This action will address the agency’s review of the New Source Performance Standards (NSPS) for Standards of Performance for Steel Plants: Electric Arc Furnaces Constructed After October 21, 1974, and on or Before August 17, 1983; and Standards of Performance for Steel Plants: Electric Arc Furnaces and Argon-Oxygen Decarburization Vessels Constructed After August 17, 1983 (EAF NSPS). The EAF NSPS, subparts AA and AAa were promulgated pursuant to section 111(b) of the Clean Air Act (CAA) on September 23, 1975 (40 FR 43850), and October 31, 1984 (49 FR 43845), respectively. The EAF NSPS established standards of performance in the form of emission limitations and monitoring requirements based on the best system of emission reductions (BSER) (taking into account the cost of achieving such reduction and any non-air quality health and environmental impact and energy requirements). The parameters regulated at electric arc furnaces and argon oxygen vessels include particulate matter emissions and opacity. This action would implement the review requirements of CAA section 111(b)(1)(B). CAA section 111(b)(1)(B) requires the EPA to review, and, if appropriate, revise the standards of performance based on the BSER, no less often than every 8 years. Pursuant to the consent decree in Our Children’s Earth Foundation v. Wheeler, No. 18-cv-04765 (N.D. Cal. entered May 10, 2019), the EPA is obligated to propose this action by November 1, 2021, and complete this action by November 1, 2022.