Mid-Atlantic Superfund

EPA Region 3 (Mid-Atlantic)

Pennsylvania
Franklin County
5 miles north of Chambersburg

EPA ID# PA2210090054

3rd and 9th Congressional District

Last Update: December 2008

Other Names

Property Disposal Office Area PDO

Current Site Status

The Letterkenny Army Depot is on the National Priorities List (NPL), a list of the most seriously contaminated hazardous waste sites in the country. There are two NPL sites associated with the Letterkenny Army Depot. The first is referred to as the Letterkenny Army Depot Property Disposal Office (PDO) Area NPL site. The second is referred to as the Letterkenny Army Depot Southeast (SE) Area NPL site. This narrative will concentrate on the Letterkenny Army Depot PDO Area NPL site. There are seven operable units (OUs) established for the PDO Area NPL Site.

The Letterkenny Army Depot covers 19,243 acres, most of which is devoted to ammunition storage (16,614 acres). The Installation was included in the 1995 Base Realignment and Closure Act (BRAC), with approximately 1,462 acres designated for transfer to the private sector for local redevelopment. Most of the remaining land will continue to be part of the active Letterkenny Army Depot. To date, approximately 792 acres have been transferred to the private sector.

The United States Army (Army), with review and input from the Environmental Protection Agency (EPA) and the Pennsylvania Department of Environmental Protection (PADEP), has completed the first five-year review for the PDO Area. The purpose of the five-year review is to determine whether the remedy at a site is protective of human health and the environment. The five-year review report concludes that the remedies in place for PDO OUs 1, 3, 6, and 7 are protective of human health and the environment. The final remedies for OU 2, OU 4, OU 5, and portions of OU 6 have not been selected. EPA concurred with the Army's determinations on March 12, 2007. The next five-year review for the PDO area is due March 12, 2012.

Site Description

The Letterkenny Army Depot was originally a 19,243 acre Army facility. It is located 5 miles north of Chambersburg, Franklin County, Pennsylvania. Approximately 17,000 people live within 5 miles of the Letterkenny Army Depot.

The Letterkenny Army Depot was established in 1942 for ammunition storage. Since 1947, activities at the Letterkenny Army Depot expanded to include the testing, maintenance, and overhaul of wheeled and tracked vehicles and missiles; the storage and transportation of industrial chemicals and petroleum; and storage, maintenance, demilitarization, and modification of ammunition. The PDO Area includes areas associated with the storage and disposal of industrial chemicals and petroleum. The PDO Area site also encompasses areas covered under Resource Conservation and Recovery Act (RCRA) corrective action investigations, including areas associated with the storage, maintenance, demilitarization, and modification of ammunition that are located in a section of the facility commonly referred to as the Ammunition Area (AA).

The PDO and SE NPL sites are separated by a major groundwater/surface-water drainage divide. Letterkenny’s industrial and maintenance areas, which are primarily located in the southeastern corner of the Depot, encompass approximately 2,500 acres and include warehousing, vehicle storage, administration, industrial/maintenance, recreational activities, and housing. Contamination from both NPL sites includes chlorinated organic solvents, blast media, paints, petroleum products, metals, and cleaning agents stored or disposed of in landfills, trenches, burn pits, or spilled from storage.

Site Responsibility

This site is being addressed by Federal action and Base Closure (BRAC 1995).

NPL Listing History

The Letterkenny Army Depot PDO Area was proposed to the National Priorities List on April 10, 1985. The LEAD PDO Area was re-proposed to the NPL, to include the corrective action authorities of RCRA Subtitle C, on July 22, 1987. The site was formally added to the NPL on March 13, 1989.

Threats and Contaminants

According to tests conducted by the Army, groundwater beneath the PDO Area and PDO Area surface water, including Rocky Spring Lake, are contaminated with low levels of chlorinated organic chemicals including trichloroethylene (TCE) and polychlorinated biphenyls (PCBs). Soils have been contaminated by xylene, heavy metals, chloroform, and other volatile organic compounds (VOCs). Residential wells are not known to be impacted by this site, but could be threatened. Individuals may be at risk if they accidentally ingest, inhale, or come in direct contact with contaminated groundwater or soil, or consume fish from contaminated areas. Additional residential wells could become contaminated.

Contaminant descriptions and associated risk factors are available at: (ATSDR web site).

The Ammunition Area is still considered an active part of the Letterkenny Army Depot, and is not included in the BRAC portion of property to be transferred to the private sector. It has not been fully investigated to date. However, future site work is planned for the Ammunition Area.

Cleanup Progress

Environmental Studies began in 1978. The majority of the two NPL sites (excluding the Ammunition Area) were identified in 1995 as excess and to be returned to the community for local reuse. The Army, EPA, and Pennsylvania signed an Interagency Agreement (also known as a "Federal Facilities Agreement") in 1989. The Army, Commonwealth, and EPA formed a BRAC Cleanup Team (BCT) in 1996. The BCT is working to streamline the cleanup process and expedite transfer of the excess property to facilitate local redevelopment and reuse. Franklin County has formed a Local Reuse Authority referred to as the Letterkenny Industrial Development Authority (LIDA) to support reuse and cleanup priorities.

