In the Supreme Court of the United States
AMERICAN TRUCKING ASSOCIATIONS, INC.,
ET AL., CROSS-PETITIONERS
CAROL M. BROWNER, ADMINISTRATOR OF THE
ENVIRONMENTAL PROTECTION AGENCY, ET AL.
ON WRIT OF CERTIORARI TO THE
UNITED STATES COURT OF APPEALS
FOR THE DISTRICT OF COLUMBIA CIRCUIT
BRIEF FOR THE FEDERAL RESPONDENTS
SETH P. WAXMAN
Counsel of Record
LOIS J. SCHIFFER
Assistant Attorney General
LAWRENCE G. WALLACE
Deputy Solicitor General
JEFFREY P. MINEAR
Assistant to the Solicitor
CHRISTOPHER S. VADEN
DAVID J. KAPLAN
MARY F. EDGAR
Department of Justice
Washington, D.C. 20530-0001
GARY S. GUZY
GERALD K. GLEASON
MICHAEL L. GOO
Washington, D.C. 20460
Whether the court of appeals properly reaffirmed the longstanding principlethat the Environmental Protection Agency is to set and revise National AmbientAir Quality Standards (NAAQS) based on consideration of the effects on publichealth and public welfare posed by a pollutant's presence in the ambientair, and not on consideration of the technological feasibility, cost, orother alleged effects of implementing measures to attain NAAQS.
In the Supreme Court of the United States
AMERICAN TRUCKING ASSOCIATIONS, INC.,
ET AL., CROSS-PETITIONERS
CAROL M. BROWNER, ADMINISTRATOR OF THE
ENVIRONMENTAL PROTECTION AGENCY, ET AL.
ON WRIT OF CERTIORARI TO THE
UNITED STATES COURT OF APPEALS
FOR THE DISTRICT OF COLUMBIA CIRCUIT
BRIEF FOR THE FEDERAL RESPONDENTS
The opinion of the court of appeals (Pet. App. 1a-69a) is reported at175 F.3d 1027.1 The opinion on petitions for rehearing and dissenting statementson denial of rehearing en banc (Pet. App. 70a-101a) are reported at 195F.3d 4.
The decision of the court of appeals was entered on May 14, 1999. Petitionsfor rehearing were granted in part and denied in part on October 29, 1999.The federal government's petition for a writ of certiorari in No. 99-1257was filed on January 27, 2000, and was granted on May 22, 2000. The conditionalcross-petition of American Trucking Association, et al., was filed on February28, 2000, and was granted on May 30, 2000. The jurisdiction of this Courtrests on 28 U.S.C. 1254(1).
STATUTORY AND REGULATORY PROVISIONS INVOLVED
Relevant portions of Sections 101, 108, 109, and 110 of the Clean AirAct, 42 U.S.C. 7401, 7408, 7409, 7410, are set forth at App., infra, 1a-8a.Other sections of the Clean Air Act are set forth at Pet. App. 105a-126a.
The EPA rules at issue in this case are set forth at Pet. App. 102a-104a.
Section 109 of the Clean Air Act (CAA), 42 U.S.C. 7409, requires EPAto establish and periodically revise primary National Ambient Air QualityStandards (NAAQS) "requisite to protect" public health with "anadequate margin of safety," and secondary NAAQS "requisite toprotect" public welfare. EPA is to set NAAQS "based on" the"air quality criteria" that EPA must prepare under Section 108.42 U.S.C. 7409(b). Section 108 of the Act further specifies that the airquality criteria for each pollutant subject to the NAAQS requirement must"accurately" reflect "the latest scientific knowledge"on the effects on public health and public welfare posed by "the presenceof such pollutant in the ambient air, in varying quantities." 42 U.S.C.7408(a)(2).
In the thirty years since enactment of these provisions, EPA has consistentlyrecognized that the plain language of Sections 108 and 109 requires theagency to set and revise NAAQS based solely on consideration of the effectsof ambient air pollutants on public health and public welfare, and not onthe feasibility or effects of measures designed to attain the NAAQS. Inan unbroken line of cases beginning with Lead Industries Ass'n v. EPA, 647F.2d 1130, 1148, cert. denied, 449 U.S. 1042 (1980), the District of ColumbiaCircuit has repeatedly, and "emphatically," affirmed this principle.NRDC v. EPA, 902 F.2d 962, 973 (D.C. Cir. 1990), cert. denied, 498 U.S.1082 (1991); see Pet. App. 19a-21a; American Lung Ass'n v. EPA, 134 F.3d388, 389 (D.C. Cir. 1998); American Petroleum Inst. v. Costle, 665 F.2d1176, 1185 (D.C. Cir. 1981), cert. denied, 455 U.S. 1034 (1982); see alsoNRDC v. EPA, 824 F.2d 1146, 1158-1159 (D.C. Cir. 1987) (en banc) (VinylChloride) (Section 109 "on its face does not allow consideration oftechnological or economic feasibility").
In their cross-petition seeking review of this longstanding interpretation,American Trucking Associations, et al. (ATA) have asked this Court to overturna principle on which three decades of federal and state air quality regulationhave rested. ATA would have EPA expand the range of factors that it considersin setting the NAAQS. Under ATA's approach, EPA would not only considerthe health and welfare effects associated with the presence of a criteriapollutant in the ambient air, but would be required additionally to considerthe feasibility, costs, and other effects of measures to remove the pollutantfrom the air.
As we explain in the Argument section of this brief, ATA's constructionof the Act is inconsistent with the statutory text, with the overall schemeof the NAAQS program, and with other indicia of congressional intent. Butit is important to emphasize at the outset a point that ATA, other industrygroups, and their amici largely ignore: The CAA provides for considerationof economic and technological feasibility, but at later stages of the regulatoryprocess. One might suppose from their submissions that setting the NAAQSis the sole component of the CAA's detailed process for improving air qualityor that economic and technological feasibility are never considered in anyother step of the CAA's elaborate process. That is simply not so.
The NAAQS serve as air quality targets for certain "criteria"pollutants based on the aggregate concentration of each in the ambient air;but the NAAQS are not, themselves, directly enforceable against regulatedentities that emit those pollutants. See Pet. App. 26a-31a. Rather, theStates seek to achieve the NAAQS through state implementation plans (SIPs),which impose enforceable emission limitations and other pollution controls.See CAA § 110, 42 U.S.C. 7410. Economic and technological feasibilityare taken into account at that stage of the regulatory program, when theStates determine, in concrete form, what pollution controls are appropriate.See Union Elec. Co. v. EPA, 427 U.S. 246, 266-269 (1976).
As this Court has recognized, Congress provided "ample opportunity"for consideration of economic and technological feasibility at the implementationstage of the regulatory process. Union Elec., 427 U.S. at 268. Moreover,if EPA or the States conclude at that later stage, when control alternativesreceive detailed consideration, that they cannot accommodate the regulatedcommunity's concerns consistent with their statutory obligations, then theregulated community can-and regularly does-present its concerns to Congress.Congress has reserved to itself the responsibility for adjusting the CAAas necessary to accommodate concerns regarding societal costs, and Congresshas taken legislative action when it has concluded that such action is warranted.See, e.g., Clean Air Act Amendments of 1990, Pub. L. No. 101-549, 104 Stat.2399 (imposing new requirements for nonattainment areas).
In our opening brief in No. 99-1257, we have provided the Court witha description of the CAA provisions governing the initial promulgation,revision, and implementation of NAAQS, Pet. Br. 2-8, as well as a summaryof the extensive explanations for the Administrator's 1997 decisions torevise the NAAQS for particulate matter (PM) and ozone, id. at 8-15. Weaccordingly will provide here only a brief discussion of the statutory provisionsput at issue by ATA's cross-petition. We will also clarify a few additionalkey points regarding the record basis for EPA's decisions to revise thePM and ozone NAAQS.
I. The Clean Air Act's NAAQS Provisions
Sections 108 and 109 of the CAA, which govern EPA's development of airquality criteria and NAAQS, were enacted in 1970. 84 Stat. 1678-1679.2 Sincethen, the CAA has required EPA to set and periodically revise "primary"and "secondary" NAAQS for certain ubiquitous air pollutants, knownas criteria pollutants. 42 U.S.C. 7409(a)(1) and (d)(1). EPA must set "primary"standards at levels that, "in the judgment of the Administrator,"are "requisite to protect the public health" with "an adequatemargin of safety." 42 U.S.C. 7409(b)(1). EPA must set "secondary"standards at levels that are "requisite to protect the public welfare"from any "known or anticipated adverse effects." 42 U.S.C. 7409(b)(2).
Section 109 requires both primary and secondary NAAQS to be "basedon * * * criteria" that EPA develops under Section 108. Under thatSection, EPA must identify, and develop "air quality criteria"for, pollutants that are emitted from "numerous or diverse" sourcesand that "may reasonably be anticipated to endanger public health orwelfare." 42 U.S.C. 7408(a)(1). Section 108 specifies that the "airquality criteria" shall reflect the effects on public health and publicwelfare associated with the "presence" of a criteria pollutant"in the ambient air":
Air quality criteria for an air pollutant shall accurately reflect thelatest scientific knowledge useful in indicating the kind and extent ofall identifiable effects on public health or welfare which may be expectedfrom the presence of such pollutant in the ambient air, in varying quantities.
42 U.S.C. 7408(a)(2). The CAA then specifies three types of information-eachof which falls within the general definition set forth above-that, "tothe extent practicable," the criteria shall "include":
(A) those variable factors (including atmospheric conditions) which ofthemselves or in combination with other factors may alter the effects onpublic health or welfare of such air pollutant;
(B) the types of air pollutants which, when present in the atmosphere,may interact with such pollutant to produce an adverse effect on publichealth or welfare; and
(C) any known or anticipated adverse effects on welfare.
42 U.S.C. 7408(a)(2)(A)-(C).
As we have previously explained in more detail (see 99-1257 Pet. Br.5-8), the CAA sets out an elaborate process, resting on principles of federal-statecooperation, to ensure that the air throughout the Nation "attains"the NAAQS. Under the CAA, the primary mechanisms for implementing the NAAQSare the SIPs, which set forth the pollution control measures necessary toattain all NAAQS by statutorily required dates. The States are expresslyauthorized under Section 110 to consider the economic and technologicalfeasibility of the pollution control measures they include in their SIPs.Union Elec., 427 U.S. at 256-269. As this Court has explained (id. at 266):
Perhaps the most important forum for consideration of claims of economicand technological infeasibility is before the state agency formulating theimplementation plan. So long as the national standards are met, the Statemay select whatever mix of control devices it desires * * * and industrieswith particular economic or technological problems may seek special treatmentin the plan itself.
In addition, EPA itself has responsibility under the Act for taking variousactions to implement the NAAQS. Just as the States may consider economicand technological feasibility in developing their SIPs, the Act generallygrants EPA discretion to consider those factors when it acts to implementthe NAAQS it has promulgated. For example, under Section 183 ("Federalozone measures"), EPA is to issue control techniques guidelines, takingcost into account. 42 U.S.C. 7511b(a) and (e)(1)(A). Similarly, under Section202(i)(2)(A)(i), EPA is to determine whether additional regulations forlight-duty trucks are required to attain or maintain the NAAQS and, if so,to promulgate cost-effective regulations. 42 U.S.C. 7521(i)(2)(A)(i).3
II. The Particulate Matter and Ozone Rules
ATA's cross-petition presents a straightforward issue of statutory constructionthat may be resolved without consideration of the records in the underlyingrulemaking proceedings. Nevertheless, we must briefly respond to the characterizationof those rulemaking records by ATA and its supporters. Contrary to thatportrayal, those records show an extensive body of newly available scientificinformation, in both the PM and ozone rulemakings, that called for revisionof the existing standards to address a wide range of adverse health effects.
1. EPA's revised PM and ozone NAAQS address real and significant effects,not merely hypothetical risks. EPA was confronted with consistent and persuasiveevidence, from study after study, that as PM levels rise the number of peoplewho actually die or enter hospitals-especially due to cardiovascular andrespiratory disease-rises correspondingly. 61 Fed. Reg. 65,641-65,643 (1996);97-1440 CA App. (PM App.) 1375-1778, 1801-1845.4 In addition to similarepidemiological evidence linking ozone to increased hospital admissionsin real populations, the ozone record contains numerous clinical studiesthat demonstrate ozone's deleterious effects on the human respiratory system.61 Fed. Reg. at 65,719-65,720. In those studies, researchers measured respiratoryeffects in human volunteers exposed to ozone under controlled laboratoryconditions. 97-1441 CA App. (Ozone App.) 1461-1462.
