Block 38 West
Current Status
Fact Sheet: English | 中文
The Department of Ecology (Ecology) is overseeing the cleanup of the Block 38 West Site (Site) in Seattle’s South Lake Union neighborhood. City Investors IX L.L.C. (City Investors IX) is the Potentially Liable Person (PLP) cleaning up the Site.
We held a comment period from November 18 to December 19, 2024, on the following documents:
- Remedial Investigation and Focused Feasibility Study (Volume 1 and Volume 2): describes contamination at the Site and evaluates and recommends a preferred cleanup action.
- Cleanup Action Plan: describes the cleanup work to address contamination at the Site.
- Consent Decree: a legal agreement between Ecology and City Investors IX, that requires City Investors IX to implement the cleanup action plan for the Site.
We received two comments and responded to them directly. No significant changes were made to the documents, and they are now final.
What Happens Next?
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General Cleanup Process
Public Participation
This plan describes how Ecology will share information with the community and how you can share information with us. Ecology will review this plan as the cleanup progresses and amend/update it as necessary.
Site Information
Site Location
The Block 38 West Site is located in the South Lake Union neighborhood of Seattle. The Site includes the Block 38 West Property, a portion of the Westlake Avenue North right of way, and a north-south-trending alley (City of Seattle public right-of-way) east of the Block 38 West Property.
Site Background
Historical operations and placement of contaminated fill at the Block 38 West Property resulted in contaminated soil and groundwater at the Site.
From October 2019 through July 2021, substantial cleanup of the Block 38 West Site was performed through interim actions (early partial cleanups) on the Block 38 West Property and east-adjacent alley. These interim actions included removal and disposal of contaminated soil and were implemented in conjunction with the redevelopment of the Block 38 West Property.
View the Interim Action Completion Report for the Block 38 West Property:
- Part 1 – Text, Figures, Tables, and Appendix A
- Part 2 – Appendix B
- Part 3 – Appendix C through Appendix K
View the Interim Action Completion Report for the Alley
These reports are also included in the Documents tab under Technical Reports at the bottom of this webpage.
Recent Redevelopment
Redevelopment of the Block 38 West Property began in late October 2019. The former structures were demolished and a multi-story mixed-use building with 12 stories above street level and 4 levels of underground parking was constructed. Construction of the new building required mass excavation across the entire Block 38 West Property to approximately 30 to 35 feet below ground level.
Contamination
- Petroleum hydrocarbons as diesel-range organics (DRO), oil-range organics (ORO), and gasoline-range organics (GRO)
- Benzene
- Naphthalenes, including 1-methylnaphthalene and 2-methylnaphthalene
- Carcinogenic polycyclic aromatic hydrocarbons (cPAHs), including benzo(a)pyrene
- Metals (barium and mercury)
Requesting Accommodation
If you speak a non-English language, free language services are available.
Site use restrictions called institutional controls are in effect
Institutional controls can be fences, signs, or restrictions on how the property is used. For instance, an institutional control may prohibit installing drinking water wells or disturbing a protective cap that isolates contamination. These restrictions keep the contamination contained and keep people from being exposed to the contamination. The controls are usually listed in environmental covenants recorded with the county.
Periodic reviews are required when institutional controls are required at a site. Ecology conducts reviews to make sure the controls remain effective and the cleanup still protects human health and the environment. We conduct periodic reviews about every five years.
Institutional Controls 2
Environmental Covenant
Restrictions/Requirements
- Ongoing Maintenance of Remedy
- Prohibit Soil Disturbance
Restricted Media
- Soil
Environmental Covenant
Restrictions/Requirements
- Control Vapor/Gas
- Ongoing Maintenance of Remedy
Restricted Media
- Groundwater
Documents 114
Legal 11
Outreach Information 12
State Environmental Policy Act 2
| Document Title | Document Date | Document Type |
| Block 38 West - Ecology SEPA Comment Letter | 5/16/2019 | SEPA Documents |
| Block 38 West - Addendum to the FEIS | 4/29/2019 | SEPA Documents |
Technical Reports 89
Contaminants 7
| Contaminant Type | Soil |
Groundwater |
Surface Water |
Air |
Sediment |
Bedrock |
|---|---|---|---|---|---|---|
| Metals - Metals - Other | RB | |||||
| Non-Halogenated Organics - Polycyclic Aromatic Hydrocarbons | RA | RB | ||||
| Metals - Mercury | RB | |||||
| Non-Halogenated Organics - Benzene | RB | |||||
| Non-Halogenated Organics - Petroleum-Diesel | RA | RB | ||||
| Non-Halogenated Organics - Petroleum-Gasoline | RB | RB | ||||
| Non-Halogenated Organics - Petroleum-Other | RA | RB |
- S
- Suspected
- C
- Confirmed Above Cleanup Levels
- B
- Below Cleanup Levels
- RA
- Remediated-Above
- RB
- Remediated-Below
- R
- Remediated
Public Comment Period
Postcard: English | 中文
Submit Comments | Read Comments
We invite you to comment on our proposal to remove the Block 38 West site from the Contaminated Sites List. Ecology has determined that cleanup actions have addressed contamination under the state’s cleanup law, the Model Toxics Control Act (MTCA).
Investigations found petroleum hydrocarbons, benzene, naphthalenes, carcinogenic polycyclic aromatic hydrocarbons (cPAHs), and metals in soil and groundwater above state standards. Most contamination was removed during interim actions tied to property redevelopment, which included large-scale soil excavation and disposal. Remaining contamination is contained under new pavement and building structures. Site restrictions will ensure the cleanup remains protective of human health and the environment.