PUBLIC HEALTH ASSESSMENT
GEORGE AIR FORCE BASE
George Air Force Base (AFB) is located in Victorville, California, in the Mojave Desert approximately 90 miles northeast of Los Angeles. Established during World War II, George AFB was a major operations and training base for the Air Force until Congress scheduled it for closure in 1988. George AFB was decommissioned in 1992, and the Air Force is overseeing the closure of the facility. Redevelopment of land and facilities at George AFB is directed by the Victor Valley Economic Development Authority. Land reuse plans at George AFB include an airport, a federal prison, and industrial and commercial uses.
Areas of concern at George AFB are divided into three operable units (OUs):
- OU 1: Trichlorethylene (TCE) plume beneath the Northeast Disposal Area. Groundwater
in the northeast portion of the base and adjacent off-site land is contaminated with volatile
organic compounds, primarily TCE. A groundwater extraction and treatment system,
designed to prevent migration of the contaminant plume towards the Mojave River, was
completed in 1997. The treatment system is projected to run for 30 years to reduce
groundwater contamination below federal drinking water standards.
OU 1 also includes two other sites: SD-25, an industrial/storm drain, and WP-26, the former sewage treatment plant percolation ponds. Contaminated sediments and piping were removed from the storm drain at SD-25. Investigations have determined that no further action is required at these sites.
- OU 2: Jet fuel releases. OU 2 consists of the facility's liquid fuel distribution system. A variety of leaks in this system resulted in an estimated of perhaps as much as a 750,000 to 800,000-gallon plume of jet propellant #4 (JP-4) encompassing an area of over 31 acres, as well as a dissolved-phase plume of benzene, toluene, ethylbenzene, and xylenes extending over an area of 121 acres. Because the OU 2 plume is almost completely covered by asphalt, and studies conducted thus far have not demonstrated significant migration of the plume, George AFB, state and federal regulators continue to evaluate the feasibility of natural attenuation as a possible cleanup strategy. Accordingly, additional monitoring wells will be installed to further characterize and monitor this plume.
- OU 3: Landfills and other disposal sites. This OU consists of the remaining Installation Restoration Program sites, including old landfills, other dump and burial sites, munitions sites, fire training areas, and spill areas. In February 1997, George AFB completed a remedial investigation/feasibility study for OU 3. A record of decision for clean up of the OU 3 sites is now under review.
The Agency for Toxic Substances and Disease Registry (ATSDR) conducted site visits to George AFB in 1991 and 1997 and examined the facility for potential exposure pathways. ATSDR identified three pathways where people may be exposed to site-related contaminants: 1) exposure to contaminated groundwater, 2) exposure to contaminated soil, and 3) exposure to radiological contamination. ATSDR also identified the following community concerns: 1) base reuse, 2) groundwater and drinking water quality, and 3) radiological contamination. The evaluation of these exposure pathways and community concerns is the focus of this Public Health Assessment.
On-site and off-site groundwater do not represent a past, present, or future public health hazard. On-site groundwater has never been used as a source for drinking water at George AFB and no supply wells are expected to be installed there in the foreseeable future. Groundwater contamination from the OU 1 plume has migrated off site towards the Mojave River, which is a major source of drinking water for downstream communities, but has not affected any municipal or private drinking water wells. Two supply wells in the path of the plume, at the Victor Valley Wastewater Reclamation Authority, have never been used to supply drinking water. The pump-and-treat system installed by George AFB for OU 1 is expected to prevent contaminants from migrating to the Mojave River and regular groundwater sampling will continue to monitor the movement of the plume over time. Federal regulators are monitoring the effectiveness of this pump-and-treat system and, as a result, George AFB is collecting additional data and taking other measures to optimize the effectiveness of this clean-up measure.
Soil at George AFB does not represent an apparent past public health hazard and does not represent a present or future public health hazard. Soil contamination has been detected above ATSDR health-based comparison values in very few areas of George AFB. Access to most areas of contamination is limited and the contaminant levels detected would not pose a health hazard to either children or adults from short-term exposure. Due to the low levels of contamination, exposure to contaminated soil through future industrial reuse of the base is not expected to pose a public health hazard to adults working at the base.
