Entergy Corp. v. Riverkeeper, Inc. , 129 S. Ct. 1498 ( 2009 )


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  • (Slip Opinion)              OCTOBER TERM, 2008                                       1
    Syllabus
    NOTE: Where it is feasible, a syllabus (headnote) will be released, as is
    being done in connection with this case, at the time the opinion is issued.
    The syllabus constitutes no part of the opinion of the Court but has been
    prepared by the Reporter of Decisions for the convenience of the reader.
    See United States v. Detroit Timber & Lumber Co., 
    200 U. S. 321
    , 337.
    SUPREME COURT OF THE UNITED STATES
    Syllabus
    ENTERGY CORP. v. RIVERKEEPER, INC., ET AL.
    CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR
    THE SECOND CIRCUIT
    No. 07–588.      Argued December 2, 2008—Decided April 1, 2009*
    Petitioners’ powerplants have “cooling water intake structures” that
    threaten the environment by squashing against intake screens (“im
    pingement”) or suctioning into the cooling system (“entrainment”)
    aquatic organisms from the water sources tapped to cool the plants.
    Thus, the facilities are subject to regulation under the Clean Water
    Act, which mandates that “[a]ny standard established pursuant to
    section 1311 . . . or section 1316 . . . and applicable to a point source
    shall require that the location, design, construction, and capacity of
    cooling water intake structures reflect the best technology available
    for minimizing adverse environmental impact.” 
    33 U. S. C. §1326
    (b).
    Sections 1311 and 1316, in turn, employ a variety of “best technology”
    standards to regulate effluent discharge into the Nation’s waters.
    The Environmental Protection Agency (EPA) promulgated the
    §1326(b) regulations at issue after nearly three decades of making
    the “best technology available” determination on a case-by-case basis.
    Its “Phase I” regulations govern new cooling water intake structures,
    while the “Phase II” rules at issue apply to certain large existing fa
    cilities. In the latter rules, the EPA set “national performance stan
    dards,” requiring most Phase II facilities to reduce “impingement
    mortality for [aquatic organisms] by 80 to 95 percent from the calcu
    lation baseline,” and requiring a subset of facilities to reduce en
    trainment of such organisms by “60 to 90 percent from [that] base
    line.” 
    40 CFR §125.94
    (b)(1), (2). However, the EPA expressly
    declined to mandate closed-cycle cooling systems, or equivalent re
    ——————
    * Together with No. 07–589, PSEG Fossil LLC et al. v. Riverkeeper,
    Inc., et al., and No. 07–597, Utility Water Act Group v. Riverkeeper, Inc.,
    et al., also on certiorari to the same court.
    2               ENTERGY CORP. v. RIVERKEEPER, INC.
    Syllabus
    ductions in impingement and entrainment, as it had done in its
    Phase I rules, in part because the cost of rendering existing facilities
    closed-cycle compliant would be nine times the estimated cost of
    compliance with the Phase II performance standards, and because
    other technologies could approach the performance of closed-cycle op
    eration. The Phase II rules also permit site-specific variances from
    the national performance standards, provided that the permit-issuing
    authority imposes remedial measures that yield results “as close as
    practicable     to     the   applicable    performance     standards.”
    §125.94(a)(5)(i), (ii). Respondents—environmental groups and vari
    ous States—challenged the Phase II regulations. Concluding that
    cost-benefit analysis is impermissible under 
    33 U. S. C. §1326
    (b), the
    Second Circuit found the site-specific cost-benefit variance provision
    unlawful and remanded the regulations to the EPA for it to clarify
    whether it had relied on cost-benefit analysis in setting the national
    performance standards.
    Held: The EPA permissibly relied on cost-benefit analysis in setting the
    national performance standards and in providing for cost-benefit
    variances from those standards as part of the Phase II regulations.
    Pp. 7–16.
    (a) The EPA’s view that §1326(b)’s “best technology available for
    minimizing adverse environmental impact” standard permits consid
    eration of the technology’s costs and of the relationship between those
    costs and the environmental benefits produced governs if it is a rea
    sonable interpretation of the statute—not necessarily the only possi
    ble interpretation, nor even the interpretation deemed most reason
    able by the courts. Chevron U. S. A. Inc. v. Natural Resources
    Defense Council, Inc., 
    467 U. S. 837
    , 843–844. The Second Circuit
    took “best technology” to mean the technology that achieves the
    greatest reduction in adverse environmental impacts at a reasonable
    cost to the industry, but it may also describe the technology that most
    efficiently produces a good, even if it produces a lesser quantity of
    that good than other available technologies. This reading is not pre
    cluded by the phrase “for minimizing adverse environmental impact.”
    Minimizing admits of degree and is not necessarily used to refer ex
    clusively to the “greatest possible reduction.” Other Clean Water Act
    provisions show that when Congress wished to mandate the greatest
    feasible reduction in water pollution, it used plain language, e.g.,
    “elimination of discharges of all pollutants,” §1311(b)(2)(A). Thus,
    §1326(b)’s use of the less ambitious goal of “minimizing adverse envi
    ronmental impact” suggests that the EPA has some discretion to de
    termine the extent of reduction warranted under the circumstances,
    plausibly involving a consideration of the benefits derived from re
    ductions and the costs of achieving them. Pp. 7–9.
    Cite as: 556 U. S. ____ (2009)                   3
    Syllabus
    (b) Considering §1326(b)’s text, and comparing it with the text and
    statutory factors applicable to parallel Clean Water Act provisions,
    prompts the conclusion that it was well within the bounds of reason
    able interpretation for the EPA to conclude that cost-benefit analysis
    is not categorically forbidden. In the Phase II rules the EPA sought
    only to avoid extreme disparities between costs and benefits, limiting
    variances from Phase II’s “national performance standards” to cir
    cumstances where the costs are “significantly greater than the bene
    fits” of compliance. 
    40 CFR §125.94
    (a)(5)(ii). In defining “national
    performance standards” the EPA assumed the application of tech
    nologies whose benefits approach those estimated for closed-cycle
    cooling systems at a fraction of the cost. That the EPA has for over
    thirty years interpreted §1326(b) to permit a comparison of costs and
    benefits, while not conclusive, also tends to show that its interpreta
    tion is reasonable and hence a legitimate exercise of its discretion.
    Even respondents and the Second Circuit ultimately recognize that
    some comparison of costs and benefits is permitted. The Second Cir
    cuit held that §1326(b) mandates only those technologies whose costs
    can be reasonably borne by the industry. But whether it is reason
    able to bear a particular cost can very well depend on the resulting
    benefits. Likewise, respondents concede that the EPA need not re
    quire that industry spend billions to save one more fish. This con
    cedes the principle, and there is no statutory basis for limiting the
    comparison of costs and benefits to situations where the benefits are
    de minimis rather than significantly disproportionate. Pp. 9–16.
    
    475 F. 3d 83
    , reversed and remanded.
    SCALIA, J., delivered the opinion of the Court, in which ROBERTS,
    C. J., and KENNEDY, THOMAS, and ALITO, JJ., joined. BREYER, J., filed
    an opinion concurring in part and dissenting in part. STEVENS, J., filed
    a dissenting opinion, in which SOUTER and GINSBURG, JJ., joined.
    Cite as: 556 U. S. ____ (2009)                              1
    Opinion of the Court
    NOTICE: This opinion is subject to formal revision before publication in the
    preliminary print of the United States Reports. Readers are requested to
    notify the Reporter of Decisions, Supreme Court of the United States, Wash
    ington, D. C. 20543, of any typographical or other formal errors, in order
    that corrections may be made before the preliminary print goes to press.
    SUPREME COURT OF THE UNITED STATES
    _________________
    Nos. 07–588, 07–589 and 07–597
    _________________
    ENTERGY CORPORATION, PETITIONER
    07–588                  v.
    RIVERKEEPER, INC., ET AL.
    PSEG FOSSIL LLC, ET AL., PETITIONERS
    07–589                     v.
    RIVERKEEPER, INC., ET AL.
    UTILITY WATER ACT GROUP, PETITIONER
    07–597                v.
    RIVERKEEPER, INC., ET AL.
    ON WRITS OF CERTIORARI TO THE UNITED STATES COURT OF
    APPEALS FOR THE SECOND CIRCUIT
    [April 1, 2009]
    JUSTICE SCALIA delivered the opinion of the Court.
    These cases concern a set of regulations adopted by the
    Environmental Protection Agency (EPA or agency) under
    §316(b) of the Clean Water Act, 
    33 U. S. C. §1326
    (b). 
    69 Fed. Reg. 41576
     (2004). Respondents—environmental
    groups and various States1—challenged those regulations,
    and the Second Circuit set them aside. Riverkeeper, Inc. v.
    ——————
    1 The  EPA and its Administrator appeared as respondents in support
    of petitioners. See Brief for Federal Parties as Respondents Supporting
    Petitioners. References to “respondents” throughout the opinion refer
    only to those parties challenging the EPA rules at issue in these cases.
    2          ENTERGY CORP. v. RIVERKEEPER, INC.
    Opinion of the Court
    EPA, 
    475 F. 3d 83
    , 99–100 (2007). The issue for our deci
    sion is whether, as the Second Circuit held, the EPA is not
    permitted to use cost-benefit analysis in determining the
    content of regulations promulgated under §1326(b).
    I
    Petitioners operate—or represent those who operate—
    large powerplants. In the course of generating power,
    those plants also generate large amounts of heat. To cool
    their facilities, petitioners employ “cooling water intake
    structures” that extract water from nearby water sources.
    These structures pose various threats to the environment,
    chief among them the squashing against intake screens
    (elegantly called “impingement”) or suction into the cool
    ing system (“entrainment”) of aquatic organisms that live
    in the affected water sources. See 
    69 Fed. Reg. 41586
    .
    Accordingly, the facilities are subject to regulation under
    the Clean Water Act, 
    33 U. S. C. §1251
     et seq., which
    mandates:
    “Any standard established pursuant to section 1311
    of this title or section 1316 of this title and applicable
    to a point source shall require that the location, de
    sign, construction, and capacity of cooling water in
    take structures reflect the best technology available
    for minimizing adverse environmental impact.”
    §1326(b).
    Sections 1311 and 1316, in turn, employ a variety of “best
    technology” standards to regulate the discharge of efflu
    ents into the Nation’s waters.
    The §1326(b) regulations at issue here were promul
    gated by the EPA after nearly three decades in which the
    determination of the “best technology available for mini
    mizing [cooling water intake structures’] adverse envi
    ronmental impact” was made by permit-issuing authori
    ties on a case-by-case basis, without benefit of a governing
    Cite as: 556 U. S. ____ (2009)                   3
    Opinion of the Court
    regulation. The EPA’s initial attempt at such a regulation
    came to nought when the Fourth Circuit determined that
    the agency had failed to adhere to the procedural require
    ments of the Administrative Procedure Act. Appalachian
    Power Co. v. Train, 
    566 F. 2d 451
    , 457 (1977). The EPA
    withdrew the regulation, 
    44 Fed. Reg. 32956
     (1979), and
    instead published “draft guidance” for use in implement
    ing §1326(b)’s requirements via site-specific permit deci
    sions under §1342. See EPA, Office of Water Enforcement
    Permits Div., {Draft} Guidance for Evaluating the Adverse
    Impact of Cooling Water Intake Structures on the Aquatic
    Environment: Section 316(b) P. L. 92–500, (May 1, 1977), at
    http://www.epa.gov/waterscience/316b/files/1977AEIguid.pdf,
    (all Internet materials as visited Mar. 30, 2009, and avail
    able in Clerk of Court’s case file); 
    69 Fed. Reg. 41584
    (describing system of case-by-case permits under the draft
    guidance).
    In 1995, the EPA entered into a consent decree which,
    as subsequently amended, set a multiphase timetable for
    the EPA to promulgate regulations under §1326(b). See
    Riverkeeper, Inc. v. Whitman, No. 93 Civ. 0314 (AGS),
    
