EPA finalized amendments to regulations to set timelines for states to finalize their plans to implement emission guidelines under the Clean Air Act’s (CAA) New Source Performance Standards for existing sources. This action applied to states in the development and submission of state plans to EPA. The rule included new requirements for state plans to include explicit steps to ensure outreach and meaningful engagement with vulnerable communities impacted by the state plan. The final rule is effective on Dec. 18, 2023.