampling were collected to evaluate potential effects of the system operation on the groundwater. Based on the data collected, the CLB system had a minimal effect biodegrading the petroleum hydrocarbon in the soils and groundwater after two years of operation
In 2010, a PAH soil investigation was conducted to characterize the nature of petroleum product near the water table in the source area and determine the presence of free product. The investigation also completed the vertical delineation of petroleum-contaminated soil and evaluated the feasibility of using thermal and solvent-based extraction to allow recovery of the petroleum product above and below the water table. In 2011, bench-scale testing was conducted on Site 4 soils. This testing evaluated thermal, biological, and solvent extraction technologies.
A steam injection system consisting of three injection wells, conveyance piping, injection manifold, and steam generation equipment was installed and steam injection that operated from April 2019 to May 2020. The non-aqueous phase liquid recovery system consisting of one recovery well, conveyance piping, control panel, and two storage tanks. The OU3 Site 4 Former Underground Storage Tanks ROD was finalized and accepted by NYSDEC in November 2015 (NAVFAC, 2015).
In July 2021, the steam injection system was converted to a biosparging system and started operation. The biosparging systems consists of seven SVE wells, nine air sparing wells, conveyance piping, a moisture separator, and a vacuum blower.
Nature and Extent
The ROD for OU3, Site 4 included the following COCs for soils:
The ROD for OU3, Site 4 included the following COCs for groundwater:
VOCs: benzene, ethylbenzene, xylenes
SVOCs: naphthalene, pentachlorophenol
Metals: cobalt, manganese
Current Site Conditions
Site 4 consists of a paved area and fenced grassy area. There is a building present on site which houses the Site 1 soil-vapor extraction (SVE) Containment System equipment and office/equipment storage trailers. Site 4 is a relatively flat area with a gentle slope to the south.
Groundwater monitoring at Site 4 will occur on an annual basis, and soil monitoring will be conducted twice over 10 years and prior to property transfer.
Operation and Maintenance (O&M) of the air sparging/ soil vapor extraction (AS/SVE) system and of soil vapor monitoring will occur over a 10-year period.
Land use controls (LUCs) consist of restrictions on land uses at Site 4 and the use of site groundwater. Administrative controls include a restriction in the Deed of Transfer to Nassau County, New York, stating that the county and its transferees and lessees cannot excavate or otherwise disturb subsurface soils at the site without submitting a written request to NYSDEC for review and approval, and restricts the use of groundwater underlying the site.
Annual LUC inspections are conducted to ensure compliance with restrictions.
Site 4 will be included in Five-Year Reviews.
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OU2 - Offsite Groundwater
Environmental activities at the former Naval Weapons Industrial Reserve Plant (NWIRP) Bethpage is addressed in four Operable Units (OUs). OU2 groundwater will be discussed below.
OU2 Site Description
OU2 consists of site-related volatile organic compound- (VOC-) contaminated groundwater beneath the Navy’s former 105-acre parcel, and VOC-contaminated groundwater that has migrated south and east off-property, where it becomes mixed with contamination originating on the Northrop Grumman (NG) property. It forms a 3,000-acre plus area of VOC-contaminated groundwater plumes that extend south of Hempstead Turnpike, at varying depths. The impacted groundwater extends to a depth of over 700 feet in places but is not continuous throughout this area and is not present at all depths. Within this plume, VOCs are present at concentrations that exceed Federal or New York State Maximum Contaminant Levels (MCLs).
Historical Site Uses/Conditions
The OU2 VOC-Impacted Groundwater plume includes contamination from several sources:
Former NWIRP Bethpage Site 1 – Former Drum Marshalling Area. (Note: OU2 does not include petroleum-contaminated groundwater associated with OU3, Site 4 – Former Underground Storage Tanks [which is the subject of a separate Navy ROD for OU3]).
Northrup Grumman facilities in area.
Other non-OU2 sources include:
Hooker Ruco Superfund Site,
Bethpage Community Park OU3 Groundwater,
Local dry cleaners,
Local gasoline stations, and
Residential properties (including septic systems).
Environmental Investigations/Interim Actions
Since 2001, both the Navy and NG have been installing vertical profile borings (VPBs) and associated monitoring wells. The Navy and NG share the results of their monitoring programs with NYSDEC and other parties, including potentially affected water districts. These investigations are used to identify potential new hotspots, and if found, to delineate the extent of the impacts.
