Afterthought Mine sits near Bella Vista in Shasta County, California. It operated intermittently from 1862 to 1952, producing copper, zinc, lead, silver, and gold. The EPA added it to the National Priorities List on September 5, 2024, making it eligible for federal cleanup funding.
Historic mine waste left behind arsenic, cadmium, copper, lead, mercury, and zinc. These contaminants are found in soil, tailings, sediment, and surface water. When water contacts the waste, it forms acid mine drainage that flows into Little Cow Creek and Afterthought Creek, both tributaries of the Sacramento River. Fish in these creeks, including Chinook salmon, rainbow trout, and several bass and trout species, pose a potential health risk if eaten. In January 2025, EPA found a sudden discharge of acid mine drainage, partly caused by stormwater entering the mine shaft. A large release could turn the creek orange and spike cadmium, copper, and zinc levels. As of January 23, 2026, monitoring shows no sign of a sudden large release, though EPA continues to watch the discharge closely.
Cleanup work is in its early stages. An initial assessment was completed in September 2019, and a remedial investigation began in May 2025 to map contamination and evaluate cleanup options. EPA has redirected clean stormwater away from the mine shaft to reduce acid mine drainage. Equipment monitors mine water flows, and a stormwater diversion ditch is complete. A removal action is estimated to start between October and December 2026, with completion targeted between October and December 2027. Physical construction of the full cleanup is not yet complete, and the site is not ready for its anticipated future use. Institutional controls, including zoning restrictions, are already in place to block residential development and limit exposure. The public should stay away from the mine and smelter areas due to cadmium, copper, zinc, mercury, and lead contamination in soil, tailings, and acid mine drainage.
Community members can stay involved through EPA's outreach process. EPA planned to meet with residents in 2025 to discuss how people can best provide input, and a Community Involvement Plan was scheduled to be completed by February 2026. As of June 2026, no Community Involvement Plan had been uploaded to the EPA's official profile page for this site.
For questions or to share feedback, contact the EPA Community Involvement Coordinator or Remedial Project Manager assigned to this site.
