Regional Haze/Arkansas: U.S. Environmental Protection Agency Public Notices Approval of State Implementation Plan Revisions

The United States Environmental Protection Agency (“EPA”) published in the September 5th Federal Register a proposed rule approving an Arkansas State Implementation Plan (“SIP”) revision. See 90 Fed. Reg. 43030.

The revision submitted by the Arkansas Department of Energy and Environment - Division of Environmental Quality (“DEQ”) is stated to satisfy the requirements of the Clean Air Act Regional Haze Rule (“RHR”) for visibility protection in mandatory Class I Federal areas for the program’s second implementation period.

The federal regional haze program is driven by 169A of the Clean Air Act. Congress sought to address visibility in 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 best available retrofit technology (“BART”). The states are responsible for determining the appropriate BART controls for certain stationary sources. EPA reviews the states’ SIP submissions for consistency with the relevant regulations.

In the event EPA determines that an SIP does not meet the Clean Air Act’s requirements, the federal agency may itself make certain choices and impose a federal implementation plan. Section 169 gives states substantial responsibility to determine appropriate BART controls and EPA may not disapprove reasonable state determinations that comply with the relevant statutory or regulatory reequipments.

EPA states that the SIP revision was submitted by DEQ on August 8, 2022, and clarified by the state agency on July 29, 2025. The federal agency states in part that:

…Arkansas’ SIP submission addresses the requirement that states must revise their long-term strategies for making reasonable progress to prevent any future and remedy any existing man-made visibility impairment in the Class I areas.

Specific requirements that the revisions are stated to have satisfied include:

1. 40 CFR 51.308(f)(1): calculations of baseline, current, and natural visibility conditions, progress to date, and the uniform rate of progress (URP);
2. 40 CFR 51.308(f)(2): long-term strategy;
3. 40 CFR 51.308(f)(3): reasonable progress goals (RPGs);
4. 40 CFR 51.308(f)(4): reasonably attributable visibility impairment (RAVI);
5. 40 CFR 51.308(f)(5) and 40 CFR 51.308(g)(1) through (5): progress report requirements;
6. 40 CFR 51.308(f)(6): monitoring strategy and other implementation plan requirements; and
7. 40 CFR 51.308(i): Federal Land Manager (FLM) consultation.

A copy of the Federal Register notice can be downloaded here.