    2001 WL 1505497
    , *1 (SDNY, Nov. 27, 2001). In the first
    phase the EPA adopted regulations governing certain new,
    large cooling water intake structures. 
    66 Fed. Reg. 65256
    (2001) (Phase I rules); see 
    40 CFR §§125.80
    (a), 125.81(a)
    (2008). Those rules require new facilities with water
    intake flow greater than 10 million gallons per day to,
    among other things, restrict their inflow “to a level com
    mensurate with that which can be attained by a closed
    cycle recirculating cooling water system.”2 §125.84(b)(1).
    New facilities with water-intake flow between 2 million
    ——————
    2 Closed-cycle cooling systems recirculate the water used to cool the
    facility, and consequently extract less water from the adjacent water
    way, proportionately reducing impingement and entrainment.
    Riverkeeper, Inc. v. EPA, 
    358 F. 3d 174
    , 182, n. 5 (CA2 2004); 
    69 Fed. Reg. 41601
    , and n. 44 (2004).
    4             ENTERGY CORP. v. RIVERKEEPER, INC.
    Opinion of the Court
    and 10 million gallons per day may alternatively comply
    by, among other things, reducing the volume and velocity
    of water removal to certain levels. §125.84(c). And all
    facilities may alternatively comply by demonstrating,
    among other things, “that the technologies employed will
    reduce the level of adverse environmental impact . . . to a
    comparable level” to what would be achieved by using a
    closed-cycle cooling system. §125.84(d). These regulations
    were upheld in large part by the Second Circuit in
    Riverkeeper, Inc. v. EPA, 
    358 F. 3d 174
     (2004).
    The EPA then adopted the so-called “Phase II” rules at
    issue here.3 
    69 Fed. Reg. 41576
    . They apply to existing
    facilities that are point sources, whose primary activity is
    the generation and transmission (or sale for transmission)
    of electricity, and whose water-intake flow is more than 50
    million gallons of water per day, at least 25 percent of
    which is used for cooling purposes. 
    Ibid.
     Over 500 facili
    ties, accounting for approximately 53 percent of the Na
    tion’s electric-power generating capacity, fall within Phase
    II’s ambit. See EPA, Economic and Benefits Analysis for
    the Final Section 316(b) Phase II Existing Facilities Rule,
    A3–13, Table A3–4 (Feb. 2004), online at http://www.
    epa.gov/waterscience/316b/phase2/econbenefits/final/a3.pdf.
    Those facilities remove on average more than 214 billion
    gallons of water per day, causing impingement and en
    trainment of over 3.4 billion aquatic organisms per year.
    
    69 Fed. Reg. 41586
    .
    To address those environmental impacts, the EPA set
    “national performance standards,” requiring Phase II
    facilities (with some exceptions) to reduce “impingement
    mortality for all life stages of fish and shellfish by 80 to 95
    ——————
    3 The EPA has also adopted Phase III rules for facilities not subject to
    the Phase I and Phase II regulations. 
    71 Fed. Reg. 35006
     (2006). A
    challenge to those regulations is currently before the Fifth Circuit,
    where proceedings have been stayed pending disposition of these cases.
    See ConocoPhillips Co. v. EPA, No. 06–60662.
    Cite as: 556 U. S. ____ (2009)            5
    Opinion of the Court
    percent from the calculation baseline”; a subset of facilities
    must also reduce entrainment of such aquatic organisms
    by “60 to 90 percent from the calculation baseline.” 
    40 CFR §125.94
    (b)(1), (2); see §125.93 (defining “calculation
    baseline”). Those targets are based on the environmental
    improvements achievable through deployment of a mix of
    remedial technologies, 
    69 Fed. Reg. 41599
    , which the EPA
    determined were “commercially available and economi
    cally practicable,” 
    id., at 41602
    .
    In its Phase II rules, however, the EPA expressly de
    clined to mandate adoption of closed-cycle cooling systems
    or equivalent reductions in impingement and entrain
    ment, as it had done for new facilities subject to the Phase
    I rules. 
    Id., at 41601
    . It refused to take that step in part
    because of the “generally high costs” of converting existing
    facilities to closed-cycle operation, and because “other
    technologies approach the performance of this option.” 
    Id., at 41605
    . Thus, while closed-cycle cooling systems could
    reduce impingement and entrainment mortality by up to
    98 percent, 
    id., at 41601
    , (compared to the Phase II targets
    of 80 to 95 percent impingement reduction), the cost of
    rendering all Phase II facilities closed-cycle-compliant
    would be approximately $3.5 billion per year, 
    id., at 41605
    , nine times the estimated cost of compliance with
    the Phase II performance standards, 
    id., at 41666
    . More
    over, Phase II facilities compelled to convert to closed-cycle
    cooling systems “would produce 2.4 percent to 4.0 percent
    less electricity even while burning the same amount of
    coal,” possibly requiring the construction of “20 additional
    400–MW plants . . . to replace the generating capacity
    lost.” 
    Id., at 41605
    . The EPA thus concluded that “[a]l
    though not identical, the ranges of impingement and
    entrainment reduction are similar under both options. . . .
    [Benefits of compliance with the Phase II rules] can ap
    proach those of closed-cycle recirculating at less cost with
    fewer implementation problems.” 
    Id., at 41606
    .
    6          ENTERGY CORP. v. RIVERKEEPER, INC.
    Opinion of the Court
    The regulations permit the issuance of site-specific
    variances from the national performance standards if a
    facility can demonstrate either that the costs of compli
    ance are “significantly greater than” the costs considered
    by the agency in setting the standards, 
    40 CFR §125.94
    (a)(5)(i), or that the costs of compliance “would be
    significantly greater than the benefits of complying with
    the applicable performance standards,” §125.94(a)(5)(ii).
    Where a variance is warranted, the permit-issuing author
    ity must impose remedial measures that yield results “as
    close as practicable to the applicable performance stan
    dards.” §125.94(a)(5)(i), (ii).
    Respondents challenged the EPA’s Phase II regulations,
    and the Second Circuit granted their petition for review
    and remanded the regulations to the EPA. The Second
    Circuit identified two ways in which the EPA could per
    missibly consider costs under 
    33 U. S. C. §1326
    (b): (1) in
    determining whether the costs of remediation “can be
    ‘reasonably borne’ by the industry,” and (2) in determining
    which remedial technologies are the most cost-effective,
    that is, the technologies that reach a specified level of
    benefit at the lowest cost. 
    475 F. 3d, at
    99–100. See also
    
