540 U.S. 461 (2004)

ALASKA DEPARTMENT OF ENVIRONMENTAL CONSERVATION
v.
ENVIRONMENTAL PROTECTION AGENCY ET AL.

No. 02-658.

Supreme Court of United States.

Argued October 8, 2003. Decided January 21, 2004. CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR THE NINTH CIRCUIT.

*462 *463 *464 *465 *466 *467 GINSBURG, J., delivered the opinion of the Court, in which STEVENS, O'CONNOR, SOUTER, and BREYER, JJ., joined. KENNEDY, J., filed a dissenting opinion, in which REHNQUIST, C.J., and SCALIA and THOMAS, JJ., joined, post, p. 502.

Jonathan S. Franklin argued the cause for petitioner. With him on the briefs were John G. Roberts, Jr., Lorane F. Hebert, Gregg D. Renkes, Attorney General of Alaska, and Cameron M. Leonard, Assistant Attorney General. Robert J. Mahoney, Robert T. Connery, and Marcy G. Glenn filed briefs in support of petitioner for Teck Cominco Alaska Inc., respondent under this Court's Rule 12.6.

Deputy Solicitor General Hungar argued the cause for respondents. With him on the brief were Solicitor General Olson, Acting Assistant Attorney General Johnson, Deputy Solicitor General Kneedler, James A. Feldman, Andrew J. Doyle, Robert E. Fabricant, Carol S. Holmes, and Juliane R. B. Matthews.^[*]

*468 JUSTICE GINSBURG delivered the opinion of the Court.

This case concerns the authority of the Environmental Protection Agency (EPA or Agency) to enforce the provisions of the Clean Air Act's (CAA or Act) Prevention of Significant Deterioration (PSD) program. Under that program, no major air pollutant emitting facility may be constructed unless the facility is equipped with "the best available control technology" (BACT). As added by § 165, 91 Stat. 735, and amended, 42 U.S.C. § 7475(a)(4). BACT, as defined in the CAA, means, for any major air pollutant emitting facility, "an emission limitation based on the maximum degree of [pollutant] reduction . . . which the permitting authority, on a case-by-case basis, taking into account energy, environmental, and economic impacts and other costs, determines is achievable for [the] facility. . . ." § 7479(3).

Regarding EPA oversight, the Act includes a general instruction and one geared specifically to the PSD program. The general prescription, § 113(a)(5) of the Act, authorizes EPA, when it finds that a State is not complying with a CAA requirement governing construction of a pollutant source, to issue an order prohibiting construction, to prescribe an administrative penalty, or to commence a civil action for injunctive relief. 42 U.S.C. § 7413(a). Directed specifically to the PSD program, CAA § 167 instructs EPA to "take such measures, including issuance of an order, or seeking injunctive *469 relief, as necessary to prevent the construction" of a major pollutant emitting facility that does not conform to the PSD requirements of the Act. 42 U.S.C. § 7477.

In the case before us, "the permitting authority" under § 7479(3) is the State of Alaska, acting through Alaska's Department of Environmental Conservation (ADEC). The question presented is what role EPA has with respect to ADEC's BACT determinations. Specifically, may EPA act to block construction of a new major pollutant emitting facility permitted by ADEC when EPA finds ADEC's BACT determination unreasonable in light of the guides § 7479(3) prescribes? We hold that the Act confers that checking authority on EPA.

I

A

Congress enacted the Clean Air Amendments of 1970, 84 Stat. 1676, 42 U.S.C. § 7401 et seq., in response to "dissatisfaction with the progress of existing air pollution programs." Union Elec. Co. v. EPA, 427 U.S. 246, 249 (1976). The amendments aimed "to guarantee the prompt attainment and maintenance of specified air quality standards." Ibid.; D. Currie, Air Pollution § 1.13, p. 1-16 (1981) (summary of 1970 amendments). Added by the 1970 amendments, §§ 108(a) and 109(a) of the Act require EPA to publish lists of emissions that "cause or contribute to air pollution which may reasonably be anticipated to endanger public health or welfare," and to promulgate primary and secondary national ambient air quality standards (NAAQS) for such pollutants. 42 U.S.C. §§ 7408(a) and 7409(a); Whitman v. American Trucking Assns., Inc., 531 U.S. 457, 462-463 (2001). NAAQS "define [the] levels of air quality that must be achieved to protect public health and welfare." R. Belden, Clean Air Act 6 (2001). The Agency published initial NAAQS in 1971, Union Elec., 427 U.S., at 251 (citing 40 *470 CFR pt. 50 (1975)), and in 1985, NAAQS for the pollutant at issue in this case, nitrogen dioxide. 40 CFR § 50.11 (2002).^[1]

