Record of Decision System (RODS)
ELLSWORTH AIR FORCE BASE
|Site Name:||ELLSWORTH AIR FORCE BASE|
|City & State:||ELLSWORTH AFB SD 57706|
|NPL Status:||Currently on the Final NPL|
|ROD Type:||Record of Decision|
|Contaminant:||JP-4 jet fuel, benzene, toluene, ethylbenzene, xylene, chlorinated VOCs, trichloroethane, perchloroethylene, 1,1-dichloroethylene, 1,2-dichloroethane|
Please note that the text in this document summarizes the Record of Decision for the purposes of facilitating searching and retrieving key text on the ROD. It is not the officially approved abstract drafted by the EPA Regional offices. Once EPA Headquarters receives the official abstract, this text will be replaced.
Ellsworth Air Force Base (EAFB) is a U.S. Air Force Air Combat Command (ACC) installation located twelve miles east of Rapid City, South Dakota, and adjacent to the small community of Box Elder. EAFB covers approximately 4,858 acres within Meade and Pennington counties and includes runways and airfield operations, industrial areas, and housing and recreational facilities. Open land, containing a few private residences, lies adjacent to EAFB on the north, south, and west. Ranches lie to the north and west of the base and residential and commercial areas lie to the east of the base. Residences and ranches lie south of EAFB.
This operable unit contains the former Fire Protection Training Area (FPTA) and is located in the southwestern segment of EAFB, northwest of the alert apron and east of Kenney (formerly Bismarck) Road. Operable Unit 1 covers approximately ten acres and consists of a centrally located bermed burn pit, a steel aircraft mock-up, and surrounding land. No containment liner was installed under the former FPTA. The burn-pit area of the FPTA is the source area of contamination.
Both humans and livestock have used shallow groundwater in the areas south and west of OU1. Deeper aquifers also exist and have been used in the past for its water supply. Presently, EAFB obtains its potable water from the Rapid City Municipal Distribution System.
The Rapid City Municipal Distribution System obtains its water from two deep, high capacity wells and four surface water intakes along Rapid Creek.
EAFB was officially activated in July 1942 as the Rapid City Army Air Base, a training facility for the B-17 bomber crews. It became a permanent facility in 1948 with the 28th Strategic Reconnaissance Wing as its host unit. Historically, EAFB has been the headquarters of operations for a variety of aircraft, as well as the Titan I Intercontinental Ballistic Missile, and the Minuteman I and Minuteman II missile systems. The base has provided support, training, maintenance, and/or testing facilities.
The various training activities conducted at EAFB have included fire-protection training for base firefighting personnel for preparedness in the event of fires associated with fueling spills or aircraft accidents. These training exercises took place at the former FPTA from 1942 to 1990. A steel aircraft mock-up located in the burn pit of the former FPTA was set on fire and extinguished for training exercises. The location of the burn area within the former FPTA has changed several times over the years. The training exercises conducted at the FPTA involved simulation of aircraft fires and spills and consisted of dispersing various fuels, oils, and solvents within the burn-pit area and subsequently igniting and extinguishing the fire. Extinguishing chemicals used during the fire-training exercises have included aqueous film-forming foam, halon, protein foams, carbon dioxide, dry chemicals, and chlorobromomethane. The former FPTA at OU1 is no longer in use and all training activity now takes place at the new FPTA.
Soils at OU1 contain JP-4 (jet fuel), benzene, toluene, ethylbenzene and xylene (BETX), and chlorinated volatile organic compounds (VOCs). JP-4 concentrations are much higher than other compounds. The areal distribution of JP-4 contamination generally reflects the extent of all the contaminants in the soil. The highest concentrations of soil contamination exist in the burn-pit area, which is the source area of contamination.
The past practices at the FPTA have resulted in the contamination of the shallow aquifer. VOCs such as trichloroethane (TCE), benzene, perchloroethylene (PCE), 1,1-dichloroethylene (1,1-DCE) and 1,2-dichloroethane (1,2-DCA) exist in the shallow groundwater at or above established Safe Drinking Water Act Maximum Contaminant Levels (MCLs). The groundwater contamination does not extend beyond the base boundary.
|Remedy:||The selected interim remedial action for soil and groundwater contamination cleanup consists of: soil vapor extraction (SVE); groundwater removal by wells and an existing interceptor trench; treatment of soil gas condensate, and groundwater; and surface discharge of treatment effluent.|
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