1 (Slip Opin i o n) OCTOBER T ERM, 20 08 Sy llabu s
N O TE : Wh er e it i s feas ibl e , a s yllab u s (h ead n ot e) wil lbe rel e as ed , as is bein g d o n e incon n ecti onwithth is cas e , a tth e ti meth e op in i o n is is s u ed

. Th e s yll abu s con s titu tes n o p a rt of th e op in i o nof th eC o u r t bu t h a s be en pre p are dbyt h e Re po rte ro f De ci sio n s fo r t h e co nveni e nce of t h e reade r . Se e United Statesv. Detroit Timbe r& Lumb er Co., 200U. S

. 3 21, 337

. 

## SUPREME CO URT O FTHE UNI TED STATES
Sy llabu s COE U R ALASKA, INC

. v . SOU T HEAST ALA S KA C O NS ERVATIO NC O U N C IL ET AL

. CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR THE NINTH CIRCUIT No. 07–9 84. Ar g u ed Jan u a r y12, 2009—Dec i ded Ju n e 22, 200 9 * In revivingaclos ed Al a s kagold m i ne us ing a“f rot hflot a t ion” t e c h

nique, petition er Coeur Alaska, Inc ., plans to dispose of the resulting wa s t e ma t e rial, arock a n d wa t e r m i xt ure ca lled “s lurry, ” b ypum p ing it into a nearb ylake and then disc ha rging purified la ke wa t e r int o a downstream c r eek. The Cle a n Water Act (CWA), inter alia, c l assif i es crus h ed rock a s a“polluta nt ,” §3 52 (6); forb ids it s dis c harge “ [ e]x c ept as inc o mplian c e” withth e Ac t, §301(a); em power s th e ArmyCor p s of Engineers (Co r ps) to “issue permits .

. . fo r the discharge of .

. . fill mater i a l ,” §4 04(a); an d a u th or izes the Environment a l Protection Agency (EPA) to “issue a pe rmit fo r the discharge of any pollutant,” “[e]xcept as pr ovided in [§404],” §402(a). The Corps and the EPA to

gether define “fill ma terial” as any “mater i al [that] has the effect of

. . . [c ]hangi ng the bottom el ev ation” of wa t e r, includin g “ s lurry .

. . or simi larmin i n g -r elated mate r i als.” 40 CF R §232. 2. Coeu rAlaska ob

t a ined a§4 0 4perm itfor t h e s l urry dis c h a rge fromt h eCorps a n d a §402 per m i tforth e lake waterdisc h a r g e from th e EPA. Respondent env i ronmental gr oups (collectiv ely , SEACC) sued the

Cor p s an d sev e r a l of its offic i als under the Administrati ve Procedure Ac t, ar g u in gth at th e CWA §404per m it w a s n o t “inac c o r d an c ewith law,” 5 U. S. C. §706( 2)(A), bec a u s e (1) Coeu rAlaskash ou ld h av e sought a CWA §40 2 permi tfrom the EPA inste a d, jus tas itdid for the lake wate rdisc har g e; and (2) the slu rry discharge would violate the “new source performance st andard” t h e EPA had promulgated u n d erCWA §306(b), forb iddin gfr oth -fl otationg o ld min e s to dis

-

——————

* Tog e th er with No. 07 –99 0, Alask av. Southeast Alaska Conservation Council et al. , a l s oon cert ior a ri t ot h e s a me cou r t

.2 COEUR ALA S KA, INC. v. S O UTHEAST ALASKA CONSERVAT ION COUNCI L Sy llabu s cha r ge“ p roce s s wa s t ewat er,” whic h includes solid was t es, 40 C F R §440.1 04(b)(1)

. Coeu rAlaska an d petit i on erAlaska in te rv en ed as de

fendants

. The Dis t rict Court gr anted the defendants summar y judg ment, but the Ninth Circ uit r e v e rsed, holding that the proposed slurry discharge would viol ate th e EPA’s performance standard and §306(e). Held: 1. The Corps, not the EPA, has au thor ityto per m it the slur r ydis

c h ar g e . Pp. 9–13. (a) By specifying that, “[e]xc ept as provided in .

. . [§4 04,]” th e EPA “may .

. . is s u e permit[s ] for the discharge of any pollutant, ” §402( a) forbid s the EPA to i ssue permit s f o r fill ma teria l s fa llingun der the Corps’ §404 authority. Evenif the r e were ambig u ity on this point, it would be resolved by the EPA’s own re gulation providing that “[d]ischarges of .

. . fill materia l

. . . which are regulated under section 404” “do not require [EPA §4 02 ] perm i t s . ” 40C F R§1 22 .3. The agencies have interpreted this regula tion to e ssenti a lly resta t e §402’ s tex t , ibi d ., an d th e EPA h a s c o n f ir m e d th at r e adin gbefor eth is Court. Because it is not “pl a inly erro neo u s or in cons is tent with the regula t i on,” t h e Courta ccept s t h e EPA’s int e rpret a t i on a s correct

. Aue r v. Robbin s , 519 U. S. 452, 4 61. Th u s , th e qu estio nwh eth e rth e EPA i s the proper agency to regula te the sl urry dischargedepends o n whether the Corps has authority to do so. If so, the EPA may not r e g u late. Pp. 9–1 1. (b) Bec a u s e §404(a) empowe r s th e Cor p s to “issu e per m i t s . . . for the discharge of .

. . fill ma t e rial,”and th e agencies’ joint regulation defines “fill m a terial” to include “slu rry . . . or similar mining-related mater i a l s” ha v i ngthe “effect of .

. . [c ]hangi ngthe bottom elev ation” of water, 40 CFR §232.2, the s l urry Coeur Alask awishes to discharge in to th e lake falls well with i nth e Cor p s’ §404 per m i ttin gau th or ity , r a th erth anthe EPA’ s §402 au th or ity

. The CWA giv e s n oin dic a tion that Congr e ss intended to b u r d en industrywith the c o nfusingdiv i

s i on of perm it t i ng a u t h orit yt h a tS EACC’s cont ra ryre a d ing would c r e ate. Pp. 11–13.

2

. The Corps act e d in a ccorda n ce wit hla w in is s u ing t h e s l urry dis

c h ar g eper m it to Coeu rAlas ka. Pp. 13–28

. (a) The CWA alone does not reso lve these cases. Pp. 14–18.

