Midvale Slag

Overview

Five lead and copper smelters operated at the 446-acre Midvale Slag site from 1871 to 1958, leaving soil and groundwater contaminated with heavy metals and other chemicals. The site spans parts of Midvale City and Murray City, Utah, and was added to the federal Superfund National Priorities List (NPL) in February 1991. Today it is a mixed-use development called Bingham Junction, with homes, offices, stores, and light rail infrastructure.

Contaminants found at the site include heavy metals such as arsenic, lead, cadmium, chromium, copper, mercury, and zinc, as well as organic chemicals including benzene, trichloroethene, and tetrachloroethene. These substances were detected in groundwater, soil, surface water, sediment, and solid waste across a Northern Zone and a Southern Zone.

Cleanup addressed both zones separately. The Northern Zone saw soil removal and replacement at Winchester Estates, plus groundwater monitoring and institutional controls. The Southern Zone involved regrading smelter waste and slag, installing a vegetated soil cover, and completing the Jordan River Riparian Improvement Project between 2008 and 2010. That project removed a damaged dam, added stabilization structures, and restored native vegetation. Construction was finished in September 2011. Groundwater migration is considered under control, and the EPA deleted the site from the NPL in April 2015. The EPA gave Midvale City an "Excellence in Site Reuse" award for the redevelopment.

As of October 2025, the EPA is reviewing risks from lead in soils and yards under a new Lead Directive that changes the blood lead level of concern and the soil screening level used at Superfund sites. Lead poses particular risks to children under 7 and pregnant or nursing women. Families near the site with young children who have not had soil replaced are advised to test their children annually for lead. Drinking water comes from the Jordan Valley Water Conservation District, and groundwater use is restricted by state and local ordinances. Five-year reviews have been conducted since 2003, most recently in April 2024, and the site has not yet achieved sitewide ready-for-anticipated-reuse status.

Community members can contact the EPA's Community Involvement Coordinator. Site records are available at the Tyler Branch Library in Midvale, the Utah Department of Environmental Quality (UDEQ) office in Salt Lake City, and the EPA Superfund Records Center in Denver. Copies of administrative record documents can be requested by calling 303-312-7273 or 800-227-8917 extension 312-7273 (toll-free for EPA Region 8 only).