Your Guide to Emerging Issues in Environmental Regulation and Litigation.
The Mercury and Air Toxics Standards (MATS) are federal air pollution regulations issued by the U.S. Environmental Protection Agency (EPA) under the Clean Air Act. Finalized in 2012 and effective beginning in 2015, MATS establish technology‑based emission limits for hazardous air pollutants (HAPs) emitted by coal‑ and oil‑fired power plants. In 2024, the EPA finalized …
In a February 5, 2026 filing before the D.C. Circuit, a coalition of industry groups strongly endorsed the U.S. Environmental Protection Agency’s method for determining when upgrades at industrial facilities must undergo federal air‑quality review. The dispute centers on the EPA’s “Project Emissions Accounting” (PEA) approach under the Clean Air Act’s New Source Review (NSR) …
The Environmental Protection Agency has taken measures to roll back the “good neighbor” rule, which limits smokestack emissions affecting downwind areas in neighboring states under the Clean Air Act (CAA). The rule is intended to address transboundary ozone pollution that can exacerbate health hazards by requiring each state to implement regulations meant to reduce emissions …
The U.S. Environmental Protection Agency this week announced new guidance on New Source Review (NSR) preconstruction permitting requirements “to provide much needed clarity for the buildout of essential power generation and reshoring of manufacturing.” The action, according to the agency, “provides flexibility to begin certain building activities that are not related to air emissions, such …
On June 18, the U.S. Supreme Court issued two decisions that clarify a deceptively simple question under the Clean Air Act: Where should lawsuits challenging EPA actions be filed? The rulings – EPA v. Calumet Shreveport Refining LLC and Oklahoma et al. v. EPA – do not change the substance of environmental law, but they do shape …
The Environmental Protection Agency intends to issue a rule updating its Clean Air Act emission standards for new and existing municipal solid waste (MSW) landfills to cut methane and other harmful landfill gas emissions. The rule follows another Clean Air Act-related proposal the EPA issued in January, designed to reduce emissions of nine pollutants, including …
On a clear day, you can’t actually see forever — if you follow the blue sky out to the horizon, you will often see it become somewhat more pale and opaque, owing to ‘visible pollution,’ or “haze” — the result of the interaction of sunlight with particulate matter in the air. Before the modern industrial …
The California Air Resources Board has requested that the U.S. Environmental Protection Agency grant California an authorization pursuant to § 209(e)(2) of the Clean Air Act to, among other things, prohibit locomotives that are 23 years of age or older from operating in California starting in 2030, a rule many in the U.S. House Committee …
Stationary combustion turbines, often referred to as gas turbines, are used to generate high volumes of electricity at power stations, dams, and industrial centers. Despite their size, noise, and prodigious output, these engines are simple, with a design that dates, at least in concept, all the way back to 150 BC when a Greek inventor …
As part of the United States Aviation Climate Action Plan – which strives to achieve net zero greenhouse gas emissions for United States Aviation by 2050 – the Federal Aviation Administration announced earlier this month its final rules to reduce greenhouse gas emissions from most large aircraft in U.S. airspace. The new rules go into …