The Slip 4 Early Action Area is on the east side of the Lower Duwamish Waterway, about 2.8 miles upstream from the point where the waterway divides to flow around Harbor Island and on into Elliott Bay, near downtown Seattle. The slip is located just north of Boeing Plant 2 and covers about 6.4 acres.
In 2003, EPA named Slip 4 as an "early action area" of the Lower Duwamish Waterway Superfund site. Early actions are areas where early sediment cleanup may significantly reduce the risk that the sediments pose to the health of people and the environment. Sediments in Slip 4 are contaminated with PCBs.
Under EPA oversight, the City of Seattle and King County are investigating the sediment contamination at Slip 4. In May 2006, EPA selected a cleanup plan for Slip 4 sediments. Sediments with the highest contamination will be removed, and the remaining sediments will be capped. The banks will also be cleaned up. In 2007, PCBs were discovered in storm drains near Slip 4. The sediment cleanup will occur after the sources of these PCBs are adequately controlled.
Decision Documents
Technical Documents
Legal Documents
Controlling Pollution | 
(2003 photo by Washington State Department of Health) |