Duwamish Marine Center
6365 1st Ave S, Seattle, WA 98108

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

The Feasibility Study phase is in progress. 


In 2011, Ecology negotiated a legal agreement called an Agreed Order with property owners James and Jacqueline Gilmur, the Potentially Liable Persons (PLPs) for the Duwamish Marine Center site.

The Agreed Order describes the work that the PLPs agree to perform on the site. Under this legal agreement, the PLPs are 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 PLPs will collect data necessary to adequately characterize the contamination in soil, groundwater, stormwater, and sediments.

•Feasibility Study (FS). The FS will use the results of the RI to evaluate and choose measures to clean up contamination and prevent recontamination of the sediment.

•Draft Cleanup Action Plan (DCAP). Ecology will identify a preferred cleanup action based on the results of the FS.

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

What happens next?

Ecology is working with the PLPs to complete the RI and move forward with the FS. The next opportunity for public comment will be when the Public Review Draft RI Report and Feasibility Study are ready for review.

Why this cleanup matters

This site is part of Ecology’s Lower Duwamish Waterway source control efforts, because it may be contributing pollution to 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 Marine Center 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 Marine site is located in an industrial area on the east side of the Lower Duwamish Waterway. The site is bordered on the north by General Biodiesel, on the east by First Avenue South, on the south and west by the Duwamish River, and on the northwest by Slip 2.

The Lower Duwamish Waterway drainage basin is divided into source control areas. This site is located within the Slip 2 to Slip 3 (river mile 1.7-2.0) source control area along the east bank of the river.

Site history

Historically, the site operated as a marine shipyard, railyard, junk dealer, various construction service companies, and a barge shipping terminal.  A marine railway operated next to the southwestern shoreline from 1940 to the mid-1970s. 

Samson Tug and Barge operates in the northern portion of the Duwamish Marine Center. Duwamish Metal Fabricators operates on the southern portion of the property. 


Contamination at the site is the result of heavy industrial use.

In the soil, contaminants of concern are:

•Petroleum hydrocarbonsMetals
•Polychlorinated biphenyls (PCBs)
•Carcinogenic polycyclic aromatic hydrocarbons (cPAHs)

In the groundwater, contaminants of concern are:

•Petroleum hydrocarbonsMetals, such as mercury.Polychlorinated biphenyls (PCBs)
•Carcinogenic polycyclic aromatic hydrocarbons (cPAHs)
•Volatile organic compounds (VOCs) 

In the sediments, contaminants of concern are:

•Polychlorinated biphenyls (PCBs)
•Carcinogenic polycyclic aromatic hydrocarbons (cPAHs)

Previous cleanup work

Several environmental investigations have been conducted at this site under the Voluntary Cleanup Program. In 2000 and 2002, soil and groundwater samples were collected from the site. Four groundwater monitoring wells were installed at the property in 2002. Groundwater was sampled in 2003 and 2004. 

In 2002, about 50 cubic yards of lead-contaminated soil classified as hazardous waste were excavated and removed from the central area of the site.  


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: # 21945598

Cleanup Site ID: 4146

Seattle, King County

Status: Cleanup Started   Get definitions of Status terminology

Victoria Sutton
Site Manager
(425) 649-7219

Brad Petrovich
Project Planner and Public Involvement Coordinator
(425) 649-4486

Document Repositories:

Northwest Regional Office
3190 160th Ave SE
Bellevue, 98008-5452