Mammoth Mills And Smelter is a superfund site located at Mouth Of Mammoth Gultch, Eureka, UT 84628. The Environmental Protection Agency (EPA) identifies sites such as Mammoth Mills And Smelter because they pose or had once posed a potential risk to human health and/or the environment due to contamination by one or more hazardous wastes. Mammoth Mills And Smelter is currently registered as an Active superfund site by the EPA. However, it is not on the NPL (National Priorities List), which means the EPA does not consider it one of the nation's most hazardous waste sites.