The 25-square-mile New Brighton/Arden Hills site includes the 4-square-mile. Twin Cities Army Ammunition Plant (TCAAP) in Ramsey County, Minnesota. Land use in the area is predominantly residential with commercial and industrial sectors. In 1981, state investigations of municipal and private drinking water wells in and around TCAAP identified contamination of ground water, onsite soil, sediment, and surface water by VOCs, other organics, and metals. Past removal actions and seven previous RODs, signed from 1983 to 1989, addressed interim remedial actions conducted by the Army and Alliant Techsystems and provided for the establishment of alternate drinking water supplies. The ROD addresses remediation of the south plume of offsite contaminated ground water, as OU3. The primary contaminants of concern affecting the ground water are VOCs, including benzene, TCE, and xylenes; other organics, including phenols; and metals, including chromium and lead. The selected remedial action for the site includes pumping and offsite treatment of contaminated ground water at the leading edge of the south plume using precipitation and filtration to remove inorganic solids and a pressurized granular activated carbon system to remove VOCs; and discharging the treated ground water offsite to the potable water supply.