New lawsuits filed in the US Courts of Appeal are seeking to upend a fundamental tenet of the Clean Air Act (CAA or the Act) Title V operating permit program—i.e., that the program does not itself impose new substantive requirements but rather has the purpose of identifying, in a single document, the CAA requirements that apply to a source. These lawsuits have been filed in the D.C. Circuit, the Fifth Circuit, and the Tenth Circuit challenging EPA orders issued in response to various third-party professional environmental advocacy groups’ requests that EPA object to Title V permits proposed for several industrial facilities in Utah and Texas. In the orders, EPA clarified that the Title V permitting and petition process set forth in 42 U.S.C. § 7661d(b)(2) is not the appropriate forum to second-guess preconstruction authorizations issued under Title I of the Act and incorporated into a facility’s Title V permit.