(August 17, 2023, 12:30 PM EDT) -- DENVER — The U.S. Environmental Protection Agency’s decision to approve Utah’s state implementation plan (SIP) for improving visibility in national parks and wilderness areas was not arbitrary or capricious because the agency rationally explained the methodology it used to test the emissions of power plants that contribute to regional haze, a 10th Circuit U.S. Court of Appeals panel found in denying a petition for review of the decision....