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Koppers Superfund in Oroville

Koppers Superfund Site in Oroville & BEC's Tests for Dioxin Levels

You may recall a 2008 story on the cancer cluster reported in Oroville but because of the time lag, you may not connect this story with the 1987 fire at the Koppers wood treatment facility in. The fire released a toxic cloud of dioxins that settled on south Oroville. In 2001, the California Dept. of Public Health (CDPH) tested backyard chicken eggs and found that dioxin levels had not gone down. Last year, the Butte Environmental Council tested another round of eggs and found there were still dangerously high levels of dioxin.

The Butte Environmental Council received a grant in September of 2010 from The California Wellness Foundation (TCWF) to educate about reducing exposure to toxic substances in Butte County. Most of this TCWF grant money was dedicated to testing eggs in south Oroville for dioxins.

Our goal was to add to the testing done by the California Department of Public Health (CDPH) Environmental Health Investigations Branch (EHIB) in 1988 and 1994, after the fire at the Koppers wood treatment facility that created dioxins by burning pentochlorophenol, a chemical used to treat wood. Testing dioxins is expensive—between $800-$1000 per test—because testing is done for the 17 most toxic “congeners” (kinds) of dioxins. This made it very unlikely that residents would do any testing on their own.

When we found out that EHIB had no plans to do any additional testing, we felt that it was important to get some idea of how high dioxin levels remained in the area, as dioxin can persist in soil for decades. The Public Health Advisory from 2004 recommended that people not eat eggs from home-raised chickens in Oroville; we wanted to know if dioxin levels were high enough that California Dept. of Public Health should run the advisory again.

Our first round of testing showed a range of dioxin levels from very low (surprisingly, the lowest level was the closest to the Koppers site) to alarmingly high. We collected another round of samples; the results were also widely varied. Click on the link to see a map of approximate egg locations and measurements.

The Toxic Equivalency Quotient (TEQ) system was developed to be able to compare the relative risk of exposure in areas of contamination that vary widely in the composition and level of the 17most toxic dioxins and furans. Each of the seventeen highly toxic dioxins/furans are assigned a Toxic Equivalency Factor (TEF) based on a particular chemical’s toxicity relative to 2378-TCDD, with the toxicity of TCDD being equal to 1.0.
The concentration of each dioxin/furan is multiplied by its respective TEF and the results are summed up. The added results are known as the TEQ of the sample. The most commonly used TEQ in the United States is the World Health Organization (WHO) 2005 version. [More on TEQ.]

The Koppers Co., Inc, a wood-treatment plant in South Oroville, closed in March after more than 50 years of operations, the byproducts of which led to its listing as a EPA Superfund site in 1984.