Adoption and Submittal of State Plans for Designated Facilities — 40 CFR Part 60, Subparts B and Ba

4/11/2025 -- EPA Announces Reassessment of the 2023 Subpart Ba Rule

Under Clean Air Act (CAA) section 111(d), EPA issues regulations directing states to submit plans to establish "standards of performance" for certain air pollutant emissions from existing facilities that are in source categories regulated under CAA section 111 (New Source Performance Standards). EPA accordingly develops emission guidelines for existing sources that meet the section 111(d) criteria and has promulgated general provisions for the Emissions Guidelines state plan adoption and submittal processes. 

General provisions for the state plan processes under CAA 111(d) were first promulgated in 1975 as 40 CFR part 60 subpart B. The subpart B provisions included timelines for submission of state plans, EPA’s action on such submissions, and EPA’s promulgation of federal plans. In 2019, EPA promulgated an updated, new set of implementing regulations codified at 40 CFR part 60 subpart Ba (84 FR 32520). In 2021, the D.C. Circuit vacated several provisions of subpart Ba related to timelines. Subsequently, in 2023, EPA issued final amendments to replace the vacated timelines and to further update these general provisions. The 2023 amendments include:

• Revised timelines, such as the submission of, and EPA’s action on, State Plans and deadlines for the promulgation of related Federal Plans;
• Clarifications regarding the consideration of sources’ remaining useful lives and other factors;
• Regulatory mechanisms for State Plan processing;
• Guidelines for enhanced engagement with stakeholders; and
• Clarifications of certain regulatory definitions.

 These updates apply to all Emissions Guidelines published after July 8, 2019.