Rocky Mountain Arsenal Usarmy

⚠ Superfund · Cleanup underway

In the late 1980s, the Army, EPA and Shell signed a Federal Facility Agreement (FFA). It specified the process by which decisions would be made for the cleanup and established cleanup goals. EPA divided the site into two separate areas, or operable units (OUs), to better address cleanup. The on-post OU includes the fenced 27 square miles of RMA proper.

Location

CityAdams County
CountyAdams County
StateColorado
Coordinates39.83340, -104.84244

Contaminants of concern

Contaminated media

Cleanup timeline

  1. Initial Assessment Completed — 06/01/1981
  2. Proposed to the National Priorities List — 10/15/1984
  3. Finalized on the National Priorities List — 07/22/1987
  4. Remedial Investigation Started — 02/15/1985
  5. Remedy Selected — 06/04/1987
  6. Final Remedy Selected — 10/20/2005
  7. Remedial Action Started — 07/01/1987
  8. Final Remedial Action Started — 07/30/2025
  9. Construction Completed — Not Yet Achieved
  10. Deleted from National Priorities List — Not Yet Achieved

EPA references

Other Superfund sites in Adams County

EPA-regulated facilities nearby

Understanding this Superfund site

Rocky Mountain Arsenal Usarmy is a federal Superfund site in Colorado. The Superfund program, created by Congress in 1980, addresses sites where hazardous substances have been released or threaten release into the environment. EPA scores potential sites using the Hazard Ranking System; those that score high enough are placed on the National Priorities List.

Current status: Cleanup underway. Active cleanup is underway, meaning EPA has approved a remediation plan and work is in progress. Cleanup timelines vary widely — some sites take decades depending on contamination depth, groundwater involvement, and funding availability.

EPA has identified 10 contaminants of concern at this site, including 1,1,1-trichloroethane, 1,1,2,2-tetrachloroethane, 1,1,2-trichloroethane. Contamination has been detected in soil gas, soil, groundwater, buildings/structures, liquid waste, solid waste.

If you live near this site and have health concerns, your state health department can provide site-specific guidance. EPA maintains a community involvement program for most NPL sites, and site documents — including the Record of Decision, five-year reviews, and public health assessments — are typically available through EPA's Superfund site profile.