The Trump administration is formally repealing an Obama-era scientific finding that greenhouse gases pose a public health threat. The climate rule, known as the endangerment finding, has been the foundation for federal climate regulations. White House press secretary Karoline Leavitt says revoking that scientific finding “”will be the largest deregulatory action in American history.” The administration believes the move will save as much as 1-point-3 trillion dollars in avoided regulations — the bulk coming from less expensive new vehicles.