After dredging in 2013, the Port of Tacoma discovered high levels of tributyltin in the sediments under Pier 4 on the Blair Waterway. Tributyl tin was historically used in antifouling ship paint. While the source of the tributyl tin contamination is unknown, the Port of Tacoma and EPA signed an Administrative Order on Consent on June 13, 2014 to conduct a removal site evaluation to determine if a removal action is necessary. Sampling was conducted in June and July of 2014.
EPA made the decision, on August 12, 2014, that a removal action is necessary to mitigate the threat to the ecosystem from the tributyltin in the sediments. The action memo and a second AOC for the work was Signed in January-February 2015. The removal action started in April 2015 to prepare the pier for dredging the contaminated sediments. Dredging began in mid July and is expected to be completed before the next fish work window closure in February 2016..
