Atlas missile sites

There are five former Atlas E intercontinental ballistic missile sites in Colorado, scattered across the northern plains in Weld and Larimer counties. The sites were decommissioned and the missiles removed in 1965. The complexes were then sold to public and private owners.

  • Two of the sites are used for commercial purposes (Atlas 11 and 13), one (Atlas 9) is being converted into a residence, another (Atlas 10) is covered with soil and is owned by the U.S. Forest Service, and one (Atlas 12) has become the Weld County Missile Park and is also used for county storage.
  • Atlas 9, 10 and 13 have been fully investigated and cleaned up.

Regulatory setting

  • The Atlas sites are being investigated and cleaned up for the Department of Defense by the U.S. Army Corps of Engineers, Omaha District.
    • The sites fall under the Formerly Used Defense Sites (FUDS) program, which follows the federal Comprehensive Environmental Response, Compensation and Liability Act, or "Superfund" process, although the sites aren’t on the Superfund National Priorities List.
    • We provide regulatory oversight of the FUDS programs in Colorado, with assistance from the U.S. Environmental Protection Agency, Region 8, and local governments.

Environmental issues

  • Soil contamination from petroleum chemicals and/or from polychlorinated biphenyls has been found at all five Atlas sites.
  • Groundwater contamination from trichloroethylene, a cleaning solvent, has been found in groundwater at Atlas sites 11, 12 and 13.
  • Trichloroethylene was used during site construction and by the missile crews to flush the fuel tanks after missile readiness tests.
    • The crews disposed of the spent trichloroethylene and residual RP-1 fuel in a sump below the launch building that discharged onto the surface and then into shallow groundwater.
    • Water from domestic wells near some of the sites was tested and no trichloroethylene contamination found.
    • Water in the launch building sump at Site 12 contains trichloroethylene.
  • Indoor air above the launch building sump at sites 11 and 12 may be a potential concern.
  • While the Atlas E missile was armed with a plutonium-based nuclear warhead, we have no evidence of radioactive contamination at the sites. Warhead maintenance occurred at the warhead manufacturing facilities, not at the sites themselves.

Ongoing environmental investigations

Environmental investigations have focused on past Department of Defense practices at the missile sites and include sampling and analysis of soil, groundwater, domestic well water, and water and air in the complexes.

Atlas 11

  • Investigations completed, including determining the full extent of groundwater contamination.
  • Soil removal action conducted in 2006.
  • Feasibility study for groundwater cleanup completed.
  • Selected remedy for the site is In-Situ Chemical Oxidation (ISCO) into the TCE plume that underlies the missile silo area in order to treat the TCE in-situ.
  • The injected material is sodium permanganate.
  • Several injections have been completed and the site is in long-term monitoring.
  • The TCE appears to be responding well to the ISCO injections.
  • During 2017, a second area of groundwater contamination was discovered to be migrating west of the original delineated plume, under adjoining land owned by USDA. Investigation is ongoing to determine the extent of this plume.

Atlas 12

  • Feasibility study for groundwater cleanup completed in 2003.
  • In June 2008, the Army Corps of Engineers awarded a cleanup contract to conduct additional site characterization work and pilot testing of cleanup options. The work began in fall 2008.
  • The remedy selected was to inject zero valent iron (ZVI) into the TCE plume underlying the site.
  • Several rounds of ZVI injections have taken place during 2010-2019 time frame but the TCE reductions have not met expectations due to fracturing in the underlying bedrock.
  • The site is undergoing re-evaluation and re-characterization to better determine how to treat the remaining TCE.

Completed environmental cleanup

Atlas 9

  • Investigations completed.
  • Soil removal action conducted in 2006.
  • Site closure completed in March 2008.
  • No further cleanup actions planned.

Atlas 10

  • Investigations completed.
  • Soil removal action conducted in 2007.
  • Site closure completed in April 2008.
  • No further cleanup actions planned.

Atlas 13

  • Investigations completed, including determining the full extent of groundwater contamination.
  • Soil removal action conducted in 2006.
  • Feasibility study for groundwater cleanup completed.
  • The Final Site Plan was published in 2014 after an Environmental Impact Statement (EIS) was completed that determined future construction of the Glade Reservoir would not adversely impact the selected remedy.
  • The selected remedy was implemented via ISCO injection and was successful.
  • The remedy was concluded and the site was closed in 2018 with a recommendation that no further action was necessary.

Evaluation of health concerns

  • Trichloroethylene in groundwater is the greatest concern at the Atlas sites.
  • To date, no contamination has been detected in any domestic or private wells.
  • Future monitoring and cleanup efforts will help alleviate any remaining concerns.
  • Because contaminated soil has been removed from the localized areas on the sites, there’s no health risk to nearby residents from soil contamination.
  • Most sites are private property and shouldn’t be entered.
  • Tours of the Weld County Missile Park site can be arranged with Weld County.

Future actions and public involvement

  • Cleanup plans, including long-term groundwater monitoring plans, will be available to the public as they’re developed.
    • Plans will be posted on this website and notices placed in local newspapers when the plans are available.
    • Public meetings will be scheduled as needed.

Information repositories

Documents related to the environmental investigations and cleanup plans at the Atlas sites can be found at the following locations:

CDPHE records review

Weld County, sites 9, 10, 11 and 12:
Weld County Library District
Farr Branch Library
1939 61st St.
Greeley, CO 80634
Larimer County, Site 13:
Fort Collins Public Library
201 N. Peterson St.
Fort Collins, CO 80524