Under § 110 of the Act, also added in 1970, each State must submit for EPA approval "a plan which provides for implementation, maintenance, and enforcement of [NAAQS]." 42 U.S.C. § 7410(a)(1); cf. § 7410(c)(1) (EPA shall promulgate an implementation plan if the State's plan is inadequate). Relevant to this case, EPA has approved Alaska's implementation plan. 48 Fed. Reg. 30626 (1983), as amended, 56 Fed. Reg. 19288 (1991); 40 CFR § 52.96(a) (2002). To gain EPA approval, a "state implementation plan" (SIP) must "include enforceable emission limitations and other control measures, means, or techniques . . . as may be necessary or appropriate to meet the applicable [CAA] requirements." 42 U.S.C. § 7410(a)(2)(A). While States have "wide discretion" in formulating their plans, Union Elec., 427 U.S., at 250, SIPs must include certain measures Congress specified "to assure that national ambient air quality standards are achieved," 42 U.S.C. § 7410(a)(2)(C). Among those measures are permit provisions, § 7475, basic to the administration of the program involved in this case, CAA's "Prevention of Significant Deterioration of Air Quality" (PSD) program.

The PSD requirements, enacted as part of 1977 amendments to the Act, Title I, § 160 et seq., 91 Stat. 731, "are designed to ensure that the air quality in attainment areas or areas that are already `clean' will not degrade," Belden, supra, p. 43. See 42 U.S.C. § 7470(1) (purpose of PSD program *471 is to "protect public health and welfare from any actual or potential adverse effect which in [EPA's] judgment may reasonably be anticipate[d] to occur from air pollution . . . notwithstanding attainment and maintenance of all national ambient air quality standards"). Before 1977, no CAA provision specifically addressed potential air quality deterioration in areas where pollutant levels were lower than the NAAQS. Alabama Power Co. v. Costle, 636 F.2d 323, 346-347 (CADC 1979). Responding to litigation initiated by an environmental group,^[2] however, EPA issued regulations in 1974 requiring that SIPs include a PSD program. Id., at 347, and n. 18 (citing 39 Fed. Reg. 42510 (1974)). Three years later, Congress adopted the current PSD program. See S. Rep. No. 95-127, p. 11 (1977) (Congress itself has "a responsibility to delineate a policy for protecting clean air").

The PSD program imposes on States a regime governing areas "designated pursuant to [42 U.S.C. § 7407] as attainment or unclassifiable." § 7471.^[3] An attainment area is one in which the air "meets the national primary or secondary ambient air quality standard for [a regulated pollutant]." § 7407(d)(1)(A)(ii). Air in an unclassiflable area "cannot be classified on the basis of available information as meeting or not meeting the national primary or secondary ambient air quality standard for the pollutant." § 7407(d)(1)(A)(iii). Northwest Alaska, the region this case concerns, is classified as an attainment or unclassifiable area for nitrogen dioxide, 40 CFR § 81.302 (2002), therefore, the PSD program applies to emissions of that pollutant in the region. In 2002, the Agency reported that "[a]ll areas of the country that once *472 violated the NAAQS for [nitrogen dioxide] now meet that standard." EPA, Latest Findings on National Air Quality 7 (Aug. 2003).

Section 165 of the Act, 42 U.S.C. § 7475, installs a permitting requirement for any "major emitting facility," defined to include any source emitting more than 250 tons of nitrogen oxides per year, § 7479(1). No such facility may be constructed or modified unless a permit prescribing emission limitations has been issued for the facility. § 7475(a)(1); see § 7479(2)(C) (defining "construction" to include "modification"). Alaska's SIP imposes an analogous requirement. 18 Alaska Admin. Code § 50.300(c)(1) (2003). Modifications to major emitting facilities that increase nitrogen oxide emissions in excess of 40 tons per year require a PSD permit. 40 CFR § 51.166(b)(23)(i) (2002); 18 Alaska Admin. Code § 50.300(h)(3)(B)(ii) (2003).

The Act sets out preconditions for the issuance of PSD permits. Inter alia, no PSD permit may issue unless "the proposed facility is subject to the best available control technology for each pollutant subject to [CAA] regulation . . . emitted from . . . [the] facility." 42 U.S.C. § 7475(a)(4). As described in the Act's definitional provisions, "best available control technology" (BACT) means:

"an emission limitation based on the maximum degree of reduction of each pollutant subject to regulation under this chapter emitted from or which results from any major emitting facility, which the permitting authority, on a case-by-case basis, taking into account energy, environmental, and economic impacts and other costs, determines is achievable for such facility through application of production processes and available methods, systems, and techniques. . . . In no event shall application of `best available control technology' result in emissions of any pollutants which will exceed the emissions allowed by any applicable standard established pursuant *473 to section 7411 or 7412 of this title [emission standards for new and existing stationary sources]." § 7479(3).