In providing a thorough and objective explanation of its decisions, EPAdid identify areas of scientific uncertainty, on which ATA and RespondentAppalachian Power Company, et al. (APC) have focused so singularly in theirstatements of the case. E.g., ATA Br. 15; APC Br. 13. As EPA explained inresponse to comments on the PM rule, "uncertainty and controversy onscientific issues are inherent in the statutory scheme, which in effectrequires decisions 'at the very "frontiers of scientific knowledge'"where 'disagreement among the experts is inevitable.'" PM App. 266(quoting Lead Indus., 647 F.2d at 1160); see also 62 Fed. Reg. 38,880-38,881(1997). Those inherent uncertainties do not transform the observed adversehealth effects addressed by the revised standards into merely theoreticalor hypothetical risks.
2. EPA did not revise the PM and ozone NAAQS simply to change its methodfor "management of predicted risks addressed by the then-current standards"(APC Br. 14). EPA acted because new scientific evidence revealed that adversehealth effects are associated with lower concentrations of PM and ozonethan had been indicated by the evidence available in prior NAAQS reviews.Congress has required that EPA periodically review the air quality criteriaand NAAQS in light of new scientific knowledge and revise them as appropriate.42 U.S.C. 7409(d)(1). When
the Administrator reviewed and revised the PM and ozone NAAQS, she didso based on "the latest scientific knowledge" of the effects associatedwith the presence of these two pollutants in the ambient air. 42 U.S.C.7408(a)(2).
The evidence available in 1997 differed significantly from that availableearlier, reflecting refinements in analytical techniques, substantial newresearch, and new information on the kind and severity of health effectsassociated with the two pollutants.5 For example, when EPA promulgated thePM10 standards in 1987, only "a small number" of epidemiologicalstudies were available for determining the concentrations at which PM islikely to affect public health. 52 Fed. Reg. 24,641 (1987). EPA set the1987 PM10 standards at levels that reasonably appeared to provide an adequatemargin of safety against the health effects identified in the studies thenavailable. See NRDC, 902 F.2d at 971-972 (summarizing basis for 1987 PMstandards).
By the time of the most recent review, however, a large body of new evidenceon the health effects of the two pollutants was available. More than 60epidemiological studies showed that PM concentrations below the level ofthe 1987 standards are the likely cause of premature death and other seriousadverse health effects. See 99-1257 Pet. Br. 9-10.6 Similarly, new researchdemonstrated that adverse health effects are caused by exposure to ozoneat lower concentrations, over longer periods, and at more moderate levelsof exertion than had been shown by studies available during previous ozonereviews. See id. at 11-12. Accordingly, the Administrator's decision torevise the standards did not reflect merely a different judgment about howto manage the same risks her predecessors had considered.
3. CASAC unambiguously advised the Administrator that the PM and ozoneNAAQS should be revised, unanimously recommending that EPA replace the one-hourozone NAAQS with an eight-hour standard (Ozone App. 236-238), and almostunanimously (19 of 21 panel members) recommending that EPA establish PM2.5standards (PM App. 3162). Cf. ATA Br. 6-7, 14-15; APC Br. 12-13. Moreover,CASAC concluded that EPA's Criteria Documents and Staff Papers, which recommendeda range of NAAQS levels that encompassed the levels actually chosen, provided"an adequate scientific basis for regulatory decisions." PM App.3151, 3162; Ozone App. 235, 236. CASAC followed its traditional practiceof declining to provide a consensus recommendation on specific levels forthe revised NAAQS, but that did not relieve the Administrator of her dutyto reach decisions on specific NAAQS levels. Once the Administrator hadconcluded that the NAAQS required revision, she- unlike CASAC-had to resolvethe uncertainties associated with those decisions. See PM App. 265-269.7
Similarly, CASAC's observation that no "bright line" distinguishedthe alternative levels EPA considered for the revised ozone NAAQS did notmean that CASAC disagreed with EPA's decision to revise the ozone NAAQS.CASAC's observation reflects the unexceptional fact that, like other commonair pollutants, ozone lacks a demonstrated "threshold," 62 Fed.Reg. at 38,863; i.e., there is no "bright line" below which scientistshave observed a cessation of physiological or biological effects. See AmericanPetroleum Inst., 665 F.2d at 1185; Lead Indus., 647 F.2d at 1152-1153 &n.43; NRDC, 902 F.2d at 969; see Casarett & Doull's Toxicology: TheBasic Science of Poisons 19, 79-80 (5th ed. 1996). The evidence showed acontinuum of risk within the range considered, with statistically significantdecreases in risk and corresponding increases in public health protectionfor successively more stringent eight-hour ozone standards, 62 Fed. Reg.at 38,864. CASAC clearly understood that observed phenomenon. Ozone App.297-298; 62 Fed. Reg. at 38,863.8
4. EPA and CASAC agreed that additional research into the health effectsof PM pollution is warranted, but that conclusion did not affect the timetablefor implementation of the revised PM standards. Cf. APC Br. 13. Instead,EPA recognized that, for practical reasons, it would take at least fiveyears to begin implementation. 62 Fed. Reg. at 38,427-38,428. Prior to implementation,a nationwide network of PM2.5 monitors has to be installed. Id. at 38,427.In addition, because the PM2.5 NAAQS are based on an average of concentrationsover three years, a prolonged monitoring effort is necessary before theStates can begin to propose designations of areas as attainment or nonattainmentfor the PM2.5 NAAQS. Id. at 38,427-38,428.9
III. Proceedings Below
The court of appeals' decision reaffirms the long-settled principle that,"in setting NAAQS under § 109(b) of the Clean Air Act, the EPAis not permitted to consider the cost of implementing those standards."Pet. App. 19a. The court of appeals has consistently held that EPA mustset NAAQS based on the "health effects relating to pollutants in theair" and not on alleged costs or any other effects that may resultfrom implementation of the NAAQS. E.g., NRDC, 902 F.2d at 973 (EPA may notconsider alleged health effects of unemployment petitioners predicted wouldflow from implementation of 1987 PM NAAQS); see Lead Indus., 647 F.2d at1148; see also pp. 2-3, supra.
The court of appeals expressly rejected ATA's argument that it shouldreconsider its decision in Lead Industries because that case was decidedprior to Chevron U.S.A. Inc. v. NRDC, 467 U.S. 837 (1984). The court explained(Pet. App. 19a-20a):
The Lead Industries decision was made in Chevron step one terms, * ** as the post-Chevron progeny of Lead Industries have made clear. See NRDC,902 F.2d at 973 ("Consideration of costs . . . would be flatly inconsistentwith the statute, legislative history and case law on this point");NRDC v. EPA, 824 F.2d 1146, 1158-59 (D.C. Cir. 1987) (in banc) ("VinylChloride") ("[S]tatute on its face does not allow considerationof technological or economic feasibility. . . . Congress considered thealternatives and chose to close down sources or even industries rather thanto allow risks to health.").
The court of appeals also rejected the argument that, even if, in initiallysetting NAAQS, EPA cannot consider costs and other effects of implementation,it may do so when revising NAAQS. Pet. App. 20a. Finally, the court rejectedthe argument that Congress's direction that CASAC advise EPA on, among otherthings, "any adverse public health, welfare, social, economic, or energyeffects which may result from various strategies for attainment and maintenance"of NAAQS, CAA § 109(d)(2)(C)(iv), 42 U.S.C. 7409(d)(2)(C)(iv), signalsthat EPA should consider those factors in revising NAAQS. Pet. App. 21a.Instead, the court of appeals held that the Act directs CASAC to providethat advice in light of EPA's separate duty to inform the States on controlstrategies. Ibid.
SUMMARY OF ARGUMENT
When Congress enacted Section 109 as part of the Clean Air Amendmentsof 1970, it made a policy choice that EPA should set NAAQS at levels requisiteto protect public health and public welfare. The text, structure, and contextof Section 109 establish that Congress intended EPA to set and revise NAAQSbased on the health and welfare effects posed by the presence of criteriapollutants in the ambient air, and not on the feasibility, costs, or othereffects of implementing the NAAQS. Congress decided that consideration ofthe latter should instead await the process of implementation, where thosefactors will be manifested in concrete terms. The Clean Air Act makes clearthat the States and EPA may give appropriate consideration to such factorsat various stages of the implementation process.
Section 109(b)(1) directs EPA to set primary NAAQS at levels "requisite"to protect "public health" with "an adequate margin of safety."42 U.S.C. 7409(b)(1). There is no ambiguity in that command. EPA must setprimary NAAQS at levels necessary to ensure that the general populationis protected, with a reasonable degree of certainty, against the risk ofadverse health effects. Similarly, Section 109(b)(2) directs EPA to setsecondary NAAQS at levels "requisite to protect the public welfare."42 U.S.C. 7409(b)(2). Congress spoke directly to the issue of what factorsEPA may consider when it sets and revises NAAQS. Section 109 states thatboth primary and secondary NAAQS are to be based on the air quality criteriathat EPA develops under Section 108. Section 108, in turn, directs thatair quality criteria are to "accurately reflect" the "latestscientific knowledge" on the effects on public health and public welfarethat may be associated with "the presence of" a criteria pollutant"in the ambient air." 42 U.S.C. 7408(a)(2).
The evolution of the 1970 Act confirms that Congress did not intend EPAto base NAAQS on consideration of any effects except those posed by thepresence of the pollutant in the ambient air. Under the Air Quality Actof 1967, the States were to set regional ambient air quality standards consistentwith two pieces of information prepared by the Department of Health, Education,and Welfare: air quality criteria (defined in the same manner as in the1970 Act) and information regarding pollution control techniques (includinginformation on the technological feasibility and cost-effectiveness of thosetechniques). When Congress determined in 1970 that uniform national standardswere necessary, it retained the requirement that EPA prepare and providethe States with information on pollution control techniques, but specifiedthat NAAQS should be based on the air quality criteria alone.
The court of appeals' and EPA's shared understanding of Congress's intentis consistent with what this Court has described as the "technology-forcing"character of the Clean Air Act. See Union Elec. Co. v. EPA, 427 U.S. 246,257 (1976). Congress understood that setting NAAQS on the basis of healthand welfare considerations would give industry an incentive, at the implementationstage, to develop innovative and cost-effective control strategies. Congress'sactions since 1970 confirm that Congress reserved to itself the responsibilityfor determining whether to adjust the NAAQS process in response to industrycomplaints about the costs, technological challenges, or other burdens ofcompliance. Since 1970, Congress has repeatedly been confronted with evidenceof widespread failure to attain NAAQS by applicable statutory deadlines.Each time, Congress has heard complaints regarding the economic and technologicalfeasibility of attaining the standards. Yet, each time, Congress has addressedthe problem by amending the timetable or manner of implementing the NAAQSand not by amending the legal standard that governs EPA's decisions to setand revise them.
ATA and its amici offer no persuasive arguments that Congress intendedNAAQS to be based on feasibility or costs of implementation. They are unableto identify any statutory provision directing EPA to consider such factors.To the contrary, ATA relies on statutory provisions that confirm Congress'sintent that EPA and the States consider such factors in the NAAQS-implementationprocess, but not in the NAAQS-setting process. The amici supporting ATAurge this Court to apply cost-benefit principles in setting NAAQS, because,in their view, it would represent a better policy choice. But the wisdomand utility of basing measures to protect public health on cost-benefitanalysis are a subject of robust public debate. Congress has chosen notto apply that regulatory approach in setting NAAQS, and any decision todepart from Congress's 30-year course should come from Congress itself andnot from the courts.
As we explain in our opening brief in the related case, No. 99-1257,Section 109 of the Clean Air Act does not violate the nondelegation doctrine.Moreover, because the meaning of Section 109 is clear, the canon that theCourt should construe ambiguous terms of legislation to avoid reaching constitutionalissues has no place in this case. But even if the court of appeals' analysisof the constitutional issue were correct, allowing EPA to consider factorssuch as economic and technological feasibility when it sets and revisesNAAQS would not resolve or avoid the constitutional issue. ATA's proposedapproach would expand, rather than narrow, the range of factors EPA mustconsider. Injecting those factors into EPA's NAAQS decision-making processwould not provide the "determinate criterion" that the court ofappeals believed was necessary under the nondelegation doctrine.
