701 Dexter

Ecology held a 30-day comment period from March-April of 2024 on an Amended Agreed Order and a Remedial Investigation. 

View a summary of the most recent comment period, the comment we received, and our response here.

​Documents available for review and comment during the most recent comment period:

• Remedial Investigation: this 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 Order: Ecology 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 to read a summary of the latest information about this cleanup site.

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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.

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)

•             Benzene

•             Chloroform

•             Acrolein

•             1,3-butadiene

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.

Ecology has considered all comments received during this public comment period and won't make changes to the Remedial Investigation or Amended Agreed Order. Since no significant changes were made, Ecology will finalize the documents and remove this site from the Contaminated Sites List.

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.