The U.S. Environmental Protection Agency (EPA) has released its preferred cleanup plan for the Sulphur Bank Mercury Mine Superfund site and is inviting the public to review and comment on the plan. The plan proposes cleaning up significant portions of the site in Clearlake Oaks, Calif., specifically the mine area, the sovereign territory of the Elem Indian Colony Tribe, and contaminated soils in the residential area to the southwest of the site.

“This proposed plan is the first step needed to reduce mercury levels in Clear Lake and address contaminated soil. These efforts will enhance public health and environmental safeguards, and advance environmental justice in the area,” says EPA Pacific Southwest Regional Administrator Martha Guzman. “EPA is committed to continuing to work with the Elem Indian Colony, the greater Clear Lake community and the Tribal nations as we develop a plan to clean up the Sulphur Bank site. We look forward to hearing the community’s feedback on our proposed plan.”

An extended public comment period is being provided to ensure that all impacted Tribes, communities, and stakeholders have adequate time to review the proposed plan before forming and submitting their comments. The plan is open for public comment until April 10, 2023, and the EPA Sulphur Bank team will meet with residents in the coming months and host virtual question-and-answer sessions, in-person open houses, and in-person final meetings.

Since 2021, EPA has offered monthly meetings for representatives from six of the Tribal nations that surround the lake and provided independent technical support through the Technical Assistance Serving Communities Program. Following the release of this proposed plan, EPA can continue close coordination with these tribal governments to ensure awareness of and involvement in cleanup efforts moving forward.

The 160-acre Sulphur Bank Mercury Mine Superfund site sits on the shore of Clear Lake in Lake County, Calif. Historic mining contaminated the property with unhealthy levels of mercury, arsenic and antimony. Contamination from the site also impacts the wetland area north of the mine and Clear Lake itself. Since the site was added to the Superfund cleanup program in August 1990, EPA has completed eight early cleanups to protect human health and the environment and reduce contamination in soil, lake water and sediments, fish and wildlife, and Tribal and residential properties near the mine.

The cleanup set out in the new proposed plan will protect the community and environment from the 2.5 million tons of mine waste and contaminated soil on the site, and also prevent that contaminated material from entering Clear Lake. EPA continues to study options for directly cleaning up mercury contamination in Clear Lake and wetlands near the mine site.

The goals for the proposed cleanup are:

  • Combining smaller waste piles with larger piles to reduce the area of contamination.
  • Putting a liner, clean earth, and clean soil over the contaminated waste and soil to: make residential areas safe for a lifetime of use; make on-mine areas safe for use by Elem Indian Colony residents (hunting, fishing, foraging, transit to nearby lands); and prevent contamination from leaving the site with stormwater or wind.
  • Limiting mercury entering Clear Lake to allow mercury levels in sediments and fish to decrease over time, and help EPA determine the cleanup needed for the lake.

This project and progress towards a final cleanup decision is being supported by the Bipartisan Infrastructure Law. The Bipartisan Infrastructure Law invests an additional $3.5 billion in environmental remediation at Superfund sites, making it one of the largest investments in American history to address the legacy pollution that harms the public health of communities and neighborhoods.

The public can submit comments to EPA on the proposed plan until April 10, 2023, in the following ways:

  • Email comments to EPA’s Gavin Pauley and Carter Jessop
  • Printed comments can be mailed to Gavin Pauley - EPA Community Involvement Coordinator, 75 Hawthorne Street (Mail Code: OPA-2) San Francisco, CA 94105. Mailed comments must be postmarked by April 10th.
  • Oral comments can be left on EPA’s voicemail box at: (800) 231-3075.

Once EPA has considered public comments on the proposed cleanup plan, it will respond to them in a “responsiveness summary” and make a formal decision on the cleanup in the “record of decision” that will guide the cleanup of the Sulphur Bank Mercury Mine site. EPA aims to make the final cleanup decision within a year of the close of public comment period. The proposed plan cleanup could begin as soon as 2025.

Learn more about the Sulphur Bank Mercury Mine site.

Learn more about EPA’s Pacific Southwest Region.