This action will address the EPA's risk and technology review (RTR) of the National Emission Standards for Hazardous Air Pollutants (NESHAP) for Hazardous Waste Combustors (HWC NESHAP). The HWC NESHAP, 40 CFR part 63, subpart EEE, was promulgated pursuant to Clean Air Act (CAA) section 112(d); the EPA finalized the current standards in October 2005 (70 FR 59402, October 12, 2005). The NESHAP established emission limitations and work practice requirements based on maximum achievable control technology (MACT) for controlling emissions of hazardous air pollutants (HAP). The HAP emitted from HWCs include metal HAP, volatile organic HAP, polycyclic organic material, and halogen acids. This action will implement the risk review requirements of CAA section 112(f)(2) and the technology review requirements of CAA section 112(d)(6). The statute directs the EPA to promulgate emission standards under CAA section 112(f)(2) if such standards are required to provide an ample margin of safety to protect public health or to prevent, taking relevant factors into account, an adverse environmental effect. Any such standards are to be promulgated within 8 years after promulgation of MACT standards under CAA section 112(d). CAA section 112(d)(6) requires the EPA to review and revise the MACT standards as necessary, taking into account developments in practices, processes and control technologies, no less often than every 8 years. The EPA has a deadline for final rulemaking action to be completed by December 31, 2025, Blue Ridge Environmental Defense Fund et al. v. EPA, No. 1:22-03134 (D.D.C. 2022).