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EPA removes Rocky Mountain Arsenal's Internal Parcel from Superfund list

Release Date: 07/31/2006
Contact Information: Jennifer Chergo, 303-312-6601,; Richard Mylott , 303-312-6654,

      Property set to join wildlife refuge; 80 percent of RMA now deleted from list of heavily polluted areas

{07/31/2006} Denver, Colo. -- The Environmental Protection Agency today announced the removal of 11.5 square miles of the Rocky Mountain Arsenal from the Superfund National Priorities List (NPL). This action will enable the U.S. Army to transfer the property to the Rocky Mountain Arsenal National Wildlife Refuge, more than doubling its size to approximately 19 square miles.

“Through the hard work of many, the Internal Parcel is ready to become a public asset instead of a polluted liability,” said Robert E. Roberts, EPA’s regional administrator. “This deletion makes this land available for future beneficial uses, including open space and wildlife habitat.”

With today's announcement, EPA and the State of Colorado have determined that all cleanup actions necessary to protect public health and the environment are complete for the 7,396 acre Internal Parcel. Major actions included the excavation and disposal of soil and materials presenting a risk to human health or the environment, including munitions debris and red ash from mustard gas demilitarization. Cleanup activities also involved the removal or destruction of 196 structures and the closure of 27 groundwater wells that posed a risk for cross-contamination between aquifers.

The deletion of the Internal Parcel from the NPL is the fourth and largest partial deletion at the Rocky Mountain Arsenal to date. In January 2003, EPA and the State of Colorado determined that the Western Tier Parcel, a 940 acre area now being redeveloped by Commerce City into Prairie Gateway, met cleanup requirements. In January 2004, two additional areas (totaling more than 5,000 acres) known as the Select Perimeter Area and Surface Deletion Area met cleanup requirements and were deleted from the NPL.

Some areas within the Internal Parcel boundaries are excluded from today's deletion. Final cleanup of these areas -- former processing areas, waste disposal sites, munitions demolition areas, selected structures, haul roads, and drainage areas -- is not complete. In addition, groundwater west of E Street and in a small area east of E Street will remain on the NPL and will continue to be addressed by existing water treatment systems.

To date, nearly 80 percent of the original Rocky Mountain Arsenal site has been deleted from EPA's list of most heavily polluted areas. Cleanup of the remaining property will be completed by 2011.

Located eight miles northeast of downtown Denver in Adams County, the Rocky Mountain Arsenal was established in 1942 by the U.S. Army to manufacture chemicals for industrial, agricultural and military uses. Shell Oil Company manufactured pesticides at the site from 1952 to1982. Common industrial and waste disposal practices resulted in contamination of structures, soil, surface water and groundwater.

EPA listed the Rocky Mountain Arsenal on the NPL in 1987. Since that time, EPA, the Colorado Department of Public Health and Environment, the Tri-County Health Department, local agencies, and citizens have been working together to clean up the legacy of more than 40 years of environmental contamination.

EPA provided for a 60-day public comment period on the proposed partial deletion of the Internal Parcel, from April 26 to June 26, 2006. The final Notice of Deletion and EPA’s response to comments are available at the Rocky Mountain Arsenal Information Repository located at both the EPA office at 999 18th Street, Ste. 300, Denver, CO 80202 (303) 312-6473, or at the Joint Administrative Records Document Facility, Rocky Mountain Arsenal, Building 129, Room 2024, Commerce City, Colorado 80022 (303) 289-0362. The documents can also be viewed on the following Web sites: or