(i) SEAC C contends that be c a use the EPA’s performancestan

dard forbids even minute soli d waste di scharge s , 40 CF R §440.1 04(b)(1) , it also forb id s Coeu rAlask a ’ s slu r r ydisc h a r g e, 30% of which is solidwaste, into t h e la ke. Thus , s a ys S E ACC, the s l urry dis c ha rge is “unla w ful” un der CWA §3 06 (e), whic h p r ohib its “a ny owner . . . of any ne w sourceto operate such source in vio l ation of any stan dar dof pe r f or man c e applic able to su c hsou r c e .” Pp. 1 4–1 6.3 Cite as: 55 7 U

. S. ____ (2009) Sy llabu s (ii) Petitioner s and the fe dera l a g encies count er t h a tCWA §404 gr an ts t h e Cor p s au th or ityto deter m in e wh eth e rto issu e a perm ita llowing t h e s l ur rydis c ha rge wi t h outrega rd t ot h e EPA’s n e w sou r c eper f or man c e stan dar dor§306(e)’ s pr oh ibition

. Pp. 16–18. (iii) The CWA is am big u ous on the question whether §306 ap

plies to discha rg es of fill materialreg u lated under §404. On the one h a n d , §306 p r ov ides th at a disc h a r g e t h at v i olate s anEPA n e w s o urce perfor m a nce s t a n dard is “ unla w ful”—without a nexception for fill m a terial. On the other hand, §404 gr ants the Corp s bl anket au

thority to permit the di scharge of fill ma terial—without mentioning §306. Th is ten s ionin dic a tes th at Con gr e ss h a s n o t “dir ec tlyspoken” to the “pr e c i se question” atissue. Chev ro n U. S. A. In c. v. Natural Resource s Defe nseCounci l, I n c. , 467 U. S. 837, 84 2. P. 18. (b) Although the agencies’ re gula tions cons truing the CWA a r e entitled to def e r e nc e if they r e so lv e th e statu t or yambig u ityina r e a sonable manner, see Ch evro n, su pra, at 842, th e r e g u la tion s bear in g on§§306 an d 404, like th e CWA i t self, d on o t do so. Forex ample, each of thetwo principal regulation s seem s to stan d onits ow nw i th

out refere nce t othe other. T h e EPA’s perform a nce s t a n da rd cont a i ns no exception for fill m a teria l , and it forb id s any discharge of “process wastewater,” including solid wast es . 40 C F R§4 40 .1 04 (b )(1 ). The agencies’ joint regulation defining f ill material includes “slurry o r . . . simi larmin i n g -r elated mat e r i als,” §2 32.2 , bu t c o n t ain s n oexc e ption for s l urry re gu la t e d b y a n EPA performa nce s t a n da rd. Additiona l regulations noted by the parties offer no basi s for reconciliation. Pp. 18–2 0. (c) In light of the ambiguitie s in the CWA and the pertinent regu

lations, the Co ur t tur n s to t h e ag en cies’ subsequent interpretation of those regulations. Auer, supra, at 461. Th e qu estionat is su e is ad

dr essed an d r e solv ed ina r e ason ab le an dc o h e r e n tway byth e two a g encies ’ pra c t i ce a n d policy , a s recit e d in t h e EPA’s int e rna l“R egas M e mor a ndum” (M emor andum), whic h ex p l ains tha tthe per f or manc e stan dar dapp l i e s on lyto th e disc h a r g e of water from the l a ke into the downstr e am c r eek, and not to the init i a l discharge of slurry into the lake. Though the Memorandum is not subjec t to suffic i entlyfor m al procedures to merit full Chevron defer e nc e, the Cour t defer s to it be

cause it is not “p lainly erroneous or inconsistentwit hthe regula

tion[s],” Auer, supra , at 461. Fiv efac t or s i n for mth at c o n c lu sion : Th e Memora ndum (1 ) confines its own s c op e to closed bodie s of water like the lake here, thereby pres erving arole for t h e perfo r m a nce s t a n dar d s; (2) g u ar ds ag ain s t th e possibili ty of evasion of those standards; (3) emp l oys th e Corps’ expertise in ev aluating the effects of fil lmate

rial on the aquatic environment; (4) does not allow tox i cc o mpounds to be d i sc h a r g ed in to n av i g able water s ; an d (5) r e c o n c iles §§3 06, 4 02,4 COEUR ALA S KA, INC. v. S O UTHEAST ALASKA CONSERVAT ION COUNCI L Sy llabu s

an d 404, an d th e r e gu lation s implemen t i n gth em, betterth anan yof the par t ies’ a l ter n ativ es. The Cour t agr e es with the p a r t ies th at a t w o-perm itregim eis cont ra ry t ot h e s t a t u t e a n d regula t i ons . Pp. 2 0– 23. (d) The Court rejects SE AC C’s c o ntention that the Reg a s M e mo r a ndum is not entitled to de fer e nc e because it contradicts the agen

cies’ publishe d st atement s and prio r pra c t i ce. ThoughS E ACC cit e s th r ee su chstatemen ts, it s ar g u men t s ar e not c o nv inc i n g . Pp. 23–28. (i) Alth ou gha 19 86 memor a n d u mof agr eemen t (M OA) be

tween the EPA and the Corps seeking t oreconcile t h eir t h en-differing “fill m a terial” definitions su g g e sts, as SE ACC as serts, t h at §402 wil l “nor mally” ap plyto disc har g es of “suspen d ed”— i.e., solid—pollutant s, that st ate m ent is not c o ntr a r yto the Reg a s M e mor a ndum, whic h ac

kn owledg es that th e EPA r e tain s au th or i t yu n d er§402 to r e g u late th e disc h a r g e of su spen ded solids fr om the lake into downstream wa

ters. The M O A does not address the question prese n ted by these c a ses, an dan s w er ed byth e Reg a s M e mor a n d u m , an d i s , infac t , c o n sistent with the agencies’ d e termin ationt h at th e Cor p s r e g u lates al l discharges of fill ma terial and that§30 6d oes not apply to these dis

c h ar g e s. Pp. 2 3–2 5. (ii) Despite SE ACC’s assert io n that the fil l reg u lation’s pream

ble demonstra t es that the fill rule was not intended to displ a ce the pre-existing froth-flotation gold mine per f or manc e standar d , the pr e amble is c o nsi s tent with the Reg a s Memo randum when it explicitly notes that the EPA has “never soughtto regulate fill m a terial under efflu e n tgu idelin es,” 67 Fed. Reg

. 31135. If a disc h a r g e does n o t qu al

ifyas fil l , th e EPA’ s n e wso u r c eper f or man c e stan dar d applie s. If th e discharge qualifies a s fill, t h e perf ormance standard do es not apply; and there wa s no earlier a g enc ypra c t i ceor policyt ot h e cont ra ry. Pp. 25–2 6. (iii) Remarks made by the t w o agencies in promulgating the fill r e g u lation, whic h pledg ethat the EPA’s “prev i ou[s] .

. . determina

tion[s]” with r e g a r dto the a pplic ation of per f or manc e st andar d s “r e main vali[d],” are not co nclusive of the question at issue. TheRegas Memora ndum ha s followed this policy b ya pplying the performa nce standard to th e discharge of water from the lake into thecreek

. The r e mar k s do no t s t ate thatth e EPA wi ll ap plysuc hstan dar d s to di s charges of fill materia l

. Pp. 26– 27. (iv) While SE ACC cite s no in stance in which the EPA has ap

plied a performance standa rd to a discha rge of fill mat e rial, Coeur Alask ac i tes t w o in stan c e s inwh ic h th e C o r p s issu ed a §404 per m i t authorizing a mine to d i scharge so lid wa ste as f ill mat e rial. Thes e permits il lust rate that the agencies did not have a prior practice of applying EPA performance standards to di scharges of mining wastes5 Cite as: 55 7 U

. S. ____ (2009) Sy llabu s that qualifyas fill materia l

. Pp. 27–2 8. 486 F. 3d 63 8, r e v e r s ed an d reman d ed.

