This action addresses the Agency’s amendments to the National Emission Standards for Hazardous Air Pollutants (NESHAP) for the Taconite Iron Ore Processing source category as a result of the D.C. Circuit court’s opinion in Louisiana Environmental Action Network v. EPA, 955 F.3d 1088 (D.C. Cir. 2020) (LEAN). The Taconite Iron Ore Processing NESHAP, 40 CFR part 63, subpart RRRRR, was promulgated pursuant to section 112(d) of the Clean Air Act (CAA) on October 30, 2003. The residual risk and technology review (RTR) for this source category was promulgated pursuant to CAA sections 112(f) and 112(d)(6) on July 28, 2020. The NESHAP establishes emission limitations and/or work practice requirements based on maximum achievable control technology (MACT) for controlling emissions of hazardous air pollutants (HAP) from new and existing major sources of HAP within the source category, including taconite ore crushing and handling operations, pellet indurating furnaces, finished pellet handling operations, and ore dryers. The court in LEAN held that EPA must set limits on uncontrolled hazardous air pollutant emissions when it conducts technology reviews under section 112(d)(6) of the CAA, 42 U.S.C. section 7412(d)(6). Pursuant to the D.C. District Court's April 15, 2021, order in Blue Ridge Environmental Defense League v. Regan, Case No: 1:16-cv-00364-CRC (D.D.C. filed Feb. 24, 2016), the EPA must complete the final action for the Taconite Iron Ore Processing NESHAP by November 16, 2023.