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NPL Site Narrative for Rocky Mountain Arsenal (USARMY)
ROCKY MOUNTAIN ARSENAL
Adams County, Colorado
Federal Register Notice: July 22, 1987Conditions at proposal (October 15, 1984): The Rocky Mountain Arsenal (RMA) is located about 10 miles northeast of downtown Denver, Adams County, Colorado. It covers over 27 square miles. Since 1942, RMA has manufactured and demilitarized mustard gas, nerve gas, and chemical munitions. From 1952 until 1982, Shell Chemical Co. used the site to manufacture pesticides and herbicides.
The Army has identified 165 "possibly polluted" areas at RMA; six received Interim Status under Subtitle C of the Resource Conservation and Recovery Act (RCRA) when the Army filed Part A of permit applications. Contamination from some of these areas has migrated and may continue to migrate off RMA, principally via ground water. The contaminated area covers about 4 square miles, with additional off-site ground water contamination.
Both the Army and Shell have constructed systems along the downgradient borders of RMA to control off-site migration. The systems pump out contaminated ground water, treat it with activated carbon to remove organic contaminants, and reinject the treated ground water. The Army is constructing a third system of this kind. The Army is also developing alternatives for controlling or eliminating the sources of contamination on RMA and the off-site contamination. These activities are part of 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. To date, the Army has spent more than $25 million on studies and control actions at RMA.
Status (July 22, 1987): The third ground water intercept and treatment system is now in service. The Army is conducting a remedial investigation/feasibility study (RI/FS) to determine the type and extent of contamination and to identify alternatives for remedial action on the facility and some areas off the facility. EPA is conducting an RI/FS on other areas off the facility.
Status (March 13, 1989): The Army has virtually completed its RI, and 13 interim response actions are underway to accelerate the cleanup.
On July 22, 1987, EPA placed RMA, excluding a lagoon known as "Basin F," on the NPL, proposed to expand the site to include Basin F, and solicited comment on the proposal. EPA's RCRA policy when RMA was proposed in October 1984 was to exclude an area from an NPL site if it was a RCRA-regulated land disposal unit. Basin F is a regulated land disposal unit, and so EPA excluded it from the NPL site. EPA has finalized the NPL/RCRA policy and is expanding this site under the policy to include Basin F. In addition, further investigation has demonstrated that Basin F is a major contributor to ground water contamination at RMA.
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.