K ENNEDY , J., delivered the opinion of theCourt, in which R OBERTS , C. J., and T HOMAS , B REYER , an d ALITO , JJ. , joined, and i nwhi c h S CALIA , J., joined in part. B REYER , J ., filed aconcur ring opinio n. S CALIA , J., filed a nopinion con c u rrin gin pa rta n d conc urri ng int h e j u dgm e n t

. G IN SB U R G , J., filed a dis s ent i ng opinion, i nwhich S TEVENS an d S OUTER , JJ., joined._________________

_________________ 1 Cite as: 55 7 U

. S. ____ (2009) Opinion of theCourt
NOTIC E : Th is op i n ionis subjec t to f o rma lrevi si onbef o r e publicat ioninth e p r eli m in ary p rin t of th e U n it edS t at es R e p o rts

. R e ad ers ar e r e qu es ted to n o tif yth e R e p o rt e rof D e c i s i on s , Su p r em e C o u rt of th e U n ited St at es , Wa s h

ington, D. C. 2054 3, of any typ o gra p hical or other f o rmal err o rs , in or der th atc o rr ect i on sm a y b e mad eb e f o r e th ep r e lim in aryp rin t go es t o p r es s . 

## SUPREME CO URT O FTHE UNI TED STATES

Nos. 07– 98 4 a n d 07–9 90
COE U R ALASKA, INC ., PETITIONER 07–984 v. SOU T HEA S T ALASKA CONSERVATION C O UN CIL ET AL

. ALASKA, P E TITIONER 07–990 v. SOU T HEA S T ALASKA CONSERVATION C O UN CIL ET AL

. ON WRITS OF CERTIORARI TO THE UNITED STAT ES COURT OF APPEAL S FOR THE NINT H CIRCUIT [Ju n e22, 2009 ] J USTICE K E NNEDY delivered the opinion of the Court. These cases require u s to addres s two quest ions under the Clean Water Ac t ( C WA or Ac t). The firs t is whethe r the Act give s authority to the United States Ar my Corps of Engineers, or instead to the Environmental Protection Agency ( E PA ), to issue a permit for the discharge of min

ing waste, called slurry. The Corps of Engineers has issued a permit to pet i tioner Coeur Alaska, Inc. (Coeur Alaska), for a discharge of slu rry into a lake in Southeast Alask a . The second qu estion is w h ether, when the Corps issued that permit, th e agency a cted in a c c o rdance wit h law. We conclude that the Corps was the appropriat e agency to issue the permit and that the permitis lawful. With regard to the first question, §404(a) of the CWA2 COEUR ALA S KA, INC. v. S O UTHEAST ALASKA CONSERVAT ION COUNCI L Opinion of theCourt grants the Corps the power to “i ssue permits

. . . for the discharge of

. . . fill ma terial.” 86Stat. 884; 33 U. S. C. §1344(a). B u t the EPA also has au thority to issue permits for the discharge of pollutants. Section 402 of the Act grants the EPA autho rity to “issue a permit for the dis

charge of any pollutant” “[e]xcept as provided in” §404. 3 3 U. S. C. §1 342(a). We conclude that because the slurry Coeur Alas ka wishes to discharge is defined by regulati on as “fill ma terial,” 40 CFR §232.2 (2008), Coeur Alaska properly obtained its permit from the Corps of Engineers, under §404, rather tha nfrom the EPA, under §402. The second question is whether the Corps permit is lawful. Three environmental groups, respondents here, sued the Corps under the Administrative Procedure Act, arguing tha tthe issuance of the permit by th e Corps wa s “not in accordance wit hlaw.” 5 U. S. C. §70 6 (2)(A). Th e environmental groups are Southeast Alaska Conservation Council, Sierra Club, and Lynn Canal Conservation (col

lectively, SEACC). The State of Alask aand Coeur Alask a are petitioners here. SEACC argues that the permit from the Corps is unlaw

ful because the discharge of slurry would violate an EPA regulation promulgated under §306(b) of the CWA, 3 3 U. S. C. §1316(b). The EPA re gulation, which is called a “new source performance standa r d,” forbids mines like Coeur Alaska’s from di scharging “process was t ewater” into the navigable waters. 40 CFR §440.104(b)(1). Coeur Alask a , the State of Alask a , and the federal agencies maintain that the Corps permit is lawful nonetheless because the EPA’s performance standard doe s not apply to discharges of fill materi al. Reversing t h e judgment of the Dis trict Court, the Cour t of Appeals held that the EPA’s performance standard applies to th is discharge so that the permit from the Corps is unlawful.3 Cite as: 55 7 U

. S. ____ (2009) Opinion of theCourt I A Petitioner Coeur Alask aplans to reopen the Kensingto n Gold Mine, located som e 45 miles n o rth of Juneau, Alaska. The mine has been closed since 1928, but Coeur Alaska seek s to ma k e it profitable on ce more by using a technique known as “froth flotati o n.” Coeur Alaska wil lchurn the mine’s crushed rock in tanks of fro t hing water. Chemicals in the wate r will caus e gold-bearing minerals to float to the surface, where they will be ski mmed off. At issue is Coeur Alask a ’s plan to dispose of the mixture of crushed rock an d water left be hind in the tanks. Th is mixture is called slurry. Some 3 0 percent of the slurry’s volume is crushed rock, resembling wet sand, which is called tailin gs. The rest is water. The standard wa y to d i spose of slurry is to p u mp it into a tailings p o nd. The s l urry separates in the pond. Soli d tailings sin kto the bottom, and water on the surface returns to the mine to be used again. Rather than build atailings pon d , Coeur Alaska pro

poses to us e Lower Sl ate Lake , located some three miles from the mine in the Tongass National Forest. This lake is small—8 00 feet at i t s widest crossing, 2,000 feet at its longest, and 23 acres in area. See App. 138a, 212a. Though small, the lak e is 51 f eetdeep at its maximum. The parties agree the lak eis a navigable water of the United States and so is subject to the CWA. They also agree there can be no discharge into the lake except as the CWA and any lawful permit allow. Over the life of the mine, Coeur Alaska inte nds to pu t 4.5 milli on tons of taili ngs in the lake. This will raise the lakebed 50 feet—to what is now the lake’s surface—an d will increase the lake’s area from 23 to about 60 acres. Id., at 361a (62 acres), 212a (56 acres). To contain this wider, shallower body of wate r, Coeur Al aska will dam the lake’s downstream shore. The transformed lake will be isolated4 COEUR ALA S KA, INC. v. S O UTHEAST ALASKA CONSERVAT ION COUNCI L Opinion of theCourt from other surface water. Creeks and stormwater runoff will detour around it. Id., at 298a

. Ultimately, lakewate r will be clea ned by puri fication systems and will flow from the lake to a stream and thence onward. Id., at 309a– 312a. B Numerous state and federal agencies reviewed an d approved Coeur Alask a ’s plans. At issue he re are actions by two of those agenci es: the Corps of Engineers and the EPA. 1 The CWA classifies crushed rock as a “pollutant.” 33 U. S. C. §13 62(6). On the one hand, the Act forbids Coeur Alaska’s di scharge of crushed roc k“[e]xcep t as in compli

ance” with the Act. CWA §301(a), 33 U. S. C. §1311(a). Section 404(a) of the CWA, on the other hand, empowers the Corps to authoriz ethe disch a rge of “ d r e dged or fi ll material.” 33 U. S. C. §1344(a). The Corps and the EPA have together defined “fill materi al” to mea nany “mate

rial [that] has the effect of

. . . [c]hanging th e bottom ele

vation” of water. 40 CFR §232.2. The agencies have further defined the “discharge of fill material” to include “placement of

