Marcella Burke joined Daniel Romito on PetroNoia to explain the legal origins and regulatory impact of the EPA’s 2009 “endangerment finding,” including the related “cause or contribute” determination. She traces the issue back to the Clean Air Act’s endangerment language and the U.S. Supreme Court’s decision in Massachusetts v. EPA (2007), which held that greenhouse gases can fall within the Act’s broad definition of “air pollutant,” while also requiring the EPA either to make an endangerment determination or explain why the science was too uncertain to do so.

The episode focuses on what the Administration is proposing in 2025: rescinding the EPA’s prior agency determination that current and projected CO₂ concentrations endanger public health and welfare. Marcella describes this as both a legal shift, i.e., rewriting the agency’s understanding of the Clean Air Act endangerment framework as applied to greenhouse gases, and a major policy change in how the federal government approaches greenhouse gas regulation going forward.

Marcella and Romito also discuss expected litigation and the role of the Administrative Procedure Act (APA), including the importance of agency process and building a defensible administrative record when reversing a long-standing rule. They address practical implications for regulated entities, with particular emphasis on vehicle greenhouse gas standards and permitting requirements (including best-available control technology analyses), as well as likely state-level pushback and the continued evolution of climate litigation strategies, including Suncor Energy v. Boulder County.