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NPL Site Narrative for Tooele Army Depot (North Area)
TOOELE ARMY DEPOT (NORTH AREA)
Tooele, Utah
Federal Register Notice: August 30, 1990Conditions at proposal (October 15, 1984): The Tooele Army Depot (TEAD) is in Tooele, Tooele County, Utah, 35 miles southwest of Salt Lake City. It consists of two separate areas, the North Area and the South Area. The North Area covers about 25,000 acres in Tooele Valley south and west of Tooele.
Since 1943, TEAD has had a fourfold mission: store ammunition, demilitarize ammunition, rebuild military equipment, and store military equipment. In fulfilling its mission, TEAD decommissions munitions by cutting the casings and removing and recycling the explosive material. The casings are then rinsed with water to remove residual explosives. Between 1948 and 1965, rinse waters were discharged into the "TNT Washout Area," which covers less than 1 acre in the North Area. The Army has detected trinitrotoluene (TNT) and cyclomethylenetriamine (RDX), an experimental explosive, in soil near the TNT Washout Area, threatening ground water. About 2,500 people depend on wells within 3 miles of the site as a source of drinking water.
TEAD is participating in the Installation Restoration Program, established in 1978. Under this program, the Department of Defense seeks to identify, investigate, and clean up contamination from hazardous materials. The Army has completed Phase I (records search).
Status (August 30, 1990): Activities at Tooele are divided into two "discrete field activities or operable units" (OUs). OU#1 involves ground water contaminated with organic solvents and metals resulting from an unlined industrial waste lagoon. The Army has closed the lagoon; the Utah Department of Health approved the closure on November 1, 1989, the deadline set in a Consent Decree entered into earlier by the Army, Utah, and the U.S. Department of Justice. A ground water assessment required by the decree shows that a plume of ground water contaminated with trichloroethylene (TCE) and trichloroethane (TCA) has migrated downgradient approximately 2 miles. The leading edge of the plume lies several hundred yards beyond the TEAD boundary and may be migrating several hundred feet per year. TCE concentrations vary from approximately 250 parts per billion (ppb) beneath the lagoon ditches to 8 ppb at the TEAD boundary. Of approximately 37 billion gallons of contaminated ground water, approximately 16 billion gallons will require cleanup. The proposed cleanup calls for installing an extraction wellfield near the northern boundary of TEAD to intercept the leading edge of the contaminant plume. Ground water pumped from the wellfield will be piped to a water treatment plant where the contaminants will be removed by air stripping techniques. Treated effluent will be piped to an injection wellfield upgradient of the contaminant plume.
OU#2 involves a landfill and facilities for ordnance demilitarization that released TCE and TNT-related contaminants. The Army is attempting to define the extent of contamination in OU#2.
EPA, the State, and the Army plan to negotiate an Interagency Agreement under CERCLA Section 120 covering future activities at TEAD.
For more information about the hazardous substances identified in this narrative summary, including general information regarding the effects of exposure to these substances on human health, please see the Agency for Toxic Substances and Disease Registry (ATSDR) ToxFAQs. ATSDR ToxFAQs can be found on the Internet at http://www.atsdr.cdc.gov/toxfaq.html or by telephone at 1-888-42-ATSDR or 1-888-422-8737.