The United States Environmental Protection Agency (“EPA”) issued a memorandum on February 19th addressing the Clean Air Act Regional Haze program styled:
Update to Guidance on Regional Haze State Implementation Plans for the Second Implementation Period (“2026 Guidance”).
The 2026 Guidance is transmitted from EPA Assistant Administrator Aaron Szabo to the Regional Administrators.
The stated purpose of the 2026 Guidance is to:
… distribute an update to the regional haze guidance document titled “Guidance on Regional Haze State Implementation Plans for the Second Implementation Period” issued on August 20, 2019 (“2019 Guidance”).
The 2026 Guidance addresses analyzing energy and non-air quality environmental impacts in determining reasonable progress.
Congress sought to address visibility of mandatory Class I federal areas in which an impairment results from manmade air pollution. Section 169A requires that certain sources contributing to visibility impairment install BART. The states are responsible for determining the appropriate BART controls for certain stationary sources. EPA reviews the State’s Implementation Plan (“SIP”) submissions for consistency with the relevant regulation.
The Regional Haze Rule requires that states submit SIPs to manage visibility impairing air pollutants affecting mandatory Class I federal areas to demonstrate progress toward the national visibility goal under the Clean Air Act.
EPA had previously stated in 2025 that it was seeking input regarding how it can “meaningfully revise the RHR to streamline regulatory requirements impacting states’ visibility improvement obligations under the CAA.”
The stated purpose of the 2026 Guidance is to:
- Assist states with the preparation of any remaining second planning period regional haze state implementation plans (SIPs) that are due to the EPA.
- Assist states with any future revisions to those SIPs.
The 2019 Guidance is noted to have included recommendations on how states should evaluate and consider the four CAA statutory factors when determining the emission reduction measures that are necessary to make reasonable progress toward Congress’s visibility goal. The 2019 Guidance is stated to not address the consideration of impacts on the electrical grid and grid reliability. As a result, EPA states that it is clarifying and conveying its encouragement for states to consider potential impacts on grid reliability when determining emission reduction measures that are necessary to make reasonable progress. It references four “special emphasis” considerations of grid reliability impacts of any future electric generating unit closure that would become federally enforceable if approved in the SIP.
A copy of the 2026 Guidance can be found here.
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