The Superfund Study Area includes Portland Harbor, an urban and industrial reach of the lower Willamette River located immediately downstream of downtown Portland and extending almost to the confluence with the Columbia River.

Portland Harbor is heavily industrialized with numerous manufacturing, shipbuilding, petroleum storage and distribution, metals salvaging, and electrical power generation activities. The area has been extensively modified by wetland draining, channelization, and dredging to accommodate a navigation channel for shipping and other industrial uses.

Public and private outfalls located on both banks of the river discharge stormwater. There are substantial agricultural, industrial, and municipal activities upstream of the harbor. State-of-the-art waste control systems are now used by many along the river and most of the sediment contamination is from historic practices.