I. CONGRESS HAS DIRECTED EPA TO ESTABLISH NAAQS BASED SOLELY ON CONSIDERATIONOF THE EFFECTS ON PUBLIC HEALTH AND PUBLIC WELFARE CAUSED BY THE PRESENCEOF CRITERIA POLLUTANTS IN THE AMBIENT AIR
Congress introduced the NAAQS concept through the Clean Air Amendmentsof 1970. See Train v. NRDC, 421 U.S. 60, 63-65 (1975); note 2, supra; seealso Union Elec., 427 U.S. at 256-257. Since then, EPA has consistentlyapplied Section 109 according to its terms, which require NAAQS to be setat levels "requisite to protect" public health and public welfare.42 U.S.C. 7409(b). Congress prescribed that NAAQS are to be "basedon" the air quality criteria EPA develops under Section 108 and thatthose criteria are to provide an accurate scientific assessment of the effectson public health and public welfare posed by "the presence of [the]pollutant in the ambient air, in varying quantities." 42 U.S.C. 7408(a)(2).Accordingly, for the last three decades, EPA has understood that, when promulgatingNAAQS, it may not consider technological feasibility, costs, or other allegedeffects flowing from implementation of the standards. Instead, Congressintended those factors to be considered when the States and EPA decide howNAAQS should be implemented.10
ATA asks this Court to overturn, not only 30 years of agency practice,but 20 years of court of appeals precedent decided in the course of reviewingprior NAAQS. See Pet. App 19a; pp. 2-3, supra. That extraordinary actionis unwarranted. Congress has unambiguously indicated its intent that NAAQSshould be based on scientific evidence regarding the health and welfareeffects of ambient pollution, and not on the technological feasibility,costs, or other effects of measures to reduce pollution levels.
A. The Text And Context Of Sections 108 And 109 Require EPA To Set NAAQSBased Solely On The Health And Welfare Effects Of The Criteria Pollutants'Presence In The Ambient Air
The court of appeals and EPA have correctly concluded that Congress "hasdirectly spoken to the precise question at issue" by specifying preciselywhat factors EPA is to consider when it sets and revises NAAQS. Chevron,467 U.S. at 842. Section 109(b)(1) of the Act directs EPA to set primaryNAAQS at a level "requisite to protect the public health" andto set secondary NAAQS at a level "requisite to protect the publicwelfare." See 42 U.S.C. 7409(b)(1) and (2). The language of the 1970Act demonstrates that Congress conceived of NAAQS as the means to identify,as the first step of the CAA regulatory program, the ambient air qualitystandards that are necessary to protect public health and public welfare.Neither Section 108, which specifies the kinds of factual information uponwhich NAAQS must be based, nor Section 109, which contains the legal testNAAQS must meet, directs EPA to consider economic or technological feasibility,or similar factors, when promulgating NAAQS. See Lead Indus., 647 F.2d at1149; NRDC, 824 F.2d at 1158.
Section 109's command that NAAQS be set at levels "requisite"to protect health and welfare unambiguously directs that the levels to beset achieve that objective, regardless of cost or other considerations.42 U.S.C. 7409(b). The plain language of the Act also specifies the factorsthat EPA may consider. Section 109(b)(1) expressly requires NAAQS to be"based on" the air quality "criteria" that EPA issuesunder Section 108. 42 U.S.C. 7409(b)(1). Section 108(a)(2), in turn, limitsthe kind of information to be included in the "criteria" to "thelatest scientific knowledge" about effects on public health and publicwelfare "which may be expected from the presence of such pollutantin the ambient air." 42 U.S.C. 7408(a)(2); see pp. 5-6, supra. Section108(a)(2) makes no mention whatsoever of effects from, or the feasibilityof, achieving the NAAQS. Congress expressly directed the focus on healthand welfare effects from the presence of a criteria pollutant in the airand not on economic or other effects of measures to remove that pollutantfrom the air.11
The context in which Sections 108 and 109 appear also confirms that reading.Congress has indicated expressly when and to what extent costs and implementationeffects shall be considered in the NAAQS regulatory process. See Union Elec.,supra. Those factors can play a role in the States' and EPA's decisionson how to attain the NAAQS. For example, the States are charged with developingSIPs governing how NAAQS will be implemented within their borders. See CAA§ 110, 42 U.S.C. 7410. States may properly consider the technologicalfeasibility and costs of implementation when formulating the SIPs, and EPAmay not override those judgments so long as the SIPs will achieve attainmentof the NAAQS. See Union Elec., 427 U.S. at 256-269. Union Electric recognizesthat the CAA does not allow a State to rely on cost and feasibility considerationsto excuse failure to meet the CAA's deadlines for attaining the nationalhealth-based standards. Id. at 266-269. Nevertheless, the Court concludedthat "the [Clean Air Amendments of 1970] offer ample opportunity forconsideration of claims of technological and economic infeasibility."Id. at 268.12
In telling contrast to the provisions governing NAAQS promulgation, Congressincluded provisions in the 1970 Act expressly directing EPA to considercosts and similar factors when making other decisions. See Union Elec.,427 U.S. at 257 n.5 (noting latter sections of 1970 Act).13 This Court "generallypresume[s]" that, "[w]here Congress includes particular languagein one section of a statute but omits it in another section of the sameAct, * * * Congress acts intentionally and purposely in the disparate inclusionor exclusion." Brown v. Gardner, 513 U.S. 115, 120 (1994) (quotingRussello v. United States, 464 U.S. 16, 23 (1983)). See also United Statesv. Shabani, 513 U.S. 10, 14 (1994).
In sum, the plain language of the CAA shows that Congress itself consideredthe costs and other effects that might flow from implementing the NAAQSand chose to have EPA set standards at levels that will protect public healthand public welfare. As in American Textile Manufacturers Institute v. Donovan,452 U.S. 490 (1981), "Congress itself defined the basic relationshipbetween costs and benefits, by placing the 'benefit' of [public] healthabove all other considerations." Id. at 509. Neither EPA nor the courtsare free to overrule that choice.
B. The Evolution Of The 1970 NAAQS Provisions Confirms That CongressMade A Policy Choice Not To Base NAAQS On Consideration Of The TechnologicalFeasibility Or Cost-Effectiveness Of Pollution Control Measures
The CAA provisions at issue here are an outgrowth of congressional actionthat began in 1963. See note 2, supra. The legislative evolution of thoseprovisions leaves no doubt that Congress meant what the plain language says.
Congress introduced the concept of air quality criteria in the CleanAir Act of 1963, Pub. L. No. 88-206, 77 Stat. 392, which expanded a federallyfunded program of air pollution research. Section 3(c)(2) of that Act requiredthe Secretary of HEW to "compile and publish criteria" when hedetermined that any particular "air pollution agent" was "producingeffects harmful to the health or welfare of persons." 77 Stat. 395.The 1963 Act defined air quality criteria much as the term is defined today:the criteria were to "reflec[t] accurately the latest scientific knowledgeuseful in indicating the kind and extent of such effects which may be expectedfrom the presence of such air pollution agent (or combination of agents)in the air in varying quantities." Ibid. Accord, S. Rep. No. 638, 88thCong., 1st Sess. 7 (1963).
The Air Quality Act of 1967, Pub. L. No. 90-148, 81 Stat. 485, retainedthe requirement that the Secretary of HEW develop air quality criteria.§ 107, 81 Stat. 490-491. But the Act also introduced into federal lawthe concept of air quality standards. Those standards, however, differedfrom NAAQS in two respects. First, Congress envisioned that the States woulddevelop those standards, with federal assistance, and apply them on a regionalbasis within each State's borders. Second, Congress encouraged the Statesto adopt regional ambient air quality standards "consistent with"both (a) the air quality criteria and (b) information on pollution controltechniques. § 108(c), 81 Stat. 492-494.
The 1967 Act preserved the 1963 Act's conception of air quality criteria,providing that they should "accurately reflect the latest scientificknowledge" on the health and welfare effects "which may be expectedfrom the presence of an air pollution agent, or combination of agents inthe ambient air, in varying quantities." § 107(b)(2), 81 Stat.491.14 The 1967 Act went beyond the 1963 Act, however, by directing theSecretary of HEW to provide the States with a separate body of informationon recommended pollution control techniques, including information on the"economic feasibility" and "cost-effectiveness" of thecontrol techniques. § 107(c), 81 Stat. 491; see H.R. Rep. No. 728,90th Cong., 1st Sess. 9-13 (1967).
The 1967 Act directed the Secretary to provide information on both airquality criteria and control techniques in order to create incentives forStates to develop their own air quality standards that were "at a minimumadequate for the protection of public health and which can be achieved throughthe application of feasible control techniques." H.R. Rep. No. 728,supra, at 18; see also S. Rep. No. 403, 90th Cong., 1st Sess. 26, 28 (1967)(standards would be "influenced not only by a concern for the protectionof health or welfare, but also by economic, social, and technological considerations").Congress accordingly provided that those standards would "be the airquality standards applicable to such State" if the Secretary of HEWdetermined that the State standards were "consistent with the air qualitycriteria and recommended control techniques issued pursuant to section 107."§ 108(c), 81 Stat. 492 (emphasis added).
Three years later, Congress determined that the "response of theStates * * * was disappointing," and it enacted the 1970 Clean AirAmendments to "sharply increase federal authority." Train, 421U.S. at 64-65. Congress directed EPA to develop nationally uniform federalstandards-the NAAQS-and it deliberately narrowed the basis for setting thestandards. Congress retained the distinction between air quality criteriaand information on pollution control techniques that it had made in the1967 Act. See 42 U.S.C. 7408(a)(2) (defining air quality criteria); 42 U.S.C.7408(b) (requiring issuance of information on air pollution control techniques).Congress specified, however, that the NAAQS would be "based on"the "criteria" alone. 42 U.S.C. 7409(b)(1) and (2). Congress consciouslyprovided for consideration of the feasibility and effects of implementingthe standards during later stages in the regulatory process. See pp. 20-21,supra. Those changes clearly reflected a deliberate legislative decisionto narrow the basis on which EPA, as HEW's successor, would establish thenational ambient air quality standards.15
Viewed in historical context, Congress's intent is thus clear. Since1963, Congress has conceived of air quality criteria as scientific informationon the effects on public health and public welfare posed by the presenceof a pollutant in the ambient air. In 1967, Congress experimented with afederal program in which States would set regional air quality standardsbased on air quality criteria and information regarding the economic andtechnological feasibility of measures to reduce pollution. In 1970, Congressconcluded that the experiment was a failure and replaced it with a programin which EPA would set national air quality standards based on air qualitycriteria alone, see Train, 421 U.S. at 63-65, while preserving the abilityof EPA and the States to consider costs and feasibility in the implementationstage of the regulatory process, where specific emission limitations andcontrol requirements are imposed, see Union Elec., 427 U.S. at 266-269.
C. Congress's Direction That EPA Set NAAQS Based Solely On Health AndWelfare Effects Is Consistent With The Clean Air Act's "Technology-Forcing"Objectives
As this Court has recognized, Congress's decision to set NAAQS at levels"requisite" to protect public health and public welfare-and topostpone questions of feasibility to the implementation stage-rests on adeliberate policy judgment that the NAAQS would have a "technology-forcingcharacter." Union Elec., 427 U.S. at 257; Train, 421 U.S. at 91. Congressknew that setting the NAAQS based on health and welfare considerations could,at the implementation stage, "force regulated sources to develop pollutioncontrol devices that might at the time appear to be economically or technologicallyinfeasible." Union Elec., 427 U.S. at 257. It also knew that technologyforcing "necessarily entails certain risks." Id. at 269. "Congressconsidered those risks in passing the 1970 Amendments and decided that thedangers posed by uncontrolled air pollution made them worth taking."Ibid.16
The Court's understanding of the CAA's "technology-forcing character"is well founded. See NRDC, 824 F.2d at 1158; Lead Indus., 647 F.2d at 1149.For example, the Senate Report accompanying the 1970 Amendments recognizedthat attaining the new standards would "require major investments innew technology and new processes" and that some facilities might evenclose. S. Rep. No. 1196, 91st Cong., 2d Sess. 2-3 (1970) (1 1970 Leg. Hist.402-403). Nevertheless, the Report emphasized (ibid.):
In the Committee discussions, considerable concern was expressed regardingthe use of the concept of technical feasibility as the basis of ambientair standards. The Committee determined that 1) the health of people ismore important than the question of whether the early achievement of ambientair quality standards protective of health is technically feasible; and,2) the growth of pollution load in many areas, even with application ofavailable technology, would still be deleterious to public health.
Therefore, the Committee determined that existing sources of pollutantseither should meet the standard of the law or be closed down * * *.