In April 2003, the Navy issued its Record of Decision (ROD) for Operable Unit (OU) 2 Groundwater. The 2003 ROD identified activities that could be conducted by the Navy. The Navy issued the Public Water Supply Contingency Plan (PWSCP) that identified the placement of outpost monitoring wells and trigger values that would start discussions between the Navy/Northrop Grumman and the water districts. The PWSCP included the 2000 and 2001 data. The modeling assumed that the shallow contaminated groundwater would flow downward.
The 2021 Five Year Review identified the need for modifications to the Navy’s ongoing and planned remedial actions and therefore require an Explanation of Significant Differences from the Navy’s April 2003 OU2 Record of Decision. The Navy reviewed additional data, conducted additional modeling, and had productive meetings with NYSDEC that resulted in recommended changes to the remedial action selected in the 2003 OU2 ROD to better address OU2 groundwater contamination associated with the Former NWIRP.
Nature and Extent
The Navy OU2 ROD (NAVFAC, 2003) and Public Water Supply Contingency Plan (PWSCP) (Arcadis, 2003), and OU2 ESD (NAVFAC, 2021) identified seventeen different chemicals of concern (COCs) in OU2 groundwater, which were associated with the NG and NWIRP facilities:
• Tetrachloroethene (Perchloroethene) (PCE)
• Trichloroethene (TCE)
• cis-1,2-Dichloroethene (DCE)
• trans-1,2-Dichloroethene (DCE)
• Carbon Disulfide
• Carbon Tetrachloride
• 1,1,2-Trichloro-1,2,2-trifluoroethane (Freon 113)
• 1,2-Dichloroethane (DCA)
• 1,1-Dichloroethene (DCE)
• 1,1-Dichloroethane (DCA)
• 1,1,2-Trichloroethane (TCA)
• Vinyl Chloride
• 1,1,1-Trichloroethane (TCA)
The offsite groundwater contamination can generally be divided into four depth intervals, each of which encompasses multiple current plumes and/or hotspots:
- Shallow VOC-Impacted Groundwater
• This includes groundwater that is 0 to 300 feet below ground surface (bgs).
- Intermediate-Depth VOC-Impacted Groundwater
• This includes groundwater that is 300 to 500 feet bgs.
- Upper Deep VOC-Impacted Groundwater
• This includes groundwater that is 500 to 700 feet bgs.
- Lower Deep VOC-Impacted Groundwater
•This includes groundwater that is greater than 700 feet bgs.
Two “hotspots” have been identified within the OU2 plume. “Hotspots” are defined as areas of groundwater with total VOC concentrations greater than 1,000 parts per billion (ppb) in three consecutive sampling events in any one well. The following is a list of hotspots identified to date:
GM38 Area Hotspot: The majority of this hotspot has been remediated, and the maximum residual TCE concentration in this area in the first quarter of 2021 is 159 µg/L.
RE108 Area Hotspot: This hotspot is predominantly trichloroethene (TCE), with lower concentrations of other VOCs.
The offsite groundwater contamination consists of three general plumes:
Deep Eastern Plume
Deep Western Plume
Shallow Plume: The shallow plume is generally located from the water table (30 to 50 feet below ground surface) to a depth of approximately 300 feet below ground surface. Groundwater in this portion of the aquifer contains a mixture of contaminants including TCE, PCE, DCE, TCA, and DCA with individual VOC concentrations less than 10 micrograms per liter (µg/L). Groundwater flows to the south southeast and is generally downward because of precipitation, infiltration and groundwater extraction at depth. The presence of confining units can locally inhibit or prevent vertical migration of the VOCs.
Deep Eastern Plume: The deep eastern plume is located east of NWIRP Bethpage. This plume starts in the Bethpage Community Park and continues south. This plume contains a mixture of contaminants including TCE, PCE, DCE, TCA, and DCA. Groundwater flow is generally to the south southeast, but can vary significantly in the areas of water supply wells, especially where clay units confine portions of the aquifer and the water supply wells operating at a high rate relative to the natural groundwater flow through the area.
Deep Western Plume: The deep western plume is located south of NWIRP Bethpage. The plume starts in the area of NWIRP Bethpage Plant 3 and NGC’s Plant 2 and continues south to Southern State Parkway. This plume is predominately TCE, with only trace concentrations of other VOCs. Groundwater flow is generally to the south southeast, but can vary significantly in the areas of water supply wells, especially where clay units confine portions of the aquifer and the water supply wells operate at a high rate relative to the natural groundwater flow through the area.
