This action supplements our proposed amendments to the national emission standards for hazardous air pollutants (NESHAP) for the Primary Copper Smelting source category published in the Federal Register on January 11, 2022. In that action, the Environmental Protection Agency (EPA) proposed amendments based on the residual risk and technology review (RTR) for the major source category and the technology review for the area source category. Although the proposal included the technology review for the area source category, this supplemental proposal does not include any changes for the area source category. In order to complete the required technology review for the major source category, the EPA is proposing additional hazardous air pollutant (HAP) standards for the following pollutants: benzene, toluene, hydrogen chloride (HCl), chlorine, polycyclic aromatic hydrocarbons (PAH), naphthalene and dioxin/furans (D/F). The EPA also evaluated the potential for changes to the previously proposed residual risk assessment and the decisions related to risk. Furthermore, in this action the EPA is also proposing revised standards for certain provisions initially proposed in the January 11, 2022, RTR proposal based on additional information gathered since the publication of the 2022 proposed rule.