The Stockton area was the center of a silver and base-metal mining, milling and smelting district from the 1860s until 1970. By 1886, several smelters had been built within the Stockton area. Jacobs Smelter was located on the northeast end of Stockton within OU1 and operated in the 1870s. The largest smelter in the Stockton area was the Waterman Smelting Works, which opened in 1871 and operated continuously until 1886. The Chicago Smelter opened on the eastern shore of Rush Lake, two miles south of Stockton in, 1873 and operated until the fall of 1880. The Carson Buzzo Smelter was located about a half mile south of the Chicago Smelter and opened two smelters in 1873.
Other smelters operated for a few years and then shut down. The exact locations of these smelters are unknown, but several sites within the boundaries of OU2 are suspected due to the presence of elevated concentrations of heavy metals detected during site sampling.
Source: US EPA region 8, Superfund