Georgetown excavation prepares for cleanup in Duwamish Waterway

BELLEVUE – The Boeing Co. (Boeing) and the city of Seattle have begun work to remove contaminated soil and groundwater from the north end of Boeing Field and the adjacent Georgetown Steam Plant property under an environmental cleanup agreement with the Washington Department of Ecology (Ecology).

The excavation is the latest in a series of projects to remove or control contamination in soil and groundwater in the North Boeing Field/Georgetown Steam Plant area of south Seattle. Ecology oversees the cleanup being conducted under an agreed order among Boeing, Seattle – which owns the steam plant property – and King County, which owns King County International Airport/Boeing Field (KCIA).

This fall, the U.S. Environmental Protection Agency (EPA) will oversee the removal of contaminated sediment from the bottom of Slip 4, a nearby inlet of the Duwamish Waterway. Cleanup work in the North Boeing Field/Georgetown Steam Plant area will help reduce potential re-contamination of the inlet. Polychlorinated biphenyls (PCBs) and other pollutants have been found in storm drains that empty to Slip 4 from city, county and Boeing property in the 137-acre area.

The cleanup of soil at North Boeing Field and the Georgetown Steam Plant property addresses contamination believed to affect Slip 4. Contractors will haul away 7,000 to 8,000 cubic yards of soil in covered trucks and will deliver clean soil to fill the excavated area. Trucks will pass through a washing station before leaving the site, making 10 to 20 trips per day for approximately three months.

Additional studies may identify other areas in the vicinity needing cleanup.

Details about this summer’s project and the overall North Boeing Field/Georgetown Steam Plant cleanup area are available online.

Other recent and ongoing actions to control and reduce potential Slip 4 recontamination include:

City of Seattle storm drain improvements: In 2009, the city closed off unauthorized storm drain connections, removed contaminated sediments from drain lines and catch basins, and replaced the Georgetown Steam Plant Flume (a conveyance system that had contaminated sediment).
Airport projects: KCIA has cleaned contaminated sediments from storm drains and vaults, and performed source-tracing activities. KCIA will repair stormwater drainage pipes in the Slip 4 basin and other basins as part of a taxiway rehabilitation project.
Boeing cleanup projects: Boeing has removed PCB-contaminated concrete joint material (caulk) and other contaminated building materials from the northern portion of its North Boeing Field facilities. Similar cleanup continues in other site areas.
Boeing stormwater treatment: The company installed a stormwater treatment system for a portion of the area that drains to Slip 4.
Ongoing testing: Ecology and Boeing sample and test stormwater and storm drain sediments to monitor the effectiveness of these actions.

More information on these projects appears in Ecology’s recently completed “Slip 4 Interim Source Control Action Report,” available online.

Information about EPA’s sediment cleanup in Slip 4 is available online.

Cleanups in the North Boeing Field/Georgetown Steam Plant area and in Slip 4 contribute to a larger effort to control sources of contamination in Lower Duwamish Waterway sediments. Ecology and EPA jointly oversee the Lower Duwamish Waterway cleanup site, approximately 5.5 miles of waterway upstream from Harbor Island. More information about the overall Lower Duwamish cleanup, is available online.

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Media Contacts:

Larry Altose, Ecology media relations, 206-920-2600, larry.altose@ecy.wa.gov
Mark MacIntyre, EPA media relations, 206-553-7302, macintyre.mark@epa.gov
Scott Thomsen, City of Seattle, 206-615-0978
Rochelle Ogershok, King County Department of Transportation, 206-296-6515
Leslie Barstow, King County International Airport, 206-296-7431
Cindy Glickert, The Boeing Company, Environment, Health and Safety Media Relations, 425-237-1095

For more information:

Georgetown Steam Plant/North Boeing Field interim cleanup action overview (Ecology) (https://fortress.wa.gov/ecy/gsp/Sitepage.aspx?csid=4765)
Fact Sheet on Georgetown Steam Plant/North Boeing Field interim cleanup action (Ecology) (https://fortress.wa.gov/ecy/gsp/DocViewer.aspx?did=4604) (Includes map of project area on page 3.)
Slip 4 drainage area source control (Ecology) (http://www.ecy.wa.gov/programs/tcp/sites_brochure/lower_duwamish/sites/slip_4/slip_4.html)
Planned Slip 4 cleanup (EPA) (http://yosemite.epa.gov/r10/cleanup.nsf/ldw/slip+4+early+action+area)
Overall Lower Duwamish cleanup (Ecology) (http://www.ecy.wa.gov/programs/tcp/sites_brochure/lower_duwamish/lower_duwamish_hp.html)
King County International Airport Taxiway Alpha Rehabilitation Project (http://www.kingcounty.gov/transportation/kcdot/Airport/TaxiwayAlpha.aspx)