The U.S. Environmental Protection Agency, led by Administrator Lee Zeldin, on 29 July proposed rescinding the 2009 “endangerment finding” that declared greenhouse gases a threat to public health and welfare. The move, previewed on a conservative podcast and announced formally at a truck dealership in Indiana, would roll back the legal cornerstone that has allowed Washington to limit carbon dioxide, methane and other emissions from vehicles, power plants and industrial facilities. Zeldin called the step the largest deregulatory action in U.S. history. An agency summary projects that eliminating the finding and the regulations built on it could remove roughly $1 trillion in compliance costs and save about $54 billion a year, largely by overturning federal tailpipe standards and other climate rules. The proposal argues that a 2024 Supreme Court decision curbing agency discretion under the so-called Chevron doctrine leaves EPA without clear authority to police climate pollution absent new direction from Congress. Environmental organizations immediately promised to sue, saying the plan defies the scientific consensus on climate change and the Supreme Court’s 2007 Massachusetts v. EPA ruling that affirmed EPA’s power to regulate greenhouse gases. Several states are expected to join the litigation. Industry reaction was mixed: the American Trucking Associations applauded the rollback as easing economic pressure, while automakers said they were still reviewing the text. The draft rule must undergo a public-comment period and inter-agency review before it can be finalized, a process likely to extend into next year and face multiple court challenges.