This rule was promulgated by the EPA on 9 May 2024 to avoid the 22 May 2024 Congressional Review Act trigger which would have allowed the rule to be repealed by the next Congress on a procedural fasttrack. It sets GHG standards for new and certain existing fossil fuel electric generating units. The rule is under attack by red state attorneys general and by fossil fuel companies. The primary attack is that the Clean Air Act does not give the EPA the authority to require CSS to control GHGs from electric generating units. Petitioners argue that CSS is not a proven, available, cost-effective technology as required by the CAA. (Petitioners’ brief). EPA argues that it will be by the deadline for electric generating units to implement CSS. The case is before the DC Circuit, which has declined to enjoin the rule. The petitioners are currently seeking an injunction from the Supreme Court through its shadow docket process.