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  HANSCOM FIELD/HANSCOM AIR FORCE BASE


Map this site in Cleanups in My Community
 Bedford; and Concord and Lexington and Lincoln,  Massachusetts
 Middlesex County
 Street Address: HARTWELL AVENUE
 Zip Code: 01730
 Congressional
 District(s):

06
 EPA ID #: MA8570024424
 Site ID #: 0100967
 Site Aliases:

 Site Responsibility: Federal, Municipal

 NPL LISTING HISTORY
 Proposed Date 05/10/1993
 Final Date 05/31/1994

Site Description
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Hanscom Air Force Base/Hanscom Field site covers approximately 1,120 acres in a light industrial area of eastern Massachusetts. The site occupies land in the Towns of Bedford, Concord, Lexington, and Lincoln. The Naval Weapons Industrial Reserve Plant and Raytheon research facility are located due north of Hanscom Air Force Base/Hanscom Field. In 1942, the military began using a public airfield at the site that had been built the previous year. In 1952, the Commonwealth of Massachusetts transferred 396 acres and leased 641 acres of the land to the Air Force. The Commonwealth retained the remaining 83 acres for its own use. Military flight operations ceased in 1973 and in August 1974, the airfield reverted to state control and was renamed L.G. Hanscom Field. It is currently operated by the Massachusetts Port Authority (MASSPORT) as a civilian airport. The primary mission of Hanscom AFB, on the 396 acres owned by the Air Force, is to support the Electronic Systems Center of the Air Force Material Command. A total of 22 possible sources of contamination have been identified on the land the Air Force has owned or leased. These include former fire training, disposal, underground storage tank, and other spill sites. In the spring of 1983, three production wells for the Town of Bedford, located « mile northwest of Hanscom Air Force Base, were shut down after volatile organic compounds were detected above drinking water standards. Since the spring of 1991, contaminated groundwater located within the vicinity of the airfield on Hanscom Field has been extracted and treated; however, investigations conducted, both by the Air Force and the Town of Bedford, have been inconclusive in terms of identifying a specific source of contamination that is the cause for the production well shutdown.

Threats and Contaminants
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Groundwater and subsurface soil are contaminated with chlorinated solvents, jet fuel, and other petroleum compounds. People who come into direct contact with or ingest contaminated groundwater or soil may be at risk.

Cleanup Approach
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This site has been addressed in three phases: initial removal actions; long term remedial action; and long term monitoring. Significant investigations and interim remedial action operations were accomplished under State oversight prior to the National Priorities List (NPL) listing in 1994. As of 2008, all remedies planned for the Hanscom Air Force Base have been constructed. Operational Maintenance and Monitoring continue.

Response Action Status
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Initial Action In mid-1988, contaminated soil and drums were excavated from Sites 1,2, and 3 located in the airfield, which were former fire training and disposal areas. In the spring of 1991, a groundwater pump and treat system began extracting contaminated groundwater from the vicinity of the airfield. Since 1989, various underground storage tanks and contaminated soils from several sites have been removed to eliminate sources of contamination. At Area 21, a former fuel distribution area, interim soil vapor extraction (SVE) and groundwater collection system operated from 1995-2000 to address contamination from distribution activities.

Sites 1, 2, 3, 5, 19, 20 OU-1 is an area with groundwater contamination that includes three distinct areas of concern, known as IRP Sites 1, 2, and 3, which are all located on Hanscom Field. OU-1 includes parts of Hanscom Field and the wetland areas and a beaver ponded area to the north/northeast of the airfield known as the Jordan Conservation Area and Hartwell Town Forest which are owned by the Town of Bedford. There are restrictions on the Bedford property which limit use to passive and/or active recreation use. There is also a small section of OU-1 which is leased from the Commonwealth by HAFB and used as a campground and as the site of the central groundwater treatment facility for OU-1. Potable water for the campground and treatment facility is provided by the Town of Bedford public water distribution system.
Contaminants of Concern (CoCs) at OU-1 consist of chlorinated and aromatic volatile organic compounds (VOCs) and the VOCs with the highest concentrations are trichloroethene (TCE), 1,2-dichlorothene (1,2-DCE) and vinyl chloride. Dense non-aqueous phase liquid (DNAPL) is known to be present at Sites 1 and 2.

