The U.S. Supreme Court has agreed to hear oral argument on the issue of whether the newly promulgated Greenhouse Emission Standard for vehicles triggers a Clean Air Act requirement to regulate emissions from stationary sources.  A ruling against the EPA could eliminate the need for stationary industrial sources, such as power plants and petroleum refineries, to obtain prevention of significant deterioration and Title V Operating Permits for their greenhouse gas emissions.  The court declined to hear other challenges to the EPA’s greenhouse gas rules, including its finding that greenhouse gas emissions present a public danger and should be regulated under the Clean Air Act.  That leaves intact the EPA’s fundamental authority to regulate greenhouse gases under the Clean Air Act.