Department of Ecology News Release - April 23, 2020
Updated: April 23, 2020

Cleanup process to move forward at Port of Seattle site on Duwamish Waterway

Terminal 115, Plant 1 area, on the Duwamish Waterway in South Seattle.


Building on earlier cleanup work, the Port of Seattle and The Boeing Company will further address contaminated soil and groundwater at the port’s Terminal 115 Plant 1 site on the Duwamish Waterway in south Seattle, under a legal agreement with the Department of Ecology.

Ecology seeks public comment on the agreement (pdf), called an agreed order, from April 27 through May 26. The agreed order outlines the process under Washington’s cleanup law for the port and Boeing to study the site’s contamination, develop cleanup options and propose a cleanup plan.

Ecology also is taking comment on a public participation plan (pdf) that describes how Ecology will inform and involve the community about the cleanup process.

History and contamination

The nearly 100 acre site is on the waterway’s west shore, at 6020 West Marginal Way South. Prior to acquisition by the port, the site contained the first Boeing aircraft factory, and has included retail gasoline service stations, gravel and cement production, a salvage yard, and a smelter. Log booms were moored at part of the site that was filled in 1969-70 to create more land.

The site has since been used by port tenants for cargo storage, loading and off-loading, gasoline sales and associated storage in underground storage tanks, seafood processing, retail sales, and vehicle and shipping container maintenance.

Previous studies have found pollutants – including diesel fuel, benzene, lead and vinyl chloride – in soil or groundwater. Past partial cleanups have removed visibly impacted soil and groundwater during underground storage tank removal. In addition, petroleum that was floating on groundwater in the southwest part of the site was removed through extraction wells.

Part of the Lower Duwamish Waterway cleanup

Continuing the cleanup process at this site will contribute to the larger Lower Duwamish Waterway cleanup. Ecology and the U.S. Environmental Protection Agency jointly manage that effort along the approximately 5 miles of waterway upstream from Harbor Island. 

Cleanup and commenting information

Information about the site’s contamination and cleanup process is available at Ecology’s website or these direct links:

In addition to commenting online, people can email comments and questions to Maureen Sanchez, site manager, at, or call 425-649-7254 with questions.

Contact information

Larry Altose
Ecology communications
206-920-2600 or
Twitter: ecyseattle
Peter McGraw
Port of Seattle communications
206-787-3446 or
Monica Zimmer
Boeing communications
425-919-3005 or