IRP Site 1, situated in the town of Bedford, is a former Air Force fire training area located on a relatively flat plateau on the southeast side of Hartwell Hill and northwest of Hanscom Field Runway 5-23. The area is slightly higher than the runways and the wetlands to the northeast.

Site 1 was reportedly used from the late 1960s through 1973 for fire training exercises. Two (2) burn pits were used at this site. Waste oils, solvents, paint thinners, and degreasers were collected from around the base, dumped into pits, ignited, and then extinguished. The size of each of the two pits was estimated to be 15 feet by 20 feet. Today the area is fenced open space.

IRP Site 2, situated in the town of Bedford, is the site of drum burial pits located on Hanscom Field north of Runway 11-29 and east of Runway 5-23 which were used for disposing of waste solvents and paint from 1966 to 1972. The area is the same elevation as the runways and is slightly higher than the wetlands to the north. Today the area is grassed open space covered by a groundwater recharge system within the security fence perimeter of Hanscom Field.

IRP Site 3, situated in the town of Concord, is the site of drum burial pits located on Hanscom Field in a triangular area bounded by Taxiway "Whiskey" to the north, Taxiway "Mike" to southwest and Runway 5-23 to the southeast. The area is the same elevation as the runways. Several hundred drums of waste oils and paint wastes were buried in this area in the early 1960’s. Today the area is grassed open space covered by a groundwater recharge system within the security fence perimeter of Hanscom Field.


Site 4 IRP Site 4 is a municipal waste landfill which covers 10.5 acres and is located approximately 1,800 feet southeast of the approach end of Runway 5-23 on Hanscom Field. Pre-1964 topographic maps of the area indicate that the site was a wetland area associated with Elm Brook. In 1988, prior to NPL listing, the Air Force, under State oversight, constructed an impervious cap over the area.
Today the area is grassed open space with a softball field in the southern half. The landfill is situated predominantly in the town of Lincoln, with a small portion protruding into the bordering town of Concord.


Sites 6 and 21 OU-3/IRP Site 6 is approximately 15 acres in area and is located in the northeast portion of HAFB and is situated in both the town of Bedford and the town of Lexington. The site is bounded to the north by a former railroad spur, to the northeast by a wetland area and small pond, to the east by a commercial industrial park, to the south by a service road (Hunter Street), and to the west by IRP Site 21. IRP Site 6 consists of three distinct areas: the former filter beds (including the former sludge beds) and two (2) hillside landfill areas (south and west). The former filter bed area is higher than the wetlands to the north. The remedial action constructed in 2001 re-graded and placed a pervious cap over the three landfill areas of the site. CoCs at Site 6 consist of semi-volatile organic compounds (SVOCs) and metals.
IRP Site 6 was classified in the 1998 Hanscom Air Force Base General Plan (master plan) as industrial in both the existing and future Land Use Plans. Based upon this designation there was a potential for future industrial use of the site. However, the 2003 General Plan Update includes the following as a change from the 1998 Plan: “Most of the area designated Industrial at ERP S 6 in the Building 1800 series area was changed to Open Space since Land Use Controls associated with the ongoing remedial action constrains development.”

Today IRP Site 6 is a grassed area which is fenced and locked with “No Digging, No Dumping” signs posted. The site is periodically used by Air Force personnel for readiness training that does not require digging.

OU-3/IRP Site 21 is approximately 5 acres in area, situated in the town of Bedford, in the northeast portion of HAFB and adjacent to IRP Site 6. The Shawsheen River bounds the site to the north. IRP Site 21 is the area of a former aviation fueling facility that was used for storage, off-loading, and dispensing of jet fuel and aviation gasoline from at least 1945 through 1973, and to store and distribute No. 2 fuel oil during the early 1970s. Fuel was stored in aboveground and underground storage tanks, which had associated pump houses and a network of underground piping. This area was also used for the storage of cleaning solvents and other petroleum products (oils and lubricants) associated with aircraft and vehicle maintenance.

Concentrations of chlorinated VOCs, benzene, toluene, ethylbenzene, and xylenes (BTEX), polycyclic aromatic hydrocarbons (PAHs), and total petroleum hydrocarbons (TPH) have been detected in various media at the site.