    id., at 98
    , and n. 10. It concluded, however, that cost
    benefit analysis, which “compares the costs and benefits of
    various ends, and chooses the end with the best net bene
    fits,” 
    id., at 98
    , is impermissible under §1326(b), id., at
    100.
    The Court of Appeals held the site-specific cost-benefit
    variance provision to be unlawful. Id., at 114. Finding it
    unclear whether the EPA had relied on cost-benefit analy
    sis in setting the national performance standards, or had
    only used cost-effectiveness analysis, it remanded to the
    agency for clarification of that point. Id., at 104–105.
    (The remand was also based on other grounds which are
    not at issue here.) The EPA suspended operation of the
    Phase II rules pending further rulemaking. 72 Fed. Reg.
    Cite as: 556 U. S. ____ (2009)                     7
    Opinion of the Court
    37107 (2007). We then granted certiorari limited to the
    following question: “Whether [§1326(b)] . . . authorizes the
    [EPA] to compare costs with benefits in determining ‘the
    best technology available for minimizing adverse envi
    ronmental impact’ at cooling water intake structures.”
    552 U. S. ___ (2008).
    II
    In setting the Phase II national performance standards
    and providing for site-specific cost-benefit variances, the
    EPA relied on its view that §1326(b)’s “best technology
    available” standard permits consideration of the technol
    ogy’s costs, 
    69 Fed. Reg. 41626
    , and of the relationship
    between those costs and the environmental benefits pro
    duced, 
    id., at 41603
    . That view governs if it is a reason
    able interpretation of the statute—not necessarily the only
    possible interpretation, nor even the interpretation
    deemed most reasonable by the courts. Chevron U. S. A.
    Inc. v. Natural Resources Defense Council, Inc., 
    467 U. S. 837
    , 843–844 (1984).4
    As we have described, §1326(b) instructs the EPA to set
    standards for cooling water intake structures that reflect
    “the best technology available for minimizing adverse
    environmental impact.” The Second Circuit took that
    ——————
    4 The dissent finds it “puzzling” that we invoke this proposition (that
    a reasonable agency interpretation prevails) at the “outset,” omitting
    the supposedly prior inquiry of “ ‘whether Congress has directly spoken
    to the precise question at issue.’ ” Post, at 6, n. 5 (opinion of STEVENS,
    J.) (quoting Chevron, 
    467 U. S., at 842
    ). But surely if Congress has
    directly spoken to an issue then any agency interpretation contradict
    ing what Congress has said would be unreasonable.
    What is truly “puzzling” is the dissent’s accompanying charge that
    the Court’s failure to conduct the Chevron step-one inquiry at the
    outset “reflects [its] reluctance to consider the possibility . . . that
    Congress’ silence may have meant to foreclose cost-benefit analysis.”
    Post, at 6, n. 5. Our discussion of that issue, infra, at 11, speaks for
    itself.
    8          ENTERGY CORP. v. RIVERKEEPER, INC.
    Opinion of the Court
    language to mean the technology that achieves the great
    est reduction in adverse environmental impacts at a cost
    that can reasonably be borne by the industry. 
    475 F. 3d, at
    99–100. That is certainly a plausible interpretation of
    the statute. The “best” technology—that which is “most
    advantageous,” Webster’s New International Dictionary
    258 (2d ed. 1953)—may well be the one that produces the
    most of some good, here a reduction in adverse environ
    mental impact. But “best technology” may also describe
    the technology that most efficiently produces some good.
    In common parlance one could certainly use the phrase
    “best technology” to refer to that which produces a good at
    the lowest per-unit cost, even if it produces a lesser quan
    tity of that good than other available technologies.
    Respondents contend that this latter reading is pre
    cluded by the statute’s use of the phrase “for minimizing
    adverse environmental impact.” Minimizing, they argue,
    means reducing to the smallest amount possible, and the
    “best technology available for minimizing adverse envi
    ronmental impacts,” must be the economically feasible
    technology that achieves the greatest possible reduction in
    environmental harm. Brief for Respondents Riverkeeper,
    Inc. et al. 25–26. But “minimize” is a term that admits of
    degree and is not necessarily used to refer exclusively to
    the “greatest possible reduction.” For example, elsewhere
    in the Clean Water Act, Congress declared that the proce
    dures implementing the Act “shall encourage the drastic
    minimization of paperwork and interagency decision
    procedures.” 
    33 U. S. C. §1251
    (f). If respondents’ defini
    tion of the term “minimize” is correct, the statute’s use of
    the modifier “drastic” is superfluous.
    Other provisions in the Clean Water Act also suggest
    the agency’s interpretation. When Congress wished to
    mandate the greatest feasible reduction in water pollution,
    it did so in plain language: The provision governing the
    discharge of toxic pollutants into the Nation’s waters
    Cite as: 556 U. S. ____ (2009)                    9
    Opinion of the Court
    requires the EPA to set “effluent limitations [which] shall
    require the elimination of discharges of all pollutants if
    the Administrator finds . . . that such elimination is tech
    nologically and economically achievable,” §1311(b)(2)(A)
    (emphasis added).       See also §1316(a)(1) (mandating
    “where practicable, a standard [for new point sources]
    permitting no discharge of pollutants” (emphasis added)).
    Section 1326(b)’s use of the less ambitious goal of “mini
    mizing adverse environmental impact” suggests, we think,
    that the agency retains some discretion to determine the
    extent of reduction that is warranted under the circum
    stances. That determination could plausibly involve a
    consideration of the benefits derived from reductions and
    the costs of achieving them. Cf. 
    40 CFR §125.83
     (defining
    “minimize” for purposes of the Phase I regulations as
    “reduc[ing] to the smallest amount, extent, or degree
    reasonably possible”). It seems to us, therefore, that the
    phrase “best technology available,” even with the added
    specification “for minimizing adverse environmental im
    pact,” does not unambiguously preclude cost-benefit
    analysis.5
    Respondents’ alternative (and, alas, also more complex)
    argument rests upon the structure of the Clean Water Act.
    The Act provided that during its initial implementation
    period existing “point sources”—discrete conveyances from
    which pollutants are or may be discharged, 
    33 U. S. C. §1362
    (14)—were subject to “effluent limitations . . . which
    shall require the application of the best practicable control
    technology currently available.” §1311(b)(1)(A) (emphasis
    ——————
    5 Respondents concede that the term “available” is ambiguous, as it
    could mean either technologically feasible or economically feasible. But
    any ambiguity in the term “available” is largely irrelevant. Regardless
    of the criteria that render a technology “available,” the EPA would still
    have to determine which available technology is the “best” one. And as
    discussed above, that determination may well involve consideration of
    the technology’s relative costs and benefits.
    10           ENTERGY CORP. v. RIVERKEEPER, INC.
    Opinion of the Court
    added). (We shall call this the “BPT” test.) Following that
    transition period, the Act initially mandated adoption, by
    July 1, 1983 (later extended to March 31, 1989), of stricter
    effluent limitations requiring “application of the best
    available technology economically achievable for such
    category or class, which will result in reasonable further
    progress toward the national goal of eliminating the dis
    charge of all pollutants.” §1311(b)(2)(A) (emphasis added);
    see EPA v. National Crushed Stone Assn., 
    449 U. S. 64
    ,
    69–70 (1980). (We shall call this the “BATEA” test.) Sub
    sequent amendment limited application of this standard to
    toxic and nonconventional pollutants, and for the remain
    der established a (presumably laxer) test of “best conven
    tional-pollutant control technology.” §1311(b)(2)(E).6 (We
    shall call this “BCT.”) Finally, §1316 subjected certain
    categories of new point sources to “the greatest degree of
    effluent reduction which the Administrator determines to
    be achievable through application of the best available
    demonstrated control technology.” §1316(a)(1) (emphasis
    added); §1316(b)(1)(B). (We shall call this the “BADT”
    test.) The provision at issue here, applicable not to efflu
    ents but to cooling water intake structures, requires, as we
    have described, “the best technology available for minimiz
    ing adverse environmental impact,” §1326(b) (emphasis
    added). (We shall call this the “BTA” test.)
    The first four of these tests are elucidated by statutory
    factor lists that guide their implementation. To take the
    standards in (presumed) order of increasing stringency,
    see Crushed Stone, 
    supra,
     at 69–70: In applying the BPT
    test the EPA is instructed to consider, among other fac
    tors, “the total cost of application of technology in relation
    ——————
    6 The statute does not contain a hyphen between the words “conven
    tional” and “pollutant.” “Conventional pollutant” is a statutory term,
    however, see 
    33 U. S. C. §1314
    (a)(4), and it is clear that in
    §1311(b)(2)(E) the adjective modifies “pollutant” rather than “control
    technology.” The hyphen makes that clear.
    Cite as: 556 U. S. ____ (2009)           11
    Opinion of the Court
    to the effluent reduction benefits to be achieved.”
    §1314(b)(1)(B). In applying the BCT test it is instructed to
    consider “the reasonableness of the relationship between the
    costs of attaining a reduction in effluents and the effluent
    reduction benefits derived.”        §1314(b)(4)(B) (emphasis
    added). And in applying the BATEA and BADT tests the
    EPA is instructed to consider the “cost of achieving such
    effluent reduction.” §§1314(b)(2)(B), 1316(b)(1)(B). There
    is no such elucidating language applicable to the BTA test
    at issue here. To facilitate comparison, the texts of these
    five tests, the clarifying factors applicable to them, and the
    entities to which they apply are set forth in the Appendix,
    infra.
    The Second Circuit, in rejecting the EPA’s use of cost
    benefit analysis, relied in part on the propositions that (1)
    cost-benefit analysis is precluded under the BATEA and
    BADT tests; and (2) that, insofar as the permissibility of
    cost-benefit analysis is concerned, the BTA test (the one at
    issue here) is to be treated the same as those two. See 
    475 F. 3d, at 98
    . It is not obvious to us that the first of these
    propositions is correct, but we need not pursue that point,
    since we assuredly do not agree with the second. It is
    certainly reasonable for the agency to conclude that the
    BTA test need not be interpreted to permit only what
    those other two tests permit. Its text is not identical to
    theirs. It has the relatively modest goal of “minimizing
    adverse environmental impact” as compared with the
    BATEA’s goal of “eliminating the discharge of all pollut
    ants.” And it is unencumbered by specified statutory
    factors of the sort provided for those other two tests, which
    omission can reasonably be interpreted to suggest that the
    EPA is accorded greater discretion in determining its
    precise content.
    Respondents and the dissent argue that the mere fact
    that §1326(b) does not expressly authorize cost-benefit
    analysis for the BTA test, though it does so for two of the
    12          ENTERGY CORP. v. RIVERKEEPER, INC.
    Opinion of the Court
    other tests, displays an intent to forbid its use. This
    surely proves too much. For while it is true that two of the
    other tests authorize cost-benefit analysis, it is also true
    that all four of the other tests expressly authorize some
    consideration of costs. Thus, if respondents’ and the dis
    sent’s conclusion regarding the import of §1326(b)’s silence
    is correct, it is a fortiori true that the BTA test permits no
    consideration of cost whatsoever, not even the “cost
    effectiveness” and “feasibility” analysis that the Second
    Circuit approved, see supra, at 6, that the dissent would
    approve, post, at 1–2, and that respondents acknowledge.
    The inference that respondents and the dissent would
    draw from the silence is, in any event, implausible, as
    §1326(b) is silent not only with respect to cost-benefit
    analysis but with respect to all potentially relevant fac
    tors. If silence here implies prohibition, then the EPA
    could not consider any factors in implementing §1326(b)—
    an obvious logical impossibility. It is eminently reason
    able to conclude that §1326(b)’s silence is meant to convey
    nothing more than a refusal to tie the agency’s hands as to
    whether cost-benefit analysis should be used, and if so to
    what degree.
    Contrary to the dissent’s suggestion, see post, at 3–4,
    our decisions in Whitman v. American Trucking Assns.,
    Inc., 
    531 U. S. 457
     (2001), and American Textile Mfrs.
    Institute, Inc. v. Donovan, 
    452 U. S. 490
     (1981), do not
    undermine this conclusion. In American Trucking, we
    held that the text of §109 of the Clean Air Act, “inter
    preted in its statutory and historical context . . . unambi
    guously bars cost considerations” in setting air quality
    standards under that provision. 
    531 U. S., at 471
    . The
    relevant “statutory context” included other provisions in
    the Clean Air Act that expressly authorized consideration
    of costs, whereas §109 did not. Id., at 467–468. American
    Trucking thus stands for the rather unremarkable propo
    sition that sometimes statutory silence, when viewed in
    Cite as: 556 U. S. ____ (2009)           13
    Opinion of the Court
    context, is best interpreted as limiting agency discretion.
    For the reasons discussed earlier, §1326(b)’s silence cannot
    bear that interpretation.
    In American Textile, the Court relied in part on a stat
    ute’s failure to mention cost-benefit analysis in holding
    that the relevant agency was not required to engage in
    cost-benefit analysis in setting certain health and safety
    standards. 
    452 U. S., at
    510–512. But under Chevron,
    that an agency is not required to do so does not mean that
    an agency is not permitted to do so.
    This extended consideration of the text of §1326(b), and
    comparison of that with the text and statutory factors
    applicable to four parallel provisions of the Clean Water
    Act, lead us to the conclusion that it was well within the
    bounds of reasonable interpretation for the EPA to con
    clude that cost-benefit analysis is not categorically forbid
    den. Other arguments may be available to preclude such
    a rigorous form of cost-benefit analysis as that which was
    prescribed under the statute’s former BPT standard,
    which required weighing “the total cost of application of
    technology” against “the . . . benefits to be achieved.” See,
    supra, at 10. But that question is not before us.
    In the Phase II requirements challenged here the EPA
    sought only to avoid extreme disparities between costs and
    benefits. The agency limited variances from the Phase II
    “national performance standards” to circumstances where
    the costs are “significantly greater than the benefits” of
    compliance. 
    40 CFR §125.94
    (a)(5)(ii). In defining the
    “national performance standards” themselves the EPA
    assumed the application of technologies whose benefits
    “approach those estimated” for closed-cycle cooling sys
    tems at a fraction of the cost: $389 million per year, 
    69 Fed. Reg. 41666
    , as compared with (1) at least $3.5 billion
    per year to operate compliant closed-cycle cooling systems,
    