Senator Muskie, the Act's principal sponsor, while acknowledging theneed to provide States with information on the economics and feasibilityof pollution control technologies, "reemphasize[d] that the conceptof this bill as it relates to national ambient air quality standards * ** is not keyed to any condition that the Secretary finds technically andeconomically feasible." 116 Cong. Rec. 33,099 (1970) (1 1970 Leg. Hist.342). Instead, "the concept is of public health, and the standardsare uncompromiseble in that connection." Ibid. See also id. at 32,902(1 1970 Leg. Hist. 227).17
The CAA is "technology forcing" precisely because it dictatesthat NAAQS shall be based on public health and public welfare considerationsand not on supposed "feasibility" constraints. The CAA was designedto stimulate the regulated community to find innovative ways, at the implementationstage, to meet the NAAQS. See 116 Cong. Rec. 32,902 (1970) (1 1970 Leg.Hist. 227) (Sen. Muskie) ("Our responsibility in Congress is to saythat the requirements of this bill are what the health of the Nation requires,and to challenge polluters to meet them."). Congress clearly understoodthat the feasibility, costs, and other effects of implementing measuresto attain the NAAQS would be considered only following promulgation of NAAQS,when the States and EPA could consider those factors in deciding how toattain the standards. See 116 Cong. Rec. at 32,918 (1 1970 Leg. Hist. 259-260)(Sen. Cooper).
D. Congress's Actions Since 1970 Confirm That EPA Has Correctly DiscernedCongressional Intent
As this Court recognized in Union Electric, Congress ensured that considerationsof economic and technological feasibility could be factored into the implementationprocess. 427 U.S. at 266-269. Congress also retained the prerogative ofdeciding-after the States and affected parties had explored both conventionaland innovative control measures under the technology-forcing pressure ofthe Act-whether and how to alter the statutory scheme if the NAAQS couldnot realistically be attained within the prescribed time frames. See LeadIndus., 647 F.2d at 1150; Pet. App. 68a-69a (Tatel, J., dissenting). Congresshas since exercised that prerogative a number of times. In doing so, ithas confirmed that EPA is to set and revise NAAQS based on health and welfareconsiderations, and not on the effects of implementing the standards.18
For example, when Congress amended the Act in 1977, it addressed thedifficulty that many areas had experienced with attaining the NAAQS. ButCongress did so by changing how the NAAQS are implemented rather than changinghow NAAQS are set. See 62 Fed. Reg. at 38,685. Congress was well aware thatsome areas of the country had been unable to attain some of the NAAQS. See,e.g., H.R. Rep. No. 294, 95th Cong., 1st Sess. 207-217 (1977). Congresswas also aware that significant scientific uncertainties are inherent insetting health-based standards. See id. at 43-51, 110-112. Furthermore,EPA had emphasized, in a memorandum responding to criticism in oversighthearings, that the original NAAQS were set without considering costs orfeasibility,19 and industrial groups had urged Congress specifically torevise Section 109 to allow consideration of "social and economic factors"in setting NAAQS.20 In response, Congress made significant changes in theCAA's provisions for implementing NAAQS, including, for example, an extensionof the deadline for attaining the ozone NAAQS. See 91 Stat. 746-747. Italso amended Section 109 of the Act to require periodic review and revisionof NAAQS and to establish CASAC. See 91 Stat. 691. Congress made no change,however, in the substantive criteria for setting and revising NAAQS. See62 Fed. Reg. at 38,685 & n.66 (describing the 1977 Amendments).
Congress also exercised its prerogative, several times during the 1980s,to adjust the NAAQS implementation scheme based on considerations of economicand technological feasibility. In 1981, it enacted legislation that gavethe steel industry three additional years to meet the NAAQS attainment dateof 1982 established by the 1977 Act. See Steel Industry Compliance ExtensionAct of 1981, Pub. L. No. 97-23, 95 Stat. 139. In 1983, when 218 areas hadfailed to meet the 1982 attainment date and could thus be sanctioned, Congressenacted a one-year moratorium on sanctions. See Department of Housing andUrban Development-Independent Agencies Appropriation Act, 1983, Pub. L.No. 98-45, 97 Stat. 219. In addition, Congress extended the time for compliancewith the carbon monoxide and ozone NAAQS from December 31, 1987, to August31, 1988. See H.R. J. Res. 395, 100th Cong., 1st Sess. (1987).
In 1990, Congress again made adjustments in the scheme for implementingNAAQS. The Clean Air Act Amendments of 1990 were an ambitious undertakingthat almost doubled the size of the CAA in the United States Code. Congressresponded, through detailed amendments, to problems that areas of the countrycontinued to encounter in attaining the NAAQS. But Congress once again didso by adjusting the implementation scheme rather than by changing the waythat NAAQS are set. See, e.g., CAA §§ 181-192, 42 U.S.C. 7511-7514a(1994 & Supp. IV 1998). The 1990 Amendments are particularly instructivebecause Congress acted with full knowledge of how NAAQS had been promulgatedover the previous 20 years.
First, Congress had before it the final report of the National Commissionon Air Quality (NCAQ), prepared pursuant to Section 323 of the 1977 Act,which charged the NCAQ with examining, among other things, "the economic,technology, and environmental consequences of achieving or not achieving"the Act's goals. Pub. L. No. 95-95, § 323(a), 91 Stat. 785. The NCAQreport discussed the long-standing principle that NAAQS are set based solelyon health and welfare considerations and recommended that this principleremain unchanged.21 Second, Congress indicated its awareness of the courtof appeals' decision in Vinyl Chloride, which had expressly reaffirmed thatEPA may not take into account economic or technological feasibility whensetting NAAQS (824 F.2d at 1158-1159), by enacting amendments addressingother aspects of the en banc court's decision. See 104 Stat. 2531 (extensivelyamending Section 112 of the CAA, 42 U.S.C. 7412, governing the regulationof especially hazardous pollutants). Third, the House and Senate Reportsaccompanying the 1990 Amendments expressly reflected the understanding thatprimary NAAQS are to be "set at a level that 'protects the public healthwith an adequate margin of safety,' without regard to the economic or technicalfeasibility of attainment." H.R. Rep. No. 490, 101st Cong., 2d Sess.,Pt. 1, at 145 (1990) (emphasis added); accord S. Rep. No. 228, 101st Cong.,1st Sess. 5 (1989). 22
This Court recently recognized that, when Congress enacts legislation"against the backdrop" of an agency's "consistent and repeatedstatements" of the agency's authority, the legislation may effectivelyratify the agency's position. See FDA v. Brown & Williamson TobaccoCorp., 120 S. Ct. 1291, 1313 (2000).23 This case, however, does not dependon an inference that Congress ratified EPA's interpretation of its authority.Congress has revisited the CAA numerous times over the past 30 years, andit has consistently adhered to its plainly stated original intention-longfollowed by EPA and the court of appeals-that NAAQS are to be set at levelsrequisite to protect public health and public welfare, without regard tothe economic or technological feasibility of implementing those standards.Congress has itself thus directly and repeatedly reaffirmed that it meantwhat it originally said. See Chevron, 467 U.S. at 842-843 ("[i]f theintent of Congress is clear, that is the end of the matter").24
II. ATA IS MISTAKEN IN INSISTING THAT THE CLEAN AIR ACT REQUIRES EPATO CONSIDER NON-HEALTH FACTORS IN SETTING PRIMARY NAAQS
Notwithstanding the foregoing, ATA and its supporters mistakenly arguethat the CAA's "text, structure, and purpose show that EPA must considernon-health factors in setting NAAQS." ATA Br. 32-47. They also arguethat EPA should, as a matter of policy, employ cost-benefit analysis insetting NAAQS. See, e.g., ATA Br. 35-36; APC Br. 30-31; AEI-Brookings Inst.Amici Br. This Court's responsibility, however, is to determine Congress'sintent. Congress has deliberately rejected the cost-benefit approach thatATA and its supporters espouse, and Congress's determination is dispositive.
A. ATA's Supposed "Trilemma" Does Not Exist
ATA argues at the outset that setting primary NAAQS for non-thresholdpollutants based on health considerations creates a "trilemma"in which EPA has only three regulatory options: (1) to set NAAQS at zero;(2) to set NAAQS at a non-zero level that cannot survive review under thearbitrary or capricious standard; or (3) to reject the court of appeals'ruling and employ cost-benefit analysis to set and revise NAAQS. ATA Br.25, 29-30. ATA's supposed trilemma rests on a false trichotomy.
ATA's first prong presents no real difficulty. EPA has never encountered(and does not expect ever to encounter) the theoretical situation in whichcomplete elimination of a criteria pollutant-including a so-called non-thresholdpollutant-would be "requisite" to protect public health or publicwelfare. 42 U.S.C. 7409(b). ATA overlooks that scientists characterize apollutant as "non-threshold" if they have not been able to identifya level below which there is no risk that exposure will cause a physiologicalor biological effect, however small or fleeting. See, e.g., 61 Fed. Reg.at 65,727; Casarett & Doull's Toxicology, supra, at 19 (describing a"threshold" as "[a] dose below which the probability of anindividual responding is zero"). Characterizing a pollutant as "non-threshold"does not mean that any group of persons, including sensitive persons, willactually suffer adverse health effects if exposed to a non-zero concentrationof that pollutant. See, e.g., 61 Fed. Reg. at 65,721-65,723; see also Casarett's& Doull's Toxicology, supra, at 80 (distinguishing between, e.g., the"no observed effect level" and the "no observed adverse effectlevel"). Accordingly, EPA's characterization of a pollutant as "non-threshold"does not require EPA to set the NAAQS for that pollutant at zero.
ATA's second prong also presents no real problem. The CAA requires EPAto set primary NAAQS at levels that protect against "adverse"health effects-not every physiological effect that can be detected-and itrequires EPA to protect the health of sensitive population groups ratherthan that of every sensitive individual. 42 U.S.C. 7409(b)(1); S. Rep. No.1196, supra, at 10 (1 1970 Leg. Hist. 410). Moreover, EPA has consistentlyadhered to the principle that NAAQS must provide "a reasonable degreeof protection
* * * against hazards which research has not yet identified." Ibid.(emphasis added). See Lead Indus., 647 F.2d at 1150. EPA therefore setsprimary NAAQS at levels that provide protection from medically significantrisks and not at levels that protect against any and all risks, or any andall effects. See, e.g., id. at 1144, 1155 n.51.25 ATA is accordingly mistakenin suggesting (ATA Br. 25, 29-30) that setting a non-zero NAAQS for a non-thresholdpollutant is necessarily arbitrary and capricious. Indeed, EPA has properlyestablished non-zero NAAQS for pollutants that are or may be non-thresholdpollutants, and the court of appeals, applying the familiar arbitrary orcapricious standard, has repeatedly rejected judicial challenges to thoseNAAQS.26
The only truly problematic option is the third prong of ATA's supposedtrilemma. ATA's suggestion that EPA should ignore Lead Industries and setNAAQS on the basis of cost-benefit analysis (ATA Br. 30, 32) would requireEPA to ignore 30 years of agency practice, 20 years of court of appealsprecedent, and-most importantly-Congress's clearly stated contrary intent.See A. Scalia, Responsibilities of Regulatory Agencies Under EnvironmentalLaws, 24 Hous. L. Rev. 97, 102 (1987) (noting that "primary [NAAQS]are to be established not in light of what is 'feasible' or 'reasonable'(a formulation that would enable counterbalancing costs to be offset againstthe benefit of clean air) but rather on the sole basis of what is 'requisiteto protect the public health'").
B. The Clean Air Act's Express Language Refutes ATA's View Of EPA's ObligationsIn Promulgating NAAQS
ATA and its supporters argue that the CAA requires EPA to consider "non-healthfactors," including "compliance costs," in promulgating NAAQS.See, e.g., ATA Br. 33, 34; APC Br. 32. The statutory language on which theyrely, however, does not support their contentions. Indeed, as we show below,their arguments depend heavily on extrapolating from isolated phrases, givingwords unnatural definitions, and overlooking context. That approach is fundamentallyunsound: statutes should not "be read as a series of unrelated andisolated provisions." Gustafson v. Alloyd Co., 513 U.S. 561, 570 (1995)."Statutory construction is not an exercise in picking apart a complexstatute and piecing the parts back together in a manner to effect a particularend." Michigan v. EPA, 213 F.3d 663, 673 (D.C. Cir. 2000).
