Region 8

Midvale Slag

Midvale Slag site location map Site Type: Final NPL
City: Midvale
County: Salt Lake
Street Address: 6400 South 700 West 7800
ZIP Code: 84027
EPA ID: UTD081834277
SSID: 0871
Site Aliases: Midvale, Tailings, Sheridan Hill Smelter
Congressional District: 2

What's New?

Updated March 2014

The third five-year review for the Midvale Slag site is currently being conducted and will be finalized by spring 2014.

The Midvale Slag site has achieved construction completion status. Achievement of this milestone documents that physical construction of all cleanup actions at a site are complete. The Preliminary Closeout Report was signed on September 21, 2011.

Groundwater and surface water monitoring and five-year reviews will continue, to ensure that all cleanup work remains protective of human health and the environment.

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Site Description

The 446-acre Midvale Slag Superfund Site is located 12 miles south of Salt Lake City in Midvale City, with a small portion extending into Murray City. The site is a former smelting facility on the Jordan River. Five separate smelters were located on or near the site from 1871 to 1958. An adjacent mill continued operating until 1971. The smelters processed ores from Bingham Canyon and other mines. Investigations at the site showed groundwater and soils are contaminated with heavy metals.

Historic smelters in Midvale

EPA listed the Midvale Slag Superfund Site on the National Priorities List (NPL), commonly known as the list of Superfund sites, in 1991. After listing on the NPL, the site was divided into two operable units. Operable Unit 1 (OU1) is the northern 266 acres of the site. Operable Unit 2 (OU2) is the remaining 180 acres to the south. The dividing boundary between OU1 and OU2 is slightly south of 7200 South, which bisects the site.

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Site Risk

Studies conducted in 1984 found that groundwater and soil were contaminated with heavy metals. Potential human health threats included drinking contaminated shallow groundwater or swallowing, inhaling, or handling contaminated soil and wastes. These risks have since been addressed by the site cleanup.

Media Affected Contaminants Source of Contamination
soils, air, groundwater, surface water, sediment, solid waste lead, arsenic, chromium, and cadmium

smelting wastes

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Cleanup Progress

Damaged Sheet Pile Dam
The walls of this damaged sheet pile dam across the Jordan River along the Midvale Slag Superfund Site were still standing along both banks, but the center section had buckled. Although the dam appeared to be stable, it could have failedin the future. This could have allowed river water to erode the riverbank and release site contaminants into the river.
New Boulder Dam
This newly constructed dam is a steel-reinforced boulder structure that replaces the damaged sheet pile dam. The structure's low flow channels direct the water toward the center of the river to avoid riverbank erosion. In addition, two safer options for canoeists and kayakers were built into the design. A low-flow boat passage was constructed, identified by signal boulders. Also, the portage passage was improved to allow boaters to bypass the structure, if referred.

In 1990, EPA initiated cleanup actions to address immediate threats at the site. Chemicals found in an abandoned lab were removed, and some 20 pounds of explosives were detonated. Also, the site was fenced to prevent public access.

In 1995, EPA issued a Record of Decision (ROD) for OU1 that included removing and replacing yard soils at Winchester Estates, a small, residential development at the northern end of the site. The ROD also called for groundwater monitoring and institutional controls meant to protect people from coming into contact with exposed mining wastes or drinking shallow groundwater at the site. Three years later, EPA and the Utah Department of Environmental Quality (UDEQ) issued an Explanation of Significant Differences (ESD) to the OU1 ROD that required the excavation of contaminated soils on one parcel of land, rather than capping, and thus eliminated the need for institutional controls governing use of that parcel. Cleanup at OU1 is complete.

In 1996, contaminated soil was excavated from the Butterfield Lumber portion of OU2 and from the small, unmarked Pioneer Cemetery.

EPA issued the ROD for OU2 in 2002 that divided the work into three parts: the smelter waste and slag, the groundwater, and the riparian zone. The smelter waste and slag remediation was completed in 2007. These wastes were regraded and a vegetated soil cover was constructed over them. The cover was designed to accommodate multiple redevelopment options, along with institutional controls to address future excavation and redevelopment. A groundwater monitoring system was implemented to ensure that groundwater from the site did not cause state water quality standards to be exceeded in the Jordan River. The OU2 ROD required that a stakeholder group be formed to focus on a plan to restore and stabilize the banks of the Jordan River as it flows through the western portion of the site.

