Region 8

Monticello Radioactively Contaminated Properties

Monticello Radioactively Contaminated Properties site location map Site Type: Federal Facilities Deleted NPL
City: Monticello
County: San Juan
Street Address: 9 North 3rd East Street
ZIP Code: 84535
EPA ID: UTD980667208
SSID: 0873
Site Aliases: Monticello Vicinity Properties, Store in Monticello, House in Monticello
Congressional District: 3

Site Description

In all, 424 properties were contaminated with radioactive mill tailings from past uranium and vanadium ore-processing operations at the Monticello Mill site in southeastern Utah.

The Department of Energy (DOE), the State of Utah Department of Environmental Quality (UDEQ) and the Environmental Protection Agency (EPA) entered into a Federal Facilities Agreement to clean up the contamination on these properties in December 1988.

The site consists of 424 private and commercial properties in and around the city of Monticello, Utah, covering approximately four square miles.

Map of the Superfund site boundary

The properties are near an ore-processing mill that the federal government established during World War II to produce vanadium, a steel hardener, for the war effort. Vanadium, though not radioactive itself, is usually found in the same ore that contains uranium and radium; therefore, the processing wastes contain significant radioactivity. Soon after construction, the mill began processing uranium (yellow cake), which may have been used for the Manhattan Project.

Uranium production continued until 1960, when the plant was closed and dismantled. Contaminated dust from the Monticello Mill tailings piles blew onto the site properties mostly within the city. Also, tailings from the mill site were used as construction material, backfill and as sand mix in concrete, resulting in the radioactive contamination of some vicinity properties in Monticello. The Mill Tailings site is located immediately south of the city, in the flood plain of Montezuma Creek.

EPA added the Monticello Radioactively Contaminated Properties site to the National Priorities List (NPL) on June 10, 1986.

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Site Risk

Exposure to radioactive materials could be harmful to human health. Direct contact with and/or inhaling or swallowing the kind of radioactive material found in tailings dust may affect lungs and bones. Also, inhalation of radon gas that results from the radioactive decay of radium 226 could harm lungs.

Media Affected Contaminants Source of Contamination
soil, debris, air radioactive mill tailings and dust from tailings piles, radon gas emanating from radioactive decay products uranium milling wastes

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Cleanup Progress

The site is being addressed through federal actions in accordance with a Federal Facility Agreement. The DOE is the Responsible Party, although the contaminated properties are not on federally owned lands. EPA and UDEQ share Superfund regulatory oversight responsibilities. Superfund is the shorthand term for CERCLA—the Comprehensive Environmental Response, Compensation and Liability Act—passed by Congress in 1980 to address the dangers of abandoned or uncontrolled sites contaminated with hazardous substances.

In 1989, EPA, DOE and UDEQ signed a Record of Decision (ROD), which selected a remedy to clean up the vicinity properties by excavating and removing the contaminated tailings, soil and construction material from the vicinity properties and storing them at the site. About 152,000 cubic yards of material were removed from the vicinity properties and have been relocated to the repository that was constructed about a mile south of the former mill site.

Cleanup has now been completed on all of the vicinity properties. EPA deleted the site from the NPL in February 2000.

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Site Documents

You will need Adobe Reader to view some of the files on this page. See EPA's PDF page to learn more.

Fourth Five-Year Review Report, June 2012

Fact Sheet: Monticello, Utah, Disposal and Processing Sites (PDF), April 2009 (4 pp, 517 K)

Monticello Radioactive Contaminated Properties Site Delisting Process (PDF), January 2000 (3 pp, 925 K)

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Vera Moritz
Remedial Project Manager
U.S. Environmental Protection Agency, Region 8
1595 Wynkoop Street (EPR-F)
Denver, Colorado 80202-1129
800-227-8917 ext. 312-6981 (toll free Region 8 only)


Jalena Dayvault
Monticello Area Project Manager
U.S. Department of Energy
Grand Junction Office
2597 B¾ Road
Grand Junction, CO 81503
970-248-6023 FAX


Michael Storck
State Project Manager
Utah Department of Environmental Quality
Environmental Response and Remediation Division
195 North 1950 West
Salt Lake City, UT 84116
801-536-4242 FAX

Dave Allison
Community Involvement Specialist
Utah Department of Environmental Quality
Environmental Response and Remediation Division
195 North 1950 West
Salt Lake City, UT 84116

Site Information Repositories:

Information Repository
Monticello Site
1665 South Main Street
Monticello, UT 84535
801-587-2272 FAX

Administrative Record
U.S. Department of Energy
Grand Junction Office
2597 B¾ Road
Grand Junction, CO 81502
970-248-6040 FAX

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U.S. Department of Energy Office of Legacy Management: Monticello, Utah, Disposal and Processing Sites

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