This action will address the agency's residual risk and technology review (RTR) of the National Emission Standards for Hazardous Air Pollutants (NESHAP) for Taconite Iron Ore Processing. The Taconite Iron Ore Processing NESHAP, subpart RRRRR, was promulgated pursuant to section 112(d) of the Clean Air Act (CAA) on 10/30/03 (68 FR 61867). The NESHAP established emission limitations and/or work practice requirements based on maximum achievable control technology (MACT) for controlling emissions of hazardous air pollutants (HAP) from ore crushing and handling operations, indurating furnaces, finished pellet handling operations and ore dryers. The HAP emitted from these sources include metal hazardous air pollutants (e.g., mercury, manganese and lead), formaldehyde and acid gases (i.e., hydrogen chloride and hydrogen fluoride). This action will implement the residual risk review requirements of CAA section 112(f)(2) and the technology review requirements of CAA section 112(d)(6). The statute directs the EPA to promulgate emission standards under CAA 112(f)(2) if such standards are required to provide an ample margin of safety to protect public health or to prevent, taking relevant factors into account, an adverse environmental effect. Any such standards are to be promulgated within 8 years after promulgation of MACT standards under CAA section 112(d). CAA section 112(d)(6) requires the EPA to review and revise the MACT standards as necessary, taking into account developments in practices, processes and control technologies, no less often than every 8 years. Pursuant to a court order, the EPA is obligated to complete the final action by June 30, 2020. In addition to the RTR, the National Wildlife Federation filed a petition for review of the initial 10/30/03 NESHAP, raising several issues, including the alleged failure of EPA to establish emission standards for mercury and asbestos. EPA requested and was granted a voluntarily partial remand of the rule with the intention to gather information on emissions of mercury and asbestos, and, if appropriate, develop proposed emissions standards for mercury and asbestos. During the development of the RTR proposed rule required by the court order, the EPA might also consider possible options to address issues raised in the NWF petition, if appropriate.