Environmental Defense v. Duke Energy Corp. (2006)
- Docket
- 05-848
- Decided
- 2006-01-01
Summary
Question: 1) Did the Fourth Circuit's decision violate the section of the Clean Air Act that provides that national Clean Air Act regulations are subject to challenge only in the D.C. Circuit? 2) Does the Clean Air Act require the EPA to interpret the term "modification" consistently in its Prevention of Significant Deterioration (PSD) provisions and New Source Performance Standards (NSPS) regulations? Conclusion: Unanswered and No. In a unanimous opinion by Justice David Souter, the Court ruled that the EPA need not interpret "modification" in PSD regulations the same way the term is interpreted in NSPS regulations. The Court's opinion acknowledged that two occurrences of the same term - sharing the same definition - are normally given the same meaning. However, the word "modification" and its definition appear in the context of two broad, open-ended grants of regulatory authority to the EPA. The Court held that "EPA's construction need do no more than fall within the limits of what is reasonable, as set by the Act's common definition." The Court concluded that differing circumstances involved in regulating under the PSD provisions as opposed to the NSPS provisions may well necessitate giving a different meaning to the term "modification" as it appears in each.