40 CFR § 51.166(b)(12) (2002) (repeating statutory definition). Alaska's SIP contains provisions that track the statutory BACT requirement and definition. 18 Alaska Admin. Code §§ 50.310(d)(3) and 50.990(13) (2003). The State, with slightly variant terminology, defines BACT as "the emission limitation that represents the maximum reduction achievable for each regulated air contaminant, taking into account energy, environmental and economic impacts, and other costs." Ibid. Under the federal Act, a limited class of sources must gain advance EPA approval for the BACT prescribed in the permit. 42 U.S.C. § 7475(a)(8).

CAA also provides that a PSD permit may issue only if a source "will not cause, or contribute to, air pollution in excess of any . . . maximum allowable increase or maximum allowable concentration for any pollutant" or any NAAQS. § 7475(a)(3). Congress left to the Agency the determination of most maximum allowable increases, or "increments," in pollutants. EPA regulations have defined increments for nitrogen oxides. 40 CFR § 51.166(c) (2002). Typically, to demonstrate that increments will not be exceeded, applicants use mathematical models of pollutant plumes, their behavior, and their dispersion. Westbrook, Air Dispersion Models: Tools to Assess Impacts from Pollution Sources, 13 Natural Resources & Env. 546, 547-548 (1999).

Among measures EPA may take to ensure compliance with the PSD program, two have special relevance here. The first prescription, § 113(a)(5) of the Act, provides that "[w]henever, on the basis of any available information, [EPA] finds that a State is not acting in compliance with any requirement or prohibition of the chapter relating to the construction of new sources or the modification of existing sources," 42 U.S.C. § 7413(a)(5), EPA may "issue an order prohibiting the construction or modification of any major stationary source in any area to which such requirement applies," *474 § 7413(a)(5)(A).^[4] The second measure, § 167 of the Act, trains on enforcement of the PSD program; it requires EPA to "take such measures, including issuance of an order, or seeking injunctive relief, as necessary to prevent the construction or modification of a major emitting facility which does not conform to the [PSD] requirements." § 7477.

B

Teck Cominco Alaska, Inc. (Cominco), operates a zinc concentrate mine, the Red Dog Mine, in northwest Alaska approximately 100 miles north of the Arctic Circle and close to the native Alaskan villages of Kivalina and Noatak. App. to Pet. for Cert. 3a; Brief for Petitioner 8; Brief for Respondents 4. The mine is the region's largest private employer. Brief for Petitioner 9. It supplies a quarter of the area's wage base. Ibid. Cominco leases the land from the NANA Regional Corporation, an Alaskan corporation formed pursuant to the Alaska Native Claims Settlement Act, 85 Stat. 688, as amended, 43 U.S.C. § 1601 et seq. Brief for NANA Regional Corporation, Inc., as Amicus Curiae 1-2, 4.

In 1988, Cominco obtained authorization to operate the mine, a "major emitting facility" under the Act and Alaska's SIP. App. 106. The mine's PSD permit authorized five 5,000 kilowatt Wartsila diesel electric generators, MG-1 through MG-5, subject to operating restrictions; two of the five generators were permitted to operate only in standby status. Ibid. Petitioner Alaska Department of Environmental Conservation (ADEC) issued a second PSD permit in 1994 allowing addition of a sixth full-time generator (MG-6), removing standby status from MG-2, and imposing a new *475 operational cap that allowed all but one generator to run full time. Ibid.

In 1996, Cominco initiated a project, with funding from the State, to expand zinc production by 40%. Brief for Petitioner 10; Reply Brief for Petitioner 11, n. 9. Anticipating that the project would increase nitrogen oxide emissions by more than 40 tons per year, see supra, at 472, Cominco applied to ADEC for a PSD permit to allow, inter alia, increased electricity generation by its standby generator, MG-5. App. 107-108; App. to Pet. for Cert. 33a. On March 3, 1999, ADEC preliminarily proposed as BACT for MG-5 the emission control technology known as selective catalytic reduction (SCR),^[5] which reduces nitrogen oxide emissions by 90%. App. 72, 108. In response, Cominco amended its application to add a seventh generator, MG-17, and to propose as BACT an alternative control technology — Low NOx^[6] — that achieves a 30% reduction in nitrogen oxide pollutants. Brief for Respondents 5, and n. 1; App. 84.

