Region 8

Rocky Flats Plant (USDOE)

Rocky Flats Plant site location map Site Type: Federal Facility Final NPL
City: Golden
County: Jefferson
Street Address: Hwy 93 between Golden & Boulder
ZIP Code: 80402
EPA ID: CO7890010526
SSID: 0857
Congressional District: 2

What's New?

Updated October 2012

The third five-year review for the Rocky Flats Plant was completed on July 30, 2012; the report is available in the Site Documents section below.

The next comprehensive site inspection will be conducted in the spring of 2014. This annual inspection is conducted by the U.S. Department of Energy (DOE) with the participation of the EPA and the Colorado Department of Public Health and Environment (CDPHE). The results of the annual inspection are included in the quarterly and annual reports, included in the briefings to the Rocky Flats Stewardship Council and available on the DOE's Rocky Flats website.

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Site Description

Rocky Flats is a 6,240-acre facility located approximately 16 miles northwest of Denver, Colorado, and approximately 10 miles south of Boulder, Colorado. The majority of the Rocky Flats site is located in Jefferson County, with a small portion located in Boulder County. Rocky Flats operated from 1952 until 1992 as part of the United States’ nationwide nuclear weapons complex. The facility manufactured trigger mechanisms for nuclear weapons from various radioactive and hazardous materials.

The plant ceased operations in 1989 because of environmental and safety concerns. Plant facilities contained substantial quantities beryllium, plutonium and other hazardous substances.

The greatest contamination and hazards were located within the 385-acre industrialized area at the center of the property, where the majority of the nearly 800 structures were located. The industrial area was surrounded by a security buffer zone, which contained some supporting activities, such as waste disposal, but was left mostly undisturbed. Contamination also spread from this area into the surrounding land and groundwater.

In 1989 the EPA listed Rocky Flats on the National Priorities List (NPL). Nearly 40 years of nuclear weapons production at Rocky Flats had left facilities, groundwater, soil, and surface waters contaminated with chemical and radioactive substances that posed potential health and safety risks to the public and workers. Under CERCLA (Superfund law), the DOE is responsible for the response action for hazardous substance releases at Rocky Flats, with the EPA and the Colorado Department of Public Health and Environment (CDPHE) as the support agencies.

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Site Risk

Manufacturing activities, accidental industrial fires and spills, and support activities including waste management resulted in the release of hazardous and radioactive substances, hazardous wastes, and hazardous waste constituents to air, soil, sediment, groundwater, and surface water at Rocky Flats. Contaminants released to the environment include (but are not limited to) plutonium-239/240, americium-241, uranium, carbon tetrachloride, tetrachloroethene (PCE or perc), trichloroethene (TCE), nitrates and chromium. Volatile organic compounds (VOCs), nitrates and uranium contaminated shallow groundwater. The radioactive elements plutonium, uranium, and americium contaminated soils. The potential for radioactive particles on soil to become airborne during strong winds or to be transported to streams was a concern and was closely monitored. The following table summarizes the media at the site and the key contaminants before cleanup was completed.

Media Affected Contaminants Source of Contamination
soils, surface water, groundwater, air americium, plutonium, uranium, volatile organic compounds leaking storage drums, unlined disposal trenches, surface water impoundments, leaking pipelines and underground storage tanks, two landfills, and contaminated buildings from past production of nuclear weapons components left

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Cleanup Progress

June 1995, before cleanup
June 1995, before cleanup
June 2007
June 2007, after cleanup
June 2011, after cleanup
June 2011

The DOE, EPA and CDPHE determined that the offsite area surrounding Rocky Flats was not contaminated to levels that required remediation. This area consists of approximately 20,480 acres of open space, residential development and agricultural lands; EPA issued a no-action Record of Decision (ROD) for the offsite area in 1997. This ROD determined that no further action was required in this area to protect human health and the environment.

The remainder of the Rocky Flats site was cleaned up as an accelerated action, with DOE as the lead agency and with oversight by EPA and CDPHE. The Rocky Flats site was divided into the following Operable Units (OUs):

  • Central Operable Unit, or OU1 (approximately 1,308 acres): includes approximately 384 acres in the industrial area in the center of the facility.
  • Peripheral Operable Unit, or OU2 (approximately 4,883 acres): formerly known as the buffer zone.

