The Fifth Circuit upheld EPA's decision to reject a challenge to a CAA Title V permit it issued for expansion of a plant in Baytown, Texas. Environmental groups requested that EPA reject the permit on the grounds that the underlying Title I preconstruction permit allowing the expansion was invalid. ...

The First Circuit vacated an air permit issued by the Massachusetts Department of Environmental Protection (MDEP) for a proposed natural gas compressor station that is part of a natural gas pipeline connecting the northeastern U.S. and Canada. Nearby municipalities and citizens argued that MDEP impr...

The D.C. Circuit granted in part and denied in part Delaware's and Maryland's challenges to EPA's denial of their CAA §126(b) petitions requesting that the Agency impose additional limitations on certain upwind sources contributing to the states' nonattainment of ozone NAAQS. Maryland's petition ar...

The D.C. Circuit granted a petition to review EPA's 2017 rule revising its emission standard for hazardous air pollutants (HAPs) emitted from pulp mill combustion sources. Environmental groups argued that EPA was required under §112(d)(6) of the CAA to consider the adequacy of the standard to contr...

The D.C. Circuit affirmed dismissal of an environmental group's request to compel EPA to produce guidelines for commercial or industrial solid waste incinerators (CISWI) and other categories of solid waste incinerators (OSWI). The group argued that the Agency failed to comply with nondiscretionary d...

The D.C. Circuit vacated a 2018 EPA rule that instituted a complete vacatur of its 2015 rule blocking the use of hydrofluorocarbons as replacements for ozone-depleting substances. An environmental group argued the 2018 rule was invalid because it was a legislative rule and was thus improperly promul...

The D.C. Circuit dismissed a petition to review EPA's Guidance on Significant Impact Levels (SILs) for Ozone and Fine Particles in the Prevention of Significant Deterioration Permitting Program, which sets numerical SILs that can be used by companies applying for PSD permits. An environmental group ...

A district court granted two Baltimore solid waste incineration facilities' partial motion for summary judgment in a challenge to the Baltimore Clean Air Act (BCAA). The facilities argued the BCAA was "conflict preempted" by Maryland law because it prohibited solid waste incinerators from operating ...

The Tenth Circuit vacated EPA orders that granted extensions of exemptions under the CAA's renewable fuels program for three small refineries. Industry groups challenged the orders, arguing that EPA failed to honor the statutory requirement of an "extension" by confusing an extension of an exemption...

The Washington Supreme Court invalidated a rule promulgated by the state's Department of Ecology authorizing regulation via emission standards of businesses that do not directly emit greenhouse gases (GHGs), but whose products do. Industry groups and utility companies argued the Department lacked au...