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Tobyhanna Army Depot
EPA Region 3 (Mid-Atlantic)
EPA ID# PA5213820892
11th Congressional District
Last Update: February 2014
Current Site Status
The Army, EPA, and the State have achieved National Priorities List ('NPL') construction completion. In September 2000, two Records of Decision ('RODs') for how to clean up the site were signed and five areas of concern ('AOCs') were closed out as "No Further Action". A partial deletion of the site from the NPL was completed in November 2001. Areas remaining on the NPL consist of three separate groundwater plumes which encompass approximately 15 acres. The Army will continue to monitor natural attenuation at these groundwater plumes.
The latest five-year review was completed in September 2012. The remedies at the sites where contaminants remain are expected to be protective of human health and the environment upon completion, and in the interim, exposure pathways that could result in unacceptable risks are being controlled. Although still protective of human health and the environment, the remedies for the two groundwater Operable Units (OUs) will be re-evaluated for other potential alternatives that may expedite the natural attenuation of the contaminated groundwater plumes.
Tobyhanna Army Depot ('TYAD') located in Monroe County, Pennsylvania is a 1,293 acre military facility. The current function of this facility is to design, fabricate, repair, and modify a wide range of communications and electronics systems. From the 1950s to early 1960s, the Army used burning and disposal areas in the southern portion of the base. Specific wastes handled included garbage, construction rubble, scrap metal, drums, and solvents. In addition, Army contractors used another nearby area as drum staging for temporary storage and disposal of building materials and other wastes generated during construction of the existing base. The Army first discovered volatile organic compounds ('VOCs') in an on-post drinking water well in 1981. In the mid-1980s, Monroe county and the state sampled nearby residential wells and identified VOC contamination. As a result, the Army provided the affected residents with an alternate water source and also conducted numerous investigations which led to the potential source areas of these contaminants. The site was then proposed to the NPL in July 1989 and placed on the list in August 1990.
In 1996, two RODs were signed for TYAD. The first ROD addressed two former hazardous waste storage buildings which had been closed out under RCRA regulations. The second ROD addressed a former electrical substation. In 1994, the Army removed 1.8 cubic yards of polychlorinated biphenyl ('PCB') contaminated soils from this area. The selected remedy for both sites was "No Further Action".
In 1997, a ROD was signed for the VOC-contaminated groundwater plume which had migrated offsite. The alternative chosen in the ROD was natural attenuation, institutional controls, and long-term monitoring.
In 2000, two RODs were signed for TYAD. The first ROD addressed an area of unexploded ordnance ('UXO'). The alternative chosen in the ROD was institutional controls. The second ROD addressed VOC-contaminated groundwater plume associated with the closed sanitary landfill. The alternative chosen in the ROD was natural attenuation, institutional controls, and long-term monitoring.
When Tobyhanna was initially listed on the NPL, there were a total of 65 AOCs to be investigated and addressed. The 5 RODs discussed above address 7 of the AOCs. In March 1998 the Army and EPA signed a closeout document to identify 35 AOCs as needing no further action. In September 1999, the Army and EPA signed a closeout document for an additional 18 AOCs that required no further action. In September 2000, the Army and EPA signed the final closeout document for the final 5 AOCs that required no further action, except that sediment contaminant levels at permitted storm sewer outfalls will continue to be monitored by the Army under the Depot's Environmental Management Program.
- Site Responsibility
This site is being addressed through federal actions.
- NPL Listing History
Proposed Date: 07/14/89
Final Date: 08/30/90
Partial NPL Deletion 11/16/01
Threats and Contaminants
The primary contaminants of concern in ground water near Areas A and B include VOCs. The VOCs detected include trans-1,2-dichloroethylene ('DCE'), trichloroethylene ('TCE'), tetrachloroethylene ('PCE'), and vinyl chloride. Contaminated ground water posed a threat to the health of area residents through ingestion of, and direct contact with, VOCs. Other concerns included UXO and elevated risk to environmental receptors due to sediment contaminant levels of polychlorinated aromatic hydrocarbons (PAHs) at permitted storm sewer outfalls in on-post waterways.
The Army has been conducting periodic sampling of both on-post monitoring wells and residential wells since 1988. The sample results show that the concentrations of VOCs have been steadily decreasing over time. In 1995, the Army excavated and removed approximately 2,100 cubic yards of VOC-contaminated soils and several deteriorated drums from a drum staging area. This area is believed to be the major source of the VOCs found in the groundwater. The ROD for this area was signed on September 30, 1997 by EPA and the Army requiring natural attenuation, long-term monitoring, and institutional controls. The rationale for selecting this alternative is that the probable source of the contamination has been removed, concentrations of VOCs in the groundwater are decreasing, and residents with contaminated wells have been given an alternate supply of water. As part of the natural attenuation remedy, the Army will ensure through the use of institutional controls that residents will not be exposed to contaminated drinking water. Also, the Army will continue to conduct monitoring of both on-post and off-post wells until such time that no wells are found to contain contaminants above the MCLs.
The inactive sanitary landfill also has a small VOC-contaminated groundwater plume. There is currently no one using the groundwater in this area for potable purposes. The 300+ acre former artillery range was fenced due to UXO and will continue to be monitored.
In July 2002, TYAD completed a Five Year review of the 3 OUs on site and EPA determined that the remedies were still protective of human health and the environment.
In the Fall of 2004, the Army removed contaminated sediments from Hummler Run and an outfall basin of Oakes Swamp using a vacuum dredge. While EPA had only suggested monitoring these points, the Army decided to remediate the sediments as suggested by the Fish and Wildlife Commission.
Under DoD's newly established Military Munitions Response Program (MMRP), TYAD's former artillery ranges have been reassessed to determine whether any further response actions by DoD were required. In March 2005, the US Army Corps of Engineers finalized an MMRP Site Inspection report which concluded that the ROD for the OU-4 UXO area selected the appropriate remedy for the site. The report recommended that an additional area be included in OU-4. In the Fall of 2005, Tobyhanna extended the fence around OU-4 to include this area. In 2009, Tobyhanna cleared 32 acres in OU-4 to be used as a radar testing facility. The Army is following institutional controls established in the OU-4 ROD as they develop this facility.
The second Five-Year Review was completed in September 2007 and it has been determined that the remedy continues to be protective of human health and the environment. However, it did recommend that a vapor intrusion study occur prior to the next Five-Year Review. Tobyhanna performed the initial phase of the vapor intrusion study in early 2011 and a follow-up round of sampling in the Fall of 2011. Indoor air and subslabs (samples taken of vapors underneath the basements) were taken in 4 residences which are located over the offsite VOC plume. No VOCs associated with the underlying groundwater plume were detected in indoor air.
The third Five-Year Review was completed in September 2012. The remedies at the sites where contaminants remain are expected to be protective of human health and the environment upon completion, and in the interim, exposure pathways that could result in unacceptable risks are being controlled. Although still protective of human health and the environment, the remedies for the two groundwater OUs will be re-evaluated during the next five-year review for other potential alternatives that may expedite the natural attenuation of the contaminated ground water plumes.