lead and arsenic. Activities to clean up 100 years of accumulated impacts began in the 1990s, under state Utah Department of Environmental Quality and federal oversight and are ongoing. The EPA lists "Kennecott South Zone/Bingham" on its superfund webpage, after it was proposed to be listed as a superfund site in 1994. The South Zone includes the Bingham Mining District in the Oquirrh Mountains, about southwest of Salt Lake City, the open pit, waste rock dumps, Copperton Mill and other historic sites. The company avoided regulatory issues of being on the NPL by voluntarily cleaning up the contaminated lands, the Superfund Alternative Approach. The listing proposal was withdrawn in 2008. More than 25 million tons of mining wastes have been removed; sludge with elevated sulfate concentrations was consolidated and capped on site. 1900–1909 By 1904, there were three large copper smelters and one lead smelter in the Salt Lake valley. The sulfur dioxide gas emissions from the smokestacks caused significant crop damage to neighboring crops. During the 1904–1905 winter, the farmers gathered together and decided to file suit against the smelters in the United States District Court of Utah. In 1906, Federal Court Judge Marshall ruled that the smelters could not smelt ores containing more than 10% sulfur, effectively closing all of the aforementioned smelters. 1910–1979 Kennecott Copper Mines was formed in 1910 after a merger of Utah Copper and Kennecott copper mining companies. By 1912, environmental protection organizations were complaining about high levels of asbestos being used in the organization. Kennecott Corporation was using asbestos for preventing fires since copper processing requires very high temperatures. Copper has a very high boiling point and also requires use of other chemicals to separate it from other metals and impurities present in the ore. Asbestos has microscopic particles that dispersed into the atmosphere and contributed to illnesses among workers and individuals living near the mines. Asbestos is responsible for illnesses such as pleural fibrosis, skin warts and lung cancer. Kennecott Corporation was also cited as contributing to emissions of heavy metals such as arsenic and mercury. By 1940, arsenic and mercury were also some of the concerns that were raised by environmental protection agencies against Kennecott Corporation. Both mercury and arsenic are dangerous to health in even small quantities. 1980–1989 Investigations in the 1980s revealed contamination in the groundwater caused by mining operations the release of hazardous materials. The State of Utah