. . . slurry, or tailings or similar mining

related materials.” Ibi d

. In these cases the Cor p s and the EPA agre e that the slurry meets their regulatory definition of “fill material. ” On that pre m ise the Corps evaluated the mine’s plan for a §404 permit. After considering the environmental factors required by §404(b), th e Corp issu ed Coeur Alaska a per

mit to pump the slurryinto Lower Slate Lake. App. 340a– 378a. In grantingthe permit the Corps followed the steps set forth by §4 04. Section 404(b) requires the Corps to co n sider the environmental consequen c es of every discharge it5 Cite as: 55 7 U

. S. ____ (2009) Opinion of theCourt allows. 33 U. S. C. §1344(b). The Corps must apply guide

lines written by the EPA pu rsuant to §404(b). See ibi d .; 40 CFR pt. 230 (EPA guidelines). Applying those guide

lines here, th e Corps de termined th at Coeur Al aska’s plan to use Lower Slate Lake as a tailings pond was the “least environmentally damaging pra cticable” way to dispose of the tailings. App. 36 6a. To conduct tha t analysis, the Corps compared the plan to the proposed alternatives. The Corps determined that the environmental damage caused by placing slurry in the lake will be temporary. And duringthat temporary disru p tion, Coeur Alaska wil l divert wate rs around the lake through pipelines built for this purpose. Id., at 2 98a. CoeurAlaska will also treat water flowi n g from t h e lake into downstr e am waters, pursuant to strict EPA criteria. Ibid

. ; see Part I–B–2, infra

. Though the slurry will at first destro y the lake ’s small population of common fis h , that po pulation may later be replaced. Afte r mini ng operations are completed, Coeur Alaska will hel p “recla[im]” the lake by “[c]apping” the tailings with about 4 inches of “native material.” App. 361a; id., at 309a. The Corps concl u ded that “[t]he reclamation of the lake will result i nmore emergent w e tlands/vegetated shallows with m o derate values for fish habitat, nutri ent recycli n g, car bon/detrital export an d sediment/toxicant re tention, and high va lues for wildlife habita t.” Id. , at 361a. If the tailings did not go into the lake, they would be placed on n e arby wetlands. The r e sulting pile would ris e twice as high as the Pentagon and cover th ree times a s many acres. Reply Brief for Petit i oner CoeurAlaska 27. If it were chosen, that alternative would destroy dozens of acres of we tlands—a permanent loss. App. 365a–366a. On the pre m ise that when the mining ends the lak ewill be at least as environmentally hospitable, if not more s o , than now, the Corps concluded tha tplacing the tailings in6 COEUR ALA S KA, INC. v. S O UTHEAST ALASKA CONSERVAT ION COUNCI L Opinion of theCourt the lak e will cause les s damage to the environment than storing them above ground: The reclaimed lake will be “more valuable to the aquatic ec osystem than a perm a nently filled wetland . . . thathas lost all aquatic functio n s and values.” Id ., at 361a; see also id., at 366a. 2 The EPA h a d the stat utory autho rity to veto the Corp s permit, and prohibit the discharge, if it f o und the plan to have “an unacceptable adverse eff e ct on mun i cipal wate r supplies, shellfish beds and fishery areas

. . . , wildlife, or recreational areas.” CWA §404(c), 33 U. S. C. §1344(c). After considering the Corps fi ndings, the EPA did not veto the Corps permit, even though, i nits view, placing the tailings in the lake was not the “environmentally prefer

able” means of disposing of them. App. 300a. By declining to exercise its veto, the EPA in effe ct deferred to the jud g ment of the Corps on this point. The EPA’s involvement exte nde dbeyond the agency’s veto consideration. The EPA als o issued a permit of its own—not fo r the discha rge from th e mine into the lake but for the disc harge from the lake into a downst ream creek. Id. , at 287a–331a. Section 402 grants the EPA authorit y to “issue a permit for the discharge of any pollutant,” “[e]xcept a s provided in [CWA §404].” 33 U. S. C. §1342(a). The EPA’s §4 02 permit authorizes Coeur Alaska to discharg ewater f r om Lower Slate Lake in to the down

stream creek, subject to strict water-quality limits that Coeur Alaska must re gularly monitor. App. 303a–304 a, 309a. The EPA’ s authority t o regulate this discharge come s from a re g u lation, termed a “ne wsource performanc e standard,” that it has promulgated under authority granted to it by §306(b) of the CWA. Section 306(b) gives the EPA authority to regulate the amountof pollutants that ce rtaincategories of ne w sources may discharge into7 Cite as: 55 7 U

. S. ____ (2009) Opinion of theCourt the navigable waters of the United States. 33 U. S. C. §1316(b). Pursuant to this auth o rity, the EPA in 1982 promulgated a new source pe rformance standard restrict

ing discharges from new froth-fl otation gold mines like Coeur Alaska’s. The standard is stringent: It allows “n o discharge o f process wastewater” from these mines. 40 CFR §440.104(b)(1). Applying that standard to the discharge of water from Lower Slat e Lake into the downstream creek, the EPA’s §402 permit sets strict limits onthe amount of pollutants the water may contai n. The per m it requires Coeur Ala s ka to treat the water using “reve rse osmosis” to remove alu

minum, suspended solids, and other pollutants. App. 298a; id. , a t304a. Coeur Alaska must monit o r the water flowing from the lake to be sure that the p o llutants are kept to low, specified m i nimums. Id., at 326a–330a. C S E AC C br ou gh ts u it ag a i n s t the Corps of Engineers and various of its officials in the United States Di strict Court for the District of Alaska. The Corps perm it was not in accordance with law, SEA CC a r gued, for two reasons. First, in S EAC C’s view, the per m it was is sued by th e wrong agen cy—Coeur Alaska ought to have sought a §402 permit from the EPA, just as the company did for the discharge o f water f r om the lake into the downstrea m creek

. See Part I–B–2, supra. Second, SEAC C contende d that regard less of which agency issued the permit, the discharge itself is unla w ful because it willviol ate the EPA new source performan c e standard for froth-fl otation gold mines. (This is the same performance standard describ e d above, which the EPA has already applied to the discharge of water fr om the lake into the downstrea mcreek. See ibid. ) SEACC argued that this performance standard als o applies to th e discharge of slurry into the lake. It con

tended further that th e performance standard is a binding8 COEUR ALA S KA, INC. v. S O UTHEAST ALASKA CONSERVAT ION COUNCI L Opinion of theCourt implementa tion of §306

. Section 306(e) of the CWA mak e s it “unlawfu l” for Coeu r Alaskato “operate” t h e mine “in violation of ” the EPA’s performance standard. 33 U. S. C. §1316(e). Coeur Alask aand the State of Alask aintervened as defendants. Both sides mo ved f o r summar y jud g ment

. The Distric tCourt gra n ted summary jud g me nt in favor of the defendants. The Court of Appeals for the Ninth Circuit rev e rsed and ordered the District C o urt to vac a te the Corps of Engi

neers’ permit. South e ast Alask a Conserv atio n Council v. United S t a t es Army Corps of Engs ., 486 F. 3d 638, 654– 655 (2007). The court acknowledged that Coeur Alaska’s slurry “faci a lly meets the Corps’ c u rrent regu latory defini

tion of ‘fill material,’ ” id., at 644, because it would have the effect of raising the lake’s bot t om elevation. But the court also noted that the EPA’s new source performance standard “prohibits discharges from froth-flotation mills. ” Ibid. The Court of Appeals concluded that “[b]oth of the regulations appear to apply in th is case, yet they are a t odds.” Ibid