1. Section 109(b)(1): The term "public health." ATA contendsthat EPA must take compliance costs into account when setting primary NAAQSat a level "requisite to protect the public health" (CAA §109(b)(1), 42 U.S.C. 7409(b)(1)) because the term "public health""has long connoted a sensitivity to comparative costs and benefits."ATA Br. 36; see also APC Br. 26; Ohio Br. 12. ATA derives that conclusionby extrapolating from a definition of the vocation of "public health"that appeared in a 1951 book entitled "The Cost of Sickness and thePrice of Health." ATA Br. 34. That book defined "public health"as "the science and the art of preventing disease, prolonging life,and promoting physical health and efficiency" through various means.See id. at 34-36; APC Br. 26 n.57. A definition of "public health"drawn from the vocational context, however, is inapt in the context presentedhere. Congress surely did not intend that NAAQS would be set at a level"requisite to protect [the science and art of preventing disease]"(42 U.S.C. 7409(b)(1)). See, e.g., Textron Lycoming Reciprocating EngineDiv. v. Automobile Workers, 523 U.S. 653, 657 (1998)("the meaning ofa word cannot be determined in isolation, but must be drawn from the contextin which it is used").27
The phrase "public health" should be given its ordinary ornatural dictionary meaning in light of the context in which it is used.See, e.g., Walters v. Metropolitan Educ. Enters., Inc., 519 U.S. 202, 207(1997). Viewed in that light, Section 109(b)(2) clearly directs that EPAmust set NAAQS at levels requisite to protect the general population, oridentifiable groups within communities, from medically significant effects.28Nothing in the language of Section 109(b)(1) directs-or even allows-EPAto set NAAQS at levels inadequate to protect the public from adverse medicaleffects because of the costs of compliance or other effects of implementation.See Scalia, supra, 24 Hous. L. Rev. at 102. See, e.g., Bates v. United States,522 U.S. 23, 29 (1997) ("[w]e ordinarily resist reading words or elementsinto a statute that do not appear on its face").
2. Section 109(b)(2): The term "public welfare." ATA also arguesthat the CAA's references to protecting "public welfare" mustinclude protecting industry from "compliance costs." ATA Br. 37-39.Section 109(b)(2) expressly directs EPA, however, to set secondary NAAQSfor criteria pollutants at a level "requisite to protect the publicwelfare from any known or anticipated adverse effects associated with thepresence of such air pollutant in the ambient air." 42 U.S.C. 7409(b)(2)(emphasis added). Congress plainly indicated that the public welfare effectsof concern are those posed by exposure to air pollutants rather than theeffects of measures to implement the NAAQS.29
3. Section 108(a)(2): The contents of air quality criteria. Similarly,ATA and others contend that, in prescribing the content of air quality criteriain Section 108(a)(2), Congress did not preclude other types of information.E.g., ATA Br. 38-40; Ohio Br. 11. Section 108(a)(2) specifies, however,that air quality criteria shall provide information on "all identifiableeffects on public health or welfare which may be expected from the presenceof such pollutant in the ambient air." 42 U.S.C. 7408(a)(2) (emphasisadded). Congress plainly indicated in Section 108(a)(2), that the effectsof concern are those posed by the presence of the pollutant in the ambientair rather than compliance costs and other effects that arise from implementingthe NAAQS.30
4. Section 108(b)(1): Dissemination of pollution control informationto States. ATA and others contend that Section 108(b)(1)'s direction thatEPA provide States with information on air pollution control techniques,42 U.S.C. 7408(b)(1), indicates that Congress intended EPA to consider thosematters in promulgating NAAQS. ATA Br. 40; APC Br. 38-39. But, as we haveexplained, Congress had directed HEW to provide the States with pollutioncontrol information under the 1967 Act, which called on States to developregional air quality standards. See pp. 22-23, supra. Congress directedEPA to continue to provide States with that information under the 1970 Act,but expressly separated it from the newly created NAAQS promulgation process.Congress did so precisely because it decided that NAAQS should be health-basedstandards. See pp. 23-24, supra. Congress has nevertheless continued toensure that States have pollution control information so that the Statescan be prepared to implement the NAAQS. See ibid.
5. Section 109(d)(2): CASAC's advice to EPA on effects of implementation.ATA and others also contend that Section 109(d)(2)'s direction that CASACprovide EPA with advice on implementation effects, 42 U.S.C. 7409(d)(2)(C)(iv),indicates that Congress intended EPA to consider those matters in promulgatingNAAQS. ATA Br. 41; APC Br. 41; Hatch Amicus Br. 22. The text of Section109(d)(2), read as a whole, indicates that this is not so. Section 109(d)(2)(B)directs that CASAC periodically review the air quality criteria and NAAQSand make recommendations to the Administrator on new or revised standardsor criteria. 42 U.S.C. 7409(d)(2)(B). Section 109(d)(2)(C) further providesthat CASAC "shall also" advise the Administrator on various matters,including "any adverse public health, welfare, social, economic, orenergy effects which may result from various strategies for attainment andmaintenance of [NAAQS]." 42 U.S.C. 7409(d)(2)(C) (emphasis added).As the CAA's text indicates, CASAC's advice on implementation effects underSection 109(d)(2)(C) is in addition to, and separate from, any recommendationson criteria and NAAQS that CASAC provides under Section 109(d)(2)(B). SeePet. App. 21a.31
6. Section 109(b)(1): Allowance for an adequate margin of safety. ATAand its supporters also contend (ATA Br. 47; APC Br. 35-36; Ohio Br. 12-13,15) that EPA has discretion to consider compliance costs because, when EPAsets primary NAAQS at a level "requisite to protect public health,"it must "allow an adequate margin of safety." CAA
§ 109(b)(1), 42 U.S.C. 7409(b)(1). The court of appeals has twicerejected that argument. See Lead Indus., 647 F.2d at 1148-1150; Vinyl Chloride,824 F.2d at 1158-1159. In context, Section 109(b)(1) plainly directs EPAto set primary NAAQS with an "adequate margin of safety" to ensurethat those health-based standards will be set at a sufficiently stringentlevel to achieve Section 109(b)(1)'s objective of protecting public health.See S. Rep. No. 1196, supra, at 10 (1 1970 Leg. Hist. 410); 116 Cong. Rec.at 33,099 (1 1970 Leg. Hist. 342) (Sen. Muskie).32
7. Section 110(a)(2): Consideration of costs in the implementation program.ATA also argues (Br. at 45-47) that EPA's longstanding interpretation ofSection 109 is inconsistent with its interpretation of other provisionsof the CAA, where EPA does consider compliance costs in making regulatorydecisions. ATA overlooks, however, that those other provisions involve differentstatutory language, subject matter, and policy choices. The cases ATA citessimply demonstrate that EPA may have discretion to consider costs in situations-unlikethe situation posed by NAAQS promulgation-where Congress has not expresslyprescribed what factors it should consider in making regulatory determinations.
For example, in Michigan v. EPA, supra, various
States challenged EPA's determination, under Section 110(a)(2)(D), thatcertain ''upwind" States were making a "significant contribution"to NAAQS-nonattainment problems in "downwind" States. 42 U.S.C.7410(a)(2)(D). EPA identified 23 States that were "significant"contributors, and it required those States to reduce emissions to a levelthat could be achieved by employing "highly cost-effective controls."See 213 F.3d at 675. The court of appeals rejected various challenges toEPA's consideration of cost effectiveness. Id. at 675-678. The court concludedthat the term "significant" was inherently ambiguous, that ithad been construed in other contexts to include consideration of costs,and there was not-as under Section 109-"clear congressional intentto preclude consideration of costs." Id. at 678 (quoting Vinyl Chloride).33
8. Section 109(d)(1): Revision of NAAQS. APC, but not ATA, contends thatSection 109(d)(1)'s directive that EPA revise the NAAQS "as may beappropriate" (42 U.S.C. 7409(d)(1)) expands the range of factors thatEPA may consider when it revises NAAQS. APC Br. 39-40. The court of appealscorrectly rejected the argument. Pet. App. 20a-21a. As that court noted,Section 109(d)(1) directs EPA to "make such revisions in such criteriaand standards * * * as may be appropriate in accordance with section 7408of this title and subsection (b) of this section." 42 U.S.C. 7409(d)(1).Accordingly, the legal standard governing a decision to revise a NAAQS,and the factors that bear on the decision, are exactly the same as thosefor an initial decision to set a NAAQS.34
9. Section 101(b)(1): Goals of the CAA. ATA and others suggest that oneof the CAA's general goals set out in Section 101(b) - to promote "theproductive capacity" of the Nation's population, 42 U.S.C. 7401(b)(1)-shouldtake precedence over the CAA's specific language in Sections 108 and 109prescribing how NAAQS should be promulgated. E.g., ATA Br. 42-43; APC Br.23, 29-30. They essentially contend that Section 101(b)(1) should be readto impose a requirement to consider economic factors in all decisionmakingunder the Act. Section 101(b)(1) simply states, however, that one of thepurposes of the Act is "to protect and enhance the quality of the Nation'sair resources so as to promote the public health and welfare and the productivecapacity of its population." 42 U.S.C. 7401(b)(1) (emphasis added).The provision expresses Congress's belief that improved air quality wouldenhance the Nation's productive capacity by reducing the harm that air pollutioncauses.35 It does not alter the specific statutory directions that Congressset out in Sections 108 and 109 to achieve that goal. Cf. American TextileMfrs., 452 U.S. at 510 ("When Congress has intended that an agencyengage in cost-benefit analysis, it has clearly indicated such intent onthe face of the statute.").
10. The UMRA and the RFA. There is no merit to the suggestion (ATA Br.48; Amici Hatch Br. 25) that two later- enacted statutes, the Unfunded MandatesReform Act, 2 U.S.C. 1501 et seq. (UMRA), and the Regulatory FlexibilityAct, 5 U.S.C. 601 et seq. (RFA), require EPA to consider costs in promulgatingNAAQS. Those Acts encourage agencies to consider the economic effects ofagency actions, but each Act also provides that its specific requirementsdo not apply if those requirements would be inconsistent with the statuteunder which the agency is taking action. 2 U.S.C. 1535(b)(2) (Supp. IV 1998);5 U.S.C. 604(a)(5) (1994 & Supp. IV 1998). There is a "clear inconsistency"(see Hatch Br. 25) between the requirements of the UMRA and the RFA andthe requirement of Section 109 that NAAQS be based on the effects of ambientpollution on health and welfare. The UMRA and the RFA are pertinent in onlyone sense: They show that Congress is well aware that there are regulatorystatutes that preclude consideration of costs. See generally Pet. App. 25a-31a.
C. The Administrator Did Not Base Her NAAQS Decisions On ConsiderationOf Compliance Costs
After arguing that EPA has improperly construed Sections 108 and 109to preclude consideration of non-health effects (ATA Br. 32-43), ATA reversescourse and contends that EPA "may actually be considering non-healthfactors in setting NAAQS" (ATA Br. 43-45). That contention is withoutmerit. Throughout the rulemaking proceedings, EPA was confronted with commentsurging it to consider the technological feasibility, costs, and other allegedeffects of implementing any new PM or ozone standards. EPA responded byexplaining that the CAA requires that NAAQS be based on consideration ofthe health and welfare effects posed by "the presence of the pollutantin the air," rather than on consideration of the feasibility or effectsof implementing the standards. See 62 Fed. Reg. at 38,683-38,689; id. at38,878-38,883.36 And while it is a matter of no relevance to this case,there is no evidence to support ATA's claim (ATA Br. 43-44) that previousEPA Administrators secretly based their NAAQS decisions on impermissiblefactors.37
D. Congress Has Resolved The Public Policy Question Of Whether Cost-BenefitAnalysis Should Be Used In Setting NAAQS
ATA and its supporters argue that EPA should set NAAQS through cost-benefitanalysis, balancing the benefits of clean air against the resulting economiccosts of achieving that goal, because that technique, in their view, wouldimprove EPA's decisionmaking process. E.g., ATA Br. 30, 35-36; APC Br. 30-31.The question here, however, is whether Congress sanctioned that approach.The CAA's specific provisions show that Congress directed EPA to set NAAQSbased on public health and public welfare objectives rather than on thecost-benefit methodology that ATA would prefer. Congress was entitled tomake that choice.38
Congress has had sound reasons for adhering to that decision. Quantifyingthe nationwide environmental benefits of NAAQS in monetary terms createsa deceptive appearance of certainty, but is fraught with difficulties, suchas placing a monetary value on preventing a senior citizen's premature deathor a child's asthma attack.39 Quantifying the costs associated with implementingNAAQS is a no less uncertain undertaking. Because NAAQS are set on a nationallevel, because States have broad latitude in the SIP process to select localpollution control strategies, and because the time period from promulgationto full implementation can span many years and produce unforeseen technologicalinnovation, estimates of implementation costs are inherently-and often extraordinarily-speculative.40Indeed, EPA's attempt to estimate the costs and benefits of the ozone andPM NAAQS at issue in this case, for informational purposes only (see note36, supra), has itself become a source of debate.41 Congress's decisionto confine the use of cost-benefit techniques to implementation efforts,which typically involve assessment of near-term requirements for specificcontrol measures on specific industries in specific locations, is entirelyunderstandable.42
In any event, it is not for this Court to rescind Congress's legislativejudgment on what is quintessentially a matter of public policy. CentralBank of Denver, N.A. v. First Interstate Bank of Denver, N.A., 511 U.S.164, 188 (1994). Congress has made its policy determination, and "itis up to Congress, not this Court, to revise the determination if it sochooses." United States v. Noland, 517 U.S. 535, 541-542 n. 3 (1996).
