A study performed in 1997 by the Environmental Protection Agency and DEQ found that sediments in the bed of the lower Willamette River between Sauvie Island and Swan Island were highly contaminated. The study is called the Sediment Investigation Report, or the Weston Report. The list of contaminants includes metals like mercury and tributyl tin, pesticides like DDT, and other hazardous substances such as PCBs, petroleum products, and dioxins. As a result, in July 2000, EPA proposed that this stretch of the river, referred to as Portland Harbor, be placed on the National Priorities List, commonly known as Superfund. Governor Kitzhaber concurred with the proposed listing in a July 2000 letter to Carol Browner, EPA Administrator, and attached a Statement of General Principles that provides a framework for State and EPA roles and responsibilities related to the complex environmental cleanup. The principles highlight the importance of both agencies working closely with Tribal governments, local governments and the community. Portland Harbor was officially placed on the federal National Priorities List on Dec. 1, 2000 Federal Register.