EPA proposed a rule to reduce the emissions of hazardous air pollutants by copper smelting facilities. The hazardous risk associated with the releases of two Arizona facilities impacted by this regulation was found by the EPA to “disproportionately affect communities with environmental justice concerns, including low-income residents, Native Americans, and Hispanics living near these facilities.” EPA said that the proposed rule would reduce the risks to an acceptable level. The original rule was proposed on Jan. 11, 2022, and a supplemental proposed additional hazardous air pollutant (HAP) standards for additional pollutants on Jul. 24, 2023. Comments on the supplemental rule were due Sep. 22, 2023.