The Rocky Mountain Arsenal is an ex-chemical weapons manufacturing facility that is located in the northwest corner of Denver, Colorado. It was established in response to World War II in Europe. Today, the Arsenal is managed by the National Wildlife Refuge. In addition to producing chemical weapons, RMA was also used as a weapons research and development base.
The Army and contractors have leased the site. It is now a national wildlife sanctuary. The site contains approximately 1,100 acres. An on-site landfill, two waste consolidation areas, and five groundwater treatment facilities are also operated by the U.S. Army.
RMA was created in 1942 in order to produce chemicals for war efforts. The cleanup of the site was completed in 2010. The operation resulted in the disposal of approximately 650 hazardous substances. These hazardous materials included solid and explosive wastes, as well other chemicals. Napalm was a dangerous pesticide, rocket fuel, chemical munitions and other compounds that were produced at the RMA. Many of these contaminated materials were found in the soil and water around them.
The Army tried a pilot project in the mid-1960s to manage toxic wastes. They developed a plan to inject chemicals into a deep injection well at the RMA. After a series earthquakes, injection activity was stopped. There were no established waste disposal procedures. The site included Basin A with 93 acres of land and Basin F with a large open lagoon. All of the basins were contaminated. The groundwater was also high in these areas. This resulted in groundwater contamination of the surrounding area.
RMA, a former chemical weapons production site, had a significant effect on the local area. Several farmers were affected by the contamination. However, there were no reported deaths. In addition, livestock were killed at nearby ranches. To prevent contamination, the Army was responsible for 14 interim response actions.
The facility manufactured agricultural products, including herbicides, in addition to chemical wastes. These products were transferred off the site via a rail spur. Some of the buildings on the RMA were damaged during the transfer of the chemicals to rail cars.
Some of the facilities were leased by the XXX Oil Co., which used them later to produce pesticides. The RMA's military use was ended and the site became part of a national wildlife sanctuary.
While the RMA’s wastes had been removed from the site's location, the chemical contamination spread to the surrounding area. There were several areas that were contaminated and required groundwater removal. Groundwater P&T systems were set up at the RMA's northwest and north borders. Operable Units 2nd and 3 were also affected. These areas also had affected domestic wells due to the off-site ROD.
The RMA's Emergency Management/Contingency Plan describes the U.S. Army's response to the contaminated land, and provides guidance to the managers of the RMA National Wildlife Refuge.