The Remedial Investigation (RI) serves as the mechanism for collecting data. Data collected in the RI is used for the development of remedial alternatives in the Feasibility Study (FS)

The Draft Remedial Investigation Report, prepared by the Lower Willamette Group, was submitted to the U.S. Environmental Protection Agency (EPA) in October 2009. The report is the foundation for decisions concerning ways to reduce potential risks to human and ecological health in the lower ten miles of Oregon's largest river.

It describes the nature and extent of contamination, characterizes physical conditions and the potential movement of contaminants, and assesses the potential risks that contamination may pose to human health and the ecosystem.