PUBLIC HEALTH ASSESSMENT
F.E. WARREN AIR FORCE BASE
CHEYENNE, LARAMIE COUNTY, WYOMING
The Agency for Toxic Substances and Disease Registry (ATSDR) prepared this public health assessment (PHA) to evaluate exposure pathways and to respond to community concerns about past, current, and potential future exposures to contaminants originating at the F.E. Warren Air Force Base (F.E. Warren). ATSDR reviewed available data and exposure information and determined that this site poses no apparent public health hazard.
F.E. Warren is an active military facility located in Laramie County, west of the city of Cheyenne, in southeastern Wyoming. The base encompasses approximately 5,900 acres. The majority of base facilities and housing, including an 11-acre airfield, are located in the southern portion of the base. The northern portion of the base is characterized by open prairie formerly used as firing ranges to test artillery. F.E. Warren serves as an U.S. Air Force (USAF) Space Command base. The majority of contamination identified at F.E. Warren resulted from past waste and resource management. In February 1990, the U. S. Environmental Protection Agency (EPA) placed F.E. Warren on the National Priority List because of groundwater contamination.
In preparing this PHA, ATSDR reviewed available data from F.E. Warren, EPA, the state of Wyoming, and the city of Cheyenne. ATSDR also spoke with community members about their health concerns. From a review of available data and discussions with community members about their health concerns, ATSDR identified dust blowing from the active borrow area (a current community concern), contamination of private wells by volatile organic compounds and metals, and recreational use of Landfills 2 and 3 as the principal possible exposure pathways of concern.
Residents in the Western Hills neighborhood, which abuts the northeastern base boundary, have expressed concern about exposure to windblown dust from an area of active excavation. The USAF began excavating soil at the active borrow area in April 1997 for use as landfill capping material. Excavation is scheduled to be complete on or before August 1999. After a detailed review of soil data collected before and during excavation, ATSDR concluded that contaminants are not present in soil at levels that are likely to pose a public health hazard. In addition, the USAF has implemented a dust control program to limit dust generation during excavation. This program includes wetting the soil, applying a tackifier (a sticky, sugar substance that creates a coating on the soil surface), and ceasing activities in high winds.
Residents in two neighborhoods located along the southern base boundary, Nob Hill and Fair Acres, have used or continue to use groundwater pumped from private wells as their primary drinking water supply. After detailed review of data from private wells in these two neighborhoods, ATSDR concluded that contaminants present in drinking water do not pose a health hazard to residents from past exposure based on conservative estimates of how often and how long residents may have been exposed. However, private wells within Nob Hill were only sampled once in 1994. Additional sampling may further support this conclusion. To prevent current and potential future exposures, the USAF connected homes in the Nob Hill neighborhood to the Cheyenne municipal water supply. Residents in the Fair Acres neighborhood continue to use their private wells. Some residents, however, purchase bottled water for their drinking water. In addition, wells were resampled in 1997 and contaminant concentrations were found to be decreasing. The Wyoming Department of Environmental Quality and local health officials continue to work with Fair Acres residents to identify potential contaminant sources and prevent harmful exposures.
An on-base family housing area is located proximate to Landfills 2 and 3 in the southern portion
of F.E. Warren. Access to these landfills is unrestricted and children have been observed biking
and playing in these areas. Therefore, ATSDR also evaluated surface-soil data from Landfills 2
and 3 and surface water and sediment data from an unnamed stream that passes through Landfill
2. After detailed review of the data, ATSDR concluded that contaminants present in these media
do not pose a health hazard to past, current, or potential future recreational users from the nearby
housing area. The USAF has completed or is conducting remedial actions at Landfills 2 and 3,
based on 1995 site investigations, to prevent current and future exposures. Landfill 2 is
composed of three subunits: Landfill 2a, 2b, and 2c. Removal actions, which include partial or
total excavation of waste, were completed at Landfill 2c and are scheduled to begin at Landfills
2a and 2b in April 2000. At Landfill 3, the USAF is scheduled to conduct additional investigations in 1999 and begin construction of a landfill cap in April 2001.