Today the northern half of the site is a controlled/fenced parking area for privately owned recreational vehicles. The southern half of the site includes Building 1823, which is currently used as the base entomology facility; the former aboveground storage tank (AST) area which is currently used by the Base roads and grounds maintenance organization for equipment and materials storage, wood/brush chipping, and composting; and Buildings 1833 and 1834 used for the base’s maintenance material receiving and storage.


Sites 7, 8 Site 7 consists of a former industrial wastewater treatment plant and its associated underground pipe network. Operation of the treatment plant ceased on 1976. Site 8 was a former disposal area used from the early 1950s through 1973. The EPA concurred with the Air Force's proposed no further action for Site 7 in 2000 and for site 8 in September 2001, after an additional round of groundwater and surface water sampling was performed with no detections. Both sites are currently covered with grass and used as recreational areas/open space.

Environmental Progress
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Remedial Action Plans for IRP Sites 1, 2 and 3 were developed and implemented prior to the NPL designation. Subsequently, in 1995, EPA advised that additional studies were necessary to ensure that these earlier actions fully addressed CERCLA requirements. An Interim Record of Decision (IROD) selecting the remedy for OU1 was signed by the Air Force and EPA on February 6, 2001 with Commonwealth of Massachusetts concurrence.

In 2006 the Project Team concluded that the existing system is a feasible technology to achieve Remedial Action Objectives (RAOs) in a reasonable period of time and that HAFB should start the process of converting the IROD to a final Record of Decision (ROD). Because of the apparent reduction of chlorinated volatile organic compounds (CVOC) contaminant concentrations in site ground water that was observed in the long-term monitoring (LTM) data set, in 2006 EPA Region I and HAFB partnered in preparing a “focused” solute transport model based on the LTM results and the adjusted ground water extractions rates through 2005. The final report for the Focused Groundwater Flow and Transport Model was issued in May 2007 and a Revised Focused Feasibility Study for OU-1, prepared by HAFB, was also issued in May 2007.

A ROD selecting the remedy for OU1 was signed by the Air Force and EPA in 2007 with Commonwealth of Massachusetts concurrence.

The remedy for OU-1 selected by the ROD is basically the same as that selected by the IROD. This 2007 ROD sets forth the final remedy for OU-1 at the Hanscom Field/HAFB NPL Site as the continued operation of the existing dynamic groundwater remediation system, land use controls including institutional controls, and the monitoring of groundwater and surface water. This remedy is expected to remove/destroy the sources of groundwater contamination, effectively contain the migration of groundwater contaminants and is expected to reduce the overall extent of the groundwater plume via a reduction in contaminant mass. The following are the major components of the selected remedy:

  • Continuing to operate the existing dynamic groundwater remediation system (groundwater collection, treatment and recharge system; vacuum enhanced recovery (VER) system; molasses and/or permanganate injections).
  • Continuing to maintain and enforced Land Used Controls (LUCs), including Institutional Controls (ICs), to prevent exposure to hazardous substances above permissible levels.
  • Continuing an environmental sampling program (including groundwater and surface water) to monitor the performance of the groundwater remediation system and to monitor progress towards achievement of the RAOs.
  • Conducting Five-Year Reviews as long as any hazardous substances, pollutants or contaminants remain at the site above levels that allow for unrestricted exposure and unlimited use to assure that the cleanup remedy continues to protect human health and the environment.

The primary objectives of the remedial measures are to:
  • Prevent exposure (via ingestion, inhalation and/or dermal contact) to groundwater containing CoC concentrations that exceed federal drinking water standards (i.e., MCLs and non-zero MCLGs, state drinking water standards (i.e., MCLs), and state groundwater risk characterization standards (i.e., MCP Method 1 GW-1 standards);
  • Prevent further migration of dissolved-phase CoCs in groundwater;
  • Prevent discharge to surface-water bodies and wetlands of groundwater containing CoC concentrations that exceed federal drinking water standards, state drinking water standards, and state groundwater risk characterization standards; and
  • Within an acceptable time period (<30 - 50 years), return groundwaters to federal drinking water standards, state drinking water standards, and state groundwater risk characterization standards.

