Opinion ID: 1033609
Heading Depth: 2
Heading Rank: 3

Heading: The EPA’s Prior Interpretation of Section

Text: 126(b) GenOn and UARG also argue that the EPA‘s prior interpretation of the meaning of the ―prohibition‖ referenced in Section 126(b) related to a SIP‘s failure to address interstate nonattainment and ran contrary to the EPA‘s current position. GenOn and UARG cite the EPA‘s issuance of a final rule in May 1999 governing ozone transport (the ―May 1999 Rule‖), where the EPA stated that it ―interprets Section 126 to provide that a source is emitting in violation of the prohibition of section 110(a)(2)(D)(i) where the applicable SIP fails to prohibit . . . a quantity of emissions from that source that [the] EPA has determined contributes significantly to nonattainment or interferes with maintenance in a downwind state.‖ Findings of Significant Contribution and Rulemaking on Section 126 Petitions for Purposes of Reducing Interstate Ozone Transport, 64 Fed. Reg. 28,250, 28,272 (May 25, 1999) (emphasis added). The May 1999 Rule is not necessarily inconsistent with the EPA‘s current position. As part of the Portland rulemaking process, the EPA responded to this alleged inconsistency by noting that the May 1999 Rule was 24 prompted by an EPA determination that the elimination of excessive trans-boundary emissions would be obtained through a pending SIP call that was in play. Unlike the circumstances surrounding the issuance of the May 1999 Rule, there is no guarantee that an imminent SIP submission will manage the interstate sulfur dioxide transport problem stemming from Portland within the three-year time period required by Section 126. Therefore, immediate action under Section 126(b) is warranted in this case because no other mechanism, such as a pending SIP call, exists in these circumstances that would remedy the Portland problem. Even if the May 1999 Rule is deemed inconsistent with the EPA‘s current interpretation, it does not undermine our decision to grant Chevron deference to the EPA‘s action. See generally Smiley v. Citibank, 517 U.S. 735, 742 (1996). A revised agency interpretation is still worthy of Chevron deference because ―[a]n initial agency interpretation is not instantly carved in stone and the agency, to engage in informed rulemaking, must consider varying interpretations and the wisdom of its policy on a continuing basis.‖ Rust v. Sullivan, 500 U.S. 173, 186 (1991) (internal quotations omitted) (citing Chevron, 467 U.S. at 863-64). The EPA is not forever held to its prior interpretations, as the continued validity and appropriateness of the agency‘s rules is an evolving process. For these reasons, we hold that the existence of a prior conflicting EPA interpretation does not have the effect of rendering the agency‘s current construction of the statute unreasonable in these circumstances.