. To resolve the conflict, the cour t turned t o what it viewed as “the plain language of the Clean Wat e r Act.” Ibid. The court held that the EPA’s new source performance standard “applies to discharges from th e froth-flotation mill atCoeur Alaska’s Kensington Gol d Mine into L o wer Slate Lake.” Ibid

. In addition to the text of the CWA , the Court of Appeals also reli ed on the agencies’ statements made when prom

ulgating their current and pr ior definitions of “fill mate

rial.” These statements, in the Court of Appeals’ view, demonstrated the agencies’ intent that the EPA’ s ne w source performance standard govern discharges like Coeur Alaska’s. Id. , at 648–654. The Court of Appeal s concluded that Co eur Alaska required a §402 permit for its slurry discha rge, that th e Corps lacked authority to issue such a pe rmit under §404 ,9 Cite as: 55 7 U

. S. ____ (2009) Opinion of theCourt and that th e proposed discharge was unlawful because it would violate the EPA new source performance standard and §306(e)

. The decision of the Co urt of Appe als in effect reallocated the divisionof respons ibility that the Corps a n d the EPA had been following. The Court granted certiorari. 55 4 U. S. ___ (2008). We now hold that the de cision of the Court of Ap peals was incorrect. II The question of which agencyhas authority to consider whether to permit the slurry disc harge is our beginning inquiry. We consider f i rst the authority of the EPA an d second the authority of the Corps. Our conclu sion is that under the CWA the Corps had authority to determine whether Co eur Alask a was enti tled to the pe rmit govern

ing this discharge. A Section 402 gives the EPA au thority to issue “permit[s] for the dis c harge of any pollutant,” with one important exception: The EPA may not issue permits for fill material that fall under the Corps’ §40 4permitti ng authori ty. Section 402(a) states:

“Except as provided in . . . [CWA §404, 33 U. S. C. §1344] , the Administr a tor may

. . . issue a p e rmit for the discharge of any pollutant, .

. . notwithstanding [CWA §301(a), 33 U. S. C. §1311(a)], upon condition that such discharge wi ll meet eith er (A) all applicable requiremen t s under [CWA §301, 33 U. S. C. § 1311(a); CWA §302, 33 U. S. C. §1312; CWA §306, 33 U. S. C. §1316; CWA §307, 33 U. S. C. §1317; CWA §308, 33 U. S. C. §1 318; CWA §403, 33 U. S. C. §1343], or (B) prior to the taking of n e cessary implementing actions relating to all such requirements, such condi t ions as the Admini strator determines are necessary to carr y10 COEUR ALA S KA, INC. v. S O UTHEAST ALASKA CONSERVAT ION COUNCI L Opinion of theCourt out the p r ovisions of this chap ter.” 33 U. S. C. §1342(a)(1) (emphasis a dded). Section 402 thus forbids the EPA from exercising permit

ting authority that is “provi ded [to the Corps] in” §404. This is notto say the EPA has no role with respect t o the environ m ental con s equences of fill. The EPA’s func

tion is diff erent, in r e gulating fill, from its function i n regulating other pollutants, but the agency does exercise some authority. Section 404 assigns the EPA two tas k s in regard to fi ll material. First, the EPA mustwrite guid e lines for the Corps to follow in determining whether to permit a discharge of fill material. CWA §404(b); 33 U. S. C. §1344(b). Second, the Act gives the EPA authority to “prohibit” anydecision by the Corps to is sue a perm it for a pa rticular disposal site. CWA §404(c); 33 U. S. C. §1344(c). We, and th e parties, r e fer to this as the EPA’s power to ve to a permit. The Act is best understood to provide that if the Corps has authority to issue a permit for a discharge under §404 , then the EPA lacks authority to do so under §402. Even if there were ambiguity on this point, the EPA’ s own regulations would resolve it. Those regulations pro

vide that “[d]ischarges of dredge d or fill material into waters of the United States which are regulated under section 404 of CWA” “do not require [§402] permits” fro m the EPA. 4 0 CFR §122.3. In SEACC’s view, this regulation implies that some “fill material” discharges are not regulated under §404—else, SEA CC as ks, wh y would the regulation lack a comm a before the word “which,” and thereby imply that only a subset of “discharges of

. . . fill material” are “regulated under section 404.” Ibi d

. The agencies, however, have interpreted this regulation otherwise. In the agen cies’ view the regulatio nessentia lly restates the text of §402, and forbi d s the EPA from issuing11 Cite as: 55 7 U

. S. ____ (2009) Opinion of theCourt permits for discharges that “a re regulated under section 404.” 40 CFR §122.3(b); cf. CWA §402(a) (“[e]xcept as provided in. . . [§404], the Administrator ma y . . . issue a permit”). B e fore us, the EPA confirms this re ading of th e regulation. Brief fo r Federal Respondents 27. Th e agency’s int e rpretation is no t “plainly erroneous or incon

sistent withthe regulat i on”; and so we acceptit as correct. Auer v. Robbins , 519 U. S. 452, 46 1 (1997) (internal quota

tion marks omitted). The questio n whether the EPA is the proper agency to regulate the slurry discharge thus depends on whether th e Corps of E n gineers has authority to do so. If the Corps has authority to issue a permit, then the EPA may not do so. We tur nto the Corps’ authority under §404. B Section 404(a) gives the Corps power to “issue per

mits

. . . for the discharge of dredged or fill material.” 33 U. S. C. §1344(a). As a ll parties concede, the s l urry meets the definition of fill material agre ed upon by the agencies in a joint regulation promulgated in 2002. Th at regulation defines “fill material” to mean any “material [that] has th e effect of

. . . [c]hanging the bottom elevation” of water—a definition that includes “slurry, or tailings or simil a r mining-related materials.” 40 CFR §232.2. SEACC concedes that the slurry to be discharged meets the regulation’s defini tion of fill material. Brief for Re

spondent SEACC et al. 20. Its co ncession onthis point is appropriate because slurry falls well within the central understanding of the term “fill,” as shown by the examples given by th e regulation. See 40 CFR §232.2 (“Exam ples of such fill material include, but are not limited to: rock, sand, soil, clay

. . . .”). The regulation further excludes “trash or g a rbage” fro mits definition. Ibid. SEA CC ex

presses a co ncern that Coeur Alas ka’s interpretation of the statute wil llead to §404 permits authorizing the dis

