Block 37
600 Westlake Ave N, Seattle, WA 98109

Block 37 Property looking southeast
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Legal Agreement Ready for Public Review and Comment

Ecology has negotiated a legal agreement called an Agreed Order with Phillips 66 Company and City Investors XI LLC for the Block 37 Cleanup Site (Site). The order names them as Potentially Liable Persons (PLPs) and requires them to investigate environmental conditions, conduct an interim cleanup action (if necessary), and develop a cleanup action plan for the Site. We would like your input on:

Agreed Order – legal document that requires the PLPs to investigate environmental conditions, complete a Remedial Investigation (RI) and Feasibility Study (FS), and a preliminary draft Cleanup Action Plan (dCAP) for the Site.

Public Participation Plan – describes how Ecology will inform the community about Site activities and opportunities to be involved in the cleanup process.

Ecology is hosting a public comment period for these documents from March 29 - April 27, 2021. During that time you can submit comments by contacting Tena Seeds or Brad Petrovich at the links to the right of this page, or by using Ecology's E-Comment system.

El Departamento de Ecología está anunciando el periodo de comentario público relacionado a la limpieza ambiental del sitio Block 37. Para obtener este documento, o más información sobre este sitio, en español favor de comunicarse con Mark Wheeler al 509-329-3444 o 

華盛頓州生態管理署邀請公眾對Block 37地產清理工作的清理行動計劃草案動提供建意見。 欲了解更多信息, 或要求翻譯服務,請致電林昊 (425) 649-7487,電子郵件

Historical aerial view of South Lake Union area in Seattle
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 The Block 37 property (Property) is located in Seattle’s South Lake Union area. It is made up of several parcels generally located at 600-630 Westlake Avenue North, and is bordered by Westlake, Mercer Street, Valley Street, and Terry Avenue North. City Investors XI LLC is the current owner of the Property, and Phillips 66 Company previously owned two parcels in the southern portion.

Historical uses of the Property date back to the late 1800s. A lumber mill, creamery, and brewery operated there until the early 1930s. A railroad occupied the northeast corner from the 1910s to 2005. A retail gasoline service station operated on the northwest portion from about 1930 to the mid-1960s. A service garage operated on the northern portion from 1971 to 2002. A second retail gasoline and automobile service station operated on the southwest portion from about 1965 to 2008. 

No permanent structures are currently on the Property. The southern portion is mostly covered with gravel and used for temporary site offices, equipment, materials staging, and temporary water treatment facilities for nearby redevelopment projects. The northern portion is paved and mostly used as a parking lot and equipment storage.

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Many environmental investigations have been done on the Property and surrounding streets since 1980. These have documented the following hazardous substances in soil and/or groundwater in amounts that exceed minimum allowed levels under the Model Toxics Control Act (MTCA):
total petroleum hydrocarbons as gasoline;
total petroleum hydrocarbons as diesel and oil;
benzene, toluene, ethylbenzene, and total xylenes; 
polycyclic aromatic hydrocarbons;
total lead; 
methyl tertiary butyl ether; 
dichloroethene and vinyl chloride. 
Several independent cleanups have been done on and around the Property. These have included removal of petroleum contaminated soil and liquid petroleum hydrocarbons, as well as in-ground treatment to reduce contamination in groundwater and remove harmful vapors that evaporate from these contaminants.

Please click on the photo for a larger view


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 implements the MTCA cleanup process  and oversees cleanups.


Map showing site location as King County, WA SITE INFORMATION


View Electronic Documents

Cleanup Site Details Report

Facility Site ID: # 46445373

Cleanup Site ID: 6134

Seattle, King County

Status: Cleanup Started   Get definitions of Status terminology

Tena Seeds
Project Manager
(425) 457-3143

Brad Petrovich
Project Planner and Public Involvement Coordinator
(425) 533-5537

Document Repositories:

Northwest Regional Office
3190 160th Ave SE
Bellevue, 98008-5452