Extensively dredged and filled since the 1800’s, this 12-square mile site consists of eight industrialized waterways, shorelines and uplands. Nearly 300 industries have produced a variety of hazardous substances such as solvents, metals, PCBs, pesticides, dioxins and PAHs which end up in the air, surface and ground water, as well as the sediments and soils of the Commencement Bay area. Beginning in the 1920's, eight channelized waterways received the releases of concentrations of 100 to 1000 times those in reference areas were measured for 28 contaminants or contaminant groups. This widespread contamination led the Environmental Protection Agency (EPA) to list the site in 1981 as a Superfund site.

Contaminants released from activities such as ship building and repair, timber-related pulp and kraft milling, oil refining, chemical manufacturing and storage, aluminum and specialty ore smelting, and automotive repair and recycling, have impacted many species of fish and wildlife of South Puget Sound. Impacted wildlife includes bottom-dwelling organisms, birds and salmon. These contaminant related impacts include fishery closures and warnings, exceedances of State water and sediment quality standards, fin erosion, tumors in fish, reproductive and behavioral effects, suppressed disease resistance, and reduced populations. Consumption advisories are in effect for many fish species in the area due to the elevated levels of PCBs, mercury, and other contaminants.

Since 1991, the Commencement Bay Trustees have negotiated 19 settlements, which have recovered funding from polluters or required polluters to take actions to restore resources injured by releases of hazardous substances and discharges of oil. The Commencement Bay Restoration Plan was finalized in 1996 to oversee and implement a series of restoration projects across the Bay. Using the ecosystem-wide approach, each project has a specific purpose to address the injuries and to promote natural processes and functions.