F.E. Warren Air Force Base (F.E. Warren) is an active military facility located in Laramie County, west of the city of Cheyenne, in southeastern Wyoming. The base encompasses approximately 5,900 acres. The majority of base facilities and housing, including an 11-acre airfield, are located in the southern portion of the base. The northern portion of the base is characterized by open prairie formerly used as firing ranges to test artillery. Residential development, including the Western Hills neighborhood, and commercial development associated with Cheyenne are located east of F.E. Warren. Open land and the Nob Hill and Fair Acres neighborhoods are to the south. Open land is present to the west and north of the site (see Figure 1) (USGS, 1991a; F.E. Warren, 1998b and 1998d).
Military functions began at the site of F.E. Warren in 1867 when a U. S. Army outpost, named Fort D.A. Russell, was established. The name was changed to Fort F.E. Warren in 1930, and the facility served as an U. S. Army training facility during and after World War II. In 1947, Fort F.E. Warren was transferred to the U. S. Air Force (USAF). Beginning in 1958, F.E. Warren became a Strategic Air Command Base, serving as an operations center first for the Atlas intercontinental ballistic missile, followed by the Minuteman I and III, and finally the Peacekeeper Missile. F.E. Warren is currently a USAF Space Command base and part of the U.S. Strategic Command (F.E. Warren, 1998a). The majority of contamination identified at F.E. Warren resulted from past waste and resource management (F.E. Warren, 1998d).
Remedial and Regulatory History
The Installation Restoration Program (IRP) commenced at F.E. Warren in 1981 with a records search to identify past waste management practices. In addition to reviewing written documentation, the search included contacting community members and past base employees. As a result of this search, 25 areas of concern were identified at F.E. Warren where hazardous materials might have been used, stored, treated, or disposed. The records search identified potential groundwater contamination as a major concern based on reported releases rather than actual sampling data (F.E. Warren, 1998c).
In February 1990, the U. S. Environmental Protection Agency (EPA) placed F.E. Warren on the National Priority List because of groundwater contamination. A Federal Facilities Agreement (FFA) was signed between the USAF, EPA, and the Wyoming Department of Environmental Quality (WDEQ) in 1991. The FFA provides the framework for EPA and WDEQ oversight of ongoing investigations and remediation at F.E. Warren (F.E. Warren, 1998c).
A base-wide remedial investigation (RI) was completed by the United States Geological Survey in 1991. The RI summarized investigations completed under the second phase of the IRP, which commenced in 1987. A total of 23 areas of concern and base-wide surface water quality were evaluated under the RI. Investigations included an initial assessment of contamination and a more comprehensive assessment designed to quantify the extent, direction, and rate of contaminant migration. The RI concluded that trichloroethylene (TCE) in groundwater was the greatest concern at F.E. Warren and recommended groundwater monitoring (USGS, 1991a; F.E. Warren, 1998a).
After the completion of the base-wide RI, potential contamination sites were divided into ten Operable Units (OUs) and more detailed investigations were conducted. F.E. Warren established OUs based on site type, location, and response actions. In summer 1998, F.E. Warren redistributed sites from the established OUs into new zone designations A through E. The zone designations were based on site type, location, and affected media. Ongoing investigations will be conducted by zone versus OU. The zone, OU, and site names are provided in Table 1 and are shown in Figure 2. Investigations are either ongoing or completed at the various sites and zones (F.E. Warren, 1998d). A summary of the sites and associated investigations and remedial actions are provided in Table 2.
Table 1: Zone, OU, and Site Designations
| Zone | OU | Site Name |
| A | 3 | Landfill 6 |
| B | 8 | Landfill 5 |
| C | 3 | Landfill 3 |
| D1 | 1 1 2 |
Spill Site 4 Spill Site 7 Groundwater TCE Plume A |
| D2 | 5 and 10 5 10 4 2 |
Fire Protection Training Area 1 Fire Protection Training Area 2 Landfill 7 Acid Dry Wells Groundwater TCE Plumes B and C |
| D3 | 1 9 2 |
Spill Site 2 Landfill 2 Groundwater TCE Plumes D and E |
| E | 1 1 1 1 9 7 6 |
Spill Site 1 Spill Site 3 Spill Site 5 Spill Site 6 Landfill 4 Firing Ranges Open Burn/Open Detonation Area |
In December 1998, the Agency for Toxic Substances and Disease Registry (ATSDR) conducted a site visit at F.E. Warren. ATSDR met with representatives of the USAF and reviewed existing information. The intent of this visit was to gain an understanding of site conditions and remedial actions and to identify potential community concerns.
