Tobyhanna Army Depot
Current Site Information
EPA Region 3 (Mid-Atlantic)Pennsylvania
EPA ID# PA5213820892
11th Congressional District
Last Update: March 2012
Current Site Status
The Army, EPA, and the State worked closely to achieve National Priorities List ('NPL') construction completion by September 2000. 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". In 2000, a base-wide ecological risk assessment was also completed and sediment contaminant levels at permitted storm sewer outfalls will continue to be monitored by the Army under the Depot's Environmental management Program. The Army will also continue to monitor natural attenuation at two former waste storage areas, as well as at the closed sanitary landfill. 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.
A five-year review was completed in September 2007. 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. However, there was a need to investigate the vapor intrusion pathway during the next five year cycle due to the offsite low concentration VOC plume. The initial phases of the vapor intrusion investigation were completed in early 2011, and nothing was found above benchmarks in indoor air. Another round of indoor air sampling took place in the Fall of 2011 in order to investigate seasonal variation. The VI investigation should be completed prior to the next five year review, which is scheduled to be completed by September 2012.
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 was discussed previously. 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 ResponsibilityThis site is being addressed through federal actions.
NPL Listing HistoryProposed Date: 07/14/89
Final Date: 08/30/90
Partial NPL Deletion 11/16/01
Threats and ContaminantsThe 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 had been conducting bi-annual 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 the drum staging area. This area is believed to be the major source of the VOCs found in the groundwater. The ROD 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.
An active remedy of groundwater extraction and treatment may slightly reduce the overall time frame for cleanup; however, because natural attenuation, long-term monitoring and institutional controls will be just as protective of human health and the environment, the additional costs associated with an active treatment system do not appear to be justified in this case. The inactive sanitary landfill had a small VOC-contaminated groundwater plume. There is currently no one using the groundwater 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. Indoor air and subslabs (where available) were taken in 4 residences which are located over the offsite VOC plume. No VOCs were detected in indoor air. Another round of sampling in these 4 residences took place in the Fall of 2011 to test for seasonal variation. Sample results are not yet available. The vapor intrusion investigation report will be finalized by the time that the third Five-Year Review is completed in September 2012.