    id., at 41605
     (or $1 billion per year to impose similar
    requirements on a subset of Phase II facilities, 
    id.,
     at
    14         ENTERGY CORP. v. RIVERKEEPER, INC.
    Opinion of the Court
    41606), and (2) significant reduction in the energy output
    of the altered facilities, 
    id., at 41605
    . And finally, EPA’s
    assessment of the relatively meager financial benefits of
    the Phase II regulations that it adopted—reduced im
    pingement and entrainment of 1.4 billion aquatic organ
    isms, 
    id., at 41661
    , Exh. XII–6, with annualized use
    benefits of $83 million, 
    id., at 41662
    , and non-use benefits
    of indeterminate value, 
    id.,
     at 41660–41661—when com
    pared to annual costs of $389 million, demonstrates quite
    clearly that the agency did not select the Phase II regula
    tory requirements because their benefits equaled their
    costs.
    While not conclusive, it surely tends to show that the
    EPA’s current practice is a reasonable and hence legiti
    mate exercise of its discretion to weigh benefits against
    costs that the agency has been proceeding in essentially
    this fashion for over 30 years. See Alaska Dept. of Envi
    ronmental Conservation v. EPA, 
    540 U. S. 461
    , 487 (2004);
    Barnhart v. Walton, 
    535 U. S. 212
    , 219–220 (2002). As
    early as 1977, the agency determined that, while §1326(b)
    does not require cost-benefit analysis, it is also not reason
    able to “interpret Section [1326(b)] as requiring use of
    technology whose cost is wholly disproportionate to the
    environmental benefit to be gained.” In re Public Service
    Co. of New Hampshire, 1 E. A. D. 332, 340 (1977). See
    also In re Central Hudson Gas and Electric Corp., EPA
    Decision of the General Counsel, NPDES Permits, No. 63,
    pp. 371, 381 (July 29, 1977) (“EPA ultimately must dem
    onstrate that the present value of the cumulative annual
    cost of modifications to cooling water intake structures is
    not wholly out of proportion to the magnitude of the esti
    mated environmental gains”); Seacoast Anti-Pollution
    League v. Costle, 
    597 F. 2d 306
    , 311 (CA1 1979) (rejecting
    challenge to an EPA permit decision that was based in
    part on the agency’s determination that further restric
    tions would be “ ‘wholly disproportionate to any environ
    mental benefit’ ”). While the EPA’s prior “wholly dispro
    Cite as: 556 U. S. ____ (2009)                 15
    Opinion of the Court
    portionate” standard may be somewhat different from its
    current “significantly greater than” standard, there is
    nothing in the statute that would indicate that the former
    is a permissible interpretation while the latter is not.
    Indeed, in its review of the EPA’s Phase I regulations,
    the Second Circuit seemed to recognize that §1326(b)
    permits some form of cost-benefit analysis. In considering
    a challenge to the EPA’s rejection of dry cooling systems7
    as the “best technology available” for Phase I facilities the
    Second Circuit noted that “while it certainly sounds sub
    stantial that dry cooling is 95 percent more effective than
    closed-cycle cooling, it is undeniably relevant that that
    difference represents a relatively small improvement over
    closed-cycle cooling at a very significant cost.”
    Riverkeeper, 
    358 F. 3d, at 194, n. 22
    . And in the decision
    below rejecting the use of cost-benefit analysis in the
    Phase II regulations, the Second Circuit nonetheless
    interpreted “best technology available” as mandating only
    those technologies that can “be reasonably borne by the
    industry.” 
    475 F. 3d, at 99
    . But whether it is “reasonable”
    to bear a particular cost may well depend on the resulting
    benefits; if the only relevant factor was the feasibility of
    the costs, their reasonableness would be irrelevant.
    In the last analysis, even respondents ultimately recog
    nize that some form of cost-benefit analysis is permissible.
    They acknowledge that the statute’s language is “plainly
    not so constricted as to require EPA to require industry
    petitioners to spend billions to save one more fish or
    plankton.” Brief for Respondents Riverkeeper, Inc. et al.
    29. This concedes the principle—the permissibility of at
    least some cost-benefit analysis—and we see no statutory
    basis for limiting its use to situations where the benefits
    ——————
    7 Dry cooling systems use air drafts to remove heat, and accordingly
    remove little or no water from surrounding water sources. See 
    66 Fed. Reg. 65282
     (2001).
    16             ENTERGY CORP. v. RIVERKEEPER, INC.
    Opinion of the Court
    are de minimis rather than significantly disproportionate.
    *    *    *
    We conclude that the EPA permissibly relied on cost
    benefit analysis in setting the national performance stan
    dards and in providing for cost-benefit variances from
    those standards as part of the Phase II regulations. The
    Court of Appeals’ reliance in part on the agency’s use of
    cost-benefit analysis in invalidating the site-specific cost
    benefit variance provision, 
    475 F. 3d, at 114
    , was therefore
    in error, as was its remand of the national performance
    standards for clarification of whether cost-benefit analysis
    was impermissibly used, 
    id.,
     at 104–105. We of course
    express no view on the remaining bases for the Second
    Circuit’s remand which did not depend on the permissibil
    ity of cost-benefit analysis. See 
    id., at 108, 110, 113, 115, 117, 120
    .8 The judgment of the Court of Appeals is re
    versed, and the cases are remanded for further proceed
    ings consistent with this opinion.
    It is so ordered.
    ——————
    8 JUSTICE  BREYER would remand for the additional reason of what he
    regards as the agency’s inadequate explanation of the change in its
    criterion for variances—from a relationship of costs to benefits that is
    “ ‘wholly disproportionate’ ” to one that is “ ‘significantly greater.’ ” Post,
    at 7–8 (opinion concurring in part and dissenting in part). That ques
    tion can have no bearing upon whether the EPA can use cost-benefit
    analysis, which is the only question presented here. It seems to us, in
    any case, that the EPA’s explanation was ample. It explained that the
    “wholly out of proportion” standard was inappropriate for the existing
    facilities subject to the Phase II rules because those facilities lack “the
    greater flexibility available to new facilities for selecting the location of
    their intakes and installing technologies at lower costs relative to the
    costs associated with retrofitting existing facilities,” and because
    “economically impracticable impacts on energy prices, production costs,
    and energy production . . . could occur if large numbers of Phase II
    existing facilities incurred costs that were more than ‘significantly
    greater’ than but not ‘wholly out of proportion’ to the costs in the EPA’s
    record.” 
    68 Fed. Reg. 13541
     (2003).
    Cite as: 556 U. S. ____ (2009)
    17
    Opinion of the Court
    Appendix to opinion of the Court
    APPENDIX TO OPINION OF THE COURT
    Entities
    Statutory              Statutorily Mandated
    Subject to
    Standard                      Factors
    Regulation
    BPT:             “Factors relating to the           Existing point
    “[E]ffluent limitations     assessment of best practicable     sources during
    . . . which shall require   control technology currently       the Clean Water
    the application of the      available . . . shall include      Act’s initial
    best practicable control    consideration of the total cost    implementation
    technology currently        of application of technology in    phase.
    available.” 33 U. S. C.     relation to the effluent
    §1311(b)(1)(A) (empha       reduction benefits to be
    sis added).                 achieved.” 
    33 U. S. C. §1314
    (b)(1)(B).
    BCT:             “Factors relating to the           Existing point
    “[E]ffluent limitations     assessment of best conven          sources that
    . . . which shall require   tional pollutant control           discharge
    application of the best     technology . . . shall include     “conventional
    conventional pollutant      consideration of the reason        pollutants” as
    control technology.” 33     ableness of the relationship       defined by the
    U. S. C. §1311(b)(2)(E)     between the costs of attaining     EPA under 33
    (emphasis added).           a reduction in effluents and       U. S. C.
    the effluent reduction benefits    §1314(a)(4).
    derived.” 
    33 U. S. C. §1314
    (b)(4)(B).
    BATEA:            “Factors relating to the           Existing point
    “[E]ffluent limitations     assessment of best available       sources that
    . . . which . . . shall     technology shall take into         discharge toxic
    require application of      account . . . the cost of achiev   pollutants and
    the best available          ing such effluent reduction.”      non
    technology economically     
    33 U. S. C. §1314
    (b)(2)(B).        conventional
    achievable . . . which                                         pollutants.
    will result in reasonable
    further progress toward
    the national goal of
    eliminating the dis
    charge of all pollut
    ants.” 
    33 U. S. C. §1311
    (b)(2)(A) (empha
    sis added).
    18            ENTERGY CORP. v. RIVERKEEPER, INC.
    Opinion of the Court
    Appendix to opinion of the Court
    Entities
    Statutory              Statutorily Mandated
    Subject to
    Standard                      Factors
    Regulation
    BADT:            “[T]he Administrator shall        New point
    “[A] standard for the      take into consideration the       sources within
    control of the discharge   cost of achieving such effluent   the categories of
    of pollutants which        reduction, and any non-water      sources identi
    reflects the greatest      quality environmental impact      fied by the EPA
    degree of effluent         and energy requirements.” 33      under 33
    reduction with the         U. S. C. §1316(b)(1)(B).          U. S. C.
    Administrator deter                                          §1316(b)(1)(A).
    mines to be achievable
    through application of
    the best available
    demonstrated control
    technology.” 
    33 U. S. C. §1316
    (a)(1) (emphasis
    added).
    BTA:           N/A                                 Point sources
    “Any standard . . .                                          that operate
    applicable to a point                                        cooling water
    source shall require                                         intake struc
    that the location,                                           tures.
    design, construction,
    and capacity of cooling
    water intake structures
    reflect the best technol
    ogy available for
    minimizing adverse
    environmental impact.”
    
