Facility Site ID: 78082 Cleanup Site ID: 15112

  • Site Status

  • Awaiting Cleanup

Public Comment Period March 25, 2024-April 23, 2024


Documents available for review and comment:

  • Remedial Investigationthis document was prepared by ARE-Seattle No. 33 LLC (ARE) with Ecology oversight. It describes where and what types of contamination are at the Site.
  • Amended Agreed OrderEcology and the Potentially Liable Person (PLP), ARE, have changed this legal agreement to remove the requirement to prepare a Feasibility Study and Cleanup Action Plan, based on results of the Remedial Investigation.
Download the fact sheet here.

Submit comments | Read comments

Public Meeting

Ecology will hold a public meeting to discuss this phase of the cleanup if we receive 10 or more requests.

Site Status - March 2024

East side of 701 Dexter
East side of 701 Dexter
Ecology has negotiated a legal agreement, called an Agreed Order, with ARE-Seattle No. 33 LLC (ARE) for the 701 Dexter Site (Site). The order names ARE as a Potentially Liable Person (PLP) and requires them to investigate environmental conditions, conduct an interim cleanup action (if necessary), and develop a cleanup action plan for the Site.

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Site Background

701 Dexter Property Map with Seattle Vicinity
701 Dexter Property Map with Seattle Vicinity
The 701 Dexter cleanup site is located at 701 Dexter Ave N. in the South Lake Union neighborhood of Seattle. The Site is approximately 0.62 acres and has been the location of single-family and multi-family residences, a restaurant, and various other businesses that covered most of the property area from 1893 to 2021. It was most recently a six-story mixed-use building with above ground parking. That structure was demolished in 2021 to make way for redevelopment as a 10-story commercial office space/laboratory with a 4-story below ground parking garage.

Site Investigation And Contamination

View of 701 Dexter from the South
View of 701 Dexter from the South

A Remedial Investigation (RI) for this site was conducted in 2021. It identified the following contaminants of concern in soil vapors on the property:

             Vinyl Chloride

             Trichloroethylene (TCE)





No sources of groundwater or soil contamination were found on the Site during the RI. Most of the RI was conducted before demolition of the building that was housed on the site. After demolition, the property was excavated to approximately 40 feet below ground level to make way for new development. During the excavation, an undiscovered heating oil tank was found and removed. The RI, including samples collected following excavation, showed no sources of contamination at the site.

A Feasibility Study is typically the next step after an RI, where a best option is selected to remove the remaining contamination at a site. A Cleanup Action Plan is then conducted to see how best to carry out the selected option. At the 701 Dexter cleanup site, all sources of contamination were successfully removed during the Remedial Investigation. Because there is no more contamination to clean up, ARE will not be required to conduct a Feasibility Study or Cleanup Action Plan.

What Happens Next?

Ecology will consider all comments received during this public comment period and may make changes to the Remedial Investigation or Amended Agreed Order. If the documents require significant changes, we will hold another public comment period. If no significant changes are made, Ecology will finalize the documents and remove this site from the Contaminated Sites List.

General Cleanup Process

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.
Click image to enlarge
Click image to enlarge
Legal 4
Document Title Document Date Document Type
701 Dexter - Agreed Order Amendment - March 2024 3/21/2024 Agreed Order Amendment
Agreed Order DE 18215 Final 10/20/2020 Agreed Order
701 Dexter - Agreed Order - Final Draft 9/3/2020 Agreed Order
701 Dexter - Early Notice Letter 12/18/2019 Early Notice Letter
Public Information 6
Document Title Document Date Document Type
701 Dexter - Fact Sheet (Chinese) - March 2024 3/18/2024 Fact Sheet\Public Notices
701 Dexter - Fact Sheet - March 2024 3/18/2024 Fact Sheet\Public Notices
701 Dexter - Factsheet - Chinese - 09-2020 Public Comment 9/14/2020 Fact Sheet\Public Notices
701 Dexter - Factsheet - Spanish - 09-2020 Public Comment 9/3/2020 Fact Sheet\Public Notices
701 Dexter - Public Participation Plan - 09-2020 Public Comment 9/3/2020 Public Participation Plan
701 Dexter - Factsheet - 09-2020 Public Comment 9/3/2020 Fact Sheet\Public Notices
Technical Reports 3
Document Title Document Date Document Type
701 Dexter - Remedial Investigation Report - 2024 3/18/2024 Remedial Investigation Report
701 Dexter - Initial Investigation Field Report 12/9/2019 Initial Investigation Report
701 Dexter - Phase I ESA & Limited Subsurface Investigation 6/1/2018 Site Specific Technical Document - other
There may be more documents related to this site. To obtain documents not available electronically, you will need to make a public records request.

Places to see print documents

  • Northwest Regional Office
    15700 Dayton Ave N
    Shoreline, 98133
    Please schedule an appointment to view print documents at this location.

Contaminants 4

Contaminant Type
Surface Water
Metals - Metals - Other B B
Non-Halogenated Organics - Non-Halogenated Solvents C
Halogenated Organics - Halogenated Solvents C C
Non-Halogenated Organics - Petroleum-Other B B
Confirmed Above Cleanup Levels
Below Cleanup Levels
This contaminant list was based on our best information at the time it was entered. It may not reflect current conditions at the site.