On March 15, 2023, the U.S. Environmental Protection Agency (EPA) issued its final Good Neighbor Plan, which secures significant reductions in ozone-forming emissions of nitrogen oxides (NOX) from power plants and industrial facilities. This final rule implements the Clean Air Act’s “Good Neighbor” or “interstate transport” provision, which requires each state to submit a State Implementation Plan (SIP) that ensures sources within the state do not contribute significantly to nonattainment or interfere with maintenance of the NAAQS in other states. Each state must make this new SIP submission within 3 years after promulgation of a new or revised NAAQS.

Where EPA finds that a state has not submitted a Good Neighbor SIP, or if the EPA disapproves the SIP, the EPA must issue a Federal Implementation Plan (FIP) within 2 years to assure downwind states are protected. Additionally, beginning in the 2026 ozone season, EPA is setting enforceable NOX emissions control requirements for certain sources at existing and new industrial facilities that have significant impacts on downwind air quality and the ability to install cost-effective pollution controls.

Key dates: 2023 and 2024 Important Dates

Fact sheet: Summary of Action and Map of States