    33 U. S. C. §1326
    (b).
    Cite as: 556 U. S. ____ (2009)           1
    Opinion of BREYER, J.
    SUPREME COURT OF THE UNITED STATES
    _________________
    Nos. 07–588, 07–589 and 07–597
    _________________
    ENTERGY CORPORATION, PETITIONER
    07–588                 v.
    RIVERKEEPER, INC., ET AL.
    PSEG FOSSIL LLC, ET AL., PETITIONERS
    07–589                    v.
    RIVERKEEPER, INC., ET AL.
    UTILITY WATER ACT GROUP, PETITIONER
    07–597                v.
    RIVERKEEPER, INC., ET AL.
    ON WRITS OF CERTIORARI TO THE UNITED STATES COURT OF
    APPEALS FOR THE SECOND CIRCUIT
    [April 1, 2009]
    JUSTICE BREYER, concurring in part and dissenting in
    part.
    I agree with the Court that the relevant statutory lan
    guage authorizes the Environmental Protection Agency
    (EPA) to compare costs and benefits. Ante, at 7–13. None
    theless the drafting history and legislative history of
    related provisions, Pub. L. 92–500, §§301, 304, 
    86 Stat. 844
    , 850, as amended, 
    33 U. S. C. §§1311
    , 1314, make
    clear that those who sponsored the legislation intended
    the law’s text to be read as restricting, though not forbid
    ding, the use of cost-benefit comparisons. And I would
    apply that text accordingly.
    I
    Section 301 provides that, not later than 1977, effluent
    2          ENTERGY CORP. v. RIVERKEEPER, INC.
    Opinion of BREYER, J.
    limitations for point sources shall require the application
    of “best practicable control technology,” §301(b)(1)(A), 
    86 Stat. 845
     (emphasis added); and that, not later than 1983
    (later extended to 1989), effluent limitations for categories
    and classes of point sources shall require application of the
    “best available technology economically achievable,”
    §301(b)(2)(A), ibid. (emphasis added). Section 304(b), in
    turn, identifies the factors that the Agency shall take into
    account in determining (1) “best practicable control tech
    nology” and (2) “best available technology.” 
    86 Stat. 851
    (emphasis added).
    With respect to the first, the statute provides that the
    factors taken into account by the Agency “shall include
    consideration of the total cost of application of technology
    in relation to the effluent reduction benefits to be achieved
    from such application . . . and such other factors as the
    Administrator deems appropriate.” §304(b)(1)(B), ibid.
    With respect to the second, the statute says that the
    Agency “shall take into account . . . the cost of achieving
    such effluent reduction” and “such other factors as the
    Administrator deems appropriate.” §304(b)(2)(B), ibid.
    The drafting history makes clear that the statute re
    flects a compromise. In the House version of the legisla
    tion, the Agency was to consider “the cost and the eco
    nomic, social, and environmental impact of achieving such
    effluent reduction” when determining both “best practica
    ble” and “best available” technology. H. R. 11896, 92d
    Cong., 2d Sess., §§304(b)(1)(B), (b)(2)(B) (1972) (as re
    ported from committee). The House Report explained that
    the “best available technology” standard was needed—as
    opposed to mandating the elimination of discharge of
    pollutants—because “the difference in the cost of 100
    percent elimination of pollutants as compared to the cost
    of removal of 97–99 percent of the pollutants in an effluent
    can far exceed any reasonable benefit to be achieved. In
    most cases, the cost of removal of the last few percentage
    Cite as: 556 U. S. ____ (2009)           3
    Opinion of BREYER, J.
    points increases expo[n]entially.” H. R. Rep. No. 92–911,
    p. 103 (1972).
    In the Senate version, the Agency was to consider “the
    cost of achieving such effluent reduction” when determin
    ing both “best practicable” and “best available” technology.
    S. 2770, 92d Cong., 1st Sess., §§304(b)(1)(B), (b)(2)(B)
    (1971) (as reported from committee). The Senate Report
    explains that “the technology must be available at a cost
    . . . which the Administrator determines to be reasonable.”
    S. Rep. No. 92–414, p. 52 (1971) (hereinafter S. Rep.). But
    it said nothing about comparing costs and benefits.
    The final statute reflects a modification of the House’s
    language with respect to “best practicable,” and an adop
    tion of the Senate’s language with respect to “best avail
    able.” S. Conf. Rep. No. 92–1236, pp. 124–125 (1972). The
    final statute does not require the Agency to compare costs
    to benefits when determining “best available technology,”
    but neither does it expressly forbid such a comparison.
    The strongest evidence in the legislative history sup
    porting the respondents’ position—namely, that Congress
    intended to forbid comparisons of costs and benefits when
    determining the “best available technology”—can be found
    in a written discussion of the Act’s provisions distributed
    to the Senate by Senator Edmund Muskie, the Act’s prin
    cipal sponsor, when he submitted the Conference Report
    for the Senate’s consideration. 118 Cong. Rec. 33693
    (1972). The relevant part of that discussion points out
    that, as to “best practicable technology,” the statute re
    quires application of a “balancing test between total cost
    and effluent reduction benefits.”       Id., at 33696; see
    §304(b)(1)(B). But as to “best available technology,” it
    states: “While cost should be a factor in the Administra
    tor’s judgment, no balancing test will be required.” Ibid.;
    see §304(b)(2)(B). And Senator Muskie’s discussion later
    speaks of the agency “evaluat[ing] . . . what needs to be
    done” to eliminate pollutant discharge and “what is
    4           ENTERGY CORP. v. RIVERKEEPER, INC.
    Opinion of BREYER, J.
    achievable,” both “without regard to cost.” Ibid.
    As this language suggests, the Act’s sponsors had rea
    sons for minimizing the EPA’s investigation of, and reli
    ance upon, cost-benefit comparisons. The preparation of
    formal cost-benefit analyses can take too much time,
    thereby delaying regulation. And the sponsors feared that
    such analyses would emphasize easily quantifiable factors
    over more qualitative factors (particularly environmental
    factors, for example, the value of preserving non
    marketable species of fish). See S. Rep., at 47. Above all,
    they hoped that minimizing the use of cost-benefit com
    parisons would force the development of cheaper control
    technologies; and doing so, whatever the initial inefficien
    cies, would eventually mean cheaper, more effective
    cleanup. See id., at 50–51.
    Nonetheless, neither the sponsors’ language nor the
    underlying rationale requires the Act to be read in a way
    that would forbid cost-benefit comparisons. Any such
    total prohibition would be difficult to enforce, for every
    real choice requires a decisionmaker to weigh advantages
    against disadvantages, and disadvantages can be seen in
    terms of (often quantifiable) costs. Moreover, an absolute
    prohibition would bring about irrational results. As the
    respondents themselves say, it would make no sense to
    require plants to “spend billions to save one more fish or
    plankton.” Brief for Respondents Riverkeeper, Inc., et al.
    29. That is so even if the industry might somehow afford
    those billions. And it is particularly so in an age of limited
    resources available to deal with grave environmental
    problems, where too much wasteful expenditure devoted to
    one problem may well mean considerably fewer resources
    available to deal effectively with other (perhaps more
    serious) problems.
    Thus Senator Muskie used nuanced language, which
    one can read as leaving to the Agency a degree of author
    ity to make cost-benefit comparisons in a manner that is
    Cite as: 556 U. S. ____ (2009)            5
    Opinion of BREYER, J.
    sensitive both to the need for such comparisons and to the
    concerns that the law’s sponsors expressed. The relevant
    statement begins by listing various factors that the statute
    requires the Administrator to take into account when
    applying the phrase “practicable” to “classes and catego
    ries.” 118 Cong. Rec. 33696. It states that, when doing so,
    the Administrator must apply (as the statute specifies) a
    “balancing test between total cost and effluent reduction
    benefits.” Ibid. At the same time, it seeks to reduce the
    likelihood that the Administrator will place too much
    weight upon high costs by adding that the balancing test
    “is intended to limit the application of technology only
    where the additional degree of effluent reduction is wholly
    out of proportion to the costs of achieving” a “marginal
    level of reduction.” Ibid.
    Senator Muskie’s statement then considers the “differ
    ent test” that the statute requires the Administrator to
    apply when determining the “ ‘best available’ ” technology.
    Ibid. (emphasis added). Under that test, the Administra
    tor “may consider a broader range of technological alterna
    tives.” Ibid. And in determining what is “ ‘best available’
    for a category or class, the Administrator is expected to
    apply the same principles involved in making the deter
    mination of ‘best practicable’ . . . except as to cost-benefit
    analysis.” Ibid. (emphasis added). That is, “[w]hile cost
    should be a factor . . . no balancing test will be required.”
    Ibid. (emphasis added). Rather, “[t]he Administrator will
    be bound by a test of reasonableness.” Ibid. (emphasis
    added). The statement adds that the “ ‘best available’ ”
    standard “is intended to reflect the need to press toward
    increasingly higher levels of control.” Ibid. (emphasis
    added). And “the reasonableness of what is ‘economically
    achievable’ should reflect an evaluation of what needs to
    be done to move toward the elimination of the discharge of
    pollutants and what is achievable through the application
    of available technology—without regard to cost.” Ibid.
    6          ENTERGY CORP. v. RIVERKEEPER, INC.
    Opinion of BREYER, J.
    (emphasis added).
    I believe, as I said, that this language is deliberately
    nuanced. The statement says that where the statute uses
    the term “best practicable,” the statute requires compari
    sons of costs and benefits; but where the statute uses the
    term “best available,” such comparisons are not “required.”
    Ibid. (emphasis added). Senator Muskie does not say that
    all efforts to compare costs and benefits are forbidden.
    Moreover, the statement points out that where the
    statute uses the term “best available,” the Administrator
    “will be bound by a test of reasonableness.” Ibid. (empha
    sis added). It adds that the Administrator should apply
    this test in a way that reflects its ideal objective, moving
    as closely as is technologically possible to the elimination
    of pollution. It thereby says the Administrator should
    consider, i.e., take into account, how much pollution would
    still remain if the best available technology were to be
    applied everywhere—“without regard to cost.” Ibid. It
    does not say that the Administrator must set the standard
    based solely on the result of that determination. (It would
    be difficult to reconcile the alternative, more absolute
    reading of this language with the Senator’s earlier “test of
    reasonableness.”)
    I say that one may, not that one must, read Senator
    Muskie’s statement this way. But to read it differently
    would put the Agency in conflict with the test of reason
    ableness by threatening to impose massive costs far in
    excess of any benefit. For 30 years the EPA has read the
    statute and its history in this way. The EPA has thought
    that it would not be “reasonable to interpret Section 316(b)
    as requiring use of technology whose cost is wholly dispro
    portionate to the environmental benefit to be gained.”
    In re Pub. Serv. Co. of N. H. (Seabrook Station, Units 1
    and 2), 1 E. A. D. 332, 340 (1977), remanded on other
    grounds, Seacoast Anti-Pollution League v. Costle, 
    572 F. 2d 872
     (CA1 1978) (emphasis added); see also In re
    Cite as: 556 U. S. ____ (2009)            7
    Opinion of BREYER, J.
    Central Hudson Gas & Elec. Corp., EPA Decision of the
    General Counsel, NPDES Permits, No. 63, p. 371 (July 29,
    1977) (also applying a “wholly disproportionate” test); In
    re Pub. Serv. Co. of N. H., 1 E. A. D. 455 (1978) (same).
    “[T]his Court will normally accord particular deference to
    an agency interpretation of ‘longstanding’ duration.”
    Barnhart v. Walton, 
    535 U. S. 212
    , 220 (2002). And for the
    last 30 years, the EPA has given the statute a permissive
    reading without suggesting that in doing so it was ignor
    ing or thwarting the intent of the Congress that wrote the
    statute.
    The EPA’s reading of the statute would seem to permit
    it to describe environmental benefits in non-monetized
    terms and to evaluate both costs and benefits in accor
    dance with its expert judgment and scientific knowledge.
    The Agency can thereby avoid lengthy formal cost-benefit
    proceedings and futile attempts at comprehensive moneti
    zation, see 
    69 Fed. Reg. 41661
    –41662; take account of
    Congress’ technology-forcing objectives; and still prevent
    results that are absurd or unreasonable in light of extreme
    disparities between costs and benefits. This approach, in
    my view, rests upon a “reasonable interpretation” of the
    statute—legislative history included. Hence it is lawful.
    Chevron U. S. A. Inc. v. Natural Resources Defense Coun
    cil, Inc., 
    467 U. S. 837
    , 844 (1984). Most of what the ma
    jority says is consistent with this view, and to that extent I
    agree with its opinion.
    II
    The cases before us, however, present an additional
    problem. We here consider a rule that permits variances
    from national standards if a facility demonstrates that its
    costs would be “significantly greater than the benefits of
    complying.” 
    40 CFR §125.94
    (a)(5)(ii) (2008). The words
    “significantly greater” differ from the words the EPA has
    traditionally used to describe its standard, namely,
    8          ENTERGY CORP. v. RIVERKEEPER, INC.
    Opinion of BREYER, J.
    “wholly disproportionate.” Perhaps the EPA does not
    mean to make much of that difference. But if it means the
    new words to set forth a new and different test, the EPA
    must adequately explain why it has changed its standard.
    Motor Vehicle Mfrs. Assn. of United States, Inc. v. State
    Farm Mut. Automobile Ins. Co., 
    463 U. S. 29
    , 42–43
    (1983); National Cable & Telecommunications Assn. v.
    Brand X Internet, 
    545 U. S. 967
    , 981 (2005); Thomas
    Jefferson Univ. v. Shalala, 
    512 U. S. 504
    , 524, n. 3 (1994)
    (THOMAS, J., dissenting).
    I am not convinced the EPA has successfully explained
    the basis for the change. It has referred to the fact that
    existing facilities have less flexibility than new facilities
    with respect to installing new technologies, and it has
    pointed to special, energy-related impacts of regulation.
    
