Pease Air Force Base (Pease AFB) occupies approximately 4,365 acres of land in southeastern New Hampshire. It is bordered on the east by the City of Portsmouth, on the north by the Town of Newington, and on the southeast by the Town of Greenland.
Pease AFB was developed in the early 1930's by the City of Portsmouth as a 300-acre municipal airport. The Navy leased the airport during World War II, and in 1946, exclusive rights to the field were transferred from the Navy to the Air Force. In 1951, the installation was selected for development as a Strategic Air Command (SAC) base. Purchase of additional land needed for expansion of the base started in 1952 and was completed in 1956. Ground breaking for the new SAC facilities took place in 1954, and the first B-47 bombers arrived in 1956. During its history, Pease AFB has been the home of the 100th Bombardment Wing and the 509th Bombardment Wing, whose mission is to develop and maintain operational capacity to permit the conduct of strategic warfare in the event of war. The New Hampshire Air National Guard relocated the 157th Military Airlift Group (MAG) from Grenier Field at Manchester, NH to Pease AFB in 1966. The mission of this group was changed in 1975 when it was designated as the 157th Air Refueling Group.
In December 1988, Pease AFB was selected as one of the 86 military installations to be closed as part of the Secretary of Defense's Commission on Base Realignment and Closure. Pease AFB closed on March 31, 1991. Military personnel began leaving the base in June 1990. In 1989, 3,461 active-duty military and 741 civil service workers and 347 non-appropriated fund employees were employed at Pease AFB. Of the active duty personnel, 49 were with the Air National Guard (US Air Force, Cost Branch Comptroller, Pease AFB, 1989). It is estimated that the base created a total of 2,466 secondary jobs within the local communities (US Air Force, Cost Branch Comptroller, Pease AFB, 1988). As of April 1, 1991, the Air Force will maintain a Disposal Management Team of civilian personnel. The New Hampshire Air National Guard has a full time staff of three hundred military and civilian personnel with a part time potential of over one thousand.
Activities at Pease AFB in support of aircraft maintenance operations have generated listed and characteristic hazardous waste including spent degreasers, solvents, paint strippers and contaminated jet fuels. The total quantity of the above referenced hazardous waste generated per year has been estimated to be 1,500 to 2,000 gallons. In addition, approximately 14,000 gallons per year of waste petroleum, oil and lubricants (POL) (mostly engine oils and some combined petroleum and solvent wastes such as hydraulic fluid, PD-680, MOGAS, diesel fuel, and JP-4) and 10,000 gallons per year of reclaimed JP-4 have been generated.
Recognized past industrial waste disposal practices at Pease AFB can be characterized as follows:
|1956 to 1971:||Most waste POL and solvents combined and burned during fire department training exercises.|
|1971 to 1982||Contractor removal of combined waste POL and solvents.|
|1976 to 1982||Contaminated JP-4 burned during fire department training exercises.|
|1982 to 1987||Virgin JP-4 burned during fire department training exercises.|
|1976 to 1991||Segregation of non-fuel wastes and contractor removal through Defense reutilization and Marketing Office (DRMO). Reclamation of most JP-4 with return to bulk storage.|
In addition, landfilling of various combinations of solid waste (primarily composed of municipal-type refuse from family housing, administration, and shop buildings) has occurred at six landfills and two construction rubble dumps (primarily receiving inert construction and demolition debris) within base boundaries. Since 1975 base refuse has been disposed of by contract collection. Since 1975 to 1982 refuse was disposed of off base; from 1982 to 1987 it was incinerated at the City of Portsmouth's refuse-to-energy plant located on base, along with off-base refuse from the greater Portsmouth Area: and since 1987 it has again been disposed of off-base by contract collection.
