Case Summary: Cleanup Settlement Addresses Contaminated Sediment Removal in Blair Waterway, Washington State
On September 30, 2015, the U.S. Environmental Protection Agency (EPA) announced that it had entered into an administrative settlement agreement and order on consent (ASAOC) with the Port of Tacoma for the performance of a time-critical removal action in connection with the Blair Waterway TBT Site Tacoma, Wash. The estimated cost for the removal work is $19.3 million.
The Port of Tacoma (Port) began dredging contaminated sediments in Blair Waterway on September 15, 2015 in preparation to expand Pier 4. The Port is preparing to reconfigure Pier 3 and 4 to expand the capacity of the waterway for shipping. During a pre-dredging inspection for Pier 4, the Port detected a hazardous substance, called tributyltin (TBT) in the sediments. The Port is agreeing to clean up the contaminated sediments.
EPA is overseeing the Port's removal of contaminated sediments at Pier 4. As part of expanding the Port’s capacity for larger ships, the Port is removing the harmful TBT contamination. The Port removed approximately 40,000 cubic yards of TBT-contaminated sediments located under Pier 4 during the dredging operation. By adding this additional capacity to its shipping business, the Port is increasing employment opportunities the region. An estimated 1,500 jobs in Washington State are connected to the movement of shipping cargo through these terminals.
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The Blair Waterway TBT Site, encompassing approximately 21 acres, is located on the west side of the northern portion of the Blair Waterway. This area is in the Port's Industrial Development District, which is next to Commencement Bay in Tacoma, Wash.
During its 2013 investigation, the Port found that the fill material used to create the bulkhead under Pier 4 was contaminated with TBT. TBT is a marine biocide, commonly added to ship paint to prevent mollusks from sticking onto vessels. EPA canceled all TBT antifouling paint product registrations in December of 2005.
The Port consulted with the Washington Department of Fish and Wildlife and came to the conclusion that dredging would be least harmful to out-migrating fish if dredging started after the beginning of August. Detailed guidelines were also developed for how to operate the clamshell bucket to accurately dredge the required depth and area, as well as making sure the lid was fully secure before lifting the contaminated sediments through the water column so as to minimize sediment loss.
For information contact
U.S. Environmental Protection Agency
1200 6th Avenue, Suite 900
Seattle, Washington 98101