Dioxin concerns

Tests for carcinogens in Oroville have troubling results

Geologist John Lane gathers soil samples near Arbuckle in Colusa County. He did the same thing in Butte County, which has led to the discovery of alarming rates of dioxins in the soil in South Oroville.

Geologist John Lane gathers soil samples near Arbuckle in Colusa County. He did the same thing in Butte County, which has led to the discovery of alarming rates of dioxins in the soil in South Oroville.


The soil around South Oroville is tainted by cancer-causing chemicals. That’s according to recent studies by local scientists concerned about dioxins left over from the Pacific Oroville Power Inc. (POPI) facility there. Some of the samples show levels so high they would make the World Health Organization shudder.

Of five local samples tested, one was determined to have 1,000 parts per trillion (PPT), far beyond the WHO’s 40 PPT level of concern. Another was found to have 170 PPT, while results for three others range from 4.4 to 32 PPT. Dioxins are a carcinogen that can cause reproductive problems and other human health problems.

The tests were triggered by the discovery of dioxins in the ash created by the operations of the POPI plant, which first fired up in the 1980s and created energy by burning timber waste—wood chips created by the downing of trees. But in the 1990s, as the timber industry died down in Northern California, the plant began burning urban waste—the remains of torn down buildings, which included asbestos, lead and other potentially environment-damaging materials.

When the Butte County District Attorney’s Office learned of the practice, it began testing the ash that resulted. High levels of dioxins were discovered. POPI was owned and operated by a New Jersey-based company called Covanta. The company stopped its Oroville operations in 2012 and was named in a lawsuit by a number of communities where such plants operated, including Butte County. Last year, the suit was settled with the local DA’s office collecting $186,000 of an $825,000 overall settlement.

Dioxins in the region may also have come from the nearby and now-closed Koppers wood treatment plant, which had major fires in 1963 and 1987 that resulted in dioxin-laden smoke and ash drifting across the area.

The soil tests are being paid for by both the DA’s office and the Butte Environmental Council (BEC) through a sub-group called the Oroville Dioxin Education Committee (ODEC). The soil samples and their location determinations are being organized by John Lane, the geologist who owns and operates Chico Environmental Science and Planning. Lane conducted the initial ash testing that revealed the presence of dioxins.

“The reason we were taking the samples initially was to investigate if anything was happening around the POPI facility,” Lane said. “Working with the District Attorney’s Office, we sampled the ash coming out of the POPI facility and it was extremely high.”

That recent soil sample test that showed 1,000 PPT was taken from private property along Bagget Marysville Road about a mile south of the POPI plant. News of the high-level test was met with serious concern by the DA’s office.

“We’ve never seen numbers that high in soil,” said Hal Thomas, the county’s environmental prosecutor, who’s been working on the POPI case since it began. “We saw 2,200 PPT in the actual ash at the POPI plant and we’ve had speculation about what we might find. Now it appears we are getting direct evidence of the problem at hand.”

The grid Lane created for soil sampling runs from about a half-mile north of downtown Oroville, west to include Thermalito and about 2 miles south of the POPI plant.

“Basically we made a grid of 30 locations in the South Oroville, Thermalito and Palermo areas,” he said. “We began the ODEC testing, which called for 30 samples that we’ve collected. We’ve spoken with Butte County Environmental Health and they are going to be putting some money up to collect some of the samples as well.”

BEC Executive Director Robyn DiFalco, whose organization has also tested chicken eggs in the area for dioxins, said she was not surprised by the test results.

“We’re glad it’s finally come through and now we can assess the risk to the county and help policy makers get more focused on how to respond,” she said.

DiFalco said the tests cost about $500 each and collecting the soil samples adds another $150. Thus far, BEC has received $4,000 from the Clif Bar Family Fund and another $3,000 from the Rose Foundation Grass Roots Fund, she said. “That is $7,000 so far, and we are hoping to get that much more for additional tests.”

Since dioxin doesn’t dissipate over time, continued testing for the presence of the carcinogen in other spots in the area are very much a necessity, she said.

“This is a multiyear process. In the past, the project felt daunting—it was so expensive that we were overwhelmed,” DiFalco said. “But the dioxin is not going anywhere. We can test this year and a test next year will still be comparable.”