LAKE COUNTY, Calif. — U.S. Environmental Protection Agency staff held an online meeting with community members on Wednesday to report on the decades long effort to plan and carry out the cleanup of the Sulphur Bank Superfund site in Clearlake Oaks.

The 160-acre site, mined for sulfur and mercury between 1865 and 1957, has two million cubic yards of contaminated mine waste along with the Herman impoundment, a flooded open pit mine that’s filled with water contaminated by mine waste that’s impacting Clear Lake.

The mine site has been on the Superfund list since 1990.

While the process has been a slow one, officials estimated they are now within four years of beginning the main cleanup project, with the proposed plan for the cleanup expected to be released this fall.

Officials said the two-hour online meeting — which included descriptions of work and planning, and a chance to discuss the site in breakout rooms — was the result of a March planning group meeting. The goal was to update the community on the status of the project and its lengthy planning process.

Rusty Harris-Bishop, the EPA California Cleanup Sites Section manager, said they recognized how the site and its contamination have impacted livelihoods, the way of life and use of the lake, and prosperity of the community, and they wanted to hear input as they move the cleanup forward.

“Superfund is a very process heavy effort,” he said.

“It takes a long time and we recognize that,” he added.

Harris-Bishop said the agency has heard from people who want to see what EPA is doing as well as more action. “Things are going on as we’re doing this engagement.”

The situation at the site

Carter Jessop, the site project manager, said the material mined out of the Herman pit is significantly higher in mercury, arsenic and other metals.

Those materials originally were contained in bedrock and not exposed to air and water. Once the materials were exposed, Jessop said they leach out acidity and metals that get into the environment and impact community health.

Next to the Herman pit is a waste rock dam, which Jessop said isn’t an engineered dam but a pile of waste rock that creates a barrier between the pit and Clear Lake. The dam causes the pit’s water level to be above that of Clear Lake.

He showed a conceptual site model that illustrated how the water from the Herman pit can flow as groundwater through waste rock and into Clear Lake.

The water from the pit itself isn’t the problem, said Jessop. Rather, it’s the waste rock the water flows through, causing it to pick up more contaminants. That’s an ongoing problem for Clear Lake.

He said the mercury carried from the mine site binds to the sediments on the bottom of the lake. It’s then transformed into another form of mercury and moves up the food chain, becoming more concentrated.

Predator fish can have high levels of mercury. Because of that high concentration of mercury in fish, the state of California has issued a fish advisory for Clear Lake that outlines how much of the fish people can safely eat, Jessop said.

Jessop said the consumption of fish from Clear Lake is the greatest source of risk from mercury.

Unauthorized entry on the mine site offers risk of arsenic contamination, said Jessop, adding that there also is substantial naturally occurring risk due to arsenic and mercury.

The proposed plan

The EPA’s work is expected to result this fall in the publication of its proposed plan for the mine site, which will have a separate public process. Jessop said the document is now going through the EPA’s internal review process.

Jessop said the plan is fairly brief; it’s about 25 pages and is meant to summarize EPA’s preferred cleanup approach.

The cleanup, as proposed, will be broken into two phases, consolidation and capping, Jessop said.

Consolidation will include moving smaller waste piles onto larger waste piles to shrink the footprint of the area that requires major remediation, he explained.

They will then place a cap — a barrier layer like heavy plastic — over the site then cover that with clean soil so vegetation can grow, Jessop said.

Jessop said the plan aims to block the mine waste’s interaction with air and water, and stormwater management will be important.

There will be additional signs and fences, work with the local community and a period of monitoring after the project is completed.

Once the plan is released in the fall, there will be a public meeting followed by a 60-day comment period, Jessop said.

He said formal decision making and final design will follow the proposed plan, which must be approved by the EPA headquarters and administrator in Washington, DC.

Jessop said the EPA has a really robust record of documents and a very strong understanding of the site, which are benefits of the lengthy process.

He said construction could begin as soon as 2025.

Because the mine doesn’t have a “responsible party,” the entire cleanup is being covered by taxpayer funds, EPA staff said.

The site also isn’t owned by the agency so it will not manage the mine site long-term. Harris-Bishop said once the cleanup is completed, the property will be the responsibility of someone else.

Staff did not specify who will be responsible, but a 2012 settlement the EPA reached with the U.S. Department of the Interior, the U.S. Forest Service, the Bradley Mining Co., the Worthen Bradley Family Trust and the Elem Indian Colony of Pomo Indians called for the Bradley Mining Co. and Bradley Trust to transfer nearly all of their land holdings at the Sulphur Bank Mercury Mine to a new trust created to retain the lands pending EPA cleanup.

EPA also is constrained to clean up the site to what it would have been under natural conditions, it was explained during the meeting.

Next steps

As far as what’s next, EPA staff, it's the proposed plan’s release in the fall.

For those who want to follow the process, sign up for the email list here or contact community involvement coordinator Gavin Pauley at This email address is being protected from spambots. You need JavaScript enabled to view it.or 415-535-3725 to be added.

The administrative record, which includes the documents and studies completed so far, will be online at the EPA website, and a physical copy will be available at the Redbud Library in Clearlake.

A summary of the meeting is expected to be posted on the EPA website by the end of June.

Email Elizabeth Larson at This email address is being protected from spambots. You need JavaScript enabled to view it.. Follow her on Twitter, @ERLarson, or Lake County News, @LakeCoNews.