The Environmental Protection Agency (EPA), under Administrator Lee Zeldin and the Trump administration, has proposed to rescind the 2009 scientific "endangerment finding" that determined greenhouse gas emissions threaten human health and welfare. This finding has served as the legal foundation for U.S. climate regulations since 2010, underpinning rules on emissions from power plants, vehicles, and other sources. The proposed repeal would effectively remove the EPA's authority to regulate greenhouse gases as pollutants, potentially ending regulations on fuel economy, tailpipe emissions, and emissions from power plants. The administration has described this move as the largest deregulatory action in U.S. history. The proposal has sparked pushback from climate scientists and environmental advocates who emphasize the established link between fossil fuel emissions and global warming. Additionally, the Trump administration has halted work on National Climate Assessments and is reportedly reversing bans on certain chemicals in drinking water. Meanwhile, a federal appeals court recently upheld a Biden-era rule aimed at reducing the use of a potent climate-warming refrigerant, indicating ongoing legal battles over environmental regulations.