On May 4, 1999, ADEC, in conjunction with Cominco's representative, issued a first draft PSD permit and preliminary technical analysis report that concluded Low NOx was BACT for MG-5 and MG-17. Id., at 55-95. To determine BACT, ADEC employed EPA's recommended top-down methodology, id., at 61:

"In brief, the top-down process provides that all available control technologies be ranked in descending order of control effectiveness. The PSD applicant first examines the most stringent — or `top' — alternative. That alternative *476 is established as BACT unless the applicant demonstrates, and the permitting authority in its informed judgment agrees, that technical considerations, or energy, environmental, or economic impacts justify a conclusion that the most stringent technology is not `achievable' in that case. If the most stringent technology is eliminated in this fashion, then the next most stringent alternative is considered, and so on." EPA, New Source Review Workshop Manual B.2 (Draft Oct. 1990) (hereinafter New Source Review Manual); App. 61-62.^[7]

Applying top-down methodology, ADEC first homed in on SCR as BACT for MG-5, and the new generator, MG-17. "[W]ith an estimated reduction of 90%," ADEC stated, SCR "is the most stringent" technology. Id., at 79. Finding SCR "technically and economically feasible," id., at 65, ADEC characterized as "overstated" Cominco's cost estimate of $5,643 per ton of nitrogen oxide removed by SCR. Id., at 113. Using Cominco's data, ADEC reached a cost estimate running between $1,586 and $2,279 per ton. Id., at 83. Costs in that range, ADEC observed, "are well within what ADEC and EPA conside[r] economically feasible." Id., at 84. Responding to Cominco's comments on the preliminary permit, engineering staff in ADEC's Air Permits Program pointed out that, according to information Cominco provided to ADEC, "SCR has been installed on similar diesel-fired engines throughout the world." Id., at 102.

Despite its staff's clear view "that SCR (the most effective individual technology) [was] technologically, environmentally, and economically feasible for the Red Dog power plant engines," id., at 103-104, ADEC endorsed the alternative proffered *477 by Cominco. To achieve nitrogen oxide emission reductions commensurate with SCR's 90% impact, Cominco proposed fitting the new generator MG-17 and the six existing generators with Low NOx. Ibid.^[8] Cominco asserted that it could lower net emissions by 396 tons per year if it fitted all seven generators with Low NOx rather than fitting two (MG-5 and MG-17) with SCR and choosing one of them as the standby unit. Id., at 87. Cominco's proposal hinged on the "assumption ... that under typical operating conditions one or more engines will not be running due to maintenance of standby-generation capacity." Ibid. If all seven generators ran continuously, however, Cominco's alternative would increase emissions by 79 tons per year. Ibid. Accepting Cominco's submission, ADEC stated that Cominco's Low NOx solution "achieve[d] a similar maximum NOx reduction as the most stringent controls; [could] potentially result in a greater NOx reduction; and is logistically and economically less onerous to Cominco." Id., at 87-88.

On the final day of the public comment period, July 2, 1999, the United States Department of the Interior, National Parks Service (NPS), submitted comments to ADEC. App. to Pet. for Cert. 33a; App. 97, 108. NPS objected to the projected offset of new emissions from MG-5 and MG-17 against emissions from other existing generators that were not subject to BACT. Letter from John Notar, NPS Air Resources Division, to Jim Baumgartner, ADEC (June 2, 1999). Such an offset, NPS commented, "is neither allowed by BACT, nor achieves the degree of reduction that would result if all the generators that are subject to BACT were equipped with SCR." Id., at 3. NPS further observed that the proposed production-increase project would remove operating restrictions that the 1994 PSD permit had placed on four of the existing generators — MG-1, MG-3, MG-4, *478 and MG-5. App. to Pet. for Cert. 34a. Due to that alteration, NPS urged, those generators, too, became part of the production-expansion project and would be subject to the BACT requirement. Ibid.

Following NPS' lead, EPA wrote to ADEC on July 29, 1999, commenting: "Although ADEC states in its analysis that [SCR], the most stringent level of control, is economically and technologically feasible, ADEC did not propose to require SCR.... [O]nce it is determined that an emission unit is subject to BACT, the PSD program does not allow the imposition of a limit that is less stringent than BACT." App. 96-97. A permitting authority, EPA agreed with NPS, could not offset new emissions "by imposing new controls on other emission units" that were not subject to BACT. Id., at 97. New emissions could be offset only against reduced emissions from sources covered by the same BACT authorization. Id., at 285-286. EPA further agreed with NPS that, based on the existing information, BACT would be required for MG-1, MG-3, MG-4, and MG-5. Id., at 97.

