Reconsideration of 2009 Endangerment Finding and Greenhouse Gas Vehicle Standards

In this action, the U.S. Environmental Protection Agency (EPA) is proposing to repeal all greenhouse gas (GHG) emission standards for light-duty, medium-duty, and heavy-duty vehicles and engines to effectuate the best reading of Clean Air Act (CAA) section 202(a). We propose that CAA section 202(a) does not authorize the EPA to prescribe emission standards to address global climate change concerns and, on that basis, propose to rescind the Administrator's prior findings in 2009 that GHG emissions from new motor vehicles and engines contribute to air pollution which may endanger public health or welfare. We further propose, in the alternative, to rescind the Administrator's prior findings in 2009 because the EPA unreasonably analyzed the scientific record and because developments cast significant doubt on the reliability of the findings. Lastly, we propose to repeal all GHG emission standards on the alternative bases that no requisite technology for vehicle and engine emission control can address the global climate change concerns identified in the findings without risking greater harms to public health and welfare.