The Environmental Protection Agency (EPA) is finalizing approval of a State Implementation Plan (SIP) revision submitted by the State of South Carolina, through the South Carolina Department of Health and Environmental Control (hereinafter referred to as SC DHEC or South Carolina) via a letter dated February 3, 2022. The SIP revision updates portions of South Carolina's Prevention of Significant Deterioration (PSD) and Nonattainment New Source Review (NNSR) regulations that pertain to Project Emissions Accounting (PEA) provisions.

The Environmental Protection Agency (EPA) is approving revisions to the Washington State Implementation Plan (SIP) that were submitted on June 22, 2023, by the Department of Ecology in coordination with the Southwest Clean Air Agency (SWCAA). In 2017, the EPA approved a comprehensive update to SWCAA 400 General Regulations for Air Pollution Sources in the SIP, which includes new source review permitting requirements as well as other general requirements for sources regulated under SWCAA's jurisdiction.

The Environmental Protection Agency (EPA) is approving, under the Clean Air Act (CAA), revisions to the sulfur dioxide (SO<INF>2</INF>) portion of the Indiana State Implementation Plan (SIP). The state of Indiana is requesting revisions to emission limits at the Northern Indiana Public Service Company Bailly Station (NIPSCO) facility reflecting permanently shut down units. Indiana is also requesting SIP revisions for two facilities formerly owned by ArcelorMittal USA LLC and currently owned by Cleveland-Cliffs LLC (the Indiana Harbor East and Indiana Harbor West facilities).

The Environmental Protection Agency (EPA) is approving, under the Clean Air Act (CAA), a revision to the Ohio State Implementation Plan (SIP) intended to provide for attainment of the 2010 primary, health-based 1-hour sulfur dioxide (SO<INF>2</INF>) national ambient air quality standard (NAAQS or standard) for the Muskingum River SO<INF>2</INF> nonattainment area.