After receiving EPA comments, ADEC issued a second draft PSD permit and technical analysis report on September 1, 1999, again finding Low NOx to be BACT for MG-17. Id., at 105-117. Abandoning the emissions-offsetting justification advanced in the May 4 draft permit, ADEC agreed with NPS and EPA that "emission reductions from sources that were not part of the permit action," here MG-1, MG-2, MG-3, MG-4, MG-5, and MG-6, could not be considered in determining BACT for MG-17. Id., at 111; id., at 199 (same).^[9]

*479 ADEC conceded that, lacking data from Cominco, it had made "no judgment . . . as to the impact of . . . [SCR] on the operation, profitability, and competitiveness of the Red Dog Mine." Id., at 116. Contradicting its May 1999 conclusion that SCR was "technically and economically feasible," see supra, at 10, ADEC found in September 1999 that SCR imposed "a disproportionate cost" on the mine. App. 116. ADEC concluded, on a "cursory review," that requiring SCR for a rural Alaska utility would lead to a 20% price increase, and that in comparison with other BACT technologies, SCR came at a "significantly higher" cost. Ibid. No economic basis for a comparison between the mine and a rural utility appeared in ADEC's technical analysis.

EPA protested the revised permit. In a September 15, 1999, letter, the Agency stated: "Cominco has not adequately demonstrated any site-specific factors to support their claim that the installation of [SCR] is economically infeasible at the Red Dog Mine. Therefore, elimination of SCR as BACT based on cost-effectiveness grounds is not supported by the record and is clearly erroneous." Id., at 127; see id., at 138 (ADEC's record does not support the departure from ADEC's initial view that the costs for SCR were economically feasible).

To justify the September 1, 1999, permit, EPA suggested, ADEC could "include an analysis of whether requiring Cominco to install and operate [SCR] would have any adverse economic impacts upon Cominco specifically." Id., at 127. Stating that such an inquiry was unnecessary and expressing "concerns related to confidentiality," Cominco declined to submit financial data. Id., at 134. In this regard, Cominco simply asserted, without detail, that the company's "overall debt remains quite high" despite continuing profits. Id., at *480 134-135. Cominco also invoked the need for "[i]ndustrial development in rural Alaska." Id., at 135.

On December 10, 1999, ADEC issued the final permit and technical analysis report. Once again, ADEC approved Low NOx as BACT for MG-17 "[t]o support Cominco's Red Dog Mine Production Rate Increase Project, and its contributions to the region." Id., at 208. ADEC did not include the economic analysis EPA had suggested. Id., at 152-246. Indeed, ADEC conceded again that it had made "no judgment. . . as to the impact of ... [SCR's] cost on the operation, profitability, and competitiveness of the Red Dog Mine." Id., at 207. Nonetheless, ADEC advanced, as cause for its decision, SCR's adverse effect on the mine's "unique and continuing impact on the economic diversity of th[e] region" and on the venture's "world competitiveness." Id., at 208. ADEC did not explain how its inferences of adverse effects on the region's economy or the mine's "world competitiveness" could be made without financial information showing SCR's impact on the "operation, profitability, and competitiveness" of the mine. Id., at 207, 299. Instead, ADEC reiterated its rural Alaska utility analogy, and again compared SCR's cost to the costs of other, less stringent, control technologies. Id., at 205-207.

The same day, December 10, 1999, EPA issued an order to ADEC, under §§ 113(a)(5) and 167 of the Act, 42 U.S.C. §§ 7413(a)(5) and 7477, prohibiting ADEC from issuing a PSD permit to Cominco "unless ADEC satisfactorily documents why SCR is not BACT for the Wartsila diesel generator [MG-17]." App. to Pet. for Cert. 36a. In the letter accompanying the order, the Agency stated that "ADEC's own analysis supports the determination that BACT is [SCR], and that ADEC's decision in the proposed permit therefore is both arbitrary and erroneous." App. 149.

On February 8, 2000, EPA, again invoking its authority under §§ 113(a)(5) and 167 of the Act, issued a second order, *481 this time prohibiting Cominco from beginning "construction or modification activities at the Red Dog mine." App. to Pet. for Cert. 49a. A third order, issued on March 7, 2000, superseding and vacating the February 8 order, generally prohibited Cominco from acting on ADEC's December 10 PSD permit but allowed limited summer construction. Id., at 62a-64a. On April 25, 2000, EPA withdrew its December 10 order. App. 300; App. to Pet. for Cert. 6a. Once ADEC issued the permit, EPA explained, that order lacked utility. On July 16, 2003, ADEC granted Cominco a PSD permit to construct MG-17 with SCR as BACT. Letter from Theodore B. Olson, Solicitor General, to William K. Suter, Clerk of the Court (Aug. 21, 2003). Under the July 16, 2003, permit, SCR ceases to be BACT "if and when the case currently pending before the Supreme Court of the United States of America is decided in favor of the State of Alaska." ADEC, Air Quality Control Construction Permit, Final Technical Analysis Report, Permit No. 9932-AC005, Revision 2, p. 7.

