International Smelting and Refining

Overview

The International Smelting and Refining site sits about two miles northeast of Tooele, Utah. It operated as a copper, lead, and zinc smelter from 1910 until 1972. Decades of smelting left soils, tailings, and slag contaminated with heavy metals across the site and neighboring lands. The U.S. Environmental Protection Agency (EPA) added it to the National Priorities List (NPL) in July 2000 and deleted it in October 2011 after cleanup goals were met.

Arsenic and lead in soil are the two contaminants of concern. Both pose risks to human health across the sitewide area. Atlantic Richfield, the responsible party, led the cleanup. Work started in 2005 and included excavating up to 18 inches of contaminated soil from residential properties, schools, and recreation areas. Clean soil or rock was placed over areas where contamination remained below cleanup thresholds. At the Pine Canyon Conservation Area, a 12-inch soil cover was placed over contaminated spots. Fencing and barriers went up to restrict access to hazardous areas. The long-term remedy, finalized in 2007, added groundwater monitoring, a conservation easement, and environmental covenants to prevent groundwater use and future soil contact.

Groundwater migration is under control. Contaminated groundwater is stabilized with no unacceptable discharge to surface water, and monitoring continues to confirm it stays within the original contamination area. However, human exposure cannot yet be fully assessed. EPA has rated human exposure control as "Insufficient Data" because uncertainty about current exposure pathways prevents firm conclusions. Cleanup goals affecting current and anticipated future land uses have not been fully achieved across the entire site. EPA is also evaluating lead risks under an updated Lead Directive released in October 2025, which changed the blood lead level of concern and the soil screening level used at Superfund sites. EPA recommends annual lead testing for children living near the site whose properties have not had soil replaced, especially children under 7 and pregnant or nursing women.

The former smelter area is now the Pine Canyon Conservation Area, managed by the Utah Division of Wildlife Resources for hiking, horseback riding, wildlife observation, and seasonal hunting. Part of the former railroad cleanup area is now the city-owned Oquirrh Hills Golf Course, and the former railroad right-of-way is a biking and walking trail. As of December 2024, three on-site businesses employed 14 people. The most recent five-year review was completed in July 2022, and the next is expected between July and September 2027.

Community members with questions can contact the EPA Community Involvement Coordinator or the Remedial Project Manager. The Utah Department of Environmental Quality also has staff available to answer questions about the site.