The State of Texas has filed its initial brief challenging U.S. EPA's endangerment finding that concludes that greenhouse gases (GHGs) pose a danger to human welfare, according to this release by the State Attorney General's office. "The EPA’s Endangerment Finding concluded that greenhouse-gas emissions contribute to the 'perceived but undefined danger' variously referred to as global warming or climate change. The States’ brief explains that the Endangerment Finding is legally flawed because the EPA 'refused to determine what ‘atmospheric concentrations’ of GHGs' pose a threat to humans – which is required by the Clean Air Act. When the EPA issues an Endangerment Finding, the Clean Air Act requires the agency to establish clear standards. The States’ brief explains that the EPA made no 'attempt to determine whether reducing GHG emissions will have any impact on climate change.'"
You can find a copy of the brief at the link as well.