The accelerated cleanup action, focused on the industrial area in OU1 where most of the weapons manufacturing took place and where plutonium, uranium, and americium contamination persists. The cleanup included decommissioning, decontamination, demolition and removal of more than 800 structures; removal of more than 500,000 cubic meters of low-level radioactive waste; and remediation of more than 360 potentially contaminated environmental sites. Site cleanup and closure were completed in October 2005.

On September 28, 2006, EPA issued a Corrective Action Decision/Record of Decision (CAD/ROD) for Rocky Flats, describing the selected response action for OUs 1 and 2. The remedy selected for the Central Operable Unit 1 was institutional and physical controls. The site conditions after remediation combined with institutional controls, a monitoring program and signage ensure that human health and the environment are protected.

Cleanup at Rocky Flats did not eliminate all contamination in the Central OU1. Although all buildings were demolished and removed, some residual contamination remained in the core production areas, settling ponds and two landfills. This area is under DOE’s ownership. The remaining contamination includes low concentrations of radioactive materials, chemical solvents and heavy metal contaminants, generally below regulatory standards. Studies show that this contamination poses no threat to human health and the environment. Ongoing monitoring and management by the DOE are overseen by the EPA and CDPHE.

The action selected in the 2006 CAD/ROD for the Peripheral OU2 (the buffer zone) was no further action. It was determined that appropriate response actions under CERCLA had been implemented in these areas, and that no further response actions were needed.

In May 2007, the EPA announced the deletion of 25,413 acres of the Rocky Flats site from the National Priorities List (NPL). This deletion reflected the completion of all response actions for OU2 (4,933 acres) and the offsite areas (20,480 acres). In July 2007, about 4,000 acres of the Peripheral OU2 that were deleted from the NPL were transferred for management by the U.S. Fish and Wildlife Service as the Rocky Flats National Wildlife Refuge.

The 1,308-acre Central Operable Unit at Rocky Flats will not be considered for deletion and will remain on the NPL. DOE retains the Central Operable Unit, including the former industrial area, for long-term management. DOE’s Office of Legacy Management (LM) conducts operation and maintenance of remedial action systems, routine inspection and maintenance, groundwater and surface water monitoring, records-related activities, and stakeholder support. LM is also responsible for approximately 948 additional acres of former buffer land in OU2, where there are still private mineral rights. This land will be transferred to the refuge as mining permits expire and reclamation required by Colorado law is completed.

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Community Involvement

Community involvement plays an important role in the Superfund process. EPA uses a number of different tools and resources to promote effective, ongoing, meaningful community involvement. The goals of the Superfund community involvement program are to:

  • Keep communities affected by sites informed throughout the cleanup process.
  • Provide opportunities for communities to comment and offer their input about site cleanup plans.
  • Facilitate the resolution of community issues tied to a site.

Because of its role in the manufacture of nuclear weapons components and well-publicized concerns over industrial fires and accidents, Rocky Flats has been the subject of strong public interest for more than 30 years. To involve and inform the many site stakeholders, the EPA, CDPHE and DOE held stakeholder meetings and invited stakeholders to many site technical meetings to present cleanup plans and receive input on major remedial activities. A formal public participation plan was implemented to inform the public about investigation and cleanup activities.

The Rocky Flats Stewardship Council was formed in 2006 to provide ongoing community outreach, with quarterly meetings to inform the public and local government about ongoing site activities.

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EPA places a high priority on land reuse as part of its Superfund response program mission. The Agency tries to select cleanup options that encourage and support future use of a site. We use two fundamental methods to facilitate reuse of Superfund sites:

  • Exploring future uses before the cleanup remedy is implemented, an approach that gives the Agency the best chance of designing cleanup remedies to support the likely future use of a site.
  • Working with landowners and communities to remove barriers not considered necessary for the protection of human health or the environment at those sites where remedies are already in place.

One option for reuse is the siting of clean and renewable energy projects on contaminated (or formerly contaminated) lands. As part of this effort, EPA is evaluating the potential for energy projects on these properties and working with landowners and communities to identify ways to remove barriers to such projects.

Rocky Flats is an example of a site where the federal government promoted ecological land reuse as an integrated part of site remediation strategies and as an alternative to conventional property development or redevelopment. The Rocky Flats National Wildlife Refuge Act of 2001 stipulated that after completion of the cleanup project, the majority of Rocky Flats would be protected as a national wildlife refuge. The wildlife refuge is not currently open to the public. It serves to restore and preserve native ecosystems, provide habitat for plants and wildlife, conserve threatened and endangered species, and provide opportunities for scientific research. The refuge act also prohibits reindustrialization of the site and annexation by local governments.

