July 1, 2022 -- Written by John Egan for Industrial Info Resources (Sugar Land, Texas) -- The most-litigated federal regulation that never actually went into effect hit another roadblock June 30 when the U.S. Supreme Court voted 6-3 to reject the Environmental Protection Agency's rationale for regulating carbon dioxide (CO2) emissions from power plants. The court remanded the issue back to the EPA, which has been working on a new Clean Air Act rule to reduce CO2 emissions from the power sector. The case, <I>West Virginia v. EPA</i>, capped a years-long effort by coal interests and coal-state Republican attorneys general to limit or abolish the EPA's ability to regulate CO2 emissions from coal-fired power plants. In one form or another, federal litigation around the EPA's ability to regulate CO2 emissions has spanned nearly 20 years and four presidents.