III. EXPANDING THE RANGE OF FACTORS THAT EPA MAY CONSIDER IN SETTINGNAAQS WOULD NEITHER RESOLVE NOR AVOID THE CONSTITUTIONAL ISSUE PERCEIVEDBY THE COURT OF APPEALS
Perhaps ATA will address in its reply brief the question that it haspresented in its cross-petition but fails to develop in its opening brief-whetherthis Court should interpret Section 109 as allowing consideration of "non-healthfactors" to "avoid confronting constitutional nondelegation issues"(ATA Br. i). Because we will have no opportunity to respond to ATA's replybrief, we address that matter in the first instance.
As we explain in the companion case, No. 99-1257, Section 109 is clearlyconstitutional under this Court's nondelegation doctrine jurisprudence.See 99-1257 Pet. Br. 22-26. Because Congress has provided sufficient guidance"to meet any delegation doctrine attack," this Court has no occasionto give Section 109 a narrowing construction to avoid an alleged "seriousquestion of unconstitutional delegation of legislative power." FederalEnergy Administration v. Algonquin SNG, Inc., 426 U.S. 548, 559 (1976).43
In any event, ATA's proposed construction would not solve the supposedconstitutional infirmity under the nondelegation doctrine. To the contrary,it would actually grant EPA broader discretion than Section 109's plainlanguage confers. See Scalia, supra, 24 Hous. L. Rev. at 102. Under ATA'ssuggested approach, EPA would have discretion to set NAAQS-and courts wouldbe required to review them-based on an open-ended inquiry into any conceivablecosts or benefits that might result from promulgation of the NAAQS. Contraryto the court of appeals' suppositions, Pet. App. 14a-18a, considerationof costs and other effects of implementation would not provide a "determinatecriterion" for EPA in setting NAAQS.44 Accordingly, while we do notdisagree with the court of appeals' and ATA's implication that Section 109would not be unconstitutional if construed as ATA proposes, we believe thatit follows a fortiori that Section 109 is also constitutional as it hasbeen construed and applied throughout its 30-year existence.
In sum, Congress fulfilled its responsibility under the nondelegationdoctrine and made the fundamental policy choice. Congress concluded thatNAAQS should be set for criteria pollutants on the basis of what is necessaryto protect public health and public welfare. Cf. American Textile Mfrs.,452 U.S. at 509. Congress "itself determined that the economic effectsof any necessary actions to meet the goals of [the NAAQS program] were acceptable."See NCAQ Report, supra, at 273; pp. 25-32, supra. It did not authorize EPAto set NAAQS on the basis of the agency's projection of compliance costs.Cf. American Textile Mfrs., 452 U.S. at 545 (Rehnquist, C.J., dissenting)(health-based standards authorize an agency "to set exposure standardswithout regard to any kind of cost-benefit analysis"). ATA and itssupporters can continue to ask Congress to reconsider that policy choice,notwithstanding the substantial benefits that the CAA has provided to theAmerican public. See, e.g., EPA, The Benefits and Costs of the Clean AirAct, 1970 to 1990 (Oct. 1997). But unless and until Congress elects to changethe law that has been in place since 1970, Congress's legislative judgmentshould be given effect.
This Court should affirm the court of appeals' ruling that the CleanAir Act requires EPA to establish NAAQS based solely on consideration ofthe effects on public health and public welfare caused by the presence ofcriteria pollutants in the ambient air.
SETH P. WAXMAN
LOIS J. SCHIFFER
Assistant Attorney General
LAWRENCE G. WALLACE
Deputy Solicitor General
JEFFREY P. MINEAR
Assistant to the Solicitor
CHRISTOPHER S. VADEN
DAVID J. KAPLAN
MARY F. EDGAR
GARY S. GUZY
GERALD K. GLEASON
MICHAEL L. GOO
1 "Pet. App." refers to the petition appendix in Browner v.American Trucking Ass'ns, No. 99-1257.
2 Congress first addressed the problem of air pollution through the AirPollution Control Act of 1955, ch. 360, 69 Stat. 322, which authorized theSecretary of Health, Education, and Welfare (HEW) to conduct research activities.Congress later expanded HEW's authority to include, among other things,compiling and publishing air quality criteria based on scientific studies,Clean Air Act of 1963, Pub. L. No. 88-206,
§ 3(c), 77 Stat. 395. Congress later directed States to developregionally based ambient air quality standards and provided mechanisms forenforcement, Air Quality Act of 1967, Pub. L. No. 90-148, § 108(c),81 Stat. 492-494. Congress substantially revised that program through theClean Air Amendments of 1970, Pub. L. No. 91-604, 84 Stat. 1676, which providedfor national ambient air quality standards and for state implementation.See 84 Stat. 1679. Congress continued to build on that program through theClean Air Act Amendments of 1977, Pub. L. No. 95-95, 91 Stat. 685, and theClean Air Act Amendments of 1990, Pub. L. No. 101-549, 104 Stat. 2399. Seetext at pp. 21-25, infra.
3 See also, e.g., CAA § 211(k)(1), 42 U.S.C. 7545(k)(1) (requiringEPA to promulgate standards for reformulated gas to be used in nonattainmentareas, taking cost into account); CAA § 211(h)(1), 42 U.S.C. 7545(h)(1)(requiring EPA to set standards for gasoline volatility in nonattainmentareas, taking cost into account); CAA § 213(a)(3), 42 U.S.C. 7547(a)(3)(requiring EPA to determine whether emissions from nonroad engines contributesignificantly to ozone concentrations in more than one nonattainment areaand to promulgate appropriate nonroad regulations, considering costs); CAA§ 202(a), 42 U.S.C. 7521(a) (authorizing EPA to set engine standardsfor pollutants that may "reasonably be anticipated to endanger publichealth or welfare," taking the cost of compliance into account).
4 Indeed, the court of appeals considered and rejected ATA's assertion(see ATA Br. 13) that EPA should not have revised the PM standard becauseof uncertainty as to the biological mechanism by which PM may cause thehealth effects shown in more than 60 epidemiological studies. Pet. App.55a-56a. The court found that the record "amply justifie[d] establishmentof new fine particle standards." Id. at 56a. No party sought reviewof this portion of the court of appeals' decision.
5 The Administrator noted that the science underlying the 1997 decisionswas more extensive and of higher quality than that underlying the previousPM and ozone standards, which had been upheld on judicial review. 62 Fed.Reg. at 38,881 n. 53; see NRDC, 902 F.2d 962 (1987 PM NAAQS); American PetroleumInst., 665 F.2d 1176 (1979 ozone NAAQS).
6 The final chapter of the PM Criteria Document, which the Clean AirScientific Advisory Committee (CASAC) characterized as the "best everexample of a true integrative summary of the state of knowledge about thehealth effects of airborne PM" (PM App. 3150), concluded that the availableevidence "provide[s] ample reason to be concerned that there are detectablehuman health effects attributable to PM at levels below the current NAAQS."Id. at 1870 (emphasis added). See 99-1257 Pet. Br. 4 (describing CASAC'srole).
7 CASAC has typically acknowledged, as it did in those reviews, thatfinal NAAQS decisions require the Administrator to make public health policyjudgments as well as determinations of a strictly scientific nature. E.g.,PM App. 3164. Since CASAC began advising EPA in the late 1970s, it has generallystopped short of offering consensus recommendations on specific NAAQS levelsand has instead advised on the ranges of levels that the science supports.Id. at 266. Nevertheless, CASAC panel members may express individual views.For example, the level of protection afforded by the revised PM NAAQS fallstoward the mid-portion of the range of protection afforded by the PM standardsrecommended by those CASAC panel members who chose to express individualviews. See id. at 265-269.
8 The scientific community's inability to detect an effects thresholdfor a pollutant does not mean that medically significant effects are actuallyknown or thought to occur at very low levels. Indeed, there may be littleor no evidence supporting that possibility. See, e.g., 62 Fed. Reg. at 38,676;Casarett & Doull's Toxicology, supra, at 20 (it is "difficult toestablish a true 'no effects' threshold for any chemical" and "impossibleto scientifically prove the absence of a threshold, as one can never provea negative").
9 Implementation of the revised ozone standard has been delayed due touncertainty arising from the court of appeals' ruling on EPA's authorityto implement the standard, which is under review by this Court in No. 99-1257.EPA is also in the process of responding to the court of appeals' remandof the ozone standard for consideration of alleged potential "beneficial"effects associated with the presence of ground-level ozone in the ambientair. Pet. App. 44a-49a. That aspect of the remand, which EPA has not challenged,has nothing to do with the question posed by ATA's cross-petition, despiteATA's suggestions to the contrary. See ATA Br. 8-9.
10 When promulgating the first NAAQS, Administrator Ruckelshaus respondedto comments questioning their feasibility by stating that the CAA "doesnot permit any factors other than health to be taken into account in settingthe primary standards." 36 Fed. Reg. 8186 (1971). See also, e.g., 62Fed. Reg. at 38,683-38,688, 38,878-38,883 (detailed response to commentson this issue in the PM and ozone rulemakings); Hearings on Clean Air Act:Ozone and Particulate Matter Standards Before the Subcomm. on Clean Air,Wetlands, Private Property and Nuclear Safety and the Senate Comm. on Env'tand Pub. Works, 105th Cong., 1st Sess. 276, 282 (1997) (1997 Hearings) (testimonyof Administrator Browner).
11 This Court has recognized that, "[w]hen a statute limits a thingto be done in a particular mode, it includes the negative of any other mode."National R.R. Passenger Corp. v. National Ass'n of R.R. Passengers, 414U.S. 453, 458 (1974) (quoting Botany Worsted Mills v. United States, 278U.S. 282, 289 (1929)).
12 Section 110 of the 1970 Act, which was construed in Union Electric,has since been revised, but the principles discussed in that case remainfully applicable. See Virginia v. EPA, 108 F.3d 1397, 1407-1409 (D.C. Cir.1997); 42 U.S.C. 7410(k).
13 In Sections 111(a)(1), 202(a)(2) and 231(b) of the 1970 Act, for example,Congress directed that EPA consider economic and technological feasibilityin establishing, respectively, standards of performance for new stationarysources of air pollution, standards for new motor vehicles (except thosesubject to statutory standards under Section 202 (b)), and aircraft emissionstandards. See 84 Stat. 1683, 1690, 1704. In Section 202(b)(5)(A), it providedfor one-year suspensions, on feasibility grounds, of the statutory motorvehicle standards and for interim standards based on the availability andcost of control technology. See id. at 1691. Similarly, in Sections 110(e)(1),110(f), and 112(c)(1) and (2) of the 1970 Act, Congress authorized EPA togrant temporary postponements, on feasibility grounds, of NAAQS attainmentdates and applicable control requirements. See id. at 1682-1683, 1685-1686.
14 The 1967 Act's definition of air quality criteria was thus virtuallyidentical to the definition carried forward into the 1970 Act. Section 107(b)(3)of the 1967 Act provided that the criteria "shall include" thesame information that is required today under Section 108(a)(2)(A) to (C).See 42 U.S.C. 7408(a)(2)(A)-(C). See pp. 5-6, supra. The criteria were toset forth "an honest appraisal of the available knowledge relatingto the health and welfare hazards of air pollution," not influencedby economic and technical considerations:
[Air quality criteria] define the health and welfare considerations thatmust be taken into account in the development of standards and regulations.Economic and technical considerations have a place in the pattern of controlactivity but not in the development of criteria.
H.R. Rep. No. 728, 90th Cong., 1st Sess. 16 (1967) (emphasis added);accord S. Rep. No. 403, 90th Cong., 1st Sess. 26-27 (1967).
15 In hearings that preceded the 1970 Act, the HEW official responsiblefor implementation of the 1967 Act testified that the intent of the 1967Act was to achieve regional air quality standards that were sufficient toprotect health, but that the regional standards that had been adopted infact "reflect[ed] the desired socio-economic status of those particularregions." Hearings on Air Pollution Before the Subcomm. on Air andWater Pollution of the Senate Comm. on Pub. Works, 91st Cong., 2d Sess.Pt. 4, at 1488, 1489 (1970), (Air Pollution Hearings) reprinted in 2 Staffof Senate Comm. on Pub. Works, 93d Cong., 2d Sess., A Legislative Historyof the Clean Air Amendments of 1970 at 1183-1184 (Comm. Print 1974) (hereinafter1970 Leg. Hist.). He therefore advocated national standards "to besure * * * throughout the Nation, that no area can be any worse than a levelof air quality that will be protective of health." Id. at 1184. Congressadopted that approach. Senator Muskie, the primary architect of the CleanAir Amendments of 1970, explained that changes in the law were necessaryprecisely because experience under the 1967 Act had revealed that economicand technological considerations had been used "to compromise the publichealth." See 116 Cong. Rec. 32,901 (1970) (1 1970 Leg. Hist. 226-227).
