4800 West 92nd Avenue Westminster, CO 80031

Rocky Flats Oversight

Information on current construction can be found on the Woman Creek Reservoir Rehabilitation Project Website.

Rocky Flats is a former nuclear weapons facility located west of the City of Westminster and Standley Lake, a key drinking water source for Westminster, Thornton and Northglenn.

Cleanup and closure of the site were completed in 2006, and the majority of the site is a national wildlife refuge that is currently not open to the public due to federal budgetary limitations. Learn more about the Rocky Flats National Wildlife Refuge.

Due to radioactive contamination that remains in the restricted zone at the center of  the site, the city tracks Rocky Flats activities, critically reviews ongoing sampling results and interpretation, and consistently communicates with regulators for ongoing protection of nearby communities.

The city’s overriding objective is to ensure that federal and state standards set for health and safety are met. This primarily involves protecting Standley Lake as a drinking water supply but includes all activities in the area, which include substantial recreation opportunities on city-owned open space and Standley Lake Regional Park.

There is a long history of Rocky Flats and its cleanup and many studies have been done to evaluate potential risks to public health in the areas outside the restricted area and refuge boundaries (offsite areas). To help people understand some of the facts associated with this issue the city has provided a useful summary that focuses primarily on well-documented and, where possible, peer reviewed investigations.

The city encourages those interested to take the time to examine and review this information. Additional information can be found on the Rocky Flats Stewardship Council website.

Detailed information is provided below, but a few initial facts are:

  • The City of Westminster has been monitoring Standley Lake for radioactivity since 1988, and all sample results have met drinking water standards.
  • Water leaving the Rocky Flats site does not enter Standley Lake. Since 1995, the Woman Creek Reservoir has been in place, just upstream of Standley Lake and downstream of Rocky Flats, diverting water from Rocky Flats around Standley Lake, via Walnut Creek.
  • Extensive sampling for radioactivity in soils, sediment, water and air indicate that the trace amounts of plutonium and americium present in the offsite soils and sediments do not pose a public health risk to those living in or recreating in the area.
  • All conservatively estimated health risks are well below U.S. Environmental Protection Agency significance thresholds, and the offsite areas are suitable for all uses, without restriction.

For greater detail, please refer to the sections below.

Rocky Flats Site Background - A high-level history of Rocky Flats is presented, including major historical events releasing materials to offsite areas and key regulatory steps.

Human Health Risks in Offsite Areas – Findings from key studies of human health risks in offsite areas are summarized. The discussion is organized by sampling media, followed by a summary of key epidemiological studies.

Summary and Recommendations – A bullet summary of major findings is provided to support development of risk communication tools.

References – A list of references evaluated is presented.

This information was prepared by Hydros Consulting of Boulder for the City of Westminster to support concise and accurate responses to questions and comments from the public regarding current health risks related to the Rocky Flats site.

Download the entire report in PDf format.

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