SW Harbor Project

Ecology is negotiating with the Port of Seattle to close the completed interim action (partial cleanup) Consent Decrees. Ecology has also proposed an Agreed Order for a Remedial Investigation and Feasibility Study (RI/FS). This RI/FS would

• Summarize the interim actions
• Summarize existing groundwater information
• Identify any potential data gaps
• Identify any proposed cleanup actions
• Determine the appropriate final cleanup levels

The Port of Seattle is reviewing Ecology's proposal.

This site was formerly called the Southwest Harbor site.

Portions of Terminal 5 have varied historic uses and contamination. These areas of contamination were divided into areas labeled RA1, RA2, RA3, RA4, and RA5. EPA is the lead agency for RA4. Ecology is the lead agency for RA1, RA2, RA3, and RA5

In 1994 and 1995, Ecology and the Port of Seattle negotiated interim action (partial cleanup) Consent Decrees for each area. The interim actions included soil removal and paving. They were completed.

From 2008 to 2011 the Port of Seattle, with Ecology’s review and approval, conducted groundwater monitoring programs. Six rounds of monitoring were conducted. In October 2011, Ecology sent a letter saying that collected groundwater data do not show contaminants above MTCA cleanup standards and that the groundwater monitoring program met groundwater monitoring plan requirements.

In November 2012, Ecology conducted a five-year periodic review for RA1, RA2, and RA3. It found that the total groundwater arsenic concentration in one monitoring well (MW-308N) did exceed the MTCA Method A drinking water level of 5 ppb. Ecology proposed that the Port of Seattle complete an RI/FS to determine if arsenic in the groundwater poses a risk.