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 ...

Minnesota's high court upheld an appellate court ruling in favor of a county's zoning ordinance that bans all industrial-mineral mining, including silica-sand mining. A silica-sand mining company argued the ordinance violated the dormant Commerce Clause by discriminating against its business. The hi...

A district court denied summary judgment to the U.S. government in a lawsuit concerning California's cap-and-trade agreement with Quebec. The government argued the agreement violated the Treaty Clause of the U.S. Constitution because it was binding and "confederat[ed] the laws of the two jurisdictio...

The Court of Federal Claims held that the U.S. government was not liable for the flooding of homes near two dams managed by the U.S. Army Corps of Engineers in Houston during Hurricane Harvey. Property owners downstream of the dams argued that the government flooded their lands by opening the dams' ...