Radiological contamination does not represent an apparent past public health hazard and does
not represent a present or future public health hazard. A small amount of radioactive material
was discovered and removed from a portion of the Southeast Disposal Area (SEDA). Radiation
surveys and exploratory soil excavation indicate that this area and the two munitions storage areas
were not used for disposal of significant quantities of radioactive waste. Although people using
the SEDA for recreation in the past may have been exposed to small amounts of low-level
radioactive material, such exposures would have been infrequent and of short duration and would
not be expected to pose a health hazard. The SEDA has recently been fenced and its landfill cover
has been rehabilitated. The George AFB property located south of Air Base Road, which includes
the SEDA, has been transferred to the Federal Bureau of Prisons and will be the site of a prison
that is currently under construction; the SEDA will remain fenced and will be within the fenceline of the prison.
George Air Force Base (George AFB) is a decommissioned military installation located in the High Desert region of San Bernardino County, California, in the Mojave Desert. This 5,347-acre facility is approximately 90 miles northeast of Los Angeles. The area immediately surrounding the base is the Victor Valley portion of the Upper Mojave River Basin (see Figure 1). Cities nearest to the base are Adelanto, directly west of the base, and Victorville, directly southeast of the base. Other communities in the Victor Valley include Apple Valley, Hesperia, Oro Grande, and Silver Lakes.
The base lies within a wedge-shaped area of the Mojave Desert, which is flanked by the Sierra Nevada Mountains to the northwest, the Radman and Cady Mountains to the northeast, the San Bernardino Mountains to the southeast, and the San Gabriel Mountains to the southwest (shown in Figure 1). The local region is comprised primarily of alluvial deposits from the surrounding mountains and recent deposits from the Mojave River (Montgomery Watson, 1997a). The facility grounds are quite flat except at the eastern edge where the surface elevation drops approximately 200 feet down to the Mojave River, which flows past the base in a northwesterly direction. The Victor Valley Wastewater Reclamation Authority (VVWRA) treatment plant is located approximately one-half mile north of the base.
George AFB, originally called the Victorville Army Airfield, was constructed between 1941 and 1943 as a flight training school. After World War II, the base was placed on standby status and used for surplus aircraft storage. The base was reopened in 1950 under the command of the newly created U.S. Air Force and renamed George Air Force Base. Flight training remained the primary mission of this base throughout its history and a number of bomber, glider, single engine, twin engine, and jet fighter aircrafts were flown there. George AFB was a major training facility for the Air Force's F-4 Phantom and was the home of the 35th Tactical Fighter Wing (U.S. Air Force, 1997c).
In 1988, George AFB was scheduled in the first round of base closures passed by Congress under the Base Realignment and Closure program. The base was officially decommissioned in December 1992. In 1993, President Clinton announced a "Five Part Plan" to speed economic recovery in communities where military bases were to be closed. One part of this plan called for improving public participation in the base's environmental cleanup program. George AFB was among a number of installations where environmental cleanup was placed on a "fast track" so that base property could be quickly transferred to the community for reuse (U.S. Air Force, 1997c).
In the course of it primary mission of pilot training, George AFB performed numerous support activities, such as aircraft and vehicle maintenance and fire fighting training, that required the use and disposal of hazardous materials. Hazardous materials used at the base included fuels, solvents, paints and thinner, acids, and alkalis. The disposal of these materials caused contamination of soil and groundwater in some areas of the base. In addition, used aircraft parts and other refuse were buried at various sites on the base (U.S. Air Force, 1997c).
The Air Force began its environmental program--called the Installation Restoration Program (IRP)--at George AFB in 1980. A preliminary assessment (PA), involving document review, personnel interviews, and a site visit, identified a total of 67 potential hazardous waste sites at the base. These sites were attributed to aircraft and vehicle maintenance, past waste handling practices, fire fighting training, and other typical base activities. The Air Force followed the PA with a site investigation to identify areas of contamination. When trichloroethylene (TCE), a common industrial solvent, was discovered in groundwater, George AFB was placed on the U.S. Environmental Protection Agency's (EPA's) National Priority List (NPL) as a federal Superfund site (U.S. Air Force 1997c). The 67 potential sites identified in the PA were all considered part of the George AFB NPL site, although subsequent investigations determined that no further cleanup actions were needed at many of the sites (U.S. Air Force, 1997b).
Additional Installation Restoration Program (IRP) sites have been identified since the PA, bringing the total to 68 sites (Site FT-19 is divided into three parts), which are listed in Table 1. These IRP sites were divided into three operable units (OUs) based on geographical location and the types of waste present (OUs are shown in Figure 2):
- OU 1: TCE plume beneath the Northeast Disposal Area (NEDA). Groundwater in the
northeast portion of the base and adjacent off-site land (called the NEDA) is contaminated
with volatile organic compounds (VOCs), primarily TCE. Contaminated groundwater has
migrated off site to the northeast, reaching as far as the VVWRA treatment plant
(Montgomery Watson, 1997a). A groundwater extraction and treatment system (called a
pump-and-treat system) was completed in 1997. The system discharges treated
groundwater to newly constructed percolation ponds. This treatment system was designed
to prevent migration of the plume towards the Mojave River and is projected to run for 30
years to reduce groundwater contamination to below federal drinking water standards
(Montgomery Watson, 1994).
