Lava Cap Mine Public Health Assessment

Timeframe: 1997 to 1999

In 1997, a severe winter storm caused a dam failure which resulted in the release of mine tailings from the Lava Cap Mine into Little Clipper Creek, Lost Lake, and the Little Clipper watershed, causing significant arsenic contamination of the area. The Agency for Toxic Substance and Disease Registry engaged IAI to conduct a public health assessment of the site for the purpose of evaluating off-site exposures to arsenic and their potential threats to public health. IAI determined that people and animals would be exposed to arsenic if they swam in the creeks or in Lost Lake, ate fish from Lost Lake, or inhaled dust or dirt near the mine site. Dust and dirt in homes in the affected area and drinking water from contaminated wells were also potential sources of exposure. In sufficient doses, exposures occurring over many years could result in an increased risk of certain skin problems, as well as a low to moderate increased risk of several cancers. For this reason, IAI recommended that the Lava Cap Mine site be classified as a Public Health Hazard.