    68 Fed. Reg. 13541
     (2003) (proposed rule). But it has not
    explained why the traditional “wholly disproportionate”
    standard cannot do the job now, when the EPA has used
    that standard (for existing facilities and otherwise) with
    apparent success in the past. See, e.g., Central Hudson,
    supra.
    Consequently, like the majority, I would remand these
    cases to the Court of Appeals. But unlike the majority I
    would permit that court to remand the cases to the EPA so
    that the EPA can either apply its traditional “wholly
    disproportionate” standard or provide an adequately
    reasoned explanation for the change.
    Cite as: 556 U. S. ____ (2009)            1
    STEVENS, J., dissenting
    SUPREME COURT OF THE UNITED STATES
    _________________
    Nos. 07–588, 07–589 and 07–597
    _________________
    ENTERGY CORPORATION, PETITIONER
    07–588                 v.
    RIVERKEEPER, INC., ET AL.
    PSEG FOSSIL LLC, ET AL., PETITIONERS
    07–589                    v.
    RIVERKEEPER, INC., ET AL.
    UTILITY WATER ACT GROUP, PETITIONER
    07–597                v.
    RIVERKEEPER, INC., ET AL.
    ON WRITS OF CERTIORARI TO THE UNITED STATES COURT OF
    APPEALS FOR THE SECOND CIRCUIT
    [April 1, 2009]
    JUSTICE STEVENS, with whom JUSTICE SOUTER and
    JUSTICE GINSBURG join, dissenting.
    Section 316(b) of the Clean Water Act (CWA), 
    33 U. S. C. §1326
    (b), which governs industrial powerplant
    water intake structures, provides that the Environmental
    Protection Agency (EPA or Agency) “shall require” that
    such structures “reflect the best technology available for
    minimizing adverse environmental impact.” The EPA has
    interpreted that mandate to authorize the use of cost
    benefit analysis in promulgating regulations under
    §316(b). For instance, under the Agency’s interpretation,
    technology that would otherwise qualify as the best avail
    able need not be used if its costs are “significantly greater
    than the benefits” of compliance. 
    40 CFR §125.94
    (a)(5)(ii)
    (2008).
    2             ENTERGY CORP. v. RIVERKEEPER, INC.
    STEVENS, J., dissenting
    Like the Court of Appeals, I am convinced that the EPA
    has misinterpreted the plain text of §316(b). Unless costs
    are so high that the best technology is not “available,”
    Congress has decided that they are outweighed by the
    benefits of minimizing adverse environmental impact.
    Section 316(b) neither expressly nor implicitly authorizes
    the EPA to use cost-benefit analysis when setting regula
    tory standards; fairly read, it prohibits such use.
    I
    As typically performed by the EPA, cost-benefit analysis
    requires the Agency to first monetize the costs and bene
    fits of a regulation, balance the results, and then choose
    the regulation with the greatest net benefits. The process
    is particularly controversial in the environmental context
    in which a regulation’s financial costs are often more
    obvious and easier to quantify than its environmental
    benefits. And cost-benefit analysis often, if not always,
    yields a result that does not maximize environmental
    protection.
    For instance, although the EPA estimated that water
    intake structures kill 3.4 billion fish and shellfish each
    year,1 see 
    69 Fed. Reg. 41586
    , the Agency struggled to
    calculate the value of the aquatic life that would be pro
    ——————
    1 To produce energy, industrial powerplants withdraw billions of
    gallons of water daily from our Nation’s waterways.            Thermo
    electric powerplants alone demand 39 percent of all freshwater with
    drawn nationwide. See Dept. of Energy, Addressing the Critical
    Link Between Fossil Energy and Water 2 (Oct. 2005), http://
    www.netl.doe.gov/technologies/coalpower/ewr/pubs/NETL_Water_Paper
    _Final_Oct.2005.pdf (all Internet materials as visited Mar. 18, 2009,
    and available in Clerk of Court’s case file). The fish and shellfish are
    killed by “impingement” or “entrainment.” Impingement occurs when
    aquatic organisms are trapped against the screens and grills of water
    intake structures. Entrainment occurs when these organisms are
    drawn into the intake structures. See Riverkeeper, Inc. v. EPA, 
    475 F. 3d 83
    , 89 (CA2 2007); 
    69 Fed. Reg. 41586
     (2004).
    Cite as: 556 U. S. ____ (2009)                  3
    STEVENS, J., dissenting
    tected under its §316(b) regulations, id., at 41661. To
    compensate, the EPA took a shortcut: Instead of monetiz
    ing all aquatic life, the Agency counted only those species
    that are commercially or recreationally harvested, a tiny
    slice (1.8 percent to be precise) of all impacted fish and
    shellfish. This narrow focus in turn skewed the Agency’s
    calculation of benefits. When the EPA attempted to value
    all aquatic life, the benefits measured $735 million.2 But
    when the EPA decided to give zero value to the 98.2 per
    cent of fish not commercially or recreationally harvested,
    the benefits calculation dropped dramatically—to $83
    million. Id., at 41666. The Agency acknowledged that its
    failure to monetize the other 98.2 percent of affected spe
    cies “ ‘could result in serious misallocation of resources,’ ”
    id., at 41660, because its “comparison of complete costs
    and incomplete benefits does not provide an accurate
    picture of net benefits to society.”3
    Because benefits can be more accurately monetized in
    some industries than in others, Congress typically decides
    whether it is appropriate for an agency to use cost-benefit
    analysis in crafting regulations. Indeed, this Court has
    recognized that “[w]hen Congress has intended that an
    agency engage in cost-benefit analysis, it has clearly indi
    cated such intent on the face of the statute.” American
    Textile Mfrs. Institute, Inc. v. Donovan, 
    452 U. S. 490
    , 510
    (1981). Accordingly, we should not treat a provision’s
    silence as an implicit source of cost-benefit authority,
    particularly when such authority is elsewhere expressly
    granted and it has the potential to fundamentally alter an
    ——————
    2 EPA, Economic and Benefits Analysis for the Proposed Section
    316(b) Phase II Existing Facilities Rule, p. D1–4 (EPA–821–R–02–001,
    Feb. 2002), http://www.epa.gov/waterscience/316b/phase2/econbenefits.
    3 EPA, Economic and Benefits Analysis for the Final Section 316(b)
    Phase II Existing Facilities Rule, p. D1–5 (EPA–821–R–04–005, Feb.
    2004), http://www.epa.gov/waterscience/316b/phase2/econbenefits/final.
    htm.
    4          ENTERGY CORP. v. RIVERKEEPER, INC.
    STEVENS, J., dissenting
    agency’s approach to regulation. Congress, we have noted,
    “does not alter the fundamental details of a regulatory
    scheme in vague terms or ancillary provisions—it does
    not, one might say, hide elephants in mouseholes.” Whit
    man v. American Trucking Assns., Inc., 
    531 U. S. 457
    ,
    467–468 (2001).
    When interpreting statutory silence in the past, we have
    sought guidance from a statute’s other provisions. Evi
    dence that Congress confronted an issue in some parts of a
    statute, while leaving it unaddressed in others, can dem
    onstrate that Congress meant its silence to be decisive.
    We concluded as much in American Trucking. In that
    case, the Court reviewed the EPA’s claim that §109 of the
    Clean Air Act (CAA), 
    42 U. S. C. §7409
    (a) (2000 ed.), au
    thorized the Agency to consider implementation costs in
    setting ambient air quality standards. We read §109,
    which was silent on the matter, to prohibit Agency reli
    ance on cost considerations. After examining other provi
    sions in which Congress had given the Agency authority to
    consider costs, the Court “refused to find implicit in am
    biguous sections of the CAA an authorization to consider
    costs that has elsewhere, and so often, been expressly
    granted.” 
    531 U. S., at 467
    . Studied silence, we thus
    concluded, can be as much a prohibition as an explicit
    “no.”
    Further motivating the Court in American Trucking was
    the fact that incorporating implementation costs into the
    Agency’s calculus risked countermanding Congress’ deci
    sion to protect public health. The cost of implementation,
    we said, “is both so indirectly related to public health and
    so full of potential for canceling the conclusions drawn
    from direct health effects that it would surely have been
    expressly mentioned in [the text] had Congress meant it to
    be considered.” 
    Id., at 469
    .
    American Trucking’s approach should have guided the
    Court’s reading of §316(b). Nowhere in the text of §316(b)
    Cite as: 556 U. S. ____ (2009)                   5
    STEVENS, J., dissenting
    does Congress explicitly authorize the use of cost-benefit
    analysis as it does elsewhere in the CWA. And the use of
    cost-benefit analysis, like the consideration of implemen
    tation costs in American Trucking, “pad[s]” §316(b)’s
    environmental mandate with tangential economic effi
    ciency concerns. Id., at 468. Yet the majority fails to
    follow American Trucking despite that case’s obvious
    relevance to our inquiry.
    II
    In 1972, Congress amended the CWA to strike a careful
    balance between the country’s energy demands and its
    desire to protect the environment. The Act required in
    dustry to adopt increasingly advanced technology capable
    of mitigating its detrimental environmental impact. Not
    all point sources were subject to strict rules at once. Ex
    isting plants were granted time to retrofit with the best
    technology while new plants were required to incorporate
    such technology as a matter of design. Although Congress
    realized that technology standards would necessarily put
    some firms out of business, see EPA v. National Crushed
    Stone Assn., 
    449 U. S. 64
    , 79 (1980), the statute’s steady
    march was toward stricter rules and potentially higher
    costs.
    Section §316(b) was an integral part of the statutory
    scheme. The provision instructs that “[a]ny standard
    established pursuant to section 1311 of this title or section
    1316 of this title and applicable to a point source shall
    require that the location, design, construction, and capac
    ity of cooling water intake structures reflect the best tech
    nology available for minimizing adverse environmental
    impact.”     
    33 U. S. C. §1326
    (b) (2006 ed.) (emphasis
    added).4 The “best technology available,” or “BTA,” stan
    ——————
    4 The two cross-referenced provisions, §§1311 and 1316, also establish
    “best technology” standards, the first applicable to existing point
    sources and the second to new facilities. The reference to these provi
    6             ENTERGY CORP. v. RIVERKEEPER, INC.
    STEVENS, J., dissenting
    dard delivers a clear command: To minimize the adverse
    environmental impact of water intake structures, the
    EPA must require industry to adopt the best technology
    available.
    Based largely on the observation that §316(b)’s text
    offers little guidance and therefore delegates some amount
    of gap-filling authority to the EPA, the Court concludes
    that the Agency has discretion to rely on cost-benefit
    analysis. See ante, at 11–12. The Court assumes that, by
    not specifying how the EPA is to determine BTA, Congress
    intended to give considerable discretion to the EPA to
    decide how to proceed. Silence, in the majority’s view,
    represents ambiguity and an invitation for the Agency to
    decide for itself which factors should govern its regulatory
    approach.
    The appropriate analysis requires full consideration of
    the CWA’s structure and legislative history to determine
    whether Congress contemplated cost-benefit analysis and,
    if so, under what circumstances it directed the EPA to
    utilize it. This approach reveals that Congress granted
    the EPA authority to use cost-benefit analysis in some
    contexts but not others, and that Congress intend to con
    trol, not delegate, when cost-benefit analysis should be
    used. See Chevron U. S. A. Inc. v. Natural Resources
    Defense Council, Inc., 
    467 U. S. 837
    , 842–843 (1984).5
    ——————
    sions in §316(b) merely requires any rule promulgated under those
    provisions, when applied to a point source with a water intake struc
    ture, to incorporate §316(b) standards.
    5 The majority announces at the outset that the EPA’s reading of the
    BTA standard “governs if it is a reasonable interpretation of the stat
    ute—not necessarily the only possible interpretation, nor even the
    interpretation deemed most reasonable by the courts.” Ante, at 7. This
    observation is puzzling in light of the commonly understood practice
    that, as a first step, we ask “whether Congress has directly spoken to
    the precise question at issue.” Chevron, 
    467 U. S., at 842
    . Only later, if
    Congress’ intent is not clear, do we consider the reasonableness of the
    agency’s action. 
    Id., at 843
