North Boeing Field Georgetown Steam Plant

Last Updated:  March 2023

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ព័ត៌មានជាភាសាខ្មែររួមបញ្ចូល

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Blog	"Cleaning up:  Two Lower Duwamish sites move forward with cleanup"

Comments

Response Summary

Interim Action Proceeds and Site-wide Remedial Investigation Continues
Ecology held a 45-day public comment period (November 7 – December 21, 2022) on a draft Interim Action Work Plan for the North Boeing Field Georgetown Steam Plant Cleanup Site.  The City of Seattle plans to develop a portion of the Georgetown Steam Plant property into an off-leash pet area and pedestrian path. This project, referred to here as the Georgetown Flume Dog Park Project Area, is located east of 1001 S. Myrtle St between Myrtle St and East Marginal Way. The City of Seattle is conducting this Interim Action under a 2008 legal agreement (Agreed Order) with Ecology.

Ecology has reviewed and considered the public comments received on the documents. No changes are necessary to the Interim Action Work Plan, and it is being finalized. The City of Seattle will proceed with the Interim Action which will allow beneficial public use of the Dog Park Project Area while the site-wide remedial investigation and feasibility study are completed.

Ecology has also reviewed and considered the comments regarding public outreach and has also responded to a previous Lower Duwamish Waterway (LDW) site comment period referenced for the Independent Metals Plant 2 site. To access this Response to Comments, please visit the Independent Metals Plant 2 webpage.  

Ecology is committed to making several changes for LDW sites regarding how Ecology will upload documents that will help the public review technical documents. See Response Summary for details.

Ecology is finalizing the following documents:

• Interim Action Work Plan: This work plan describes the cleanup of contaminated soils on the Dog Park Project Area.
• State Environmental Policy Act (SEPA) Determination of Non-Significance: This is the Ecology determination that the cleanup work is not likely to harm the environment.

Language Information
Para ver una copia de este boletín informativo en español visite: https://bit.ly/Ecology-NorthBoeingField, llame (360) 407-6097, o envié un correo electrónico a preguntas@ecy.wa.gov

如需瀏覽中文版的概況介紹，請訪問網址https://bit.ly/Ecology-NorthBoeingField，致電 
(425) 457-3842，或發送電子郵件到sunny.becker@ecy.wa.gov

Để xem bản sao của tờ thông tin này bằng tiếng Việt, hãy truy cập: https://bit.ly/Ecology-NorthBoeingField, gọi (360) 790-4730, hoặc gửi email đến Lngu461@ecy.wa.gov

ដើម្បីមើលឯកសារថតចម្លងនៃអង្គហេតុនេះជាភាសាខ្មែរ សូមចូលមើល៖ https://bit.ly/Ecology-NorthBoeingField, ហៅទូរស័ព្ទលេខ (425) 324-5901, ឬអ៊ីម៉ែល ian.fawley@ecy.wa.gov

The North Boeing Field Georgetown Steam Plant site is adjacent to the Lower Duwamish Waterway (LDW) Superfund Site, which includes a 5-mile stretch of the Duwamish River. The U.S. Environmental Protection Agency (EPA) added the LDW Superfund Site to the Superfund National Priorities List in 2001. Ecology is working to stop or reduce sources of contamination to the LDW Superfund Site, an effort known as “source control,” so that the EPA can proceed with the cleanup of the river sediment. 

Project area background
This 1.1 acre Georgetown Flume Dog Park Project Area extends from Myrtle Street south to East Marginal Way, just east of Ellis Ave South in the Georgetown neighborhood of Seattle.  The area is on the margin of the 115.6 acre North Boeing Field-Georgetown Steam Plant Site.  The Site is in the remedial investigation process (see cleanup graphic below). Additional details about ongoing cleanup actions at the larger Site can be found on the Ecology’s North Boeing Field Georgetown Steam Plant  webpage. 

The Dog Park Project Area was the location of the southern end of the Georgetown Steam Plant Flume.  The flume was a pipe and ditch system that discharged water from the historical steam plant to Slip 4 of the Lower Duwamish Waterway (LDW) until the 1960’s.  The Dog Park Project Area also contained the former Ellis Ave. electrical substation, which along with the remnants of the flume, were removed in 2009.  Currently, the Dog Park Project Area is an undeveloped parcel covered with vegetation, bare dirt, and gravel.  This interim action will allow beneficial public use of the Dog Park Project Area while the Site-wide RI and feasibility study are completed.

Contaminates of concern
These contaminants may be present in soils at concentrations that exceed screening standards set under the state’s cleanup law, the Model Toxics Control Act (MTCA ), and must be addressed. 

