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Lower Duwamish Waterway
Source Control Investigation

North Boeing Field/Georgetown Steam Plant Site

Site Location

The North Boeing Field (NBF) and Georgetown Steam Plant (GTSP) are located at 7370 East E. Marginal Way S and 6700 13th Avenue S in Seattle, Washington.  They are on the East side of the Lower Duwamish Waterway.  The Sites are bordered to the Northwest by Ellis Avenue South, the Southwest by East Marginal Way South, and the East by King County International Airport.

Site Background

The GTSP was built by the Seattle Electric Company in 1906 to provide power during periods of high use. In 1912, Puget Sound Power and Light Company bought Seattle Electric Company. Use of the GTSP decreased after 1912. When built, the GTSP was next to the Duwamish River. When the river was straightened in 1916 to form the Duwamish Waterway, the GTSP flume was constructed to carry cooling water to Slip 4. A condenser pit under the powerhouse connects to an underground concrete tunnel that discharges into the GTSP flume (Flume). The Flume extends for about 0.4 miles into the head of Slip 4. Cooling water discharges ended in the 1960s when the GTSP was shut down. In 1951, the city of Seattle bought the GTSP and now owns the 7.29-acre property that contains the powerhouse and property next to the Flume. Seattle City Light will be demolishing the Flume and replacing it with a closed piping system in the summer of 2008.

Most of the 130-acre NBF property is leased by the Boeing Company from King County. The Boeing Company leases a few acres on either side of the Flume from the city of Seattle. The Boeing Company also owns a parcel that includes a NBF building and a lot next to it used for parking. The Boeing Company has operated at NBF since the 1940s; yet there are few historical records on site operations before the 1970s. Many buildings have been built and torn down over the years. This makes it hard to track operations in detail. Currently there are about 80 buildings on NBF. NBF has a complex storm drain system that includes over 400 catch basins, 400 manholes, up to 16 oil water separators and lift stations, parking lot ditches, and roof drains. The system connects with seven to eight miles of piping ranging from four to 48 inches in diameter. Stormwater from the Flume and NBF flows into Slip 4. Slip 4 is part of the Lower Duwamish Waterway (LDW) Superfund site.

Contamination

Contamination at the site is most likely the result of industrial operation and maintenance activities performed on this site since the 1940’s. The potential for sediment recontamination from site stormwater has delayed cleanup of sediments in Slip 4. Past studies have found pollutant concentrations above applicable cleanup standards.

• Polychlorinated biphenyls (PCBs).
• Total petroleum hydrocarbons (TPH).
• Polynuclear aromatic hydrocarbons (PAHs).
• Antimony, arsenic, cadmium, chromium, copper, lead, mercury, and zinc.

• Total petroleum hydrocarbons (TPH).
• Volatile and semi-volatile organic compounds (VOCs and SVOCs).
• Antimony, arsenic, chromium, and lead.

• Polychlorinated biphenyls (PCBs).
• Polynuclear aromatic hydrocarbons (PAHs).
• Semi-volatile organic compounds (SVOCs).
• Arsenic, copper, lead, mercury, and zinc.

• Polychlorinated biphenyls (PCBs).
• Semi-volatile organic compounds (SVOCs).

Agreed Order

The Boeing Company, King County, the City of Seattle, collectively the potentially liable parties (PLPs), and the Department of Ecology have negotiated an Agreed Order to conduct an investigation at this site. Under the Agreed Order, Ecology will do a Remedial Investigation/Feasibility Study (RI/FS) at the site. The purpose of the Remedial Investigation is to define the nature and extent of contamination at the site and find if it is contributing to the sediment contamination in the Lower Duwamish Waterway. The Feasibility Study will use the results of the Remedial Investigation to evaluate and choose measures to prevent such releases from the site. Ecology has prepared a Scope of Work that describes the planning and technical work that will be done to complete the RI/FS for the site. It also provides an approximate schedule for completing the RI/FS. For this site, Ecology will oversee a private contractor to complete the work and The Boeing Company, King County, and the City of Seattle will share the cost of the RI/FS.

For more information regarding the North Boeing Field/Georgetown Steam Plant Site or to be added to the site mailing list, please contact Mark Edens, Site Manager, at (425) 649-7070.

Site Documents

• August 2009
  
• North Boeing Field and Georgetown Steam Plan Supplemental Report:  Summary and Existing Information and Identification of Data Gaps   
  
  
• August 2008
• English
• Fact Sheet
• Agreed Order
• Exhibit A - Site Diagram
• Exhibit B - Scope of Work
• Exhibit C - Public Participation Plan
• Exhibit D - Receivables Agreement
• Español
• Trang tiếng Việt

Related Information

• Slip 4 Early Action Area and GTSP Flume Removal Remedial Action
• More information on the Lower Duwamish Waterway
• Watershed Information for WRIA 9

Additional Resources

• Glossary and Acronyms used by the Toxic Cleanup Program
• Cleanup Process: Major Steps & Definitions
• Data Submittal Requirements for All Cleanup Sites
• Facility/Site Atlas
• Toxics Cleanup publications