commencement bay, near shore/tide flats


The Commencement Bay Nearshore/Tideflats Site covers 12 square miles in Tacoma, Washington, and includes more than 300 active businesses and nearly 500 identified point and non-point sources of contamination. The site is divided into a number of separate Project Areas being managed as distinct sites. Construction is underway or completed at some of the Project Areas. These Project Areas include Asarco Tacoma Smelter, Ruston/North Tacoma Study Area, and Commencement Bay Nearshore/Tideflats. Project Area #1: Asarco Tacoma Smelter Tacoma/Ruston, Pierce County, Washington Asarco’s smelter property (or plant site) occupies about 67 acres. Prior to 1890, sawmills were active in the area and deposited wood waste along the shoreline. From 1890 through 1912, the property was used as a lead smelter and refinery. Asarco purchased the property in 1905 and converted it in 1912 into a facility to smelt and refine copper from copper-bearing ores and concentrates shipped in from other locations. By-products of the smelting operations were further refined to produce other marketable products, such as arsenic, sulfuric acid, liquid sulfur dioxide, and slag. Asarco ended operation of the smelter in 1985. Many of the smelter buildings and structures were constructed on slag fill. The shoreline was extended when molten slag from smelting operations was poured into Commencement Bay. The 23-acre slag peninsula comprises different forms of slag (molten and granulated) that were poured or placed on many occasions since the 1940s. Its primary surface features are the Tacoma Yacht Club building, a paved access road, and paved parking areas. An estimated 15 million tons of slag exist at the smelter property and slag peninsula. Project Area #2: Ruston/North Tacoma Study Area Tacoma/Ruston, Pierce County, Washington The Study Area, approximately 950 acres, comprises an arc of approximately one mile radius surrounding the Asarco Tacoma smelter and includes the town of Ruston and a northern portion of the city of Tacoma. The Study Area land is primarily residential and includes schools, playgrounds, and parks. The Study Area includes a population of approximately 4,290 and about 1,820 housing units. Project Area #3: Tacoma Tar Pits Tacoma, Pierce County, Washington The Tacoma Tar Pits Operable Unit 3 is within the Tacoma Tideflats industrial area near Commencement Bay. It is situated on a peninsula of land located between the Puyallup River and the Thea Foss Waterway, approximately three-quarters of a mile north of Interstate 5. The total area of the site encompasses approximately 52 acres. Imported or dredged fills were placed in the vicinity of the site around the turn of the last century to provide foundation support for structures associated with a meat packing plant, a bulk fuel storage facility, and railroad tracks. In 1924, a manufactured coal gasification plant began operating on the eastern portion of the site. It operated on the site through 1956 and the facility was demolished in 1966. Waste materials remaining on site from coal gasification operations included coal ash, coal tar liquor, and coal tar solids and semisolids. This waste material was either buried on site at shallow depths or disposed of in on site ponds. Starting in 1967, a portion of the Tacoma Tar Pits site was used for metal recycling operations by Joseph Simon & Sons (JS&S, now Simon Metals). As part of construction and operation of the metals recycling facility, a variety of new fills were emplaced, including metal debris, soil, and shredded car interiors referred to as “auto fluff.” During the early operational history of the recycling facility, metals predominantly from automobiles and electrical transformers were recycled. Recycling of transformers led to the release of oils containing polychlorinated biphenyls (PCBs). The auto fluff used as fill also contained PCBs as well as heavy metals. The metal recycling operations on site are still currently active; however, auto fluff and other materials containing PCBs are no longer being handled at the facility. Several active facilities are currently within the site boundaries including Simon Metals, the Northwest Detention Center (NWDC; an immigration detention facility), and a capped engineered waste pile and groundwater treatment plant constructed as part of the remedial action for the site. Project Area #4: Tideflats Areas Tacoma, Pierce County, Washington Commencement Bay Nearshore/Tideflats (CB/NT) consists of 10-12 square miles of shallow water, shoreline and adjacent land, most of which is developed and industrialized. Marine sediments are contaminated from diverse industrial activities including shipbuilding, oil refining, chemical manufacturing and storage, and pulp and paper mills, dating from the turn of the century. EPA’s 1989 Record of Decision (ROD) set forth a cleanup plan which included control of upland sources, followed by sediment remediation by dredging and containment or capping, for eight contaminated sediment problem areas in the St. Paul, Sitcum, Hylebos, Thea Foss, Wheeler Osgood, and Middle Waterways. CB/NT was the first site in the nation to complete a partial delisting of clean areas from the NPL. The delisted areas comprise about 1,000 acres or 10-15% of the site. The partial delisting was completed on October 29, 1996.

Hazardous Ranking Score

42 / 100

A score of 28.5 or higher qualifies a site for the Superfund National Priority List.

Regional Contact

Region 10
Phone: (800) 424-4372

Contact Region



Site Inspection
Preliminary Assessment
Final Listing On NPL

Contaminants & Health Effects

      Endocrine Disrupter
      Reproductive Toxin
      Persistent, bioaccumulative and toxic


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        within a 1 mile radius


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