Sharon Steel operated as a custom ore milling facility from 1906 to 1971 and ores processed at the site supplied the Midvale Smelter and several other smelters. The mill was closed when the Sharon Steel Corporation purchased the facility in 1971 from United States Smelting, Refining, and Mining. The site today includes about 270 acres and contains an estimated 12 million tons of mine tailings from 1 to 60 feet in depth. Lead and arsenic are the most significant toxic contaminants on the site, though cadmium, zinc, nickel, mercury, and other heavy metals are also present. The Jordan River is contaminated by tailings deposition and runoff adjacent to and downstream from the site. The soils of an adjacent residential area are contaminated with lead as a result of wind-blown tailings and smelter fallout.
Midvale Slag, located immediately north of the Sharon Steel site, encompasses about 300 acres. Various smelting wastes (slag, dross, bag house dust, etc.) are present on approximately one-half of the site, the result of smelter operations from 1902 to 1958. An estimated 2 million tons of slag currently exist at Midvale Slag. Heavy metals, most notably lead and arsenic, are also the primary contaminants of concern at the site. Aerial photographs taken in 1937 show that tailings from Sharon Steel were deposited in the Jordan River floodplain and eroded into the river. In the 1950's, the Jordan River was routed to the west around the Sharon Steel site by channelization for flood control purposes. By 1965, tailings from Sharon Steel had completely buried the old Jordan River channel. During operation of the Sharon Steel mill, the tailings ponds were covered with shallow water that attracted large numbers of waterfowl during migration periods. Though dead birds were reported from that period, no documentation exists to confirm numbers or species. The tailings ponds have been dry since cessation of mill operations, except for temporary impoundment of water after heavy precipitation.
Though slag from the smelter at Midvale Slag was also placed directly in Jordan River floodplain wetlands, it is not known whether slag was placed in the Jordan River itself. In 1975, a series of sewage lagoons were developed in a wetland complex located on the north end of the site. In these wetlands, special construction measures allowed for development of treatment lagoons despite the "swampy nature of the soils" in the area. In 1985, the facility was closed and the majority of the original wetlands were filled.