The Tenth Circuit denied environmental groups' petition to review an EPA rule that partially approved Colorado's SIP to reduce ozone pollution. The groups sought vacatur of the approval, arguing the Agency violated the CAA by approving the reasonable further progress and motor vehicle emissions budg...

A district court granted EPA's and OMB's motion to dismiss a challenge brought by California youth against certain agency policies for allegedly undervaluing the lives of children in cost-benefit analyses and thus harming them by failing to resolve the climate crisis. The youth argued the policies v...

A district court granted the state of California's motion to dismiss a challenge to two California laws—SB 253, Climate Corporate Data Accountability Act, and SB 261, Greenhouse Gases: Climate-Related Financial Risk—that require large businesses to publicly disclose their greenhouse gas emission...

The Montana Supreme Court affirmed a trial court ruling that declared the Montana Environmental Policy Act (MEPA) violated youths' state constitutional right to a "clean and healthful environment." The youths argued a provision of MEPA that precluded analysis of greenhouse gas emissions in EAs and E...

A district court granted in part environmental groups' motion for summary judgment in a CAA citizen suit concerning EPA's duty to update emissions standards for hazardous waste combustors. The groups sought declaratory judgment stating that EPA failed to comply with its obligations and injunctive re...

The Fifth Circuit granted EPA's motion to vacate its disapprovals of portions of regional haze SIPs submitted by Texas and Oklahoma and the issuance of federal implementation plans (FIPs) establishing a long-term strategy and/or reasonable progress goals for the states. EPA argued that because key d...

The Sixth Circuit vacated EPA's 2023 disapproval of a SIP proposed by Kentucky to comply with Agency changes to ozone NAAQS. Kentucky challenged the disapproval, which rested on different modeling that came out after the Agency's deadline for submitting the plan and on a lower threshold than the one...

In a per curiam opinion, a divided en banc Fifth Circuit affirmed a district court's civil penalty award of $14.25 million against an oil company in a long-running dispute concerning alleged CAA permit violations at an industrial complex in Baytown, Texas. Environmental groups had filed a CAA citize...

The Hawaii Supreme Court held that greenhouse gases (GHGs) were "pollutants" under several insurance policies' pollution exclusions and that an "accident" included an insured's reckless conduct for purposes of a challenge against fossil fuel companies for climate change-related harms. The city and c...

A district court denied industry groups' motion for summary judgment in a challenge to California's adoption of an emissions regulation for railroads operating within the state. The groups argued that the regulation, which would require companies to phase out locomotives that are more than 23 years ...