EPA Issues Proposed Revisions to Subpart DDDDD (Boiler MACT Rule)

Commercial Boiler

Updated Original Post Dated: July 20, 2020

On July 8, 2020, the EPA Administrator signed proposed revisions to 40 CFR Part 63, Subpart DDDDD, National Emission Standards for Hazardous Air Pollutants for Major Sources: Industrial, Commercial, and Municipal Boilers and Process Heaters.

EPA is proposing to revise 34 different emission limits, which it had previously promulgated in 2011 and amended in 2013. Of these 34 emission limits, 28 would become more stringent, and 6 would become less stringent. The proposed rule would provide affected facilities with up to three (3) years after the effective date of the final rule to demonstrate compliance with these revised emission limits. The proposed revisions were published in the Federal Register on August 24, 2020, and a copy can be found here.

The proposed rule includes specific technical corrections and contains language to allow the use of CO/CO2 CEMS instead of CO/O2 CEMS without obtaining approval of an alternate monitoring approach. Comments on the proposed Boiler MACT rule amendments must be received on or before 60 days after the proposed rule is published in the Federal Register.

Due to the COVID-19 pandemic, the EPA Docket Center and Reading Room were closed to public visitors on March 31, 2020. EPA encourages the public to submit comments online at  regulations.gov or email to a-and-r-docket@epa.gov (Attention Docket ID No. EPA-HQ-OAR-2020-0058). There may be a delay in processing mail and faxes. Hand deliveries and couriers may be received by scheduled delivery only. Comments must be received on or before October 23, 2020.