The U. S. Nuclear Regulatory Commission (NRC) is amending its regulations regarding decommissioning of licensed thorium mills and uranium recovery facilities to provide specific radiological criteria for the decommissioning of lands and structures. This final rule uses the existing soil radium standard to derive a dose criterion (benchmark approach) for the cleanup of byproduct material other than radium in soil and for the cleanup of surface activity on structures to be released for unrestricted use. This final rule is intended to provide a clear and consistent regulatory basis for determining the extent to which lands and structures can be considered to be decommissioned.