The Port of Tacoma was officially created in 1918 and has spread from 240 acres to over 2,700 acres. Recently, maintenance and redesign of the docks at Pier 4 have been undertaken to accommodate larger deeper draft containerships. During project planning, a hot spot of contamination was found in the near shore environment. The main contaminant of concern was tributyltin (TBT). The nature of TBT, being a relatively stable compound and not easily degraded or absorbed to soil, led design engineers to the electrocoagulation (EC) process. Orion Marine Group was the successful bidder on the project and worked with WaterTectonics to develop a treatment plan that included a settling pond and the EC treatment train. Operations lasted 6 months and successfully treated 11 million gallons of stormwater and dredge return water that was discharged back to Commencement Bay.