BRAC Parcel Transfers
A Record of Decision (ROD) was signed in September 1998 for the Phase I BRAC Parcels, which cover approximately 233 acres in both the PDO and SE Areas. The ROD specified institutional controls as the interim remedy for groundwater. Institutional controls were adopted by the Letterkenny Industrial Development Authority (LIDA) in October 1998 at the time of the Phase I Properties transfer. Permanent deed restrictions were placed on the Phase I Parcels restricting access to groundwater underlying the property without the prior written approval of the Army, PADEP, and EPA. A Finding of Suitability to Transfer (FOST), which is an agreement between the Army and EPA, was signed in October 1998 for the Phase I Parcels.

In July 2001, a ROD was signed for the Phase II Parcels, which consist of approximately 358 acres in both the PDO and SE Areas. A FOST was signed in February 2002. Due to groundwater contamination, the property was transferred by a limited depth transfer. Accordingly, the property transferred includes buildings, structures, and soil from the ground surface down to a depth of 8 feet below ground surface, which is above the seasonal high water table. The groundwater was not included in the transfer. As with Phase I, permanent deed restrictions were placed on the Phase II Parcels restricting access to groundwater underlying the property without the prior written approval of the Army, PADEP, and EPA.

A ROD and FOST for the Phase III Parcels were signed in August 2003. Phase III covers 201 acres in both the PDO and SE Areas. This area includes 28 acres of subsurface property that is deeper than 8 feet below ground surface, located underneath parcels previously transferred as part of Phase II. Based on a finding of no VOC impacted groundwater, these parcels were transferred without any restrictions.

Several Findings of Suitability to Lease (FOSLs) covering parcels in the PDO Area have been signed. The purpose of the FOSLs is to document environmental conditions at selected buildings and parcels at Letterkenny Army Depot for lease to LIDA. In addition, FOSLs identify use restrictions necessary to protect human health and the environment and to prevent interference with any existing or planned environmental response actions.

PDO OU 1 Source Area Soils
OU 1 consisted of the Defense Revitalization and Marketing Office (DRMO) Drum Storage Revetments and the Oil Burn Pit (OBP). The DRMO used the Drum Area Revetments for storing drummed wastes as recently as the 1980s. The OBP was used as a fire training area during the 1970s and 1980s. Oils and solvents were dumped into the OBP and set on fire as part of fire training exercises by the Letterkenny Fire Department.

Investigations conducted in the early 1980s concluded that the OBP and the DRMO Drum Area Revetments were the major sources of the VOC groundwater contamination, but the soils were no longer an active source of contamination. Based on the findings of the remedial investigation, a “No Action” Record of Decision (ROD) was signed in August 1991. The ROD stated that the VOCs had migrated from the soils into the underlying bedrock. Therefore no soil remediation was necessary at the OBP and the DRMO Drum Revetments. However, in 1995 soil contamination was discovered while backfilling the Oil Burn Pit. Later that year, sampling results showed the soil to be contaminated with 1,1,1 – trichloroethane (TCA) and other VOCs. As a result, PDO OU 4 was created to administratively manage the newly discovered contamination.

PDO OU 2 PDO Area Groundwater and Surface Water
PDO OU 2 consists of VOC-contaminated groundwater (on and off-post) and surface water in the PDO Area. The PDO groundwater becomes surface water at the Rocky Spring. The primary sources of the VOC contaminated groundwater are the DRMO Drum Storage Revetments and the Oil Burn Pit (OBP).

Approximately 20 residential water wells south of the PDO Area have been sampled periodically since 1982. Over time, VOC concentrations at Rocky Spring have decreased to the point that monitored natural attenuation is being considered as a potential remedy. Only 2 contaminants of potential concern are currently present above risk-based values, trichloroethene and 1,1-dichloroethene. However, remedy selection is currently on hold until the extent of the VOC-contaminated groundwater plume emanating from the OBP is delineated and characterized. At this time, no final remedial action for the groundwater and surface water has been selected.

PDO OU 3 Mercury Detections in Rocky Spring Lake
PDO OU 3 addressed the sporadic detections of mercury in the Rocky Spring Lake. During two sampling events in 1991, mercury was detected in the lake. However, follow-up studies in 1992-1994 did not detect mercury levels above region background in the lake. The 1996 remedial investigation concluded that the 1991 mercury detections were due to drought conditions that caused enhanced bioaccumulation of mercury and subsequent release during algal die-off. This caused a short-term release of mercury into the lake. Since there were no further mercury detections above background, a “No Further Action” Decision Document was finalized in February 2000.

