Require CAA Section 126(b) petitions to identify a discrete group of upwind sources

Research notes

• Negative search (2026-08-27): EPA’s final and proposed rules in the Federal Register, among the federal records we keep and search, include no §126(b) petition response, rule or policy statement in the window; a Federal Register full-text search for section 126 petitions returns only state implementation plan actions.
• The §126(b) petition process is close kin to the Good Neighbor Plan (#1068) and moves with it, but the Quote asks for a distinct guardrail — that a petition identify a reasonably discrete group of upwind sources — and no EPA document in the window states that position.
• EPA’s full regulatory agenda, searched 2026-09-01. We read EPA’s entire Unified Agenda on reginfo.gov (214 entries across the active, long-term and completed stages), because the Federal Register prints only the entries that need a Regulatory Flexibility analysis and the 2026-08-27 negatives were taken from that shortened version. Nearest entries: RIN 2060-AV04, Revised Response to Clean Air Act Section 126(b) Petition From New York and RIN 2060-AV05, … From Maryland (both EPA/OAR, Long-Term Actions, 40 CFR 52, NPRM “To Be Determined”): https://www.reginfo.gov/public/do/eAgendaViewRule?pubId=202510&RIN=2060-AV04 and https://www.reginfo.gov/public/do/eAgendaViewRule?pubId=202510&RIN=2060-AV05. Both are responses to individual petitions on D.C. Circuit remands (New York v. EPA No. 19-1231; Maryland v. EPA No. 18-1285), not the general guardrail the Quote asks for. An agenda entry in the ask’s subject area that does not name its object leaves the ask not started, so they are recorded here and the Status does not move.