OU 1 also includes two other sites: SD-25, an industrial/storm drain, and WP-26, the former sewage treatment plant percolation ponds. Investigations have determined that no remedial action is required at these sites (James Montgomery 1992). (Table 1 summarizes the OU 1 IRP sites.)
- OU 2: Jet fuel releases. OU 2 consists of the base's liquid fuel distribution system (including five above-ground storage tanks, six 50,000-gallon underground storage tanks, 30,000 feet of piping, five 5,000 gallon overflow tanks, and seven concrete fuel transfer pits). A variety of leaks in this system resulted in an estimated 750,000 to 800,000-gallon plume of jet propellant #4 (JP-4) encompassing an area of over 31 acres, as well as a dissolved-phase plume of benzene, toluene, ethylbenzene, and xylenes (BTEX) extending over an area of 121 acres (IT, 1996; U.S. Air Force, 1997b). Because the OU 2 plume is almost completely covered by asphalt and studies have shown that little or no migration of the plume is expected over time, George AFB and state and federal regulators are evaluating natural attenuation as a possible cleanup strategy (IT, 1996; U.S. Air Force, 1997b). In the meantime, George AFB operates six permanent extraction units, three mobile extraction units, and two bioventing systems to remove free product from wells within this plume. (Table 1 summarizes the OU 2 IRP sites.)
- OU 3: Landfill and other disposal sites. This OU consists of the remaining 62 IRP sites including old landfills, other dump and burial sites, munitions sites, and fire training areas. In February 1997, a remedial investigation/feasibility study was completed for OU 3. (Table 1 summarizes the OU 3 IRP sites.)
The Agency for Toxic Substances and Disease Registry (ATSDR) performed an initial site scoping visit on February 14 and 15, 1991, to meet with base environmental personnel, regulators, and community members and to identify completed and potential pathways for human exposure to contamination. At that time, community concerns focused on base reuse after closure. ATSDR again visited George AFB on August 18 and 19, 1997, to meet with base environmental personnel and state public health officials and to gather information pertinent to the preparation of a public health assessment (PHA) for George AFB.
George Air Force Base
Population data, housing data, and a census tract map of the George AFB area are presented in Appendix B. The combined military and civilian work force at George AFB in 1992 was 3,725, although peak employment at the facility was approximately 5,500. Approximately 9,000 people (base personnel and their families) lived in residential units at the base during the peak of base operations (U.S. Air Force, 1998c). Since the base closed in 1992 there have been no permanent on-site residents.
Of the four regions of San Bernardino County, the High Desert region that includes George AFB is expected to see the greatest population growth in the future, with an annual growth rate of 5% until 2010. This is attributed to an influx of people looking to escape the traffic, high cost of living, and air pollution of Los Angeles. The area is also experiencing growth from development of vacation homes and retirement communities (U.S. Air Force, 1991).
Before closure, George AFB was the largest employer in the area and provided an important economic base for the surrounding communities. As of November 1997, approximately 440 new jobs had been created through base reuse (discussed in "Land Use and Natural Resources" below) (U.S. Air Force, 1997c; CEDAR, 1997). Despite the closure of George AFB, the military remains the largest employer in the High Desert region, with nearby installations including the Fort Irwin Training Center and the Marine Corps Logistics Base. The top non-military employers in the High Desert region are the Hesperia and Victorville school districts and the Desert Valley Medical Group and Hospital (U.S. Air Force, 1997c).
Major land use in the Victor Valley involves residential development, government and commercial services, cement manufacturing, railroad and highway transportation, and limited agriculture and industrial mining. Although George AFB is located in a remote area, a residential area of Adelanto is located within 1 mile west of the base and includes two schools and parks located west of the base. A residential area of Victorville is also situated near the southeast border of the base. Land uses in the vicinity of George AFB are shown in Figure 3. The airport area (landing field and taxiways) is fenced off and patrolled regularly. Access to all other base property located north of Air Base Road is through one road and is monitored by a security guard; a second access road will be opened in the future. Base property located south of Air Base Road is not fenced or monitored, although the Southeast Disposal Area (SEDA) located on this property is fenced in. The base property south of Air Base Road has been transferred to the Federal Bureau of Prisons and will be the site of a prison that is currently under construction.