Remedial Actions Completed
In 1998, NGC installed and started operation of an Onsite Containment System (ONCT) at the south-southwest border of the NG property as an Interim Remedial Measure. This system provides hydraulic containment of the on-property portion of the VOC-impacted groundwater from NWIRP. Since 1998, the OU2 ONCT has removed approximately 218,000 pounds of VOCs from the aquifer through May 2021. NG continues to operate, maintain, and monitor the ONCT system. While the ONCT provides an effective hydraulic barrier that controls the off-property migration of VOC-impacted groundwater, it currently does not treat for 1,4-dioxane. 1,4-Dioxane in groundwater will be addressed as part of planned remedial actions as a result of the 2020 ESD.
In December 2009, the GM-38 Hotspot Area Groundwater Treatment System (GWTS) was completed. This remedy originally consisted of two recovery wells to extract the VOC-impacted groundwater and treat it via air stripping, vapor-phase granulated activated carbon (GAC), and liquid phases GAC. In May 2021, advanced oxidation process (AOP) treatment was added to the system to also address 1,4-dioxane (estimated at 5 µg/L) in the groundwater. This system remains in operation.
Additional wellhead treatment systems for Public Water Supplies (PWS) have been installed and are operating at:
Bethpage Water District (BWD) Plants 4, 5, and 6 ;
South Farmingdale Water District (SFWD) Plants 1 and 3; and
New York American Water (NYAW) Facility at Seaman’s Neck Road – NYAW Wells 3A and 4S.
New York State Department of Health’s (NYSDOH) contaminant-specific Water Quality Regulations continue to be met at these water supply wells through air stripping, AOP, and/or GAC treatment technologies. The water that is distributed to the community is tested at least monthly to ensure that the drinking water standards promulgated by the NYSDOH are met. The Navy continues to work with several water districts to ensure protection of the public water supplies from VOCs in the OU2 plume.
Remedial Actions Planned and On-Going
As a result of the OU2 ESD, the following remedial actions are planned to treat offsite groundwater.
RE-137 Interim Mass Removal System
The RE137 System is being operated to evaluate capture of the RE108 Area groundwater hotspot in the area of recovery wells RE137 and to a lesser extent RW4. To support this evaluation, a temporary RE137 Groundwater Extraction, Treatment, and Discharge System (RE137 System) was installed south of the former NWIRP Bethpage in the area of RE137. The RE137 System started operation in February 2022, with preliminary prove-out testing. The system is anticipated to start regulator operation in April 2022 and operate for approximately 20 months (November 2023). This system is also expected to provide interim control of plume migration and provide significant removal of VOCs.
RE108 Phase I Treatment System
The RE108 Area Hotspot Phase I Treatment System includes the addition of a recovery well to address contamination in the northern portion of the RE108 Area Hotspot. Installation of the well and pipeline is complete. As of April 2021, extracted groundwater from RW4 is being pumped to the existing GM38 GWTP for treatment.
RE108 Phase II Treatment System and Extension
The objective of the RE108 Area Phase II Treatment System is to extract groundwater contaminated with chlorinated VOCs using recovery wells located near the leading edge of the hotspot. Additional recovery wells to address chlorinated VOC contamination south of the planned RE108 Phase II Treatment System will also be installed. The Phase II Treatment System is being designed to address 1,4-dioxane to comply with the recently promulgated NYSDOH MCL, as well as to treat chlorinated VOC contamination, by including AOP in the planned treatment system.
Phase III Southern Plume Intercept Treatment System
The Phase III Southern Plume Intercept Treatment System (Phase III System) would add up to four recovery wells and one or two treatment systems to capture, or intercept, as practicable, the OU2 plumes to maintain their approximate current footprint. The Phase III Treatment System would likely be designed to address 1,4-dioxane as well as chlorinated VOC contamination, by including AOP in the planned treatment system.1,4-dioxane concentrations in this groundwater will be determined during pre-design investigations.
Long Term Monitoring (LTM) is ongoing to further delineate the configuration of the groundwater plumes and to determine the effectiveness of remedial measures implemented to date. Monitoring wells are sampled quarterly, semi-annually or annually by the Navy and NG as a part of LTM. Results are shared on a quarterly and annual basis. The installation of vertical profile borings and monitoring wells will be continued to delineate the plume. The LTM program is continually optimized to help track the progress of the OU2 plume.
The groundwater data is evaluated annually to provide updated mapping of plumes, evaluate the current and potential future impacts to public water supplies, discuss mitigation strategies, and propose new remedies/modifications to existing remedies as needed.