Sulphur Bank Mercury Mine

⚠ Superfund · Cleanup underway

Operable Unit 1 Status (Mine Site Area and Residential Soils North and South of the Mine)

Location

CityClearlake Oaks
CountyLake County
StateCalifornia
Coordinates39.00555, -122.67030

Contaminants of concern

Contaminated media

Cleanup timeline

  1. Initial Assessment Completed — 06/01/1987
  2. Proposed to the National Priorities List — 06/24/1988
  3. Finalized on the National Priorities List — 08/30/1990
  4. Remedial Investigation Started — 09/28/1990
  5. Remedy Selected — 11/09/2023
  6. Remedial Action Started — 09/26/2024
  7. Construction Completed — Estimated Dec 2027 - Feb 2028
  8. Deleted from National Priorities List — Not Yet Achieved
  9. Most Recent Five-Year Review — Not Yet Achieved
  10. Achieved Sitewide Ready for Anticipated Reuse — Estimated Dec 2027 - Feb 2028

EPA references

Understanding this Superfund site

Sulphur Bank Mercury Mine is a federal Superfund site in California. The Superfund program, created by Congress in 1980, addresses sites where hazardous substances have been released or threaten release into the environment. EPA scores potential sites using the Hazard Ranking System; those that score high enough are placed on the National Priorities List.

Current status: Cleanup underway. Active cleanup is underway, meaning EPA has approved a remediation plan and work is in progress. Cleanup timelines vary widely — some sites take decades depending on contamination depth, groundwater involvement, and funding availability.

EPA has identified 4 contaminants of concern at this site, including antimony, arsenic, mercury. Contamination has been detected in soil, groundwater.

If you live near this site and have health concerns, your state health department can provide site-specific guidance. EPA maintains a community involvement program for most NPL sites, and site documents — including the Record of Decision, five-year reviews, and public health assessments — are typically available through EPA's Superfund site profile.