Commencement Bay, South Tacoma Channel

Overview

The Commencement Bay, South Tacoma Channel site covers 2.5 square miles in Tacoma, Washington. It includes three cleanup areas: Well 12A, South Tacoma Field, and Tacoma Landfill. Industrial activities dating back to 1892, including rail car manufacturing, waste oil reprocessing, foundry operations, and landfill use, contaminated soil and groundwater with hazardous chemicals. The site was added to the National Priorities List (NPL) in 1983. Physical cleanup construction finished in 1999, but the site has not been fully deleted from the NPL and still needs more work before it is ready for all anticipated uses.

Contaminants found across the site include volatile organic compounds (VOCs) such as benzene, toluene, vinyl chloride, and trichloroethene. Chlorinated solvents including tetrachloroethene and 1,1,1-trichloroethane are present in groundwater and soil. The South Tacoma Field also contains metals like lead, arsenic, and copper, along with pesticides, polychlorinated biphenyls (PCBs), petroleum hydrocarbons, and polycyclic aromatic hydrocarbons (PAHs). Contaminants have been found in soil, groundwater, surface water, and landfill gas. An unsafe level of contamination remains, and people could potentially be exposed, though groundwater migration has been stabilized.

Each area has its own cleanup history. Well 12A, a former municipal water supply well, has had groundwater extraction and treatment running since 1983. A 2009 update added soil excavation, in-situ thermal treatment, and anaerobic bioremediation. Vapor intrusion sampling at nearby properties began in spring 2023 to check whether solvents are entering buildings. A new removal action is scheduled to run from November 2024 to July 2025. At South Tacoma Field, soil cleanup and capping were completed by 1999, and 150 acres are being redeveloped into a warehouse complex. In spring and summer 2024, contaminated soils were consolidated and covered in coordination with EPA. Tacoma Landfill closed in 2013, and its groundwater extraction system was removed in September 2022 after most of the site met cleanup levels. An active gas collection system remains in place, and gases are not moving beyond the site boundary. Long-term groundwater monitoring at the landfill is expected to continue through at least fall 2028.

As of December 2024, 21 businesses on the site employ 615 people and generate about $107.8 million in annual sales. Institutional controls, including environmental restrictive covenants and local ordinances, limit land use to prevent residential development and restrict groundwater use and soil disturbance in contaminated areas. EPA completed its sixth Five-Year Review in fall 2023, with the next review estimated between September and November 2028.

Community members can review site documents at the Tacoma Public Library's Northwest Room at 1102 Tacoma Avenue South, Tacoma, WA 98402, reachable at 253-280-2814. For questions, contact EPA's Community Involvement Coordinator or Remedial Project Manager.