The day EPA issued its first order against Cominco, February 8, 2000, ADEC and Cominco petitioned the Court of Appeals for the Ninth Circuit for review of EPA's orders. App. 11. The Agency initially moved to dismiss, urging that the Court of Appeals lacked subject-matter jurisdiction. In an order released March 27, 2001, the Ninth Circuit concluded that it had adjudicatory authority pursuant to 42 U.S.C. § 7607(b)(1), which lodges jurisdiction over challenges to "any . . . final [EPA] action" in the Courts of Appeals. Alaska v. United States EPA, 244 F. 3d 748, 750-751.^[10]

The Court of Appeals resolved the merits in a judgment released July 30, 2002. 298 F. 3d 814 (CA9). It held that *482 EPA had authority under §§ 113(a)(5) and 167 to issue the contested orders, and that the Agency had properly exercised its discretion in doing so. Id., at 820-823. Concerning EPA's authority under §§ 113(a)(5) and 167, the Court of Appeals observed first that "the question presented is what requirements the state must meet" under the Act to issue a PSD permit, not what the correct BACT might be. Id., at 821 (emphasis in original). Concluding that EPA had "authority to determine the reasonableness or adequacy of the state's justification for its decision," the Court of Appeals emphasized that the "provision of a reasoned justification" by a permitting authority is undeniably a "requirement" of the Act. Ibid. EPA had properly exercised its discretion in issuing the three orders, the Ninth Circuit ultimately determined, because (1) Cominco failed to "demonstrat[e] that SCR was economically infeasible," and (2) "ADEC failed to provide a reasoned justification for its elimination of SCR as a control option." Id., at 823. We granted certiorari, 537 U. S. 1186 (2003), to resolve an important question of federal law, i. e., the scope of EPA's authority under §§ 113(a)(5) and 167, and now affirm the Ninth Circuit's judgment.

II

ADEC contested EPA's orders under 42 U.S.C. § 7607 (b)(1), which renders reviewable in the appropriate federal court of appeals any EPA "final action." Before the Ninth Circuit, EPA unsuccessfully urged that its orders were "interlocutory," and therefore unreviewable in court unless and until EPA chose to commence an enforcement action.^[11] A pre-enforcement contest could be maintained in the Court of Appeals under § 7607(b)(1), the Ninth Circuit held, for in the circumstances presented, EPA's actions had the requisite finality.

*483 It was undisputed, the Court of Appeals observed, that EPA had spoken its "`last word'" on whether ADEC had adequately justified its conclusion that Low NOx was the best available control technology for the MG-17 generator. 244 F. 3d, at 750. Further, EPA's orders effectively halted construction of the MG-17 generator, for Cominco would risk civil and criminal penalties if it defied a valid EPA directive.

In this Court, EPA agrees with the Ninth Circuit's finality determination. See Brief for Respondents 16-20; Tr. of Oral Arg. 43-44. We are satisfied that the Court of Appeals correctly applied the guides we set out in Bennett v. Spear, 520 U. S. 154, 177-178 (1997) (to be "final," agency action must "mark the `consummation' of the agency's decisionmaking process," and must either determine "rights or obligations" or occasion "legal consequences" (some internal quotation marks omitted)). As the Court of Appeals stated, EPA had "asserted its final position on the factual circumstances" underpinning the Agency's orders, 244 F. 3d, at 750, and if EPA's orders survived judicial review, Cominco could not escape the practical and legal consequences (lost costs and vulnerability to penalties) of any ADEC-permitted construction Cominco endeavored, ibid.

No question has been raised here, we note, about the adequacy of EPA's preorder procedures under the Due Process Clause or the Administrative Procedure Act. Cf. Vermont Yankee Nuclear Power Corp. v. Natural Resources Defense Council, Inc., 435 U. S. 519, 544 (1978) (agencies have authority to "fashion their own rules of procedure," even when a statute does not specify what process to use). Furthermore, in response to ADEC's initial contention that the record was incomplete, the Ninth Circuit gave EPA an opportunity to supplement the record, and thereafter obtained from all parties agreement "that the record as it stood was adequate to resolve [ADEC's review petition]." 298 F. 3d, at 818.

*484 III

A

Centrally at issue in this case is the question whether EPA's oversight role, described by Congress in CAA §§ 113(a)(5) and 167, see supra, at 473-474, extends to ensuring that a state permitting authority's BACT determination is reasonable in light of the statutory guides. Sections 113(a)(5) and 167 lodge in the Agency encompassing supervisory responsibility over the construction and modification of pollutant emitting facilities in areas covered by the PSD program. 42 U.S.C. §§ 7413(a)(5) and 7477. In notably capacious terms, Congress armed EPA with authority to issue orders stopping construction when "a State is not acting in compliance with any [CAA] requirement or prohibition . . . relating to the construction of new sources or the modification of existing sources," § 7413(a)(5), or when "construction or modification of a major emitting facility . . . does not conform to the requirements of [the PSD program]," § 7477.

