Duwamish Shipyard
5658 W Marginal Way SW, Seattle, WA 98106

Approximate site boundary is in yellow. Click on the image to enlarge it.
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Updated February 2020

In 2010, Ecology entered into a legal agreement called an Agreed Order with Duwamish Shipyard, Inc. (the site owner, also known as the Potentially Liable Person or PLP) to begin working on the site cleanup.  

The Agreed Order describes the work that the PLP agrees to perform on the site. The purpose of the Agreed Order is to protect human health and the environment. It ensures that the cleanup happens in a timely manner and according to Washington State’s cleanup law, the Model Toxics Control Act.

Duwamish Shipyard Inc. is required to complete the following:

  • Remedial Investigation (RI). The purpose of the RI is to define the nature and extent of contamination at the site and to determine if it is contributing to the sediment contamination in the Lower Duwamish Waterway. During the RI, the PLP will collect data necessary to adequately characterize the contamination in soil and groundwater. 
  • Feasibility Study (FS). The FS will use the results of the RI to evaluate and choose alternatives to clean up contamination and prevent recontamination of the sediment.

To view site reports and fact sheets, click on the "View Electronic Documents" link to the right.

What happens next?

Ecology is working with Duwamish Shipyard, Inc. to finalize the Remedial Investigation and move forward with the Feasibility Study. The next opportunity for public comment will be when the Remedial Investigation and Feasibility Study reports are completed.

Why this cleanup matters

This site is part of Ecology’s Lower Duwamish Waterway source control efforts, because it is contributing pollution the Lower Duwamish Waterway (LDW) Superfund Site. The 5-mile stretch of the Duwamish River that flows north into Elliot Bay was added to the Superfund National Priorities List by the U.S. Environmental Protection Agency (EPA) in 2001.

The sediments (mud) in the river contain a wide range of contaminants due to decades of industrial activity and runoff from urban areas. EPA is leading efforts to clean up the river sediments.

Ecology is leading efforts to control sources of contamination from the surrounding land area. The long-term goal is to minimize recontamination of the river sediment and restore water quality in the river. 

The Duwamish Shipyard Site is one of several sites that will be cleaned up as part of Ecology’s Source Control Strategy – controlling sources of pollution to the river. Contaminants in the soil and groundwater around the river pose a risk to human health and the environment. They can also find their way into the river through storm runoff and other pathways. For more information, visit our Source Control page.

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Site location

The Duwamish Shipyard site is located in an industrial zoned area on the west bank of the Lower Duwamish Waterway. It includes the upland area and the sediments in the Lower Duwamish Waterway next to the upland area. The upland area is bordered to the north by the Alaska Marine Lines container facility, on the west by West Marginal Way Southwest, and on the south by Glacier Northwest, Inc.

The Lower Duwamish Waterway drainage basin is divided into source control areas. This site is located within the Kellogg Island to Lafarge Cement (river mile 1.0-1.3) source control area along the west bank of the river.

Site history

Duwamish Shipyard, Inc. purchased the property from King County in May 1941, and specialized in repair and maintenance of floating vessels and equipment. Services included machine and electrical work, carpentry, steel fabrication, pipe-fitting, sandblasting, pressure washing, and painting.

Shipyard operations included the use of two dry-docks and a graving dock formerly leased from General Construction Company (former owner of the Alaska Marine Lines property) and Alaska Marine Lines. Alaska Marine Lines filled in the graving dock to expand their freight terminal operations.

Duwamish Shipyard, Inc. sold the dry-docks and ceased active shipyard operations in 2007, but they still own the property. The site is currently leased by Alaska Marine Lines for storage of shipping containers and truck access.


Contamination at this site is likely a result of shipyard operations.  Soil, groundwater, stormwater, and sediments are contaminated. 

The contaminants of concern in the soil and groundwater are:

•Total Petroleum Hydrocarbons (TPHs)
•Polynuclear aromatic hydrocarbons (PAHs)
•Semi-volatile organic compounds (SVOCs)
•Volatile organic compounds (VOCs)
•Metals (arsenic, cadmium, chromium, copper, lead, and zinc)

The contaminants of concern in the stormwater and stormwater solids are:

•Polynuclear aromatic hydrocarbons (PAHs)
•Semi-volatile organic compounds (SVOCs)
•Metals (copper, mercury, and zinc)

The contaminants of concern in sediments in the adjacent Lower Duwamish Waterway are:

•Polynuclear aromatic hydrocarbons (PAHs)
•Semi-volatile organic compounds (SVOCs)
•Dioxins and FuransTributyltin (TBT)
•Metals (arsenic, copper, lead, and zinc)
•Polychlorinated biphenyls (PCBs)

Previous cleanup work

Duwamish Shipyard, Inc. performed several independent cleanups on the site. The property has been the subject of several environmental investigations and cleanups beginning in the 1980s. In 1986, one underground storage tank (UST) was filled in place. In 1993, soil affected by an unknown release of petroleum product was discovered, and the affected area was partially excavated and capped. In 2000, four USTs were removed, but contaminated soil above MTCA levels remained. 
In 2007, Duwamish Shipyard, Inc. cleaned out the stormwater drainage system in response to a request from Ecology. In the solids collected from the stormwater drainage system, there were concentrations of the following contaminants above sediment management standards:·         

•Polynuclear aromatic hydrocarbons (PAHs)         
•Semi-volatile organic compounds (SVOCs)         
•Metals (copper, mercury, and zinc)


The Model Toxics Control Act (MTCA; Chapter 70.105D RCW is Washington’s environmental cleanup law). It provides requirements for contaminated site cleanup and sets standards that protect human health and the environment. Ecology enacts the MTCA and oversees cleanups. The MTCA site cleanup process is completed in steps (see graphic below) over a variable timeline.

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Map showing site location as King County, WA SITE INFORMATION


View Electronic Documents

Cleanup Site Details Report

Facility Site ID: # 2071

Cleanup Site ID: 54

Seattle, King County

Status: Cleanup Started   Get definitions of Status terminology

Jing Liu
Site Manager
(206) 594-0082

Brad Petrovich
Project Planner and Public Involvement Coordinator
(206) 594-0088

Document Repositories:

Northwest Regional Office
15700 Dayton Ave N
Shoreline, 98133