The EPA's final decision will cost the responsible parties $342 million and will cover 177 acres of the lower Duwamish River. 960,000 cubic yards of contaminated sediment will be dredged from the bottom of the river, and 24 acres will be capped with clean sediment to lock away contaminants below the surface of the riverbed.
The EPA's final plan will cost $37 million more than the draft plan it released last year. It requires 20 percent more dredging be done. Dredging, while more costly than capping polluted areas, is widely seen as the most effective way to permanently remove pollution from waterways. It can be more disruptive in the short term because it stirs up contaminated sediment.
The EPA’s draft plan received 2,300 public comments, the majority of which called on the EPA to make the responsible parties dredge more contaminated sediment out of the river and ensure that the river is safe for recreational use and fishing.
“We have listened. We’ve been responsive,” EPA regional administrator Dennis McLerran said in an interview.
He called the final plan both achievable and affordable, adding that it "certainly is going to make the river much cleaner, over 90 percent cleaner than previously.”
The Duwamish has been an industrial hot spot for more than 100 years. It’s also now a hot spot for PCBs, dioxins and other contaminants that make the water unsafe for swimming and the resident fish and shellfish unsafe for human consumption. Despite warnings, people do catch and eat fish from the Duwamish.
Previously, the EPA had said there can be no guarantees that it will ever be safe to eat the resident fish and shellfish caught in the lower Duwamish.
GRAPHICS: EPA's dredging and capping plan
But this time around, the federal agency changed its tune. McLerran said people should eventually be able to eat fish from the river, depending on the success of the cleanup and ongoing efforts to limit stormwater runoff and other contamination from the urban environment surrounding the Duwamish.
Boeing, the Port of Seattle and others have already spent more than $100 million on six “early action” cleanups targeting the most contaminated parts of the lower Duwamish. The EPA says those actions will reduce PCB contamination by 50 percent. That early action cleanup spending is outside from the $342 million price tag on the final cleanup plan.
"The port and our partners have invested over $190 million in scientific studies and hot-spot cleanups in the river to get started on this effort," Peter McGraw, spokesperson for the Port of Seattle, said in an email. "We look forward to reviewing the EPA’s Record of Decision and continuing our work with them, along with our partners in the Duwamish cleanup."
The Duwamish River Cleanup Coalition has said it will convene community meetings to discuss the EPA’s decision in the coming months. BJ Cummings, policy advisor at the coalition, said the plan is an improvement over the EPA's draft plan, in that it permanently removes more toxic material from the river, but it's "most definitely not the end game."
Cleanup on the so-called early action sites is ongoing, with the final cleanup expected to get underway within the next two years. It is projected to take 17 years to complete, including monitoring.