Are chemicals still spreading near Northern California’s Placer County missile site? New research data reveals the latest

The latest data collected by the U.S. Army Corps of Engineers at the Titan 1 missile site in Placer County shows that despite long-standing concerns, new soil vapor probes placed closest to homes in the Sun City Lincoln Hills development show no signs of trichloroethylene (TCE), a chemical that can cause health problems.

However, the monitoring probes did detect low levels of benzene, a chemical linked to cancer, in the wells closest to the homes. Officials said the source of the benzene was not immediately clear, but the levels found did not appear to be dangerous.

Titan 1 missiles were a Cold War project. The Lincoln site, one of three in California, covered dozens of acres in a then-remote part of Lincoln, with miles of tunnels, three 160-foot-deep silos and other operations and housing buried underground.

A chemical called TCE leaked from the silos after it was used to clean up the site during three years of operation. Groundwater and soil vapors containing the toxic substance have spread toward Sun City Lincoln Hills, a community of about 11,000 people, for people 55 and older.

As the Army Corps conducts tests to determine how to address TCE contamination, they update the public on the findings during quarterly meetings of the Restoration Advisory Board.

During one of those meetings, the board presented early findings from the most recent data collected by the Army Corps, according to a press release from the Restoration Advisory Board. Those findings were preliminary, as a final report of the most recent data has not yet been made public.

“In order to produce these reports, they have to go through a lot of internal reviews and comments,” Ranny Eckstrom, co-chair of the board of directors, said in an interview.

Eckstrom said the final report should be released in the coming weeks, after the federal Comprehensive Environmental Response, Compensation, and Liability Act process the Army Corps must follow is completed.

“They announced that they found benzene because they didn’t want to hide it or fuel conspiracies. Benzene is very common,” Eckstrom said.

The preliminary findings came from newly installed soil vapor monitoring probes closest to Sun City homes. Although other probes have been around the site for years, these were added to help determine how far the soil vapor plume extends from the site.

Probes in the center of the known soil vapor and groundwater plumes have shown the most concentrated levels of TCE. Homes in Sun City remain outside the edge of the estimated plume.

Benzene was detected in two soil vapor probes near Sun City homes and three near St. Joseph Catholic Church, which is adjacent to the site, the advisory board said. No other data on groundwater levels of TCE or benzene were released.

Eckstrom, a retired engineer, added that the benzene most likely did not come from military activities at the site because they occurred so long ago. A toxicologist at the meeting also said that the benzene levels measured would be no more dangerous than filling up your car at a gas station.

The Army Corps formed the Restoration Advisory Board in response to a survey of local residents, which revealed that residents knew less about the restoration effort than they thought.

Eckstrom said the board communicates updates and history of the site to the community and tries to articulate findings and processes in plain language that is more understandable than official Army Corps documents and reports.

In addition to hearing and discussing residents’ concerns, the restoration council, made up of 11 volunteer residents, oversees the Army Corps and its processes, Eckstrom said.

“We can take a very critical look at what they can and may do within the context of the law.”

Cleanup efforts were conducted by the Army Corps in the early 2000s, using extraction trenches and wells that removed 10 pounds of TCE from the groundwater. The efforts were halted in 2009 when the Army Corps began questioning whether the county should be responsible for the cleanup because of its ownership and use of the site, The Sacramento Bee reported in 2011.

Between 2000 and 2022, the TCE-contaminated groundwater plume spread at an average rate of 7 feet per year, moving a total of 150 feet toward Sun City Lincoln Hills.

Dispelling fears and misunderstandings about the dangers of the site is also a key role of the board, Eckstrom added. They have worked to meet with realtors and create a fact sheet with meeting and restoration schedules.

“One of the things the Army Corps could do better is communication. We’re part of that,” Eckstrom said. “I understand the fear, but I don’t think the level of fear is warranted.”

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