16 Since 1970, industry has largely met the challenge of technologicalinnovation with the result that, historically, EPA has overestimated, atthe time of promulgation, the cost of attaining NAAQS. PM App. 3471-3473;see also E. Goodstein & H. Hodges, Polluted Data, The American Prospect,No. 35, at 64-69 (Nov.-Dec. 1997) ("In every case we have found whereresearchers have calculated actual regulatory costs and then compared themto ex ante estimates, the estimate exceeded the actual cost by at least30 percent and generally by more than 100 percent.").
17 Senator Muskie's understanding was shared by others. For example,Senator Cooper stated:
[T]he philosophy of the bill abandons the old assumption of requiringthe use of only whatever technology is already proven and at hand and ofpermitting pollution to continue when it is not economically feasible tocontrol it. The bill proceeds instead to set out what is to be achieved,and places its reliance on a great effort to develop technology, to trainand put to work the manpower to accomplish that purpose, and it assumesa readiness by industry and the people or the country to pay the costs ofpollution control.
116 Cong. Rec. at 32,919 (1 1970 Leg. Hist. 262); see also S. Rep. No.1196, supra, at 9 (1 1970 Leg. Hist. 409) (providing control techniquesinformation to the States should not "lock in existing technology").
18 Indeed, Congress had anticipated that it would conduct continuingoversight over disputes respecting economic and technological feasibility.See, e.g., Air Pollution Hearings 1491 (2 1970 Leg. Hist. 1186) (Sen. Baker);116 Cong. Rec. at 32,905 (1 1970 Leg. Hist. 236) (Sen. Muskie). Congresshas been vitally involved in both "setting up the machinery on theone hand and making it work on the other." Air Pollution Hearings 1491(2 1970 Leg. Hist. 1186) (Sen. Baker).
19 Hearings on Implementation of the Clean Air Amendments of 1970 Beforethe Subcomm. on Air and Water Pollution of the Senate Comm. on Pub. Works,92d Cong., 2d Sess., Pt. 1, at 311, 312 (1972) (memorandum from Robert L.Baum, Assistant General Counsel, to the Administrator).
20 See, e.g., Hearings on the Clean Air Amendments of 1977 Before theSubcomm. on Envtl. Pollution of the Senate Comm. on Env't and Pub. Works,95th Cong., 1st Sess., Pt. 2, at 1077, 1085 (1977) (Manufacturing ChemistsAss'n and Dow Chemical Company).
21 National Comm'n on Air Quality Report 7, 55, 70 (Mar. 1981). The NCAQreport was the subject of joint hearings in 1981 and an important sourcefor Congress's 1990 deliberations. See, e.g., Joint Hearing on Reports ofthe Nat'l Comm'n on Air Quality and the Nat'l Academy of Sciences Beforethe Senate Comm. on Env't and Pub. Works and the Subcomm. on Health andthe Env't of the House Comm. on Energy and Commerce, 97th Cong., lst Sess.2-3 (1981) (remarks of Senators Stafford and Chafee); H.R. Rep. No. 490,101st Cong., 2d Sess., Pt. 1, at 213 (1990).
22 After enactment of the 1977 Clean Air Act Amendments, various partieshad continued to urge Congress to amend Section 109 to allow considerationof compliance costs. See, e.g., Hearings on Clean Air Act Oversight Beforethe Senate Comm. on Env't and Pub. Works, 97th Cong., lst Sess., Pt. 3,at 199, 238 (1981); Hearings on Health Standards for Air Pollutants Beforethe Subcomm. on Health and the Env't of the House Comm. on Energy and Commerce,97th Cong., 1st Sess. 86-87, 214 (1981). Congress again declined to do so.
23 See also Bob Jones Univ. v. United States, 461 U.S. 574, 600-602 (1983);Lorillard v. Pons, 434 U.S. 575, 581 (1978); NLRB v. Bell Aerospace Co.,416 U.S. 267, 274 (1974) (according "great weight" to longstandinginterpretation "where Congress has re-enacted the statute without pertinentchange"); Red Lion Broad. Co. v. FCC, 395 U.S. 367, 381 (1969).
24 Even if there were any ambiguity in Congress's pronouncements, EPA'sinterpretation of the Act would be a reasonable one entitled to deference.See Chevron, 467 U.S. at 843-845.
25 ATA is wrong in contending (ATA Br. 30) that the court of appeals'decision in Lead Industries bars EPA from engaging in a "systematicweighing of pros and cons" when promulgating primary NAAQS. That decisionrecognized that EPA must weigh factors that are relevant in deciding whatlevel of protection is "requisite" to protect public health andpublic welfare. See 647 F.2d at 1146-1147.
26 NRDC, 902 F.2d 962 (1987 PM NAAQS); American Petroleum Inst., 665F.2d 1176 (1979 ozone NAAQS); Lead Indus., 647 F.2d 1130 (lead NAAQS). ATA'sassertion that a non-zero NAAQS must be arbitrary (ATA Br. 31) also misconceivesthe arbitrary or capricious standard of judicial review. Under that standard,"a reviewing court may not set aside an agency rule that is rational,based on consideration of the relevant factors, and within the scope ofthe authority delegated to the agency by the statute." Motor VehicleMfrs. Ass'n v. State Farm Mut. Auto. Ins. Co. 463 U.S. 29, 42 (1983). Whena court reviews a NAAQS, it accordingly examines whether EPA has set anair quality standard that is reasonable in light of the pertinent recordevidence. See NRDC, 902 F.2d at 972; American Petroleum Inst., 665 F.2dat 1187; see also 99-1257 Pet. Br. 26-31. The court of appeals below didnot reach the question whether EPA's revised PM and ozone rules satisfythat standard. Pet. App. 4a-5a. But as we have explained in the companioncase, EPA's revisions are plainly rational and rest on comprehensive analysesof the evidence respecting the public health and public welfare effectsof PM and ozone. See 99-1257 Pet. Br. 8-15, 31-34 (describing EPA's PM andozone rulemakings.
27 ATA's reference to the vocation of public health is pertinent in thislimited sense: Numerous public health professional associations commentedfavorably on EPA's proposed health-based PM and ozone NAAQS revisions. Forexample, the American Public Health Association (APHA), the oldest and largestsuch association, endorsed "the process by which the standards weredeveloped" as "public health practice at its best- good science,good judgment, and active public participation." Letter from M. Akhter,M.D., M.P.H.., Executive Director, APHA, to C. Browner, Administrator, EPA,Docket IV-G-1826, at 1 (June 27, 1997).
28 The word "public," in the context presented here, means"of, relating to, or affecting the people as an organized community."Webster's Third New International Dictionary 1836 (1976). Congress usedthat word to make clear that NAAQS protect the "health" of thegeneral population, or of population groups, rather than of any specificindividual. The word "health," in the context presented here,means "the state of being sound in body or mind." Id. at 1043.Congress used that term to denote the absence of medically significant adversereactions to pollution exposure, in contrast to inconsequential physiologicalresponses that would not impair the "soundness" of body or mind.Consistent with those definitions, the phrase "public health"means the "health of the community at large." Black's Law Dictionary724 (7th ed. 1999).
29 The CAA's definition of "effects on welfare" further reinforcesthat conclusion. Section 302(h) states that reference to "effects onwelfare" includes, but is not limited to, "effects on soils, water,crops, vegetation, manmade materials, animals, wildlife, weather, visibility,and climate, damage to and deterioration of property, and hazards to transportation,as well as effects on economic values and on personal comfort and well-being,whether caused by transformation, conversion, or combination with otherair pollution." 42 U.S.C. 7602(h) (emphasis added). Although that definitionincludes "effects on economic values," the context plainly showsthat the "effects" of concern are those caused by the pollutionitself. See Lead Indus., 647 F.2d at 1148 n.36 (definition of "welfare"does not include the cost of compliance with NAAQS; it "only refersto the economic costs of pollution"); see generally Babbitt v. SweetHome Chapter of Communities, 515 U.S. 687, 702 (1995) ("a word 'gathersmeaning from the words around it'"); Jarecki v. G.D. Searle & Co.,367 U.S. 303, 307 (1961) (the canon of noscitur a sociis is applied to avoidgiving "unintended breadth to the Acts of Congress").
30 ATA and Ohio emphasize the last sentence of Section 108(a)(2), whichspecifies air quality criteria shall include, "to the extent practicable,"information on (A) variable factors (such as atmospheric conditions) whichmay alter the effects of a pollutant; (B) pollutants that may interact toproduce adverse effects; and (C) any known or anticipated adverse effectson welfare. 42 U.S.C. 7408(a)(2). Those three categories of information,however, are all encompassed within, and limited by, Section 108(a)(2)'sgeneral directive that "air quality criteria" shall provide informationon the health and welfare effects posed by "the presence of such pollutantin the ambient air." 42 U.S.C. 7408(a)(2). Section 108(a)(2)'s additionaldirective to include the three specific types of information "to theextent practicable" does not expand the content of the criteria, butinstead further refines it. 42 U.S.C. 7408(a)(2). See pp. 5-6, 21-22 andnote 14, supra.
31 Congress plainly drew a distinction between effects that are relevantfor purposes of promulgating a NAAQS-viz., effects associated with "thepresence of [a] pollutant in the ambient air" (42 U.S.C. 7408(a)(2))-andeffects that are the subject of CASAC's advice-providing role under Section109(d)(2)(C)-viz., effects "which may result from various strategiesfor attainment" (42 U.S.C. 7409(d)(2)(C)(iv)). If Congress had notwished to draw that distinction, it would not have employed the distinctivelydifferent language. Indeed, the House Report that described the purposeof Section 109(d)(2)(C)(iv) suggests that CASAC's advice under that provisionplays a limited role, even in the implementation process. It states thatthe information is not "to be used as a basis for the Administratorto disapprove any [SIP]," but "may be of interest and assistanceto the States and to Congress in fashioning future legislation." H.R.Rep. No. 294, supra, at 183.
32 ATA mistakenly relies on the court of appeals' decision in Vinyl Chloride,which ruled that EPA may consider economic and technological feasibilitywhen setting emission standards for especially hazardous pollutants underthe 1970 version of Section 112. See pp. 3, 30-31, supra. The court concludedthat Section 112 permitted EPA first to determine a "safe" levelfor a hazardous air pollutant-based solely on health factors-and then toconsider cost and technological feasibility for the purpose of determiningwhether additional protection should be afforded by, for example, settinga standard at "the lowest feasible level." 824 F.2d at 1165-1166.The court expressly distinguished, however, the standard for promulgatingNAAQS under Section 109. Writing for the en banc court, Judge Bork explainedthat the language and structure of the CAA showed that "Congress simplydid not intend the economics of pollution control to be considered in [Section109's] scheme of ambient air regulations." Id. at 1159. Congress hassince amended Section 112, essentially creating a new scheme for settingemission standards for especially hazardous air pollutants. 42 U.S.C. 7412.See pp. 30-31, supra.
33 The other cases on which ATA relies (Br. 45-47) also involved provisionsof the CAA that do not specify what factors EPA is to consider and thatpresent no evidence of congressional intent to exclude costs. See GeorgeE. Warren Corp. v. EPA, 159 F.3d 616, 624 (D.C. Cir. 1998) (considerationof cost "appears to be congruent with both the congressional purposenot to disrupt the market for imported gasoline and the Supreme Court'sinstruction to avoid an interpretation that would put a law of the UnitedStates into conflict with a treaty obligation of the United States");NRDC v. EPA, 937 F.2d 641, 645-646 (D.C. Cir. 1991) (text of provisionsgoverning "prevention of significant deterioration" supports inferencethat Congress meant to "balance the values of clean air, on the onehand, and economic development and productivity, on the other.").
34 APC's argument that EPA faces a higher burden to revise a standardthan to set an initial standard is also wrong. APC mistakenly relies uponinapposite case law regarding an agency's obligation to explain a changein policy. See APC Br. 42. When EPA revises a NAAQS, it is not changingpolicy, but carrying out a specific duty imposed by the CAA to review NAAQSat least once every five years. 42 U.S.C. 7409(d)(1).
35 See, e.g., 116 Cong. Rec. at 42,522 (1 1970 Leg. Hist. 118) (remarksof Rep. Anderson) ("[a]ir pollution costs the United States over $12billion annually," through ruined crops, aging of buildings and clothing,deterioration of steel in bridges, rails and ships); 116 Cong. Rec. at 32,901(1 1970 Leg. Hist. 224) (remarks of Sen. Muskie) ("The costs of airpollution can be * * * measured in the billions of dollars of property losses.").
