Tucson International Airport Area

Tucson International Airport

Superfund Site | U.S. Air Force Plant 44

EPA #: AZD980737530

Superfund National Priority List (NPL) Status: The EPA listed this site on Sept. 9, 1983

Location

The U.S. Air Force Plant 44 (AFP-44) is located about eight miles south of downtown Tucson, Arizona and is bounded to the north and east by the Tucson International Airport (TIA), to the south by Hughes Access Road and to the west by the Nogales Highway (Route 89).

Contaminants of Concern

The current contaminants of concern in soil and groundwater include metals and volatile organic compounds (VOCs). The principal contaminants of concern are trichloroethene (TCE), 1,1-dichloroethene (1,1-DCE), 1,4-dioxane and chromium. The concentration of TCE in groundwater at the site currently ranges from less than 0.5 parts per billion (ppb) to 1,520 ppb.  The federal drinking water standard for TCE is 5.0 ppb.  Contaminants of concern at the site may change as new data become available.

Health Concerns

The City of Tucson is the main municipal water provider at this site. All municipal wells in the area that were contaminated with VOCs have been shut down. The municipal water supply in the area now comes from wells outside the site. Some privately owned domestic use wells in the area have been impacted, but these wells have either been shut down or converted to irrigation wells. If you are drinking water from a private well within the boundaries of the TIAA site, please contact the ADEQ Project Manager. Areas with soil contamination at or very close to the surface have been excavated so that there are no known public health impacts from contaminated soils.

Environmental Considerations

The regional aquifer beneath most of AFP-44 is divided into three main hydrogeologic units including the upper zone, a middle aquitard, and the lower zone. The middle aquitard pinches out several miles north of the site, and the upper and lower zones merge into one regional undivided aquifer. The upper zone (where nearly all of the groundwater contamination is present) is composed of layers of gravelly sand interbedded with clayey sand and sandy clay. A low permeability layer of clay and silt occurs near the potentiometric surface within the upper zone which, due to its hydraulic properties, retains high concentrations of VOCs.