The 220-acre Tinker AFB (Soldier Creek/Building 3001) site, which includes an active military facility and the adjacent Soldier Creek is in Oklahoma City, Oklahoma. Surrounding land use is urban residential. Underlying the site is a surficial perched aquifer and a sole-source aquifer for the region. The Building 3001 (B3001) facility is used as an aircraft overhaul and modification complex for jet engine service, repair, and upgrades. From the 1940s to the 1970s, organic solvents were used to degrease metal parts in subsurface pits. Ground water contamination has occurred onsite as a result of seepage from these pits, direct discharge of solvents to storm drains, spills, and faulty drainage system connections. A North Tank Area contains several active and abandoned underground waste oil and fuel tanks. Contamination in the area has resulted from leaking tanks and fuel spills directly onto the ground. In addition, there is onsite Volatile Organic Compounds contamination, which may be the result of leaking utility lines in the area. Investigations by the Air Force from 1982 to 1989, documented ground water contamination under the B3001 complex; the potential threat of further contamination from Pit Q-51, one of the former degreasing pits; and leakage of underground storage tanks in the North Tank Area. The Record of Decision (ROD) addresses remediation of onsite ground water, along with remedial actions relating to Pit Q-51 and the North Tank Area. The primary contaminants of concern affecting the soil, debris and ground water are Volatile Organic Compounds including benzene, PCE, TCE, toluene, and xylenes; other organics including phenols; and metals including chromium and lead.