This action addresses the agency's risk and technology review (RTR) of the National Emission Standards for Hazardous Air Pollutants (NESHAP) for Hazardous Waste Combustors (HWC MACT). The HWC MACT, subpart EEE, was promulgated pursuant to section 112(d) of the Clean Air Act (CAA) on 09/30/1999 for incinerators, cement kilns, and lightweight aggregate kilns. These standards were vacated on 7/24/2001 and on 2/13/2002. The EPA promulgated interim standards for these units while final standards for these units were being prepared. On 10/12/2005, EPA promulgated the final replacement standards for incinerators, cement kilns and lightweight aggregate kilns, as well as standards for liquid fuel boilers, solid fuel boilers, and hydrochloric acid production furnaces. 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 hazardous waste combustors include metal HAP as well as volatile organic HAP, polycyclic organic material, and halogen acids. In August 2009 EPA obtained a full remand of all HWC MACT standards. This action will implement the residual 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 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 is currently under litigation in the federal district court for the District of Columbia to complete the risk and technology review, by plaintiffs (Blue Ridge Environmental Defense Fund, Louisiana Bucket Brigade, Missouri Coalition for the Environment, River Valley Organizing, Sierra Club, United Congregations of Metro East, and Utah Physicians for a Healthy Environment acting through counsel Earthjustice).