Superfund site safe, but cleanup continues

The U.S. Environmental Protection Agency, in its third five-year review of the Koppers Superfund cleanup site in Oroville, has concluded that constraints on its use have made it safe. Groundwater contamination on- and off-site remains, however, despite 15 years of “pump-and-treat” remediation.

For 43 years, until March 31, 2001, Koppers operated a wood-treatment facility at the 205-acre site. Faulty handling of hazardous substances such as pentachlorophenol resulted in serious contamination of the soil and groundwater. Nearby wells used for drinking water were found to contain toxins.

Contaminated surface soil was placed in two lined and capped landfill cells, and the entire site was restricted to industrial use. Residents whose wells are within the contaminated plume have received an alternate source of drinking water. Efforts to clean up the remaining polluted groundwater continue.