Secondary objectives are to ensue that excavation at the three source areas (IRP Sites 1, 2 and 3) is controlled to prevent exposure to any residual contamination in the subsurface soil and to prevent exposure to vapors that could accumulate in buildings affected by the contaminated groundwater plume.

As discussed earlier, the remedy for OU-1/IRP Sites 1, 2 and 3 was constructed/ implemented prior to the listing of Hanscom Field/HAFB on the NPL and appropriateness of the remedy was re-confirmed by the OU-1 IROD. The term “dynamic” is included to reflect the Remedial Process Optimization (RPO) of the system since it was placed in operation in April 1991. Over time, significant RPO changes have included vacuum enhanced recovery (VER), permanganate injection, and extending the network of interceptor, recovery and monitoring wells

Institutional controls, maintained and enforced by the Air Force, are intended to limit groundwater use to passive and/or active recreation use and to prevent drinking water use. Access controls are in place and inspections are conducted regularly. For further discussion see Section 6.0.

OU-2/IRP Site 4

In 1988, prior to NPL listing, the Air Force, with the Mass DEP as the lead regulatory agency, constructed an impervious cap on Site 4. The landfill was also bermed with drainage ditches to channel runoff from the capped area to the surrounding wetlands.

Following the listing of HAFB on the NPL, EPA requested CERCLA Human Health and Ecological Risk Assessments, to include Supplemental Sampling and Analysis, be completed for Site 4. These Assessments indicated no significant risk. EPA subsequently, determined that the Remedial Action completed in 1988 was acceptable as a final remedial action. No further action was recommended and no Remedial Investigation/Feasibility Study was performed.

There are no institutional controls for Site 4. For further discussion see Section 6.0.

OU-3/IRP Site 6

A ROD selecting the remedy for OU3/IRP Site 6 was signed by the Air Force and EPA on December 5, 2000 with Commonwealth of Massachusetts concurrence.

The selected remedy for OU-3/IRP Site 6 consists of:
  • Containment of three landfill areas,
  • Removal of contaminated sediments and landfill debris and placing of this material within the capped landfill area,
  • Long-term monitoring, and
  • Institutional controls.

In addition, the remedy includes establishment of a groundwater compliance boundary and a contingency groundwater remedy in the event monitoring results show that the remedy is not effective in maintaining groundwater quality outside the compliance boundary. The contingency groundwater remedy calls for extending the compliance boundary. EPA, consistent with Close Out Procedures for National Priorities List Sites, Section 3.5.4, does not believe that the contingency for OU-3/IRP Site 6, if deemed necessary, requires further construction, but rather, administratively extending the compliance boundary.

The major components of the RA scope of work included
  • Conducting a property line survey to verify the location of the Base property line to the north and east of the Former Filter Bed Area,
  • Excavation of the contaminated sediments from two wetland hotspot areas and the placement of this material under the Former Filter Bed Area cap,
  • Excavation of the debris extending off the Base property and the placement of this material under the Former Filter Bed Area cap,
  • Constructing a permeable cap at the Former Filter Bed Area, South Landfill, and West Landfill,
  • Restoring the wetlands in the wetland remediation areas,
  • Re-establishment of perimeter and security fencing with signs on each gate, and
  • As-built surveys and drawings.

Construction of the remedy was completed on September 17, 2001. The Remedial Action Report for Landfill Capping Project at Operable Unit 3-Site 6; prepared by IT Corporation, April 2002, describes the construction of the RA.

Institutional controls, maintained and enforced by the Air Force, are intended to limit groundwater use to passive and/or active recreation use and to prevent drinking water use. Access controls are in place and inspections are conducted regularly. For further discussion see Section 6.0.

OU-3/IRP Site 21

A ROD selecting the remedy for OU3/IRP Site 21 was signed by the Air Force and EPA on August 29, 2002 with Commonwealth of Massachusetts concurrence.

