The U.S. Environmental Protection Agency’s repeal of the 2024 MATS amendments may signal a broader shift in environmental rulemaking and the treatment of ancillary benefits.
Continue Reading The EPA’s MATS Repeal May Signal a Broader Shift on Ancillary Benefits
Three recent developments — a proposed EPA overhaul of New Source Review requirements, updated turbine emissions standards, and a DOJ intervention in a Clean Air Act citizen suit — may signal that air quality permitting is becoming a defining factor in data center and large infrastructure development.
There are instances where the EPA is applying or plans to apply AI in connection with its regulatory functions. Stakeholders should be aware of what EPA has done to date and its future plans.
On Feb. 12, 2026, the U.S. Environmental Protection Agency (EPA) announced its final rule (published at 91 Fed. Reg. 7686) rescinding the 2009 Endangerment and Cause or Contribute Findings for Greenhouse Gases Under Section 202(a) of the Clean Air Act, 74 Fed. Reg. 66496 (Dec. 15, 2009) (Endangerment Finding) and all subsequent federal greenhouse gas (GHG) emission standards for vehicle and engine model years 2012 and onward that relied on the Endangerment Finding.
On November 17, 2025, the U.S. Environmental Protection Agency (EPA) and the Army Corps of Engineers (the Corps) announced a proposed rule (PR) to revise the definition of “waters of the United States” (WOTUS) by excluding several types of waters from the definition of WOTUS in their respective regulations (40 C.F.R. § 120.2 and 33 C.F.R. § 328.3).
Continue Reading The Never-Ending Rule: EPA and Army Corps of Engineers Propose Narrowing the Post-Sackett Definition of ‘Waters of the United States’
On Sept. 5, 2025, the D.C. Circuit reversed EPA’s 2023 rule rescinding the “startup, shutdown and malfunction” (SSM) affirmative defense under the Title V permitting program. The decision carries implications for Title V programs nationwide and for stationary source regulations more broadly.
Continue Reading DC Circuit Reinstates Title V Emergency Affirmative Defense
On Sept. 4, 2025, EPA released its Semiannual Regulatory Agenda, signaling that the Agency is expected to continue to focus its deregulatory efforts on rules and regulations under the CAA in furtherance of this administration’s policy to increase domestic energy production and supply by easing rules on producers
Continue Reading Recent Federal Developments May Undercut the Clean Air Act
On June 11, 2025, EPA issued a proposed rule that repeals carbon pollution standards for new and reconstructed gas turbines and existing and modified coal and oil/gas-fired units.
On March 12, 2025, EPA Administrator Lee Zeldin announced the agency’s intention to reconsider 31 environmental regulations, describing the effort as the “single most impactful day of deregulation in EPA history.” While the scope of this initiative spans air, water, and climate regulations, the most consequential actions—legally and practically—center on a handful of cross-cutting programs and sector-specific rules.
In June 2024, the U.S. Supreme Court issued its opinion in Loper Bright Enterprises v. Raimondo, No. 22-451, and Relentless, Inc. v. Dep’t of Commerce (U.S. June 28, 2024)
Continue Reading Assessing Loper Bright’s Potential Real-World Effects on Environmental Regulation