On June 25, 2007, the Supreme Court ruled 5-4 that the Endangered Species Act does not prevent the EPA from transferring its authority to issue Clean Water Act permits to a state pollution control agency. Transferring such authority is non-discretionary, and the Clean Water Act does not require consideration of statutes not specifically mentioned in that Act when doing so.
Had the Clean Air Act been read to include requirements from other statutes, EPA might have been similarly required to incorporate various other statutory requirements into a variety of laws. This could have affected Section 404 permits, federal flood insurance issued by FEMA, and permits for federal projects that might be required to consider terrorism risk during environmental impact studies under the National Environmental Policy Act.