The principal components of the selected remedial action for cleaning up OU-3/IRP Site 21 include:
  • Three (3) interceptor trenches with passive recovery wells, one main trench covering LNAPL Pools A and B near northern boundary of the site and two smaller trenches at hotspot areas within LNAPL Pool C;
  • Network of active recovery wells in non-hotspot areas of LNAPL Pool C;
  • Enhancement of biodegradation of dissolved-phased contaminants (VOCs and fuel compounds) by ORC® application in all trenches;
  • Monitoring;
  • Land Use Controls/Institutional Controls; and
  • Groundwater Containment/Treatment and VER Contingencies.
  • Five-year Reviews

The major construction components of the RA for this Site were:
  • Removal of petroleum contaminated soils from various hotspot locations – a total of 2,763 tons of contaminated soil was sent transported of-site.
  • Construction of four trenches with passive recovery wells – one main trench covering LNAPL Pool A with three passive wells, one trench covering LNAPL Pool B with two passive wells, and two smaller trenches at hotspot areas within LNAPL Pool C, each with a passive well;
  • Application of ORC® in each trench to enhance the biodegradation of dissolved-phased contaminants (VOCs and fuel compounds) - a total of 1,170 pounds was applied during construction;
  • Installation of a network of ten active recovery wells in non-hotspot areas within LNAPL Pool C connected to a retrofitted LNAPL recovery and treatment system that had been used at the site for previous removal actions;
  • Installation of provisions to implement groundwater containment/treatment and/or enhanced vapor recovery contingencies in the future;
  • Surveying and as-built drawings;
  • A six-month start-up and prove-out period for the LNAPL/groundwater recovery and treatment system.

The design and construction of the selected Remedial Action for IRP Site 21 was completed in September 2003 and the LNAPL recovery/groundwater treatment system officially started on September 15, 2003. The Final Remedial Action Report for the Remedial Action at Operable Unit 3- Site 21, Hanscom AFB, MA; prepared by Shaw Environmental, Inc. and dated March 2004 describes the construction of the RA.

EPA, consistent with Close Out Procedures for National Priorities List Sites, Section 3.5.4, does not believe the contingency for OU-3/IRP Site 21 will be required.

Institutional controls, maintained and enforced by the Air Force, are intended to limit groundwater use to passive and/or active recreation use and to prevent drinking water use. Access controls are in place and inspections are conducted regularly. For further discussion see Section 6.0.

Current Site Status
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Decision documents to implement remedies have been finalized at all sites. Remedy implementation, operational maintenance, and monitoring continue. A Federal Facility Agreement (FFA) between EPA and the Air Force was signed on September 18, 2009.

Site Photos
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Links to Other Site Information
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Disclaimer Instructions about PDF

Newsletters & Press Releases:
Press Releases about this project  

Federal Register Notices:
Final NPL Listing  

Reports and Studies:
Five Year Review Report, September 15, 1997 (2396KB)  
Second Five Year Review Report, September 23, 2002 (332KB)  
Third Five Year Review Report, September 27, 2007 (34.32 MB)  
Fourth Five Year Review Report, September 26, 2012 (56.8 MB)  

Decision Documents:
View Records of Decision (RODS) on-line (EPA HQ)  
Record of Decision, Operable Unit 3/Installation Restoration Program Site 21, August 29, 2002  
Record of Decision, Operable Unit 1, September 28, 2007 (Opening File is 31.09 MB with Links to Two Additional Files)  
Institutional Controls at this Site  

Other Links:
NPL Site Narrative at Listing:  
Site Progress Profile  
Federal Facility Agreement Under CERCLA Section 120, Administrative Docket Number: CERC-02-2009-3FF, September 2, 2009 (5.75 MB)  

Site Repositories
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Hanscom AFB, Base Library, Bldg. 1530, Table of Contents only Hanscom AFB, Environmental Flight Office, Bldg. 1810, Documents


Contacts
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EPA Remedial Project Manager: Matthew Audet
Address: US Environmental Protection Agency
5 Post Office Square, Suite 100
Mail Code OSRR07-3
Boston, MA 02109 - 3912
Phone #: 617-918-1449
E-Mail Address: audet.matthew@epa.gov

EPA Community Involvement Coordinator: Pamela Harting-Barrat
Address: US Environmental Protection Agency
5 Post Office Square, Suite 100
Mail Code ORA20-1
Boston, MA 02109-3912
Phone #: 617-918-1318
E-Mail Address: harting-barrat.pamela@epa.gov

 


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