The U.S. Environmental Protection Agency (EPA) listed the lower Duwamish River--a five-mile stretch through South Seattle--as a federal SUPERFUND site in 2001. The Superfund List is a roster of the most toxic contaminated sites in the country. In 1998, King County found that fish and crab caught in the Duwamish River have up to seven times more cancer-causing chemicals in them than those from clean sites. PCBs--an industrial cancer-causing chemical--are found in nearly all salmon in the river, and the river bottom exceeds safe standards for heavy metals like mercury by up to 400%.

While thousands of salmon still return to the river and restoration efforts are slowly rebuilding pockets of habitat, historical and ongoing pollution threatens a full recovery. Because of the serious health concerns, EPA is requiring extensive studies of the risks to people, fish and wildlife and will require the major contributors to the pollution to pay for its cleanup.