| Abstract |
The 17,000-acre Rocky Mountain Arsenal (RMA) (Operable Unit 22) site is a former U.S. Army chemical warfare and incendiary munitions manufacturing and assembly plant in Adams County, Colorado. Operable Unit 22 (OU22), the Complex Disposal Trenches, is one of several areas being addressed as part of the Other Contaminated Sources Interim Remedial Action. These disposal trenches are located in the 107-acre Site 36-17N in the center of the RMA. During the 1940s and 1950s, this area was the primary disposal area for solid chemical waste, contaminated tools and equipment, rejected incendiaries, and empty munitions casings. This waste was decontaminated, placed in onsite pits, and burned using fuel oil to ensure complete decontamination. Salvageable materials such as metal were sold as scrap after burning, and nonsalvageable materials were buried in onsite pits. Investigations by RMA in 1988 and 1989 identified onsite contaminated soil and a variety of buried waste, including scrap metal, concrete rubble, wood, charcoal, drums of waste chemicals, and glass vials containing unknown liquids. The main source area for the contaminant plume, however, appears to be from upgradient trenches located south of Site 36-17N. The selected interim remedial action is designed to prevent taking measures that may be incompatible with final decisions. Therefore, the ROD will not address the primary contaminants of concern affecting the soil and ground water. Remediation of contaminated media will be a component of the final site remedy. |
