1.1.1 Incident Category
Time Critical Removal Action

1.1.2 Site Description

Tributyl tin-contaminated sediments under Pier 4 in Tacoma, Washington.

1.1.2.1 Location

1 Sitkum Way, Tacoma, WA

1.1.2.2 Description of Threat

Tributyltin at levels exceeding 50,000 ug/kg were found in the sediments under Pier 4 during a predredge sampling performd by the Port of Tacoma in 2013. Tributyltin is an environmental toxin affecting mollusks and was banned in the 1990s.

1.1.3 Preliminary Removal Assessment/Removal Site Inspection Results

The Port of Tacoma collected and analyzed samples of sediment under Pier 4 in July 2014 to determine the extent and depth of contamination. Results indicated a removal action was necessary to dredge and remove approximately 50,000 cubic yards of sediment.

2.1.1 Narrative

2.1.2 Response Actions to Date
The Port of Tacoma began work in April 2015 to mobilize equipment to Pier 4 and start disconnecting utilities. Work then proceeded with removal of the pier deck. On June 15, 2015, OMI (contractor to the Port of Tacoma) began pulling the pilings holding up the pier deck using a vibratory hammer. On August 17, 2015 OMI began removing clean sediment upslope from the contaminated sediment and dumping it at an open-water disposal site managed by the Department of Natural Resources. Removal of clean sediments was completed on September 14, 2015.

On September 15, 2015, OMI began dredging TBT-contaminated sediments, barging it to the APM terminal (contiguous to Pier 4), transloading the sediments to trucks, and hauling the material to the LRI waste disposal facility. Water dredged with the sediment was pumped to a holding pond, treated to remove TBT, and discharged to Puget Sound. Water quality testing results indicate the treatment system was effective at removing TBT and particulates and that the dredging was not mobilizing particulates or TBT off-site above levels of concern.

2.1.3 Enforcement Activities, Identity of Potentially Responsible Parties (PRPs)

The Port of Tacoma is the PRP performing the removal action. research is being conducted to identify additional PRPs.

2.1.4 Progress Metrics

2.2.1 Anticipated Activities
A news release was issued by EPA on September 25, 2015 that contaminated dredging had begun.

2.2.1.1 Planned Response Activities

Contaminated dredging and operation of the transload and water treatment site at APM terminal is expected to continue into December 2015.

2.2.1.2 Next Steps

2.2.2 Issues

EPA

The Port of Tacoma

Orion Marine Contractors (OMI)

Subcontractors to OMI