36 Pursuant to executive order, EPA prepared a Regulatory Impact Analysis(RIA) for the two rules at issue here, as it must for any significant regulatoryaction. 62 Fed. Reg. at 38,702. EPA explained, however, that the RIA wasfor informational and implementation planning purposes only and could notplay a part in the Administrator's decision on standard-setting. See id.at 38,703 (PM); id. at 38,887 (ozone); see also PM App. 3461-3462. An RIAis normally not a part of the record for judicial review of a NAAQS decision.Compare 42 U.S.C. 7607(d)(7)(A) with 42 U.S.C. 7607(d)(4)(B)(ii). EPA neverthelesselected to include the RIA in these rulemakings because it was potentiallyrelevant to judicial review of issues arising under the RFA, 5 U.S.C. 601et seq. See 5 U.S.C. 611 (1994 & Supp. IV 1998) (judicial review provisions).The court of appeals rejected the RFA challenges, Pet. App. 26a-31a, andthey are not before this Court.
37 ATA claims (ATA Br. 43-44), on the basis of a highly speculative reconstructionof the 1979 ozone rulemaking, that Administrator Douglas Costle "admitted"that he considered costs in reaching his 1979 decision to revise the ozoneNAAQS. See M. Landy, M. Roberts & S. Thomas, The Environmental ProtectionAgency: Asking the Wrong Questions from Nixon to Clinton 66-70 (Oxford Univ.Press 1994); see also W. Wagner, The Science Charade in Toxic Regulation,95 Colum. L. Rev. 1613, 1641-1643 (1995) (relying on Landy, et al.). Thatclaim is not accurate. Costle understood that the statute required him toreach a decision based solely on the scientific evidence regarding healtheffects, and he ultimately made his decision on that basis. See Landy, etal., supra, at 70-74; see also American Petroleum Inst., 665 F.2d at 1185(upholding 1979 ozone standard and specifically rejecting the claim thatthe Administrator should have considered the cost of implementing the standard).
38 Congress's decision reflects what economists readily acknowledge:cost-benefit analysis can frequently play an important role in environmentalregulation, but that methodology does not provide an appropriate basis formaking decisions in every regulatory context. See AEI-Brookings Inst. AmiciBr. 9-10 (noting that "[a]gencies should not be bound by a strict benefit-costtest," that "[n]ot all impacts of a decision can be quantifiedor expressed in dollar terms," and that decisionmakers must "givedue consideration to factors that defy quantification"). Congress hasmade the legislative judgment that the methodology is not the appropriateone for EPA to use in setting NAAQS. See note 42, infra.
39 See, e.g., L. Heinzerling, Regulatory Costs of Mythic Proportions,107 Yale L.J. 1981, 2044, 2065-2068 (1998); T. McGarity, A Cost-BenefitState, 50 Admin. L. Rev. 24-25 (1998); S. Shapiro & T. McGarity, NotSo Paradoxical: The Rationale for Technology-Based Regulation, 1991 DukeL.J. 729, 732; H. Latin, Good Science, Bad Regulation and Toxic Risk Assessment,5 Yale J. on Reg. 89, 92 (1988).
40 See note 16, supra; see also, e.g., W. Harrington, R. Morgenstern& P. Nelson, On the Accuracy of Regulatory Cost Estimates, Resourcesfor the Future Discussion Paper 99-18, at 10 (1999); T. McGarity, supra,50 Admin. L. Rev. at 7, 55, 76.
41 ATA argues (ATA Br. 9-11) that EPA's RIA shows that costs exceed benefits.In fact, the RIA, which did not quantify many "nonmonetizable benefitscategories" (ES-3, ES-15 to ES-16), estimated that the benefits ofthe revised PM standards would far outweigh their costs and that the costsand benefits of the revised ozone standard would be roughly commensurate.See ES-1 to ES-22; 13-2. The RIA necessarily had to rely on highly uncertaindata. See ES-3 to ES-5. The fact that the parties do not agree on the conclusionsthat can be drawn from the economic analysis in this case illustrates thedifficulties that ATA's position entails.
42 In effect, Congress has defined the CAA's goals in terms of a publichealth and welfare objective, while recognizing the validity of the viewof economists that "[e]conomic analysis can be useful in designingregulatory strategies that achieve a desired goal at the lowest possiblecost." AEI-Brookings Amici Br. 10. EPA's Administrator has made thatpoint in explaining why cost-benefit analysis is not appropriate in settingthe NAAQS: "While cost-benefit analysis is a tool that can be helpfulin developing strategies to implement our nation's air quality standards,we believe it is inappropriate for use to set the standards themselves."See 1997 Hearings 282 (prepared testimony of Administrator Browner).
43 The principle that a statute must be construed so as to avoid doubtsas to its constitutionality applies only when the statute's meaning is unclear.See, e.g., Miller v. French, 120 S. Ct. 2246, 2255 (2000). Here, Congresshas made unmistakably clear its intent that EPA should base its NAAQS decisionssolely on the health and welfare effects posed by the presence of the pollutantin the ambient air. See, e.g., CFTC v. Schor, 478 U.S. 833, 841 (1986) (thecanon of constitutional doubt "does not give a court the prerogativeto ignore the legislative will").
44 Casting the NAAQS decision in cost-benefit terms would not resolvethe underlying scientific uncertainties that EPA must face in setting NAAQS.See pp. 9, 11, supra. At the same time, it would introduce new uncertaintiesrespecting the quantification of costs and benefits that would result fromimplementing the NAAQS. See pp. 45-47, supra. Economists readily admit that,in cases where information on costs and benefits is uncertain, "benefit-costanalysis cannot be used to prove that the economic benefits of a decisionwill exceed or fall short of costs." AEI-Brookings Inst. Amici Br.9.
Section 101 of the Clean Air Act provides in relevant part:
§ 7401. Congressional findings and declaration of purpose
* * * * *
The purposes of this subchapter are-
(1) to protect and enhance the quality of the Nation's air resourcesso as to promote the public health and welfare and the productive capacityof its population.
* * * * *
42 U.S.C. 7401.
Section 108 of the Clean Air Act provides in relevant part:
§ 7408. Air quality criteria and control techniques
(a) Air pollutant list; publication and revision by Administrator; issuanceof air quality criteria for air pollutants
(1) For the purpose of establishing national primary and secondary ambientair quality standards, the Administrator shall within 30 days after December31, 1970, publish, and shall from time to time thereafter revise, a listwhich includes each air pollutant-
(A) emissions of which, in his judgment, cause or contribute to air pollutionwhich may reasonably be anticipated to endanger public health or welfare;
(B) the presence of which in the ambient air results from numerous ordiverse mobile or stationary sources; and
(C) for which air quality criteria had not been issued before December31, 1970 but for which he plans to issue air quality criteria under thissection.
(2) The Administrator shall issue air quality criteria for an air pollutantwithin 12 months after he has included such pollutant in a list under paragraph(1). Air quality criteria for an air pollutant shall accurately reflectthe latest scientific knowledge useful in indicating the kind and extentof all identifiable effects on public health or welfare which may be expectedfrom the presence of such pollutant in the ambient air, in varying quantities.The criteria for an air pollutant, to the extent practicable, shall includeinformation on-
(A) those variable factors (including atmospheric conditions) which ofthemselves or in combination with other factors may alter the effects onpublic health or welfare of such air pollutant;
(B) the types of air pollutants which, when present in the atmosphere,may interact with such pollutant to produce an adverse effect on publichealth or welfare; and
(C) any known or anticipated adverse effects on welfare.
(b) Issuance by Administrator of information on air pollution controltechniques; standing consulting committees for air pollutants; establishment;membership
(1) Simultaneously with the issuance of criteria under subsection (a)of this section, the Administrator shall, after consultation with appropriateadvisory committees and Federal departments and agencies, issue to the Statesand appropriate air pollution control agencies information on air pollutioncontrol techniques, which information shall include data relating to thecost of installation and operation, energy requirements, emission reductionbenefits, and environmental impact of the emission control technology. Suchinformation shall include such data as are available on available technologyand alternative methods of prevention and control of air pollution. Suchinformation shall also include data on alternative fuels, processes, andoperating methods which will result in elimination or significant reductionof emissions.
(2) In order to assist in the development of information on pollutioncontrol techniques, the Administrator may establish a standing consultingcommittee for each air pollutant included in a list published pursuant tosubsection (a)(1) of this section, which shall be comprised of technicallyqualified individuals representative of State and local governments, industry,and the academic community. Each such committee shall submit, as appropriate,to the Administrator information related to that required by paragraph (1).
(c) Review, modification, and reissuance of criteria or information
The Administrator shall from time to time review, and, as appropriate,modify, and reissue any criteria or information on control techniques issuedpursuant to this section. * * *
(d) Publication in Federal Register; availability of copies for generalpublic
The issuance of air quality criteria and information on air pollutioncontrol techniques shall be announced in the Federal Register and copiesshall be made available to the general public.
* * * * *
42 U.S.C. 7408.
Section 109 of the Clean Air Act provides in relevant part:
§ 7409. National primary and secondary ambient air quality standards
(1) The Administrator-
(A) * * * shall publish proposed regulations prescribing a national primaryambient air quality standard and a national secondary ambient air qualitystandard for each air pollutant for which air quality criteria have beenissued prior to such date; and
(B) after a reasonable time for interested persons to submit writtencomments thereon (but no later than 90 days after the initial publicationof such proposed standards) shall by regulation promulgate such proposednational primary and secondary ambient air quality standards with such modificationsas he deems appropriate.
* * * * *
(b) Protection of public health and welfare
(1) National primary ambient air quality standards, prescribed undersubsection (a) of this section shall be ambient air quality standards theattainment and maintenance of which in the judgment of the Administrator,based on such criteria and allowing an adequate margin of safety, are requisiteto protect the public health. Such primary standards may be revised in thesame manner as promulgated.
(2) Any national secondary ambient air quality standard prescribed undersubsection (a) of this section shall specify a level of air quality theattainment and maintenance of which in the judgment of the Administrator,based on such criteria, is requisite to protect the public welfare fromany known or anticipated adverse effects associated with the presence ofsuch air pollutant in the ambient air. Such secondary standards may be revisedin the same manner as promulgated.
* * * * *
(d) Review and revision of criteria and standards; independent scientificreview committee; appointment; advisory functions
(1) Not later than December 31, 1980, and at five-year intervals thereafter,the Administrator shall complete a thorough review of the criteria publishedunder section 7408 of this title and the national ambient air quality standardspromulgated under this section and shall make such revisions in such criteriaand standards and promulgate such new standards as may be appropriate inaccordance with section 7408 of this title and subsection (b) of this section.The Administrator may review and revise criteria or promulgate new standardsearlier or more frequently than required under this paragraph.
(2)(A) The Administrator shall appoint an independent scientific reviewcommittee composed of seven members including at least one member of theNational Academy of Sciences, one physician, and one person representingState air pollution control agencies.
(B) Not later than January 1, 1980, and at five-year intervals thereafter,the committee referred to in subparagraph (A) shall complete a review ofthe criteria published under section 7408 of this title and the nationalprimary and secondary ambient air quality standards promulgated under thissection and shall recommend to the Administrator any new national ambientair quality standards and revisions of existing criteria and standards asmay be appropriate under section 7408 of this title and subsection (b) ofthis section.
(C) Such committee shall also * * * (iv) advise the Administrator ofany adverse public health, welfare, social, economic, or energy effectswhich may result from various strategies for attainment and maintenanceof such national ambient air quality standards.
42 U.S.C. 7409.
Section 110 of the Clean Air Act provides in relevant part:
§ 7410 State implementation plans for national primary and secondaryambient air quality standards
(a) Adoption of plan by State; submission to Administrator; content ofplan; revision; new sources; indirect source review program; supplementalor intermittent control systems
(1) Each State shall, after reasonable notice and public hearings, adoptand submit to the Administrator, within 3 years (or such shorter periodas the Administrator may prescribe) after the promulgation of a nationalprimary ambient air quality standard (or any revision thereof) under section7409 of this title for any air pollutant, a plan which provides for implementation,maintenance, and enforcement of such primary standard in each air qualitycontrol region (or portion thereof) within such State. * * *
(2) Each implementation plan * * * shall-
* * * * *
(D) contain adequate provisions-
(i) prohibiting, consistent with the provisions of this subchapter, anysource or other type of emissions activity within the State from emittingany air pollutant in amounts which will-
(I) contribute significantly to nonattainment in, or interfere with maintenanceby, any other State with
respect to any such national primary or secondary ambient air qualitystandard * * *.
* * * * *
42 U.S.C. 7410.