    . Assuming ambiguity and moving to the
    Cite as: 556 U. S. ____ (2009)                     7
    STEVENS, J., dissenting
    Powerful evidence of Congress’ decision not to authorize
    cost-benefit analysis in the BTA standard lies in the series
    of standards adopted to regulate the outflow, or effluent,
    from industrial powerplants. Passed at the same time as
    the BTA standard at issue here, the effluent limitation
    standards imposed increasingly strict technology require
    ments on industry. In each effluent limitation provision,
    Congress distinguished its willingness to allow the EPA to
    consider costs from its willingness to allow the Agency to
    conduct a cost-benefit analysis. And to the extent Con
    gress permitted cost-benefit analysis, its use was intended
    to be temporary and exceptional.
    The first tier of technology standards applied to existing
    plants—facilities for which retrofitting would be particu
    larly costly. Congress required these plants to adopt
    “effluent limitations . . . which shall require the applica
    tion of the best practicable control technology currently
    available.” 
    33 U. S. C. §1311
    (b)(1)(A). Because this “best
    practicable,” or “BPT,” standard was meant to ease indus
    try’s transition to the new technology-based regime, Con
    gress gave BPT two unique features: First, it would be
    temporary, remaining in effect only until July 1, 1983.6
    Second, it specified that the EPA was to conduct a cost
    benefit analysis in setting BPT requirements by consider
    ing “the total cost of application of technology in relation
    to the effluent reduction benefits to be achieved from such
    application.”7     §1314(b)(1)(B).   Permitting cost-benefit
    ——————
    second step reflects the Court’s reluctance to consider the possibility,
    which it later laments is “more complex,” ante, at 9, that Congress’
    silence may have meant to foreclose cost-benefit analysis.
    6 Congress later extended the deadline to March 31, 1989.
    7 Senator Muskie, the Senate sponsor of the legislation, described the
    cost-benefit analysis permitted under BPT as decidedly narrow, assert
    ing that “[t]he balancing test between total cost and effluent reduction
    benefits is intended to limit the application of technology only where
    the additional degree of effluent reduction is wholly out of proportion to
    the costs of achieving such marginal level of reduction for any class or
    8            ENTERGY CORP. v. RIVERKEEPER, INC.
    STEVENS, J., dissenting
    analysis in BPT gave the EPA the ability to cushion the
    new technology requirement. For a limited time, a tech
    nology with costs that exceeded its benefits would not be
    considered “best.”
    The second tier of technology standards required exist
    ing powerplants to adopt the “best available technology
    economically achievable” to advance “the national goal of
    eliminating     the     discharge    of    all   pollutants.”
    §1311(b)(2)(A). In setting this “best available technology,”
    or “BAT,”8 standard, Congress gave the EPA a notably
    different command for deciding what technology would
    qualify as “best”: The EPA was to consider, among other
    factors, “the cost of achieving such effluent reduction,” but
    Congress did not grant it authority to balance costs with
    the benefits of stricter regulation. §1314(b)(2)(B). Indeed,
    in Crushed Stone this Court explained that the difference
    between BPT and BAT was the existence of cost-benefit
    authority in the first and the absence of that authority in
    the second. See 
    449 U. S., at 71
     (“Similar directions are
    given the Administrator for determining effluent reduc
    tions attainable from the BAT except that in assessing
    BAT total cost is no longer to be considered in comparison
    to effluent reduction benefits”).
    The BAT standard’s legislative history strongly supports
    the view that Congress purposefully withheld cost-benefit
    authority for this tier of regulation. See ibid., n. 10. The
    House of Representatives and the Senate split over the
    role cost-benefit analysis would play in the BAT provision.
    The House favored the tool, see H. R. Rep. No. 92–911, p.
    107 (1972), 1 Leg. Hist. 794, while the Senate rejected it,
    ——————
    category of sources.” 1 Legislative History of the Water Pollution
    Control Act Amendments of 1972 (Committee Print compiled for the
    Senate Committee on Public Works by the Library of Congress), Ser.
    No. 93–1, p. 170 (1973) (hereinafter Leg. Hist.)
    8 Although the majority calls this “BATEA,” the parties refer to the
    provision as “BAT,” and for simplicity, so will I.
    Cite as: 556 U. S. ____ (2009)            9
    STEVENS, J., dissenting
    see 2 id., at 1183; id., at 1132. The Senate view ultimately
    prevailed in the final legislation, resulting in a BAT stan
    dard that was “not subject to any test of cost in relation to
    effluent reduction benefits or any form of cost/benefit
    analysis.” 3 Legislative History of the Clean Water Act of
    1977: A Continuation of the Legislative History of the
    Federal Water Pollution Control Act (Committee Print
    compiled for the Senate Committee on Environment and
    Public Works by the Library of Congress), Ser. No. 95–14,
    p. 427 (1978).
    The third and strictest regulatory tier was reserved for
    new point sources—facilities that could incorporate tech
    nology improvements into their initial design. These new
    facilities were required to adopt “the best available dem
    onstrated control technology,” or “BADT,” which Congress
    described as “a standard . . . which reflect[s] the greatest
    degree of effluent reduction.” §1316(a)(1). In administer
    ing BADT, Congress directed the EPA to consider “the cost
    of achieving such effluent reduction.” §1316(b)(1)(B). But
    because BADT was meant to be the most stringent stan
    dard of all, Congress made no mention of cost-benefit
    analysis. Again, the silence was intentional. The House’s
    version of BADT originally contained an exemption for
    point sources for which “the economic, social, and envi
    ronmental costs bear no reasonable relationship to the
    economic, social, and environmental benefit to be ob
    tained.” 1 Leg. Hist. 798. That this exemption did not
    appear in the final legislation demonstrates that Congress
    considered, and rejected, reliance on cost-benefit analysis
    for BADT.
    It is in this light that the BTA standard regulating
    water intake structures must be viewed. The use of cost
    benefit analysis was a critical component of the CWA’s
    structure and a key concern in the legislative process. We
    should therefore conclude that Congress intended to forbid
    cost-benefit analysis in one provision of the Act in which it
    10            ENTERGY CORP. v. RIVERKEEPER, INC.
    STEVENS, J., dissenting
    was silent on the matter when it expressly authorized its
    use in another.9 See, e.g., Allison Engine Co. v. United
    States ex rel. Sanders, 553 U. S. ___, ___ (2008) (slip op., at
    7–8); Russello v. United States, 
    464 U. S. 16
    , 23 (1983)
    (“[W]here Congress includes particular language in one
    section of a statute but omits it in another . . . , it is gener
    ally presumed that Congress acts intentionally and pur
    posely in the disparate inclusion or exclusion” (internal
    quotation marks omitted)). This is particularly true given
    Congress’ decision that cost-benefit analysis would play a
    temporary and exceptional role in the CWA to help exist
    ing plants transition to the Act’s ambitious environmental
    standards.10 Allowing cost-benefit analysis in the BTA
    standard, a permanent mandate applicable to all power
    plants, serves no such purpose and instead fundamentally
    ——————
    9 The   Court argues that, if silence in §316(b) signals the prohibition of
    cost-benefit analysis, it must also foreclose the consideration of all
    other potentially relevant discretionary factors in setting BTA stan
    dards. Ante, at 12. This all-or-nothing reasoning rests on the deeply
    flawed assumption that Congress treated cost-benefit analysis as just
    one among many factors upon which the EPA could potentially rely to
    establish BTA. Yet, as explained above, the structure and legislative
    history of the CWA demonstrate that Congress viewed cost-benefit
    analysis with special skepticism and controlled its use accordingly. The
    Court’s assumption of equivalence is thus plainly incorrect. Properly
    read, Congress’ silence in §316(b) forbids reliance on the cost-benefit
    tool but does not foreclose reliance on all other considerations, such as a
    determination whether a technology is so costly that it is not “avail
    able” for industry to adopt.
    10 In 1977, Congress established an additional technology-based stan
    dard, commonly referred to as “best conventional pollutant control
    technology,” or “BCT,” to govern conventional pollutants previously
    covered by the BAT standard. See 
    33 U. S. C. §1311
    (b)(2)(E). The BCT
    standard required the EPA to consider, among other factors, “the
    relationship between the costs of attaining a reduction in effluents and
    the effluent reduction benefits derived.” §1314(b)(4)(B). That Congress
    expressly authorized cost-benefit analysis in BCT further confirms that
    Congress treated cost-benefit analysis as exceptional and reserved for
    itself the authority to decide when it would be used in the Act.
    Cite as: 556 U. S. ____ (2009)                   11
    STEVENS, J., dissenting
    weakens the provision’s mandate.11
    Accordingly, I would hold that the EPA is without au
    thority to perform cost-benefit analysis in setting BTA
    standards. To the extent the EPA relied on cost-benefit
    analysis in establishing its BTA regulations,12 that action
    was contrary to law, for Congress directly foreclosed such
    reliance in the statute itself.13 Chevron, 
    467 U. S., at 843
    .
    ——————
    11 The Court attempts to cabin its holding by suggesting that a “rigor
    ous form of cost-benefit analysis,” such as the form “prescribed under
    the statute’s former BPT standard,” may not be permitted for setting
    BTA regulations. Ante, at 13. Thus the Court has effectively in
    structed the Agency that it can perform a cost-benefit analysis so long
    as it does not resemble the kind of cost-benefit analysis Congress
    elsewhere authorized in the CWA. The majority’s suggested limit on
    the Agency’s discretion can only be read as a concession that cost
    benefit analysis, as typically performed, may be inconsistent with the
    BTA mandate.
    12 The “national performance standards” the EPA adopted were
    shaped by economic efficiency concerns at the expense of finding the
    technology that best minimizes adverse environmental impact. In its
    final rulemaking, the Agency declined to require industrial plants to
    adopt closed-cycle cooling technology, which by recirculating cooling
    water requires less water to be withdrawn and thus fewer aquatic
    organisms to be killed. Riverkeeper, Inc. v. EPA, 
    358 F. 3d 174
    , 182,
    n. 5 (CA2 2004); 
    69 Fed. Reg. 41601
    , and n. 44. This the Agency de
    cided despite its acknowledgment that “closed-cycle, recirculating
    cooling systems . . . can reduce mortality from impingement by up to 98
    percent and entrainment by up to 98 percent.” 
    Id., at 41601
    . The EPA
    instead permitted individual plants to resort to a “suite” of options so
    long as the method used reduced impingement and entrainment by the
    more modest amount of 80 and 60 percent, respectively. See 
    40 CFR §125.94
    (b). The Agency also permitted individual plants to obtain a
    site-specific variance from the national performance standards if they
    could prove (1) that compliance costs would be “significantly greater
    than” those the Agency considered when establishing the standards, or
    (2) that compliance costs “would be significantly greater than the
    benefits of complying with the applicable performance standards,”
    §125.94(a)(5).
    13 Thus, the Agency’s past reliance on a “wholly disproportionate”
    standard, a mild variant of cost-benefit analysis, is irrelevant. See
    ante, at 14. Because “Congress has directly spoken to the precise
    12            ENTERGY CORP. v. RIVERKEEPER, INC.
    STEVENS, J., dissenting
    Because we granted certiorari to decide only whether the
    EPA has authority to conduct cost-benefit analysis, there
    is no need to define the universe of considerations upon
    which the EPA can properly rely in administering the BTA
    standard. I would leave it to the Agency to decide how to
    proceed in the first instance.
    III
    Because the Court unsettles the scheme Congress estab
    lished, I respectfully dissent.
    ——————
    question at issue,” Chevron, 
    467 U. S., at 842
    , longstanding yet imper
    missible agency practice cannot ripen into permissible agency practice.
    