-12 COEUR ALA S KA, INC. v. S O UTHEAST ALASKA CONSERVAT ION COUNCI L Opinion of theCourt charges of other solid s that are now restricted by EPA standards. Brief for Respondent SEACC et al. 44–45 (listing, for example, “feces and uneaten feed,” “ litter, ” and waste produced in “battery manufacturing”). But these extreme instances are not presented by the cases now before us. If, in afuture case, a discharger of one o f these solids were to seek a §404 permit, the dispositive question for the agencies would b e whether the solidat issue—for instance, “feces anduneatenfeed”—came within the regulation’s definition of “fill.” SEACC ci tes no instance in which the agencies have so interpreted the i r fill regulation. If that instance did arise, and the agenci es were to interpret the fill regu lation as SEACC fears, then SEACC could challenge that de cision as an unlawful interpretati on of the fill re gulation; or SEACC could claim that the fill regulation as interpreted is an unreasonable interpretati on of §404. The difficu lties are n o t presented here, however, because the slurrymeets the regulation’s definition of fill. Rather tha nchallenge the agenci es’ decision to define the slurry as fill, SEACC in stead contends that §404 contains an implicit exception. According to SEACC, §404 does not au thorize the Corps to permit a discharge of fill material if that materi al is subjec t to an EPA new source performance standard. But §404’s text does n o t limit its grant of power in this way. Instead, §404 refers to all “fill material” without qualification. Nor do the EPA re gulations support SEACC’s reading of §404. The EPA has enacted gui d e lines, pursuant to §40 4 (b), to gui d e the Corps permitti ng decision. 40 CFR pt. 230. Those guidelines do not stri p the Corps of power to issue permits for fill in cases where the fill is al so subject to an EPA new source performance standard. SEACC’s re ading of §404 would create numerous diffi

culties for the regulated industry

. As the regulatory r e -13 Cite as: 55 7 U

. S. ____ (2009) Opinion of theCourt gime stands now, a di scharger m u st ask a s i mple ques

tion—is the substance to be dis c harged fill material or not? The fill regulati on, 40 CFR §232.2, offers a clea r answer to that question; and un der the agencies’ view, that answe r decides the matter—if the discharge is fill, the discharger must seek a §404 permit from the Corps; if not, only th en must th e discharge r consider whether an y EPA performance standard applie s, so that the discharger requires a §402 permit from the EPA. Under S E A CC’s inter p retati on, however, the discharger would face a more difficult problem. The discharger would have to ask—is the fill material also subject to one of th e many hundreds of EPA performance standards, so that the permit must come from the EPA, not the Corps? Th e statute gives no indication that Congress intended to burden industry withthat confu s ing division of permi t authority. The regulatory scheme discloses adefined, and worka

ble, line for determining whetherthe Corps or the E PA has the pe rmit autho rity. Und e r this fra m ework, t h e Corps of Engineers, and not the EPA, has authority to permit Coeur Alaska’s discharge of the slurry. III A second question rema ins: In issu i n g the permit did the Corps act in violation of a statutory mandate so that the issuance was “not in accordance with law”? 5 U. S. C. §706(2)(A). SEACC contends that the slurry discharge will violate the EPA’s new so urce performance standard and that the Corps permit is m a de “unlawful” by CWA §306(e). Petitioners and the a g encies argue that the pe r mit is lawful because the EPA pe rformance s t andard, and §306(e), do not apply to fill ma terial regulated by the Corps. In order to dete rmine whet her the Cor p s permit is lawful we must answer the question: Do EPA performance standards, and §306(e) , apply to discharges of fill mate

-14 COEUR ALA S KA, INC. v. S O UTHEAST ALASKA CONSERVAT ION COUNCI L Opinion of theCourt rial? We address in turnth e statutorytextof the CWA, th e agencies’ regulations construing it, and the EPA’s subs e quent interpretation of those regulations. Because Con

gress has n o t “direc tly spoken” to t h e “precise question” of whether a nEPA performance standard a p plies to dis

charges of fill material, the statute alone does not resolve the case. Chevron U. S. A. Inc. v. Na tural Resource s De

fense Coun cil, Inc. , 46 7 U. S. 837 , 842 (1984). We look first to the agency reg u lations, which are entitled to def e r ence if they resolve the ambiguity in a reason able manner. Ibid.; see United S t a t es v. Mead Corp., 533 U. S. 218, 226– 227 (2001). But the regulations, too, are ambiguous, so w e next tu rn to the age n cies’ subsequent interpretation of those regulations. Id., at 234–238; Auer, 519 U. S., at 46 1. In an internal memorandum the EPA expla i ned that its performance standards do not apply to discharges of fill material. That interp retation is not “plainly erroneous or inconsistent with the r e gulation [s] , ” and so we accept it as correct. Ibid . (internal quotation marks omitted). Though SEA CC con t ends that the agencies’ interpret a tion is not entitled to deference because it contradicts t h e agencies’ published statements and prior practice, we disagree with SEACC’s reading of th ose state m ents and of the regu la

tory record. A As for the statutory a r gument, SE ACC claims the CWA §404 permit is unlawful because §306(e) forb ids the slurry discharge. Petitioners and the federal agencies, in con

trast, conte n d that §306(e) does not apply to the slurry discharge. 1 To address SEACC’s statutory argument, it is necessary to review the EPA’s responsibi lities under the CWA. As15 Cite as: 55 7 U

. S. ____ (2009) Opinion of theCourt noted, §306 empowers the EPA to regulate the froth

flotation gold mining industry. See 33 U. S. C. §1316(b). Pursuant to this authority, EPA promulgated the new source performance standard relied upon by SEACC. The standard is stringent. If it were to apply he re, it would allow “no di scharge of process wastewater” fro mthe min e . 40 CFR §440.104(b)(1). The term “ p rocess wastewater” in cludes solid waste. So the regulation forbids not only pollutants that dissolve in water but a l so solid pollutant s suspended in water—what the agencyterms “tot a l suspended solids,” or TSS. S ee §440.104(a) (limiting the amount of TSS from other kin d s of mines); s ee also EPA Development Document for Efflu

ent Limitations Guidelines and Standards for the O r e Mining and Dressing Point Source Category 157–158 (Nov. 1982) (the amount of TSS in “wastewater” fro m froth-flotation mines is “generally high”); id., at 175 (Tab le VI–6) (measuring the amounts of TSS in samples of froth

flotation mines’ discharges); id., at 194 (stating an intent to “regulat[ e]” TS S); id., at 402 (evaluating the costs o f constructin ga “settling pond”); id ., at 535 (concluding th at even in mountainous regions, a froth-flotation mine will be able to construct a “tailings im poundment” to “provide a disposal area for mill ta ilings”). Were there any doubt about wh ether the EPA’s ne w source performance standard forbade solids as well a s soluble pollutants, the agency’s action inthese cas e s would resolve it. Here, the EPA’s §402 perm it authorizes Coeur Alaska to disch a rge wa ter from LowerSlate Lake into a downstream cr eek, provid ed the wat e r meets the quality requirements set by the performan c e standard. This demonstrates that the performance standard regu

lates solid waste. The EPA’s permit not only restricts the amount of total suspen ded solids, App. 327a (Table 3), bu t also forbids the mine fr om allowin gany “floating solids” to flow from the lak e . Id., at 328a. No party disputes the16 COEUR ALA S KA, INC. v. S O UTHEAST ALASKA CONSERVAT ION COUNCI L Opinion of theCourt EPA’s au th ority to reg u late these discharges of solid min

ing waste; and no party questions th e validity of the EPA’ s new source performance standard when it is applicable. When the performance standard applies to a point source, §30 6 (e) makes it “unlawfu l” for that point source t o violate it: “[I]t shall be unlaw ful for any owne r or operato r of any new source to operate such source in violation of any standa r d of performance applicable to such source .” CWA §306(e), 33 U. S. C. §1316(e). SEACC argues that this provision , §306(e), f o rbids the mine fromdischarging slurry into Lower Slate Lake

