Department of Ecology News Release - May 22, 2019
Updated: May 21, 2019

New agreement broadens cleanup process at Boeing site on Duwamish

The Boeing Developmental Center, between the Duwamish River and East Marginal Way South in Tukwila.


The Boeing Company will continue cleanup work and expand studies of contaminated areas at its Developmental Center on the Duwamish Waterway under a proposed cleanup agreement (PDF file) with the Washington Department of Ecology. The company has been conducting cleanup work at the facility under Ecology’s Voluntary Cleanup Program (VCP) since 1999.

Because Boeing formerly managed hazardous waste at the facility, special state and federal requirements – beyond the scope of the VCP – apply to the site’s cleanup. The agreement, called an agreed order, incorporates these requirements into the cleanup process that Boeing will follow under Ecology supervision. This will include a detailed investigation of contamination in soil and groundwater, a study of cleanup alternatives, and a cleanup action plan, all of which Ecology will make available for public comment before deciding whether to accept them.
Ecology invites the public to review and comment on the agreement and several related documents through June 21, 2019:

Past studies and partial cleanup

Previous studies show that soil and groundwater on the roughly 164-acre site, at 9725 East Marginal Way South in Tukwila, now or did contain toxic substances, including petroleum products, solvents that can release vapors, metals and polychlorinated biphenyls.
Boeing has done cleanup work at three areas on the site under the VCP. Since 2002, the company has injected non-toxic “food” into the groundwater for natural bacteria that can break down contaminants. From 1993 to 2001 Boeing pumped groundwater through a treatment system. Before that, the company removed 1,400 tons of contaminated soil.

Part of the Lower Duwamish Waterway cleanup

The cleanup will contribute to a larger effort to control sources of contamination in Lower Duwamish Waterway sediments. Ecology and the U.S. Environmental Protection Agency jointly manage the Lower Duwamish Waterway cleanup, along the approximately 5 miles of waterway upstream from Harbor Island. 
Ecology oversees a variety of efforts to control sources of pollution that could re-contaminate waterway sediments after cleanup. This source control work includes cleanups at contaminated sites along or near the Duwamish. The agreed order for the Boeing Developmental Center adds this site to a list that includes 20 other formal Ecology cleanup sites along or near the Duwamish Waterway as well as five sites managed by EPA under the federal Superfund program.

Cleanup and commenting information

Information about the site’s contamination and cleanup process is available at:

  • Ecology’s website.

  • Seattle Public Library South Park Branch, 8604 8th Ave. S.

  • Ecology’s Northwest Regional Office, 3190 160th Ave. S.E., Bellevue. By appointment: 425-649-7190. 

Submit comments with Ecology’s online comment form. Or, submit comments or technical questions to Byung Maeng, site manager, 426-649-7253, Department of Ecology, 3190 160th Ave. S.E., Bellevue WA, 98004-5452.
An Ecology fact sheet (PDF) provides additional information about the site and the order.

Contact information

Larry Altose
Twitter: ecyseattle
Byung Maeng
Site manager