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On September 1, 1995 (60 FR 45948), EPA promulgated the National Emission Standards for Aerospace Manufacturing and Rework Facilities (40 CFR part 63, subpart GG) under section 112(d) of the Clean Air Act (CAA). The national emission standards for hazardous air pollutants (NESHAP) sets maximum achievable control technology (MACT) standards for existing and new major sources of hazardous air pollutant (HAP) emissions and includes standards to control volatile organic compounds (VOC) emissions. Under CAA section 112(d)(6), the EPA is required to review standards issued under section 112 and to revise them "as necessary (taking into account developments in practices, processes and control technologies)" no less frequently than every 8 years. The EPA also must evaluate the MACT standards within 8 years after promulgation and promulgate standards under CAA section 112 (f)(2), if required, to provide an ample margin of safety to protect public health or prevent an adverse environmental effect. Amendments to the NESHAP for Aerospace Manufacturing and Rework Facilities were proposed on February 17, 2015, and the comment period closed April 3, 2015. The source category was assessed for inhalation risks, including cancer risk and incidence, population cancer risk, and non-cancer effects (chronic and acute). The EPA also evaluated multi-pathway risk associated with this source category. The agency followed the Benzene Policy to determine if the source category had low risk, acceptable risk, or unacceptable risk. The EPA then evaluated the effectiveness and cost of additional risk reduction options and made acceptability and ample-margin-of-safety determinations. After assessing the risk from exposure to toxic air emissions from aerospace manufacturing and rework facilities, the EPA proposed that the emission standards provide an acceptable level of risk with an ample margin of safety to protect public health. Furthermore, the technology assessment did not identify any practices, processes, or control technologies that were not already required by the Aerospace NESHAP or considered in its development. The EPA also did not identify any improvements to those practices, processes or control technologies that could be transferred and applied to this source category. However, we did propose standards to limit organic and inorganic HAP emissions from specialty coating application operations and updated the provisions regulating emissions during periods of startup, shutdown, and malfunction to ensure the standards are consistent with the requirements of the CAA as interpreted by the courts. The EPA is currently reviewing comments and revising the proposed amendments as needed.