Site Description
Terminal 5 (T-5) is a 185-acre property addressed at 3443 West Marginal Way Southwest in Seattle, Washington. The Site is located along the base of the West Seattle highlands on the shoreline of the West Waterway near the mouth of the Lower Duwamish Waterway (LDW). T-5 is bound by Elliot Bay to the north, the West Waterway to the east, Southwest Spokane Street to the south, and by Harbor Avenue Southwest to the west. The operational portion of T-5 is an active freight terminal and provides shipping container storage. T-5 also includes a Public Access Area (PAA), Jack Block Park, in the northern portion of the property and a consolidated landfill (known as the CEM Landfill) area along the western boundary of the terminal. The cleanup portion of the Site is known as the Southwest Harbor Project (SWHP).
Site History
Most of T-5 overlies former tide flats that have been filled and used for various industrial purposes, including but not limited to railroad yards, wood treatment facilities, steel scrap storage, and a municipal and wood waste landfill. For the purposes of upland cleanup, the SWHP was divided into five Remediation Areas (RAs). RA-1, 2, 3, and 5 were remediated under oversight by the Washington State Department of Ecology (Ecology), while RA-4 was addressed under agreement with the United States Environmental Protection Agency (USEPA). Read about the operational history of each RA.
Contamination Issue
Soil and groundwater contamination within the SWHP area originated from former industrial operations located in an upgradient of the Site prior to the redevelopment of T-5. During the 1990s, the RAs were remediated, which consisted of a combination of removing soil with elevated contaminant concentrations, consolidation of subsurface contamination, and installation of engineered environmental controls to manage contaminated soil and groundwater remaining in place. These environmental controls include asphalt covers/caps, ballast covers, and containment systems specific to each RA. Learn more about soil contaminants of concern (COCs) and engineered controls of the individual RAs.
From 2008 to 2011, the Port conducted groundwater monitoring to confirm that the remedial actions completed for each RA were protective of surface water quality for the site as a whole and to confirm the effectiveness of the engineered controls in place to prevent. Data showed groundwater contaminants under MTCA cleanup standards and Ecology determined that the requirements of the groundwater monitoring plan had been satisfied.
Why Did the Port do this Cleanup?
The Site’s varied historical operations led to soil and groundwater contamination. The Port performed this cleanup to ensure protection of human health and prevent sources of contamination discharging into the West Waterway and Elliot Bay. The engineered environmental controls employed at each RA protect the public, terminal workers, and the environment from being exposed to underlying potentially contaminated material.
The Ecology-lead portions of the cleanup (RA-1, 2, 3, and 5) were completed under a Consent Decree (CD) for each Site. The EPA-lead portion of the cleanup (RA-4) was completed under the Administrative Order on Consent (ASAOC) for the Site.
Status
The Site is currently in the long-term operation and maintenance (O&M) phase of the cleanup. The Port’s primary obligation involves monitoring and maintaining the engineered and institutional controls employed at each RA.
The Port performs semiannual inspections of site pavement caps, drainage, ballast cover areas, fencing, and warning signs for the Ecology-led portions of the SWHP project (RA-1, 2, 3, and 5 and the CEM Landfill). CEM’s landfill gas collection system currently operates in passive mode. The Port recently implemented recommendations to enhance the system’s passive gas extraction. Landfill gas monitoring is conducted monthly.
For the EPA-lead portion of the Site (RA-4), the Port performs annual inspection of the IY and the Jack Block Park Public Access Area. Groundwater monitoring and dense non-aqueous phase liquid gauging and recovery is conducted quarterly.
Contact Information
Jalyn Buckley | Environmental Management Specialist | [email protected]
Additional Resources
For more information, visit Ecology’s Southwest Harbor Project webpage.
