EPA discovered Phoenix violated its 40% over a 6-minute average opacity limit, seven times on the days of June 16, 2020, July 20, 2021, July 22, 2021, May 12, 2022, and September 28, 2022. Subsequently, EPA issued three NOV/FOV letters to Phoenix on September 28, 2021, August 2, 2022, and February 16, 2023. There will be a concurrent CAFO with this action. This ACO requires Phoenix to install new innovative control equipment to reduce fugitive emissions, on both of Phoenix?s slag processing plants that will reduce emissions of particulate matter and hazardous metal air pollutants. Phoenix has agreed to reduce fugitive emissions by increasing the moisture content of its slag materials through wet suppression. Specifically, the ACO will require Phoenix to: (1) develop and comply with new operational parameters, including a minimum quench time and updated moisture content for its slag materials; (2) install four wet suppression cannons, a mobile dust spray/fogger system, a overhead quench tower, and a permanent dual dust mister/fogger system at the basic oxygen furnace and desulfurization slag pits; (3) install and operate a booster pump, equipped with a flow meter to accurately record water flowrate and generate more watering power; and (4) install a local meteorological station to measure wind direction and velocity which Phoenix will use to monitor weather on-site to make adjustments to the slag handling operating schedule as needed. These equipment upgrades required substant