Investigations of past hazardous waste disposal practices to determine potential environmental impacts began at Pease AFB in 1983 under the Department of Defense's Installation Restoration Program (IRP). The Phase I, Installation Assessment/Records Search identified past disposal locations and recommended locations needing further consideration. The Records Search identified 18 sites as potential areas requiring some degree of further investigation. The 18 sites consisted of six landfills, three spill sites, two construction rubble dumps, two Fire Departments Training Areas, a solvent disposal site, a leaded fuel sludge disposal site, an industrial shop zone, an equipment cleaning site, and a munitions residue burial site.
Between 1984 and 1987, Phase 2 - Stage 1, field investigations were conducted to determine which locations need further study. In 1987, based upon the recommendations of Stage 1 report, Phase 2 - Stage 2 investigation work was initiated at various sites. The Stage 2 report, released to the general public in August 1990, revealed that contaminants were detected in groundwater at sixteen sites. Chlorinated VOCs occur more frequently than other types of contaminants in groundwater and at the highest concentrations of the VOCs detected in groundwater at Pease AFB. Ambient Water Quality Criteria (AWQC) in surface waters were exceeded in all drainage basins sampled, with the exception of one. Background concentrations have been exceeded in sediment samples from all drainage basins. Analytes that may be attributable to historical site activities were detected in soils at all Stage 2 sites where soil samples were collected.
As the Stage 2 work effort evolved, five (5) sites were removed from the Stage 2 and placed into a new work effort, (i.e., Stage 3), to facilitate the implementation of Interim Remedial Measures (IRM's) at these sites. The IRP at Pease was to include four phases of investigation/cleanup. However, only two were implemented at the base before the IRP converted to EPA's "Superfund" terminology which follows the guidelines of the National Oil and Hazardous Substances Contingency Plan (NCP).
On July 14, 1989, Pease AFB was proposed for inclusion on the National Priorities List (NPL) and, on February 21, 1990 (55 Fed. Reg. 6154), Pease AFB was listed on the NPL.
As such, Pease AFB became a Superfund Site and subject to the requirements of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) as amended by the Superfund Reauthorization Act of 1986 (SARA), (collectively referred to as CERCLA or Superfund).
On February 24, 1991, the Pease Air Force Base Federal Facility Agreement Under CERCLA Section 120 (Pease FFA) was signed. The Pease FFA established the procedural framework for implementing the actions in accordance with CERCLA. Under the State's, and EPA-New England's oversight, the Air Force carried out the investigatory activities necessary to fully characterize 32 sites and conduct another basewide preliminary assessment/site inspection (PA/SI). The second PA/SI was to ensure all potential sources of contamination present at Pease AFB which were not known to exist, or were not adequately addressed during previous IRP efforts, were identified and evaluated. The second PA/SI, evaluated 21 additional locations to determine if remedial investigations under Superfund are warranted.
In 1992, the sites were grouped into eight zones, based on physical proximity and similar characteristics, in order to: 1) provide a more efficient and effective means to manage the sites at Pease AFB; 2) facilitate the selection of the most appropriate environmental response actions; and 3) expedite the swift implementation of the remedial actions.
An amendment to the Pease FFA was drafted to incorporate additional sites into the Pease FFA that the second PA/SI indicated warranted inclusion and formalize the revised schedule for remedial activities that were developed as a result of grouping the sites into zones. Modification #1 to the Pease AFB Federal Facility Agreement became effective on March 18, 1993.
NHDES has concurred with all of the eleven Superfund Records of Decisions (RODs) signed by EPA and the Air Force. The following Superfund remedial actions were taken:
In 1993, the Air Force completed the excavation of contaminated soils at the Jet Engine Test Cell site (Site 34), which removed a source of groundwater contamination and has resulted in an improvement in groundwater quality.
In 1994 and 1995, the Air Force excavated waste in contact with groundwater at Landfill 5 and consolidated solid waste from Landfills 2, 4 and 6 into Landfill 5. Including the quantities of petroleum contaminated soil, excavated under the Underground Storage Tank program and placed in Landfill 5 to prevent contact with groundwater and rainwater infiltration. At Landfill 6, a wetland was constructed where the landfill once existed to compensate for wetlands impacted by the closure of Landfill 5. Groundwater monitoring is ongoing.