Reuse of the Central Operable Unit is precluded by the 2006 Record of Decision.

Rocky Flats Plant: Reuse Fact Sheet, September 2013

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Land Use Controls and Other Institutional Controls

Land use controls are the most common type of institutional control (IC). ICs are administrative or legal controls that help reduce the likelihood for human exposure to contamination. ICs can also help protect the integrity of the remedy. Examples of ICs are:

  • Zoning ordinances.
  • Environmental covenants.
  • Deed notices.
  • Well-drilling restrictions.
  • Building permits.
  • Informational advisories.

Institutional Controls in the Central OU (former industrial area) are part of the selected remedy/corrective action at Rocky Flats. These controls prohibit soil disturbance activities that are not appropriately controlled, activities that could damage the landfill covers or other remedy components, and the non-remedy-related use of surface water or groundwater. Other physical controls include signage at access points to the Central OU listing the institutional controls and around the perimeter prohibiting access.

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Five-Year Reviews

EPA or the lead agency conducts five-year reviews following the start of a Superfund cleanup when contamination is left on the site. These reviews are repeated every five years. We use these reviews to determine:

  • How the remedy is working.
  • If the remedy remains protective of human health and the environment.

Because remaining contamination in the Central OU (OU1) does not allow for unlimited use and unrestricted exposure, DOE, as the lead agency, conducts five-year reviews at Rocky Flats. The first five-year review was conducted for the period May 1997 through April 2002 and was performed when cleanup and closure activities were ongoing. The second five-year review covered the period May 2002 through April 2007 and evaluated the performance of the remedy implemented under the CAD/ROD. EPA issued annual updates to the five-year review in February 2010 and January 2011. The second five-year review concluded that the Central OU remedy continues to be protective of human health and the environment. Since OU2 and the offsite area were deleted from the NPL, they were not included in the five-year review nor will they be addressed in future reviews. The third five-year review covers the period from May 2007 through April 2012 and consists of reviews of Central OU environmental monitoring, physical controls and institutional controls.

The third five-year review was completed on July 30, 2012 and concluded that the Rocky Flats site continues to be protective of human health and the environment.

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Site Documents

You will need Adobe Reader to view some of the files on this page. See EPA’s About PDF page to learn more.Note: Best way to open a very large file: right-click and save it to a folder.

Third Five-Year Review Report (PDF), July 2012(243 pp, 13.3 MB)

Corrective Action Decision/Record of Decision Amendment for Central Operable Unit (PDF), September 2011(137 pp, 1.1 MB)

Rocky Flats Legacy Management Agreement (PDF), February 2007(94 pp, 2.8 MB)

Corrective Action Decision/Record of Decision for Peripheral Operable Unit and Central Operable Unit, September 2006

CERCLA Administrative Record Database (DOE site)

Records of Decision (EPA site)

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Vera Moritz
Rocky Flats Project Coordinator
U.S. Environmental Protection Agency, Region 8
1595 Wynkoop Street (8EPR-F)
Denver, Colorado 80202-1129
800-227-8917 ext. 312-6067 (toll free Region 8 only)

View Documents at:

EPA Superfund Records Center
1595 Wynkoop Street
Denver, CO 80202-1129
To request copies of administrative record documents call:
800-227-8917 ext. 312-7273 (toll free Region 8 only)

Colorado Department of Public Health and Environment
HMWMD Records Center
4300 Cherry Creek Drive South
Denver, Colorado 80246-1530
888-569-1831 ext. 3331 (toll free)
303-759-5355 FAX
By appointment only


Carl Spreng
Rocky Flats Program Manager
Colorado Department of Public Health and Environment
Hazardous Materials and Waste Management Division
4300 Cherry Creek Drive South
Denver, CO 80246-1530
888-569-1831 ext. 3358 (toll free)

Warren Smith
Community Relations Manager
Colorado Department of Public Health and Environment
4300 Cherry Creek Drive South
888-569-1831 ext. 3373 (toll free)

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Photo/Video Gallery

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U.S. DOE Rocky Flats site

Rocky Flats site at the Colorado Department of Public Health and Environment Exit

Rocky Flats Stewardship Council Exit

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