In keeping with its trust responsibility with respect to Indian tribes, the federal government holds title to the Navajo and Hopi tribal land in trust for the benefit of the tribes and their members. In this context, this section provides information on (1) the Navajo Nation and Hopi Tribe; (2) uranium mining and processing on the Navajo reservation and its environmental effects; (3) Navajo people's exposure to uranium contamination and related health effects; (4) key statutes relevant to addressing uranium contamination; and (5) the roles of federal and tribal agencies and selected actions taken to address uranium contamination on the Navajo and Hopi reservations prior to 2008.