Kaiser Trentwood’s plant along the Spokane River has a long, illustrative history.
Built to produce aluminum for military planes during World War II, the factory later became a steady source of blue-collar jobs for generations of Spokane-area residents.
But the site bears the scars of nearly 70 years of heavy industrial use. The soil and groundwater surrounding the plant are polluted with hydrocarbons, some dating back to the Bunker C fuel oil used at the factory during the 1940s.
PCBs – which were added to hydraulic oils as flame retardants – are also present in the groundwater.
Kaiser Aluminum’s plans for a $16 million cleanup of historic pollution at the property over the next 30 years will be discussed at a Thursday meeting. Public comments on the plan will be accepted through March 6.
Cleanup of the 512-acre site is a top priority for the Washington Department of Ecology.
“It’s a large site with a significant amount of contamination over the aquifer and it’s very close to the Spokane River,” said Jani Gilbert, an Ecology Department spokeswoman.
The Spokane River violates state standards for cancer-causing PCBs, also known as polychlorinated biphenyls, which has led to health advisories for limiting meals of fish from the river. The Ecology Department is working with other agencies and partners to identify how the long-banned PCBs are getting into the river.
“Here’s a source that’s known, and it’s a big source, so we need to get it cleaned up,” Gilbert said.
Bud Leber, Kaiser Trentwood’s environmental manager, said the company is committed to cleaning up the site and protecting the river’s water quality.
Kaiser has already spent $12 million on environmental remediation, he said. The company has installed 160 monitoring wells at the Trentwood property, skimmed 4,000 of gallons of oil from groundwater, removed underground petroleum tanks and hauled off 23,000 cubic yards of tainted soil. To keep plumes of polluted groundwater from reaching the Spokane River, an ongoing pumping and treatment system is in place, Leber said.
Based on extensive analysis, including tracking the chemical “fingerprints” of PCBs on the site, Kaiser officials believe that contaminants aren’t leaving the Trentwood property, Leber said. But Ecology Department officials say they need assurance that low levels of PCBs aren’t migrating into the river.
The company’s cleanup plans call for removing up to 20 feet of soil in polluted areas. Where pollution is deeper, the ground would be capped to prevent water from filtering through the site and mobilizing contaminants.
Kaiser officials have also been intrigued by a site where bacteria in the soil appear to be breaking down PCBs.
“The biological activity is a bonus,” Leber said. “It’s almost like Mother Nature is saying, ‘We’ll jump on it from here.’ ”
Kaiser has proposed additional monitoring and studies of the bacteria’s actions. To date, company officials haven’t been able to pinpoint exactly what is happening, Leber said.
Ecology officials, however, say they would need hard evidence that bacteria is breaking down PCBs before the state officials would accept it as a cleanup remedy at Trentwood.
“We have no scientific documentation that that would work,” Gilbert said. “The whole thing about PCBs is that they persist for so long in the environment. We have not heard of a process that breaks them down.”