In 1995, the Air Force constructed a Soil Vapor Extraction (SVE) system and groundwater treatment plant at Fire Department Training Area 2 that has removed more than 25,000 kg of contaminants. The SVE system consists of 189 soil vapor extraction vents, 121 passive vents, a catalytic oxidation unit for the destruction of vapor-phase contaminants, six groundwater extraction wells, and a groundwater treatment plant with a metals removal system, an air stripper and carbon adsorption. Soil and groundwater treatment and monitoring is ongoing.
In 1995, the Air Force installed sheetpiling to the top of bedrock to form a physical barrier around the source of groundwater contamination at Building 113 and constructed a groundwater treatment plant to treat groundwater pumped from seven hydraulic containment extraction wells. At complex sites like Building 113 it is technically impracticable to extract the source of contamination (Dense Non-Aqueous Phase Liquids) from the subsurface. Until remedial response technologies are developed that the can overcome the limitations of current technologies, the Air Force will be required to contain the source of contamination until the threat to groundwater quality is mitigated. Groundwater treatment and monitoring is ongoing.
In 1996, additional groundwater extraction wells were installed and the Jet Engine Test Cell (Site 34) pilot groundwater treatment plant was modified to treat contaminated groundwater emanating from an adjacent hangar. Groundwater treatment and monitoring is ongoing.
At the Old Engine Test Stand (Site 45) the SVE system has cleaned up contaminated soils to below regulatory standards and the system has been shut down. Low levels of groundwater contamination are being naturally attenuated and groundwater monitoring is ongoing.
In 1996, the excavation and disposal of sediments in Upper Newfields Ditch and Upper Grafton Ditch was completed.
In May 1997, an SVE/air sparging system became operational at Burn Area 1, which is located on the west side of the runway. Here, the removal of contaminants is enhanced by the injection of air below the groundwater table, which transfers contaminants from soil particles to the vapor phase (also known as air sparging). In 2005 the SVE/Air Sparging was determined to have met soil clean-up objectives and soil treatment was terminated. Groundwater monitoring is ongoing.
In 1997, the excavation and disposal of sediments in McIntyre Brook and Pauls Brook was completed.
In 1999 a subsurface Permeable Reactive Wall was installed at Site 73, Building 234, to treat contaminated groundwater as it flows through the wall.
As a result of an environmental site assessment conducted at a site where redevelopment activities were planned, chlorinated solvents were discovered in groundwater in the vicinity of Building 22. The Air Force has conducted a site investigation and a soil removal action. The site is now identified as Site 49. A PRW was installed in June and July of 2000 to treat groundwater contamination.
In 2003 the Zone 3 ROD was amended because the EPA and DES determined the Site 39 remedy was not operating properly and successfully. The amended ROD required construction of a contingency wellhead treatment system for the Haven well, optimization of the groundwater extraction system at Site 39, termination of groundwater extraction at Site 34 and modification of the long-term monitoring plan. In the summer of 2005 the wellhead treatment plant was completed and the Site 39 groundwater extraction system was determined to be operating properly and successfully.
Current environmental site conditions: At sites under Superfund's jurisdiction where the source of contamination has been removed but the concentration of contaminants in groundwater exceed the groundwater quality standards, natural processes associated with natural attenuation should restore groundwater quality to acceptable levels in a reasonable time frame. At those Superfund sites where either the source of contamination is undergoing treatment or further migration of the contaminant plume represents a potential threat to human health and the environment, active treatment of contaminated groundwater in a treatment plant is on going.
Current phase of remediation: The Department has concurred with all of the eleven Superfund Record of Decisions (RODs) signed by EPA and the Air Force. All remedial actions required by Superfund were implemented by 1997 and determined to be operating properly and successfully (OPS) by the summer of 2005. The OPS determination at all sites allowed the Air Force to transfer by deed the Air Base property. By the Fall of 2005 the Pease Development Authority was deeded all portions of the former Air Base located on Pease Tradeport.