When active, George AFB was a military installation and residential community where light industrial activities were performed. The base includes two runways, 6.3 million square feet of aircraft ramp space and associated facilities, 1,651 units of housing (vacant), 14 dormitory buildings, a hospital, and numerous office and industrial buildings. The city of Adelanto operates two schools on George AFB property (see Figure 3).
The Air Force is overseeing closure of the base. Redevelopment of land and facilities at George AFB is directed by the Victor Valley Economic Development Authority (VVEDA), a joint powers authority comprised of the county of San Bernardino, the cities of Victorville and Hesperia, and the town of Apple Valley. (The city of Adelanto declined to participate in the VVEDA [CEDAR, 1997].)
The city of Victorville oversees the development of an airport, Southern California International Airport (SCIA), that uses George AFB's flight line and related facilities. SCIA is now open to commercial traffic and Victorville is currently attempting to attract major air cargo carriers to the airport. Although passenger service is not expected in the near future, SCIA does receive approximately 110,000 U.S. Army troops en route to Fort Irwin, California (U.S. Air Force, 1997b). The airport also leases space to approximately 35 military, commercial, industrial, and service entities.
The VVEDA is responsible for the redevelopment of the remaining properties outside of the airport, including housing units, office buildings, warehouses, a golf course, and the sewer and water distribution systems. VVEDA has no plans to reuse base housing units, although temporary dormitories may be used occasionally for military personnel (U.S. Air Force, 1997a; Earthtech, 1993; Montgomery Watson, 1997c). Earlier plans to allocate a portion of base housing to homeless providers have been canceled in favor of off-base locations.
The Federal Bureau of Prisons has acquired 940 acres in the southern portion of George AFB (south of Air Base Road) and is constructing a 1,152-bed medium-security men's prison and a 768-bed minimum-security women's prison. Occupancy is expected to begin in late 1999.
Groundwater at George AFB has never been used as a source for drinking water (U.S. Air Force, 1997a). Drinking water wells were installed at the base in the 1980s but were never used. These wells are currently capped (U.S. Air Force, 1997b). Since 1942, George AFB drinking water has been supplied by a number of production wells--built by the Air Force on land leased from the city of Adelanto--located beyond the eastern boundary of the base, next to the Mojave River. These wells are not located in or near areas of contaminated groundwater. Locations of all known drinking water wells near George AFB are shown in Figure 4. Although the land where the wells are located will revert back to Adelanto after base closure, the Air Force contends that water rights from this property should remain with the Air Force and should be transferred along with the base for redevelopment (CEDAR, 1997). Adelanto has sued the Air Force over these water rights and has constructed an additional municipal well next to the Air Force wells. The VVEDA is connecting the base to Victorville public water to supply the base with additional capacity if needed. A number of small capacity domestic and irrigation wells are believed to exist in the vicinity, although none are believed to be located in areas of contaminated groundwater.
In preparing this PHA, ATSDR relied on the information provided in the referenced documents
and from the referenced contacts. ATSDR assumes that adequate quality assurance and control
measures were followed with chain-of-custody, laboratory procedures, and data reporting. The
validity of the analyses and conclusions drawn in this document are dependent upon the
availability and reliability of the referenced information.
George AFB prepared community relations plans 1991 and 1996, which presented the results of interviews with members of local environmental and community groups, representatives from chambers of commerce, and officials from city and county organizations (e.g., VVEDA, the regional water quality control board, and city and town councils) (U.S. Air Force, 1991, 1997c). Through these interviews, George AFB learned that the predominant community concerns regarding the base were not about environmental contamination, but rather centered on base closure and reuse plans. Community members did, however, express concerns about water supply and quality, endangered species in the area, and noise pollution.
Some community members also were concerned about continuity in communication and environmental plan implementation once the base is closed; specifically, they wondered if the Air Force would take responsibility for contamination that might be discovered after base closure. More recently, some community members have also expressed concerns regarding the possibility that radioactive waste was stored at the base (U.S. Air Force, 1997a, 1997b).
Since these interviews, the Air Force has conducted extensive investigations and cleanup activities that address the potential health and environmental concerns related to the base. As these various activities have been completed, George AFB has made the relevant reports available to the public. ATSDR has thoroughly reviewed all available investigation, remedial, and other relevant documents to assess the public health concerns associated with George AFB. ATSDR's public health evaluations of the IRP sites are summarized in Table 1.