EPA is proposing a Federal plan to implement the revised emission guidelines for existing other solid waste incineration (OSWI) units. The EPA promulgated emission guidelines for existing OSWI units in 2005 and revised the emission guidelines on June 30, 2025. If a State or Tribe with existing OSWI units subject to the 2025 revised OSWI emission guidelines does not submit an approvable plan by June 30, 2027, the EPA will develop, implement, and enforce a Federal plan for existing OSWI units located in that State or area of Indian Country. This action proposes a Federal plan to implement the 2025 revised OSWI units emission guidelines for existing OSWI units located in States and on Tribal lands without effective State or Tribal plans by the effective date of this Federal plan. Comments must be received on or before 17 August 2026. POC is Felica Davis, Ph.D., tele: (919) 541-4857, email: davis.felica@epa.gov. (Federal Register 2 July 2026 [Proposed Rule] Pages 40494-40508)