. SEACC con t ends the new source performance standard is, in the words of §306( e), “applicable to” the mine. Both the text of the performance standard and the EPA’s applica

tion of it to the discharge of mining waste from Lower Slate Lake demonstrate that the performance standard is “applicable to” Coeur Alaska’s mine in some circu m stances. An d so, SEACC reasons, it follows that because the new source performance standard forbids even minute discharges of solid waste, it also forbids the slurry dis

charge, 30 % of which i s solid waste. 2 For their p a rt, the S t a t e of Alaska and the federal agen

cies claim that the Act is unambiguous in the opposite direction. They rely on §404 of the Act. As explained above, that section authorizes the Corps of Engineers to determine whether to issue a permit allow i ng the dis

charge of the slurry. Petitioners and the agencies argue that §404 grants the Corps authority to do so without regardto t h e EPA’ s n e w source performanc e standard or the §306(e) prohibition discussed above. Petitioners and the agencies mak etwo statutory argu

ments based on §404’s silence in regard to §306. First, they note that nothing in §404 requires the Corps to co n sider the EPA’s new s o urce performance standard or th e17 Cite as: 55 7 U

. S. ____ (2009) Opinion of theCourt §306(e) prohibition. That s ilence advances the argument that §404’s grant of a u thority to “issue permits” contra

dicts §306(e)’s declara t ion that discharges inviolation of new source performance standards are “unlawful.” Second, petitioners and the agen cies point to §404(p), which protects §404 permitees from enforcement actions by the EPA or private citizens: “Compliance with a p e rmit issued pursuant to this section

. . . shall be de emed compliance, for purposes of sections 1319 [CWA §309] and 1365 [CWA §505] of this title, with sections 1311 [CWA §301], 13 17 [CWA §307], and 1343 [CWA §403] of th is title.” 33 U. S. C. §1344(p). Here again, their argu ment is that silence is significant. Section 404(p) protects the permitee from la wsuits alleg

ing violations of CWA §301 (which bars the discharge o f “any pollutant” “excep t as in compliance” with the Act), §307 (which bars the discharge of “toxic pollutants”); an d §403 (which bars discharges into the sea). But §404(p) does not in express te rms protect the permitee from a lawsuit alleging aviolation of §306(e) or of the EPA’s ne w source performance standards. Section 40 4(p)’s silence regarding §306 is made evenmor e significan t because a parallel provision in §402 does protect a §402 permitee from an enforcement action alleging a violation of §306

. CWA §402(k), 33 U. S. C. §1342(k). In our view, Congress’ omission of §306 from §404, and its inclusion of §306 in §402(k), is evidence that Congre ss did not inte nd §306(e) to apply to Corps §404 permits or to discharges of fill material. If §306 did apply, then the Corps would be required to ev aluate each permit applic a tion for compliance with §306, and issue a permit only if it found the discharge wo uld comply with §306. But even i f that finding were made, it is not clear that the §404 per

mitee would be protected froma suit seeking a judicial18 COEUR ALA S KA, INC. v. S O UTHEAST ALASKA CONSERVAT ION COUNCI L Opinion of theCourt determination that the discharge vi olates §306. 3 The CWA is ambiguou s on the q u estion wh ether §306 applies to discharges of fill materia lregulated under §404. On the on e hand, §3 06 provides that a discharge th at violates an EPA new source performance standard i s “unlawful”—without any excepti o n for fill material. On the other h and, §404 grants the Corps blanket authority to permit the discharge of fill materia l—without any mention of §306. This tension indicates that Congress has not “directlysp oken” to th e “precise q u estion” of whether §3 06 applies to di scharges of fill materi al. Chevron, 467 U. S., at 842. B Before turning to how the agencies have resolved that question, we consider the formal regulations that bear on §§306 and 404. See Mead , 533 U. S., at 23 4–238. The regulations, like the statutes, do not address the question whether §306, and the EPA new source performance stan

dards promulgated under it, appl y to §404 permits and th e discharges they authorize. There is n oregulation, for example, interpreting §306(e)’s text—“s t an dard of per formance applicable to such source”—to mean that a performance standard ceases to be “applicable” the m o ment the di scharge qu alifies as fill material, which would resolve the cases in petitioners’ favor. N o r is there a regulation providing t hat the Cor p s, in decid i ng whethe r to grant a permit under §404, mustdeny that permit if the discharge would violate §306( e), which would decide th e cases for SEAC C. Rather tha naddress the tensionbetween §§306 and 404, the r e gulations instead im plement the statutory framework without elaboration on this point. Each of the two principal regulations, which have been mentioned above, seems to stand on its own without reference to th e19 Cite as: 55 7 U

. S. ____ (2009) Opinion of theCourt other. The EPA’s ne w source performance standard con tains no exception for fill material; and itforbids an y discharge o f “process wastewater ,” a term t hat includes solid wastes. 40 CFR §440.104(b)(1); see Part III–A–1, supra. The agencies’ joint regulation defining fill material is also unq ualified. It includes “slurry, or tailings or simi

lar mining-related materials” in its definition of a “dis

charge of fill material,” 40 CFR §232.2; and it contains no exception for slurry tha tis regulated by an EPA perform

ance standard. The parties point to additi onal regulations, but these provisions do not offer a clear bas is of reconciliation. An EPA regu lation, mentioned above, provides that “[d]ischarge s of dredged or fill material into waters of the United Sta t es which are regulated under s e ction 404 of CWA” “do not require [§402] permits” from the EPA. §122.3. As we have explained, however, this merely states that a permit for this discharge cannot be issued by the EPA. See Part II, supra. The regulation does not answer the question whether the EPA’ s new source performan c e standard, a n d §306(e), apply to adischarge regulated b y the Corps under §404. The agencies als o dir e ct us to th e §404(b) guidelines written by t h e EPA to g u ide the Corps permitti ng decision. See 40 CFR pt. 230. The agencies note that these guide

lines do not expressly require t h e Corps, in issuing a permit, to consider whether the discharge would violate EPA’s perf ormance standards. Here we th ink failure to mention §3 06 or the EPA new source performance stan

dards does offer some indication that these are not rele

vant to the §404 perm it, though the argument falls short of being conclusive. The Corps’ own regul a tions require the agency to evaluate permit appl ications “for compliance with appli c able [EPA] effluent limitations. ” 33 CFR §320.4(d) (2 008). The regulations do not ans wer whethe r the new source performance standard is “applicable” to a20 COEUR ALA S KA, INC. v. S O UTHEAST ALASKA CONSERVAT ION COUNCI L Opinion of theCourt discharge of fill materia l

. C The regulations do not give a definitive answer to the question whether §30 6applies to discharges regulated b y the Corps u n der §404, but we do find that age n cy interpre

tation and agency application of the regulations are in

structive a n d to the point. Auer , 519 U. S., at 461. The question is addressed and resolved in a reasonable an d coherent way by the p r actice andpolicy of the two agen

cies, all as recited in amemorandum written in May 200 4 by Diane Regas, then the Directo r of the EPA’s Office o f Wetlands, Oceans and Watersheds, to Randy Smith, the Director of the EPA’s regional Office of Water with r e sponsibilityover the mi ne. App. 14 1a–149a (Regas Memo

randum). The Memorandum, though not su bject to suffi

ciently for m al procedures to merit Chev ron deference, see Mead , supr a , at 234–238, is entitled to a mea s ure of defer

ence because it interprets the a g encies’ own regulator y scheme. See Auer , sup ra , at 461. The Regas Memorandum explains: “As a result[of the fact that the dis c harge is re gulated under §404], the regul a tory re gime applicable to dis

charges un der section 402, including effluent limita

tions guidelines and st andards, such as those applica

ble to gold ore mining

. . . do not apply to the placement of tailings into the pro p osed impoundment [of Lower Slate Lake]

