Slip Opinion — Utility Water Act Group Group v. Riverkeeper, Inc. (Nos. 07-597, 07-588, 07-589)

(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 of the opinion of the Court but has been

pared by the rter of Decisians for the convenience of the reader.

e 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 “[aJny 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 etal. 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.

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), (i). 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 IT 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 possibie 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: 556U.S.__— (2009) 3

Syllabus

(b) Considering §1326(b)’s text, and comparing it with the text and

stetutory 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 lI’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) l

Opinion of the Court

NOTICE: This opinion is subject to formal revision before publication in the

prelimi print of the United States Readers are gate to

notify the of Decisions, Supreme ourt of the United States, W

ington, D. C. 20543, of any ppt hy boom pong Ayn wi

that corrections may be made 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 U.

RIVERKEEPER, INC., ET AL.

PSEG FOSSIL LLC, ET AL., PETITIONERS

07-589 U.

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 States'—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/3 16b/files/1977AEI guid. 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.”? §125.84(b)(1).

New facilities with water-intake flow between 2 million

2Closed-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).

A 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. 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. /bid. 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 A341 (Feb. 2004), online at http://www.

epa.gov/waterscience/3 16b/phase2/econbenefits/fin al/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. /d., 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.” Jd.,

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.” J/d., at 41605. The EPA thus concluded that “[all-

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.” /d., 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)G), or that the costs of compliance “would be

significantly greater than the benefits of complying with

the applicable performance standards,” §125.94(a)(5)(i).

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)Q@), (a).

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. Jd., 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. Jd., at 104—105.

(The remand was also based on other grounds which are

not at issue here.) The EPA suspended operation of the

Phase [I rules pending further rulemaking. 72 Fed. Reg.

Cite as: 556U.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. __ (2608).

Il

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’ 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

*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 FENTERGY 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,” Websters 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: 556U.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 §13 16(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 | 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.°®

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

®’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 FPA 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 besi

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 HPA vy. 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-pollutaut control technology.” §1311(b)(2)(E).° (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

‘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(6)(2)(F) the adjective modifies “pollutant” rather than “control

technology.” The hyphen makes that clear.

Cite as: 556U.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 posi, at 3-4,

our decisions in Whitman v. American Trucking Assns.,

Inc., 5381 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. Jd., 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 I] 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)@i). 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.” Jn re Public Service

Co. of New Hampshire, 1 E. A. D. 332, 340 (1977). See

also In re Central Hudson Gas and Eleciric 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 systems’

as the “best technology available” for Phase | 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

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.

7 * ”

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

“‘whoily 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 LI 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 IT

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: 556U.S. ss (20009) 17

Appendix to opinion of the Court

APPENDIX TO OPINION OF THE COURT

Statutory Statutorily Mandated Entities

Standard Factors Subject to

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

tue application ofthe | 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 ofthe best |technology...shallinclude | “conventional

conventional pollutant |consideration ofthe 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). areduction 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 shail 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.” 33U.5.C.

§1311(b)(2)(A) (empha-

sis added).

18 ENTERGY CORP. v. RIVERKEEPER, INC.

Appendix to opinion of the Court

Statutory Statutorily Mandated B.. . mol

Standard Factors A

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. §1816(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.”

83 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 Uv.

RIVERKEEPER, INC., ET AL.

PSEG FOSSIL LLC, ET AL., PETITIONERS

07-589 v.

RIVERKEEPER, INC., ET AL.

UTILITY WATER ACT GROUP, PETITIONER

07-597 U.

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[njentially.”. 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., Ist 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.” /d., 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.” Jbid.;

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.” /bid.

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.” Jbid. 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.” Jbid.

Senator Muskie’s statement then considers the “di/ffer-

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.” /bid. 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.” Jbid. (emphasis

added). And “the reasonableness of what is ‘econornically

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.” Jbid.

6 ENTERGY CORP. v. RIVERKEEPER, INC.

Opinion of BREYER, J.

(emphasis added).

| believe, as | 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 reflecis its ideal objective, moving

as closely as is technelogically 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.” Jbid. 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.”)

| 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 (CAl 1978) (emphasis added); see also /n 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); Jn

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 |

agree with its opinion.

i]

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)@) (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 & ~elecommunications 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 relerred 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, | would remand these

cases to the Court of Appeals. But unlike the majority |

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 Vv.

RIVERKEEPER, INC., ET AL.

PSEG FOSSIL LLC, ET AL., PETITIONERS

07-589 v.

RIVERKEEPER, INC., ET AL.

UTILITY WATER ACT GROUP, PETITIONER

07-597 U.

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,' see 69 Fed. Reg. 41586, the Agency struggled to

calculate the value of the aquatic life that would be pro-

1To 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/NET L_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: 556U.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.? 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. /d., 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.”%

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

2EPA, 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:/Awww.epa.gov/waterscience/3 1 6b/phase2/econbenefits.

SEPA, Economic and Benefits Analysis for the Final Section 316(b)

Phase IT Existing Facilities Rule, p. DI-5 (EPA-821—R—04—005, Feb.

2004), http:/Avwww.epa.gov/waterscience/316b/phase2/econbenefits/inal.

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’ 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.” /d., at 469.

American Trucking’ 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. /d., 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 vy. 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-

‘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-filing 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).

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.

5The 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. 7d., 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.”” §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.

®Congress later extended the deadline to March 31, 1989.

‘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,”® 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 assess.ng

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 rbid., 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: 556U.S.___s (2009) 4

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.’ 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]Jhere 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.'° Allowing cost-benefit analysis in the BTA

standard, a permanent mandate applicable to all power-

plants, serves no such purpose and instead fundamentally

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-ormothing reasoning rests on the deeply

flawed assumption that Congress treated cost-benefit analysis as just

one among many factors upom which the EPA could potentially rely to

establish BTA. Yet, as explamed above, she 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.

19TIn 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. !!

Accordingly, | 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, that action

was contrary to law, for Congress directly foreclosed such

reliance in the statute itself.'* Chevron, 467 U.S., at 843.

'! 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.

'2The “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.” 7d., 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).

'8Thus, 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.

lil

Because the Court unsettles the scheme Congress estab-

lished, | respectfully dissent.

question at issue,” Chevron, 467 U.S., at 842, longstanding yet imper-

missible agency practice cannot ripen into permissible agency practice.