Rule 2026-17494

A plan written by a state, approved into federal regulation — the most common rule type, and visibility at national parks

Environmental Protection Agency Published Aug 27, 2026 91 FR 55268

The Environmental Protection Agency approved a revision to Arkansas regional haze state implementation plan. A state writing a plan and the federal government reviewing and incorporating it into regulation is the rule type that appears most often in the Federal Register.

Document overview (primary data)

  • Document typeRule
  • AgencyEnvironmental Protection Agency
  • Citation91 FR 55268

Key points

  • The Environmental Protection Agency approved a revision to Arkansas regional haze state implementation plan.
  • On approval, a state plan is incorporated into federal regulation and becomes enforceable as a matter of federal law.
  • The regional haze program protects visibility in mandatory Class I federal areas such as national parks, not health directly.
  • The state submitted in August 2022, supplemented in July 2025 and May 2026, and approval came in August 2026.
  • The program proceeds in bounded periods, and this revision addresses the second implementation period.

1The most common rule type

Across the Federal Register records this site holds, rules titled air plan approval recur constantly. A state writes a plan and the federal government approves it, published in volume with the state and the subject varying. The content differs by locality; the mechanism is shared.

  1. 1The state writes a planA state prepares and submits a plan meeting the requirements of the Clean Air Act
  2. 2The federal government reviewsThe agency confirms it satisfies those requirements
  3. 3Approval as regulationOn approval, the state plan is incorporated into federal regulation
  4. 4EffectThe contents of that plan become enforceable as a matter of federal law

The key is that approval makes a state plan part of federal regulation. A state wrote it, yet after approval it becomes the object of federal enforcement — a middle form, neither a uniform federal standard nor a matter left wholly to the states.

2A plan about what

What the regional haze program protectsWhat is required
Visibility in mandatory Class I federal areasPreventing future man-made visibility impairment
National parks and wilderness areas among themRemedying existing impairment
The view across distance from such placesStates revising long-term strategies for reasonable progress

The subject is not harm to health but the view. How far one can see from a national park, and how much human activity dims it. Pollution crosses state lines, so emissions in one state affect visibility at a park in another — which is why each state is required to hold a long-term strategy.

3Four years from submission to approval

The plan was submitted on August 8, 2022, and the approving final rule issued August 27, 2026, with supplements from the state in July 2025 and May 2026 in between. Submission opens the review rather than closing it. This site also covers rulemakings that stay on a regulatory agenda for more than a decade, which conveys the range of timescales.

4The second implementation period

The regional haze program is designed to proceed in bounded periods. This revision addresses the second, revisiting long-term strategies after the first. Making a plan once is not the end; each period calls for an update. Other Federal Register documents this site holds concern revisions for the first implementation period.

Why it matters

A state writing a plan that federal approval turns into regulation is a middle form between a uniform federal standard and leaving matters to the states. Four years from submission to approval conveys the timescale of such procedures.

FAQ

What is a state implementation plan?
A plan a state writes and submits to meet the requirements of the Clean Air Act. Federal approval incorporates it into federal regulation.
What does the regional haze program protect?
Visibility in mandatory Class I federal areas — how far one can see from places such as national parks, and how much human activity dims that view.

Sources (primary)

Source: Federal Register (federal documents, public domain). Links go to the official site.

#Environmental Protection Agency#Clean Air Act#State implementation plans#Regional haze#National parks
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