Document Info

Docket Number: 07-588

Citation Numbers: 173 L. Ed. 2d 369, 129 S. Ct. 1498, 556 U.S. 208, 2009 U.S. LEXIS 2498

Judges: Breyer, Ginsburg, Scalia, Souter, Stevens

Filed Date: 4/1/2009

Precedential Status: Precedential

Modified Date: 8/3/2023

Authorities (16)

seacoast-anti-pollution-league-v-douglas-m-costle-as-administrator-of , 572 F.2d 872 ( 1978 )

seacoast-anti-pollution-league-v-douglas-m-costle-as-administrator-of , 597 F.2d 306 ( 1979 )

riverkeeper-inc-natural-resources-defense-council-waterkeeper-alliance , 475 F.3d 83 ( 2007 )

riverkeeper-inc-natural-resources-defense-council-waterkeeper-alliance , 358 F.3d 174 ( 2004 )

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appalachian-power-company-baltimore-gas-and-electric-company-carolina , 566 F.2d 451 ( 1977 )

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Thomas Jefferson University v. Shalala , 114 S. Ct. 2381 ( 1994 )

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Barnhart v. Walton , 122 S. Ct. 1265 ( 2002 )

Alaska Department of Environmental Conservation v. ... , 124 S. Ct. 983 ( 2004 )

National Cable & Telecommunications Assn. v. Brand X ... , 125 S. Ct. 2688 ( 2005 )

Russello v. United States , 104 S. Ct. 296 ( 1983 )

Chevron U. S. A. Inc. v. Natural Resources Defense Council, ... , 104 S. Ct. 2778 ( 1984 )

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