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In 2001, the U.S. Environmental Protection Agency (EPA) used the federal Superfund law (also known as CERCLA) to begin its own cleanup efforts and liability assignments in the Lower Duwamish. The Washington State Department of Ecology is also involved, using its authority under the Model Toxics Control Act.

The Superfund cleanup seeks to reduce risks to human and environmental health by improving the quality of the Lower Duwamish Waterway’s muddy river bed, also known as sediments. This cleanup will build on more than 40 years of work King County and Metro have undertaken to reduce the contamination flowing into the Lower Duwamish.

Learn more about the cleanup process:

Milestones for Lower Duwamish Waterway Superfund Site cleanupSource: Page 6 of Executive Summary, Draft Final Feasibility Study, Lower Duwamish Waterway (PDF, external link).

Duwamish Waterway, looking southeast with Mount Rainier in the distance

Why is the cleanup happening?

State and federal regulators are using the Superfund process to assess conditions at specific sites within the waterway, establish and implement appropriate cleanup plans and enforce a long-term cleanup process for the waterway.