PDO OU 4 Off-PDO Area Groundwater
As stated above in the discussion of OU 1, PDO OU 4 was created to address soil, sediment and groundwater contamination discovered at the Oil Burn Pit (OBP). In 1995, Letterkenny was backfilling the OBP when black sludge-like material was seen oozing from beneath the fill material. The sludge was sampled and discovered to have high levels of VOCs. Later that year, soil boring sampling results showed the soil to be contaminated with 1,1,1- trichloroethane (TCA) and other volatile organic compounds (VOCs). These results showed that the OBP was still an active source of groundwater contamination. Therefore, the Army initiated in-situ chemical oxidation as an interim removal action in 1997. A second phase of in-situ treatment was in conducted in 1998 and 1999. Soil sampling results indicate that while the interim action achieved a significant reduction in VOCs, the removal action goals were not achieved.

Additional monitoring wells were installed in 1999 to determine if contaminated groundwater was migrating southwest over the groundwater divide into PDO OU 2. The results of that effort showed that the very low levels of VOCs were attributed to the nearby Transfer Burning Revetments and the Open Trench Landfill. In 2003, EPA requested additional groundwater sampling to better delineate the groundwater plume. Sampling results from 2003 and 2004 indicated that TCA appeared to be migrating over the groundwater divide into PDO OU 2. Letterkenny is currently undergoing additional fieldwork to delineate the TCA plume southwest of the OBP that encompasses the Transfer Burning Revetments and the Open Trench Landfill.

PDO OU 5 DRMO Scrap Yard and PCB Investigation of the Rocky Spring System
PDO OU 5 encompasses the Rocky Spring Drainage Area. Contaminants of concern include PCBs and pesticides. During the removal of sediments from the Spring House at Rocky Spring in 1995, elevated levels of PCBs were discovered in the sediments. Additional sediment sampling showed that PCB sediments were continuing to discharge from Rocky Spring and flow into Rocky Spring Lake. Fish samples indicated possible risk to human health from ingestion. Therefore, the Letterkenny Commander issued a fishing ban at Rocky Spring Lake in 1995.

The remedial investigation determined that capacitor crushing as well as PCB storage and handling operations at the DRMO Scrap Yard were the source of the PCB-contaminated sediments. The DRMO Scrap Yard is located within the upper PDO Drainage System, upstream of Rocky Spring.

In 1999, the Army performed a time-critical removal action to removed the source of the PCBs. 10,660 tons of contaminated soil were removed as part of this effort. After the completion of the time-critical removal action, additional soil sampling revealed elevated levels of PCBs within an area referred to as the plunge pool. The plunge pool area received the majority of the surface water run-off from the DRMO Scrap Yard and directs the flow to the Upper Rocky Spring Branch. Based on these results, the Army performed a removal action in the fall of 2002. Forty-two tons of PCB-contaminated sediment was excavated and disposed of in September 2002.

PDO OU 6 Possible Waste Sites Being Investigated Under the 1995 BRAC Decision
The BRAC Area within the PDO Area has been designated as PDO OU 6. Several parcels were transferred under the Phase I and Phase II Findings of Suitability to Transfer (FOSTs) in 1998 and 2002, respectively. RODs for both transfers specified institutional controls as the final remedy for soils and the interim remedy for groundwater. Several remaining parcels are currently being investigated for potential environmental contamination.

Institutional controls were adopted by the LIDA at the time of the Phase I and Phase II Properties transfers. Permanent deed restrictions were placed on the parcels to restrict the use of the property to industrial and commercial; prohibit the excavation of soil deeper than 3 ft above the water table without the prior approval of the Army; and restrict access to groundwater underlying the property without the prior written approval of the Army, PADEP, and EPA.

In 2002, an engineering evaluation/cost analysis (EE/CA) was completed for the Former PDO
Scrap Yard site, located in PDO OU 6, to evaluate and recommend a potential remedy for contaminated soils. Evidence from historical aerial photographs indicates that the Former PDO Scrap Yard was used as a storage area for scrap and other waste materials from initial operations at Letterkenny until the late 1960s. The historical records indicate that drums were buried at the site and that burning of scrap materials and limited burying of materials may have occurred there. A streamlined risk evaluation indicated that dioxins/furans, zinc, and asbestos were present in soils at levels that potentially pose an unacceptable level of risk based on the likely future use scenarios. Therefore, to mitigate the existence of unacceptable levels of risk at the site, the EE/CA recommended that further action be taken in order to be protective of human health. Specifically, the EE/CA recommended excavation and off-site treatment or recycling as the remedy. As a result, a removal action was completed in September 2005.

PDO OU 7 - Southern Martinsburg Shale Region (SMSR)
The Southern Martinsburg Shale Region (SMSR) is a part of Letterkenny that contains an area of shale bedrock surrounded by down-gradient limestone bedrock. This shale bedrock area forms the “highland” or elevated ridge areas in the Phase III parcels. Groundwater flows radially away from the SMSR. Groundwater sampling in 1999, 2000, and 2002 proved that the SMSR was not impacted by any previous industrial activities at Letterkenny. Based on the finding of no VOC impacted groundwater, the SMSR was redefined as PDO OU 7 and subsequently became the basis for the Phase III property transfer. The ROD and FOST for the Phase III areas were signed in August 2003. These parcels were transferred without any restrictions.

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