This rule regulates Hazardous Air Pollutants (HAP) from secondary aluminum production facilities that are major sources of HAP and that operate aluminum scrap shredders, thermal chip dryers, scrap dryers/delacquering kilns/decoating kilns, group 2 furnaces, sweat furnaces, dross only furnaces, rotary dross coolers, and secondary aluminum processing units (SAPUs). SAPUs include group 1 furnaces and in-line fluxers. Area sources of HAP are regulated only with respect to emissions of dioxins/furans (D/F) from thermal chip dryers, scrap dryers/delacquering kilns/decoating kilns, sweat furnaces, and SAPUs. The Clean Air Act (CAA) requires EPA to review maximum achievable control technology (MACT) standards and to revise them "as necessary (taking into account developments in practices, processes and control technologies)" no less frequently than every eight years. Under the "residual risk" provision of the CAA, EPA must evaluate the MACT standards within eight years after promulgation and promulgate standards, if required, to provide an ample margin of safety to protect public health or prevent an adverse environmental effect while considering costs. energy, safety and any other relevant factors. The existing rule, 40 CFR part 63, subpart RRR, National Emission Standards for Hazardous Air Pollutants (NESHAP) for Secondary Aluminum Production facilities, was promulgated in 2000. This risk and technology review for secondary aluminum production facilities will be conducted in this rulemaking, which will address possible residual risks, technology advancements, and clarifications to the existing rule.