Second Federal Court Strikes Down New York’s Climate Change Superfund Act
On September 23, 2026, a second federal district court struck down New York’s Climate Change Superfund Act (the Act), this time in a lawsuit brought by the United States and the U.S. Environmental Protection Agency (EPA). In United States v. State of New York, Judge P. Kevin Castel of the U.S. District Court for the Southern District of New York held that the Act is preempted both by the Clean Air Act (CAA) and, independently, by the federal government’s exclusive authority over foreign affairs. The Court declared the Act unconstitutional and permanently enjoined New York officials from enforcing it.
In Landmark TSCA Decision, Fifth Circuit Vacates EPA’s Methylene Chloride Rule, Limits EPA’s Interpretation of “Unreasonable Risk”
On September 15, 2026, a unanimous panel of the U.S. Court of Appeals for the Fifth Circuit vacated the EPA’s 2024 risk management rule for methylene chloride and the unreasonable-risk determination underlying it. East Fork Enterprises, Inc. v. EPA, Nos. 24-60227 & 24-60256 (5th Cir. Sept. 15, 2026). The Court granted the industry petitioners’ petition for review, denied Sierra Club’s separate challenge seeking more stringent regulation, and remanded the matter to the EPA.
EPA Issues Final Rule Repealing Most 2024 Power Plant GHG Standards and a Proposal That Would Eliminate the Remaining Power Plant GHG Standards
On September 14, 2026, the U.S. Environmental Protection Agency (EPA) took two related actions to substantially change the federal framework for regulating greenhouse gas (GHG) emissions from fossil fuel-fired power plants under Clean Air Act Section 111.
EPA and the Army Corps Seek Comment on Another WOTUS Alternative for Implementing Sackett v. EPA
On September 4, 2026, the U.S. Environmental Protection Agency (EPA) and the Department of the Army, U.S. Army Corps of Engineers (together, the agencies), announced a supplemental notice of proposed rulemaking (SNPRM) that requests additional public input on rules the agencies are considering to reflect the appropriate extent of federal Clean Water Act (CWA) jurisdiction over streams and wetlands. The SNPRM follows on the heels of roughly 220,000 comments the agencies received on their November 20, 2025 proposal to revise the definition of “waters of the United States” (WOTUS) in light of Sackett v. EPA, 598 U.S. 651 (2023), and it meaningfully expands the range of alternatives the agencies are considering for the final rule.
EPA Proposal Could Reduce New Source Review-Related Delays for Major Construction Projects
The U.S. Environmental Protection Agency (EPA) recently proposed a rule that could allow project developers of data centers, energy projects, and other facilities to begin certain site-development and infrastructure activities before obtaining a Clean Air Act (CAA) New Source Review (NSR) permit. The proposed rule, published on May 11, 2026, would clarify that certain non-emitting activities may occur before an NSR permit is issued, potentially providing greater flexibility for project development without altering the substantive air permitting requirements applicable to pollutant-emitting equipment. (more…)
EPA Proposes Two-Year Delay of Biden-Era Vehicle Emissions Standards
On May 14, 2026, the U.S. Environmental Protection Agency (EPA) announced that it is reconsidering the criteria pollutant standards for new light- and medium-duty vehicles. The first phase of EPA’s proposal would push back the phase-in schedule of the “Tier 4” criteria pollutant standards from model year 2027 to model year 2029, giving automakers two additional model years to comply with the existing Tier 3 framework before the more stringent requirements begin to apply—and giving EPA time to conduct a second rulemaking to amend the Tier 4 emissions standards.
Congress Signals Changes to EPA-OSHA Coordination for Chemical Safety Regulation in 2026 Spending Package
As part of the 2026 appropriations package, on January 6, 2026, the U.S. House and Senate Committees on Appropriations issued a joint statement outlining several procedural changes they are seeking for the U.S. EPA’s regulation of toxic chemical substances. The appropriations bill passed in the House last week, and is now pending before the Senate.
EPA Memo Emphasizes “Compliance First” Enforcement Approach
On December 5, EPA’s Office of Enforcement and Compliance Assurance (OECA) issued a memorandum to staff affirming a “compliance first” approach to civil enforcement. The memo, signed by Acting Assistant Administrator Craig J. Pritzlaff, applies to all civil enforcement matters and reflects EPA leadership’s instruction to staff regarding inspections, investigations, and enforcement negotiations.
EPA and Army Corps Propose to Narrow Federal Jurisdiction Under the Clean Water Act
On Monday, November 17, 2025, the U.S. Environmental Protection Agency (EPA) and U.S. Army Corps of Engineers (Corps) (collectively, the “Agencies”) released a pre-publication proposed rule to revise the definition of “Waters of the United States” (WOTUS) under the Clean Water Act (CWA). The proposal responds to the U.S. Supreme Court’s 2023 decision in Sackett v. EPA, 598 U.S. 651 (2023), but goes further than the Biden Administration’s response to the Sackett ruling in August 2023 (the “Conforming Rule”).[1] Sidley’s blog post on the prior administration’s rule can be found here.
EPA Proposes Exemptions to TSCA PFAS Reporting Rule
On November 13, 2025, the U.S. Environmental Protection Agency (EPA) published a proposed rule that would revise the scope of EPA’s Toxic Substances Control Act (TSCA) Section 8(a) rule requiring a one-time expansive data submission on per- and polyfluoroalkylated substances (PFAS Reporting Rule). The proposal introduces several exemptions designed to reduce compliance costs and improve implementation. The revisions aim to make the one-time PFAS reporting requirements more practical, particularly for small manufacturers and importers, while preserving EPA’s access to use and exposure information. EPA will accept public comments until December 29, 2025.