In 2006, EPA issued an ESD for OU1 that changed land use restrictions to accommodate multiple land uses and created an approach in riparian management and a comprehensive groundwater monitoring plan that was consistent for both operable units.

From 2008 through 2010, EPA implemented the Jordan River Riparian Improvement Project, the final component of the Midvale Slag Superfund Site cleanup. The objective of the riparian project was to stabilize and reinforce the banks of the river as it flows through the site to eliminate erosion of the banks, which could potentially deposit buried contamination into the river. This was done with many goals in mind, including aesthetics, recreation, habitat and innovation.

The Jordan River Riparian Improvement Project was conducted in four phases. During Phase I, in the fall/winter of 2008/2009, EPA removed a damaged sheet pile dam from the river which was a relic of past mining activities. EPA then installed a new dam structure to stabilize the riverbed slope and prevent potential riverbank erosion. This phase also included stabilizing certain areas along the riverbank with boulder and rock and installing flow control devices in the river downstream of the new structure. Phase II involved additional bank stabilization work near the newly constructed dam structure and along portions of the river. In addition, two box culverts were designed to maintain the Jordan Village Pond along the Sharon Steel NPL site, located upstream and adjacent to the Midvale Slag site. By increasing water storage capacity at the Jordan Village Pond, the amount of water scouring the riverbanks during storm events along the Midvale Slag site is reduced.

To aid in this work, EPA hired the United States Geological Survey to survey the Jordan River channel and to develop a two-dimensional hydraulic model to evaluate the hydraulic characteristics of the river at different stream flows. This model allowed EPA to locate areas susceptible to erosion that could impact the integrity of the cap. The model also provided water level and volume information, to assist in finalizing the box culvert design and to stabilize water flow adjacent to the grouted boulder structure.

During Phases III and IV, EPA completed stabilizing the riverbank, from where Phase II left off to the north end of the site at Winchester Estates. EPA provided grant money to Salt Lake County to construct graded slopes along the riverbank, called emergent benches, above previously-placed rock armoring and elsewhere along the riverbank. Salt Lake County then planted the emergent benches and other areas with native and riparian wetland vegetation.

EPA led the design and installation of the landscaping and associated irrigation system for the area. Many unique activities were included in this work effort. EPA hired a Ph.D. student to perform a weed assessment to determine the presence, frequency and location of noxious weeds. EPA hired another Ph.D. student to perform a soil assessment. Both studies were useful guides for removing invasive species and replanting site-appropriate plantings.

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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, on-going, 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.

In 1992, a concerned group, Citizens for a Safe Future for Midvale, received a Technical Assistance Grant (TAG) from EPA to hire a technical advisor to study and inform the community about issues related to site cleanup. Members of the TAG met regularly with EPA and the State of Utah and Midvale City representatives throughout the Midvale Slag Superfund Site cleanup.

Occasionally, EPA and the state held community forums to provide timely updates of cleanup activities to elected officials and interested citizens.

During key points in the cleanup process, EPA issued public notices and press releases, held public comment periods and public meetings and initiated other activities to keep the public informed about pending cleanup decisions and/or actions.

In the summer of 2007, EPA brought together the TAG members and a group of interested citizens and agency representatives to form the Jordan River Stakeholder Group. This group met bimonthly to work together on the design plans for the Jordan River Riparian Improvement project. This forum was very valuable to the success of the project.

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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.

single-family homes
Single-family residential
multifamily homes
Multifamily residential
upscale residential
Upscale residential
recreational development
Recreational development
recreational development
West Jordan side of the river parkway
recreational development
West Jordan side of the river parkway
retail development
Retail development
UTA light rail transportation
UTA light rail transportation
commercial development
Commercial development

Early in the cleanup process, EPA partnered with the state and local governments to ensure that the site's remedy would be compatible with mixed residential and commercial land uses planned for the site. In 1999, the site was named Region 8's pilot project for the Superfund Redevelopment Initiative (SRI). In 2006, Midvale Slag was named an SRI Return to Use Demonstration Project, and in 2008 a Ready for Reuse (RfR) Determination was completed for the 446-acre site. Redevelopment is currently underway at the site, now known as Bingham Junction.