The federal Act enumerates several "[p]reconstruction requirements" for the PSD program. § 7475. Absent these, "[n]o major emitting facility . . . may be constructed." Ibid. One express preconstruction requirement is inclusion of a BACT determination in a facility's PSD permit. §§ 7475(a) (1) and (4). As earlier set out, see supra, at 472, the Act defines BACT as "an emission limitation based on the maximum degree of reduction of [a] pollutant . . . which the permitting authority, on a case-by-case basis, taking into account energy, environmental, and economic impacts and other costs, determines is achievable for [a] facility." § 7479(3). Under this formulation, the permitting authority, ADEC here, exercises primary or initial responsibility for identifying BACT in line with the Act's definition of that term.

All parties agree that one of the "many requirements in the PSD provisions that the EPA may enforce" is "that a *485 [PSD] permit contain a BACT limitation." Brief for Petitioner 34; see id., at 22, 25 (same). See also Brief for Respondents 23. It is therefore undisputed that the Agency may issue an order to stop a facility's construction if a PSD permit contains no BACT designation.

EPA reads the Act's definition of BACT, together with CAA's explicit listing of BACT as a "[p]reconstruction requiremen[t]," to mandate not simply a BACT designation, but a determination of BACT faithful to the statute's definition. In keeping with the broad oversight role §§ 113(a)(5) and 167 vest in EPA, the Agency maintains, it may review permits to ensure that a State's BACT determination is reasonably moored to the Act's provisions. See id., at 24. We hold, as elaborated below, that the Agency has rationally construed the Act's text and that EPA's construction warrants our respect and approbation.

BACT's statutory definition requires selection of an emission control technology that results in the "maximum" reduction of a pollutant "achievable for [a] facility" in view of "energy, environmental, and economic impacts and other costs." 42 U.S.C. § 7479(3). This instruction, EPA submits, cabins state permitting authorities' discretion by granting only "authority to make reasonable BACT determinations," Brief for Respondents 27 (emphasis in original), i. e., decisions made with fidelity to the Act's purpose "to insure that economic growth will occur in a manner consistent with the preservation of existing clean air resources," 42 U.S.C. § 7470(3). Noting that state permitting authorities' statutory discretion is constrained by CAA's strong, normative terms "maximum" and "achievable," § 7479(3),^[12] EPA reads §§ 113(a)(5) *486 and 167 to empower the federal Agency to check a state agency's unreasonably lax BACT designation. See Brief for Respondents 27.

EPA stresses Congress' reason for enacting the PSD program — to prevent significant deterioration of air quality in clean-air areas within a State and in neighboring States. §§ 7470(3), (4); see id., at 33. That aim, EPA urges, is unlikely to be realized absent an EPA surveillance role that extends to BACT determinations. The Agency notes in this regard a House Report observation:

"Without national guidelines for the prevention of significant deterioration a State deciding to protect its clean air resources will face a double threat. The prospect is very real that such a State would lose existing industrial plants to more permissive States. But additionally the State will likely become the target of `economic-environmental blackmail' from new industrial plants that will play one State off against another with threats to locate in whichever State adopts the most permissive pollution controls." H.R. Rep. No. 95-294, p. 134 (1977).

The House Report further observed that "a community that sets and enforces strict standards may still find its air polluted from sources in another community or another State." Id., at 135 (quoting 116 Cong. Rec. 32909 (1970)). Federal Agency surveillance of a State's BACT designation is needed, EPA asserts, to restrain the interjurisdictional pressures to which Congress was alert. See Brief for Respondents 33-34, 43; Brief for Vermont et al. as Amici Curiae 12 ("If EPA has authority to ensure a reasonable level of consistency among BACT determinations nationwide, then every State can feel more confident about maintaining stringent standards without fear of losing its current industry or alienating prospective industry.").

*487 The CAA construction EPA advances in this litigation is reflected in interpretive guides the Agency has several times published. See App. 268-269 (1983 EPA PSD guidance memorandum noting the Agency's "oversight function"); id., at 274 (1988 EPA guidance memorandum stating EPA may find a BACT determination deficient if it is "not based on a reasoned analysis"); id., at 281-282 (1993 guidance memorandum stating that "EPA acts to ensure that the state exercises its discretion within the bounds of the law" (internal quotation marks omitted); as to BACT, EPA will not intervene if the state agency has given "a reasoned justification for the basis of its decision" (internal quotation marks omitted)). See also Approval and Promulgation of Air Quality Implementation Plans; Commonwealth of Virginia — Prevention of Significant Deterioration Program, 63 Fed. Reg. 13797 (1998) (EPA will "review whether any determination by the permitting authority was made on reasonable grounds properly supported on the record, described in enforceable terms, and consistent with all applicable requirements"). We "normally accord particular deference to an agency interpretation of `longstanding' duration," Barnhart v. Walton, 535 U.S. 212, 220 (2002) (quoting North Haven Bd. of Ed. v. Bell, 456 U.S. 512, 522, n. 12 (1982)), recognizing that "well-reasoned views" of an expert administrator rest on "`a body of experience and informed judgment to which courts and litigants may properly resort for guidance,'" Bragdon v. Abbott, 524 U.S. 624, 642 (1998) (quoting Skidmore v. Swift & Co., 323 U.S. 134, 139-140 (1944)).