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

Current interim action and future land use 
The objective of this interim action is to remove readily accessible soil that contains chemicals of concern at concentrations greater than MTCA direct contact screening levels for unrestricted site use.  Residual soils related to Dog Park Project Area contamination and historical industrial uses will be removed to a minimum depth of 1-2.5 feet and transported to a licensed disposal facility.  Once the excavation has been completed, the Dog Park Project Area will be backfilled with clean soil and redeveloped into a community amenity featuring an off-leash pet area, bicycle/pedestrian path, and bioswale.  The Dog Park Project Area chemicals of concern were not detected in groundwater samples, indicating there is low likelihood of leaching to groundwater from the vicinity soils. 

The Model Toxics Control Act (MTCA) 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.

Ecology considered all comments received during this public comment period (November 7 - December 21, 2022) on the Interim Action Work Plan and State Environmental Policy Act (SEPA) Determination.

Ecology is finalizing the documents and the City of Seattle will proceed with the Interim Action.

Current North Boeing Field Georgetown Steam Plant cleanup site Public Participation Plan

This plan includes information for the public regarding opportunities to get involved in the Site cleanup process. The outreach activities and mechanisms presented reflect Ecology’s current plans for keeping the public informed and for receiving information and comments from the public. 

Site location

The North Boeing Field and Georgetown Steam Plant Site is located in an industrial area on the east side of the Lower Duwamish Waterway. It is bordered to the southwest by East Marginal Way South, to the east by King County International Airport, and to the northwest by Ellis Avenue South. On the other side of Ellis Avenue South is a residential neighborhood.

The Lower Duwamish Waterway drainage basin is divided into source control areas. This site is located within the Slip 4 Early Action Area (river mile 2.8) source control area along the east bank of the river.




Site History

Georgetown Steam Plant

In 1906, Seattle Electric Company built the Georgetown Steam Plant (GTSP) along the Duwamish River to provide power during periods of high electricity use.  After 1912, use of the steam plant decreased under Puget Power ownership. The City of Seattle acquired the plant in 1951 and operated it on standby until it was fully decommissioned in 1973.
 
The GTSP is a National Historic Landmark. The City still owns the 7.29-acre property and operates a historical museum there.
 
When built, the GTSP was next to the Duwamish River. When that part of the river was straightened in 1913 to form the Duwamish Waterway, the GTSP Flume was constructed to carry cooling water to Slip Four.

North Boeing Field

King County owns most of North Boeing Field (NBF). Boeing leases about 117 acres from King County, and owns the improvements it has built on the property. Boeing has operated at North Boeing Field since the 1940s for aircraft and aerospace manufacturing, maintenance, and research.


Contamination

Contamination at the site is most likely the result of industrial operation and maintenance activities performed on this site since the 1940’s.
 
In soil, the contaminants of concern are:

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

In groundwater, the contaminants of concern are:

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

In stormwater solids, the contaminants of concern are:

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

In Slip 4 sediments, the contaminants of concern are:

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

Previous cleanup work

EPA’s Early Action cleanup in Slip 4 was completed in 2012. As part of this project, Boeing and the City removed debris and cleaned up sediments in the Slip. Boeing also installed a stormwater treatment system to remove solids from the stormwater draining off the northern portion of the site. This area had very high levels of PCBs, due to the historical handling of electrical transformer oil and aircraft hydraulic oil. Controlling this runoff made a significant difference in the amount of PCBs reaching the river.
 
In 1985 and 2006, the City independently removed PCB-contaminated soil from the southwest portion and southern boundary of the GTSP property. This portion of the site is referred to as the low-lying area because surface water historically flowed into this region from portions of the GTSP and offsite areas.
 
In 2009, the City independently cleaned up and replaced the GTSP Flume, which was known to be a source of contamination to the river.
 
2011, Boeing conducted an Interim Action to remove accessible PCB-contaminated soil along the fence line adjacent to the Steam Plant.
 
Also In 2011, the City and Boeing conducted an Interim Action under the direction of Ecology to remove soil contaminated with PCBs and petroleum from the low-lying area near the GTSP, which had the potential to move offsite and contaminate Slip 4. They also capped areas where the soil was contaminated with other chemicals.
 
Boeing continues to make progress on a large scale effort to remove PCB-contaminated materials such as caulk, paint, building materials, and surface debris. EPA regulated this action is under the federal Toxic Substances Control Act.
 
Since 2010, Boeing has removed thousands of linear feet of PCB-contaminated concrete joint material from the site, and re-sealed the joints. They have also cleaned, repaired, and replaced many of the storm drains on the north end of the property.