Outcomes from the site's Bingham Junction development are striking: approximately 600 jobs, $1.5 million in annual property tax revenues and a $131 million increase in the value of the site property. SRI's 2011 case study, Cleanup and Mixed-Use Revitalization on the Wasatch Front, explores this complex project, sharing key lessons learned with parties interested in learning more about mixed-use redevelopment and revitalization opportunities at contaminated lands.

Additionally, in July 2012, EPA’s Office of Site Remediation Enforcement published a case study, From Midvale Slag to Bingham Junction: A Superfund Success Story, highlighting the use of the innovative enforcement mechanisms at the site.

The Bingham Junction light rail station on the Utah Transit Authority's Mid-Jordan/University Line opened on the site in August 2011.

Midvale Slag: 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.

All redevelopment construction at the Midvale Slag Superfund Site must be performed in accordance with the institutional controls, which may be found in the Midvale City Municipal Code Exit.

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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.

At the Midvale Slag Superfund Site, EPA has conducted two five-year reviews and issued two five-year review reports detailing its findings. In the 2008 five-year review report, EPA found that the remedy for both OU1 and OU2 continues to be protective of human health and the environment. The report also identified some outstanding issues needing to be addressed. See Site Documents to view the report. The third five-year review for the Midvale Slag site is currently being conducted and will be finalized by spring 2014.

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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.

Update to the Five-Year Review, June 2012

Preliminary Closeout Report, September 2011

Riparian Improvement Project Fact Sheet, September 2010

Second Five-Year Review Report (PDF), December 2008 (74 pp, 2.4 MB)

Riparian Improvement Project Fact Sheet, October 2008

OU1 Explanation of Significant Differences (PDF), February 2006 (9 pp, 476 K)

OU2 Record of Decision (PDF), October 2002 (276 pp, 8.4 MB)

OU1 Explanation of Significant Differences, May 1998

OU1 Record of Decision (PDF), April 1995 (73 pp, 148 K)

Reuse/Redevelopment Documents

Midvale Slag: Reuse Fact Sheet, September 2013

Case Study: From Midvale Slag to Bingham Junction: A Superfund Success Story, July 2012

SRI Return to Use 2006 Demonstration Project (PDF), Updated April 2012 (2 pp, 350 K)

Case Study: Cleanup and Mixed-Use Revitalization on the Wasatch Front (PDF), May 2011 (18 pp, 1.9 MB)

Ready for Reuse (RfR) Determination (PDF), May 2008 (103 pp, 10.1 MB)

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Kerri Fiedler
Environmental Engineer
U.S. Environmental Protection Agency, Region 8
1595 Wynkoop Street (EPR-SR)
Denver, CO 80202-1129
800-227-8917 ext. 312-6493 (toll free Region 8 only)

Jennifer Chergo
Office of Communication and Public Involvement
U.S. Environmental Protection Agency, Region 8
1595 Wynkoop Street (8OC)
Denver, CO 80202-1129
800-227-8917, ext. 312-6601 (toll free Region 8 only)

Site Information Repositories:

Tyler Branch Library
315 South Wood
Midvale, UT 84047

Utah Department of Environmental Quality
Division of Environmental Response and Remediation
195 North 1950 West
Salt Lake City, UT 84116

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)


Tony Howes
Environmental Scientist
Utah Department of Environmental Quality
195 North 1950 West
Salt Lake City, UT 84116

Dave Allison
Community Involvement Coordinator
Utah Department of Environmental Quality
195 North 1950 West
Salt Lake City, UT 84116

Midvale City

Ray Limb
Development Site Coordinator
655 West Center Street
Midvale, UT 84047

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Photo/Video Gallery

From Midvale Slag to Bingham Junction: how a complex multi-stakeholder process helped turn a badly contaminated former mining site into a major mixed-use redevelopment in the heart of Salt Lake Valley. Watch the video »


The following links exit the site Exit

Midvale City Website

Midvale City Municipal Code

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