EPA is approving a September 30, 2005 request from the designee of the Governor of South Dakota to redesignate the "Rapid City Area" under section 107 of the Clean Air Act (CAA) from unclassifiable to attainment for PM-10. EPA is approving the redesignation request because the State has adequately demonstrated that the "Rapid City Area" is in attainment of the PM-10 National Ambient Air Quality Standards (NAAQS) and has committed to the continuation of fugitive dust controls that should help ensure that the area continues to attain the PM-10 NAAQS. The requirements that will apply in the "Rapid City Area" will not change as a result of this action because, for the purposes of the requirements of the CAA, unclassifiable and attainment areas are treated the same. This action is being taken under section 107 of the Clean Air Act.