The opinion in NY v. EPA was written by D.C. Circuit Judge Judith Rogers (Judges Janice Rogers Brown and David Tatel joined). The Washington Post had this front page story, “Looser Emission Rules Rejected; Court Says Changes By EPA Violated Clean Air Act.” A snippet:

The central question in the case focused on what constitutes an industrial facility “modification,” because that is what triggers the federal requirement to cut down on the smog or soot emitted by utilities, oil refineries, incinerators, chemical plants and manufacturing operations. Previous administrations, including Bill Clinton’s, had interpreted that phrase to encompass any physical activity that increases pollution from a given facility, with the exception of routine maintenance.
EPA officials in the Bush administration sought to broaden this exemption by asserting that “routine maintenance” is any activity that amounts to less than 20 percent of a plant’s value. But the ruling, written by Judge Judith W. Rogers, rejected that reasoning as illogical.
“EPA’s approach would ostensibly require that the definition of ‘modification’ include a phrase such as ‘regardless of size, cost, frequency, effect,’ or other distinguishing characteristic,” Rogers wrote. “Only in a Humpty Dumpty world would Congress be required to use superfluous words while an agency could ignore an expansive word that Congress did use. We decline to adopt such a world-view.”