This document assesses and compares the environmental impacts of various alternatives for remedial action at the shiprock uranium mill tailings site located on the Navajo Indian Reservation, one mile south of Shiprock, New Mexico. The site contains 72 acres of tailings and four of the original mill buildings. The Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA), Public Law 95-604, authorizes the US Department of Energy to clean up the site to reduce the potential health impacts associated with the residual radioactive materials remaining at the site and at associated properties off the site. The US Environmental Protection Agency promulgated standards for the remedial actions (40 CFR 192). Remedial actions must be performed in accordance with these standards and with the concurrence of the Nuclear Regulatory Commission. The proposed action is to stabilize the tailings at their present location by consolidating the tailings and associated contaminated soils into a recontoured pile. A seven-foot-thick radon barrier would be constructed over the pile and various erosion control measures would be taken to assure the long-term integrity of the pile. Three other alternatives which involve moving the tailings to new locations are assessed in this document. These alternatives which involve moving the tailings to new locations are assessed in this document. These alternatives generally involve greater short-term impacts and are more costly but would result in the tailings being stabilized in a more remote location. The no action alternative is also assessed. 99 refs., 40 figs., 58 tabs.