This action finalizes amendments to the National Emission Standards for Hazardous Air Pollutants (NESHAP) for Clay Ceramics Manufacturing source category. The amendments are in response to a petition for reconsideration filed by industry stakeholders on the final rule promulgated on October 26, 2015 (80 FR 65470), as well as our review of the 2015 rule with respect to other issues raised by stakeholders. This action revises the temperature monitoring methodology used to demonstrate continuous compliance with the dioxin/furan emissions limit of the final rule. In addition, we are addressing concerns raised by industry stakeholders regarding visible emissions monitoring of tunnel kiln stacks for continuous compliance with particulate matter and mercury emission limitations. This action also amends the requirements for weekly visual inspections of system ductwork and control device equipment for water curtain spray booths. Lastly, this action amends the NESHAP regarding emissions averaging and makes technical corrections.