ATSDR held public availability meetings in communities surrounding F.E. Warren during January 1999. Public availability meetings provide a forum for community members to discuss their concerns about site contamination issues. ATSDR used information gathered at these meetings to complete the public health assessment (PHA).
F.E. Warren and Cheyenne are located in Laramie County in southeastern Wyoming. The Cheyenne population is approximately 50,000 and the county population is approximately 68,700. The Cheyenne and county populations are reportedly increasing slowly. The military employs approximately 8.6 percent of the Laramie County population. Cheyenne, residential neighborhoods, and commercial businesses are located east of F.E. Warren. Open land, agriculture, and low-density residential neighborhoods are located along the remaining base boundaries (F.E. Warren, 1998c and 1998d).
In 1997, F.E. Warren supported an on-base population of approximately 3,400 residents, a decline from the nearly 3,800 residents in on-base housing in the early 1990s. On-base housing occupies approximately 280 acres of the base in the southern and central portions of F.E. Warren. Landfills 2 and 3 are located proximate to the southern housing area. The Firing Range is to the north and several of the spill sites are to the south of the central housing area. Military personnel, including their families and children, may live in the southern or central housing area. Access to the landfills and spill sites from the housing areas is not restricted. Access to the firing range is restricted (F.E. Warren, 1998c, 1998d, and 1998e).
Access to F.E. Warren is restricted to military personnel, on-base residents, and civilian employees. Members of the general public and contractors, however, may enter the base after registering their vehicles and obtaining passes. The base is surrounded by a perimeter fence that is regularly patrolled. People entering the base must pass through a gate with a security guard. Once within F.E. Warren boundaries, however, access to areas found containing contamination is generally not limited (F.E. Warren, 1998d and 1998e).
There are no on-base schools. One day care center is located at the western end of Randall Avenue. This center provides care for pre-school children for both military personnel and civilians in Laramie County. A Head Start program is located along Randall Avenue across from the parade grounds. The Head Start program serves families within Laramie County and operates morning and afternoon classes for pre-school children (Urban, 1999). Neither the day care center nor Head Start program is located in an area of contamination. Open space and recreational areas, including a family camping area along Crow Creek, are located throughout F.E. Warren. No contamination sites are located in areas designated for recreation (F.E. Warren, 1998f).
Several surface water bodies are located within the base and may be used for recreation. Crow Creek flows through the southern portion of F.E. Warren and is the major perennial stream that drains the base. Crow Creek gains flow from groundwater discharge and two tributaries: Diamond Creek and an unnamed stream. Diamond Creek is the second largest stream at F.E. Warren and is also perennial along most its length. The unnamed stream is an interrupted stream, with alternating reaches that are perennial, intermittent, or ephemeral. Both Diamond Creek and the unnamed stream also gain flow through seeps and groundwater discharge. Dry Creek and several other unnamed streams are located in the northern portion of the base. These streams are intermittent and not likely frequented by base employees or residents. Three lakes, North Pearson, South Pearson, and Centennial Lakes, are located at F.E. Warren. Each of these lakes is used for recreation, including fishing. The USAF stocks North and South Pearson Lakes with fish from the U. S. Fish and Wildlife Service. Full size fish are stocked two or three times a year. Recreational users may use these fish for human consumption. At Centennial Lake, only catch and release fishing is permitted. No areas of contamination were identified in recreational areas (F.E. Warren, 1998d, 1998e, and 1998f).
Quality Assurance and Quality Control
In preparing this public health assessment (PHA), ATSDR relied on information provided in the referenced documents. 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 on the availability and reliability of the referenced information.
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