We have previously accorded dispositive effect to EPA's interpretation of an ambiguous CAA provision. See Chevron U.S.A. Inc. v. Natural Resources Defense Council, Inc., 467 U.S. 837, 865-866 (1984); Union Elec., 427 U.S., at 256. The Agency's interpretation in this case, presented in internal guidance memoranda, however, does not qualify for the dispositive force described in Chevron. See Christensen v. Harris County, 529 U.S. 576, 587 (2000) ("Interpretations *488 such as those in ... policy statements, agency manuals, and enforcement guidelines, all of which lack the force of law — do not warrant Chevron-style deference."); accord, United States v. Mead Corp., 533 U.S. 218, 234 (2001). Cogent "administrative interpretations . . . not [the] products of formal rulemaking . . . nevertheless warrant respect." Washington State Dept. of Social and Health Servs. v. Guardianship Estate of Keffeler, 537 U.S. 371, 385 (2003). We accord EPA's reading of the relevant statutory provisions, §§ 7413(a)(5), 7470(3), 7470(4), 7475(a)(4), 7477, and 7479(3), that measure of respect.

B

ADEC assails the Agency's construction of the Act on several grounds. Its arguments do not persuade us to reject as impermissible EPA's longstanding, consistently maintained interpretation.

ADEC argues that the statutory definition of BACT, § 7479(3), unambiguously assigns to "the permitting authority" alone determination of the control technology qualifying as "best available." Brief for Petitioner 21-26. Because the Act places responsibility for determining BACT with "the permitting authority," ADEC urges, CAA excludes federal Agency surveillance reaching the substance of the BACT decision. Id., at 22-25. EPA's enforcement role, ADEC maintains, is restricted to the requirement "that the permit contain a BACT limitation." Id., at 34.

Understandably, Congress entrusted state permitting authorities with initial responsibility to make BACT determinations "case-by-case." § 7479(3). A state agency, no doubt, is best positioned to adjust for local differences in raw materials or plant configurations, differences that might make a technology "unavailable" in a particular area. But the fact that the relevant statutory guides — "maximum" pollution reduction, considerations of energy, environmental, and economic impacts — may not yield a "single, objectively `correct' BACT determination," id., at 23, surely does not *489 signify that there can be no unreasonable determinations. Nor does Congress' sensitivity to site-specific factors necessarily imply a design to preclude in this context meaningful EPA oversight under §§ 113(a)(5) and 167. EPA claims no prerogative to designate the correct BACT; the Agency asserts only the authority to guard against unreasonable designations. See 298 F. 3d, at 821 ("the question presented is what requirements the state must meet," not what final substantive decision the State must make (emphasis in original)).^[13]

Under ADEC's interpretation, EPA properly inquires whether a BACT determination appears in a PSD permit, *490 Brief for Petitioner 34, but not whether that BACT determination "was made on reasonable grounds properly supported on the record," 63 Fed. Reg., at 13797. Congress, however, vested EPA with explicit and sweeping authority to enforce CAA "requirements" relating to the construction and modification of sources under the PSD program, including BACT. We fail to see why Congress, having expressly endorsed an expansive surveillance role for EPA in two independent CAA provisions, would then implicitly preclude the Agency from verifying substantive compliance with the BACT provisions and, instead, limit EPA's superintendence to the insubstantial question whether the state permitting authority had uttered the key words "BACT."

We emphasize, however, that EPA's rendition of the Act's less than crystalline text leaves the "permitting authority" considerable leeway. The Agency acknowledges "the need to accord appropriate deference" to States' BACT designations, Brief for Respondents 43, and disclaims any intention to "`second guess' state decisions," 63 Fed. Reg., at 13797. Only when a state agency's BACT determination is "not based on a reasoned analysis," App. 274, may EPA step in to ensure that the statutory requirements are honored.^[14] EPA *491 adhered to that limited role here, explaining why ADEC's BACT determination was "arbitrary" and contrary to ADEC's own findings. Id., at 149-150. EPA's limited but vital role in enforcing BACT is consistent with a scheme that "places primary responsibilities and authority with the States, backed by the Federal Government