. See 40 CF R §122.3(b).” App. 144a–145a. The regulation that the Memor andum cites—40 CFR §122.3—is one we considered above and found ambiguous. That regul a tion provides: “[d]ischarges of dredged or fill material into waters of the United States which are regu

lated under section 40 4 of CWA” “do not require [§402 ] permits.” The Regas Memorandum takes a ninstructi ve21 Cite as: 55 7 U

. S. ____ (2009) Opinion of theCourt interpretive step when it explains thatbeca use the dis

charge “do[ es] not require” an EPA permi t , ibid. , the EPA’s performance standard “d o[es] not ap ply” to the discharge. App. 145 a. The Memorandum presents a reasonable interpretati on of the r e gulatory regime. We defer to the interpretat i on bec ause it is not “plainly erro

neous or inconsistent with the regulation[s].” Au er, sup ra , at 461 (internal quotation marks omitted). Five facto rs inform that conclusion. First, the Memorandum preserv e s a role for the EPA’ s performance standard. It confines the Memorandum’s scope to clo s ed bodies of water, lik ethe lak ehere. App. 142a–143a, n. 1. When slurry is discharged into a closed body of water, the Memorandum explains, the E PA’s performance standard retains an important role in regu

lating the d i scharge int o surrounding wa ters. The Memo

randum does not purport to invalidate the EPA’s perform

ance standard. Second, the Memorandum acknowledges that this is not an instance in which the discharger attempts to evade the requiremen t s of the EPA’s performance standard. The Kensington Mine is not, for example, a project that smu g gles a discharge of EPA-regulated pollutants into a sepa

rate discharge of Corps-regulated fill m a terial. The in

stant cases do not pre s ent a process or plan designed to manipulate the outer boundaries of the definition of “fill material” by labeling minute qua ntities of E PA-regulate d solids as fill. The Me morandum states that when a dis

charge has only an “i ncidental fi lling effect, ” the EPA’s performance standard continues to govern th at dischar g e . Id., at 145a. Third, the Memorandum’s interp retation pr eserves the Corps’ auth o rity to determin e whether a dis c harge is in the public interest. See 33 CFR §320.4(a)(1); 40 CFR §230.10. T h e Corps has significa n t expertise in making this deter m ination. Applyingit , the Corp s determined22 COEUR ALA S KA, INC. v. S O UTHEAST ALASKA CONSERVAT ION COUNCI L Opinion of theCourt that placing slurry in the lake will improve that body o f water by m a king it wi der, s hallower, and so more capable of sustaining aquatic life. The Corps determined, fur

thermore, that the alternative—a heap of tailings large r than the Pentagon placed upon wetlands—would cause more harm to the environment. Because the Memoran

dum preserves an important role for the Corps’ expertis e , its conclusion that the EPA’ s performance standard doe s not apply is a reasonab le one. Fourth, the Regas Memorandum’s interpretation does not allow t o xic pollut ants (as di stinguished from other, less danger ous pollutants, such as slurry) to enter the navigable waters. The EPA has re gulated toxi c pollutants under a separate pro vision, §30 7 of the CWA, and the EPA’s §404(b) guidelines require the Corps to deny a §40 4 permit for any discharge that would violat e the EPA’s §307 toxic-effluent limitations. 40 CFR §230.10(b)(2). Fifth, as a final reasonto defer to the Regas Memoran

dum, we fi nd it a sensible and rational construction th at reconciles §§306, 402, and 404, and the regulations im

plementing them, which the alternatives put forward b y the parties do not. SEACC’s argu ment, that §402 applies to this discharge and not §404, is not consistent with th e statute and regulations, as already noted. See Part II, supra . The Court requested the parties to submit supplemental briefs addressing whether the CWA contemplated th at both agenci es would issue a perm it for a discharge. 55 6 U. S. ___ (2009). A two-permit regime would allow the EPA to apply its performanc e standard, wh ile the Corps could apply its §404(b) criteria. The parties agree, how

ever, that a two-perm it regime is contrar yt othe statute and the reg u lations. We conclude that this is correct. A two-permit regime would cause confusion, delay, expense, and uncert a inty in the permitting process. In agreement with all of the parties, we conclude that, when a permit is23 Cite as: 55 7 U

. S. ____ (2009) Opinion of theCourt required to discharge fi ll material, either a §402 or a §404 permit is n e cessary. Here, we n o w hold, §404 applies, not §402. See P a rt II, supr a . The Regas Memorandum’s interp retation of the agen

cies’ regula tions is consistent wit hthe regul a tory sche me as a whole. The Memorandum preserves a role for the EPA’s perfo r mance standards; it guards against the possi

bility of evasion of those standards; it employs the Corps ’ expertise i nevaluatin g the effects of f ill m a terial on th e aquatic environment; it does not allow toxic pollutants to be discharged; and we have been offered no b e tter way to harmonize the regulations. We defer to the E PA’s conclu

sion that its performance standard does not apply to th e initial discharge of slurry into the lake but applies only to the later di scharge of water f r om the lake in to the down

stream creek. D SEACC argues against deference to the Regas Memo

randum. I nits view the Regas Memorandum is contrary to published agency s t atemen ts and earlier agency p r a c tice. SEACC cites three agency statements: A 1986 “memorandum of understanding” between the EPA and the Corps regarding the definition of fill material; the preamble to the agenci es’ current 2002 fill regulation; and comments made by th e agencies in promulgating the 2002 fill regulati on. These a r guments are not convincing. 1 In 1986, to reconcile their then-differing definitions of “fill materi al,” the EPA and the Corps issued a “memoran

dum of agreement.” 51 Fed. Reg. 8871 (MOA). The memorandum was n o t made subject to notice-and

comment procedures, but it was published in the Federal Register. It defined the stat utory term “fill material” until the current definition took effect in 2002. B r ief for Fed

-24 COEUR ALA S KA, INC. v. S O UTHEAST ALASKA CONSERVAT ION COUNCI L Opinion of theCourt eral Respon dents 30–31, n. 8. SEA CC poi n ts to paragraph B(5) of the MOA, whi c h reads: “[A] pollutant (other than dredged material) will nor

mally be considered by EPA and the Corps to be sub

ject to section 402 if itis a discharge in liquid, semi

liquid, or suspended form or if it is a discharge of solid material of a homogeneous natu r e normally associ

ated withsingle industry wastes

. . 

### . . These materials include placer mining was t es, phosphate mining wastes, titanium min i ng wastes, sand and gravel wastes, fly ash, and drilling muds. As appropriate, EPA and the Corps will identi fy additional such mate

rials.” 51 Fed. Reg. 8872. It is true, a s SEACC notes, that this passage suggests that §402 will “normally” apply to discharges of “suspended”— i.e., solid—pollutants. But that s t atement is not contra r y to the Rega s Memorandum, whichackno w ledges that th e EPA retain s authority under §402 to regulate the dis

charge of suspended solids from Lower Slate Lake into downstrea mwaters. This passage does not address the question presented by these cases , and answered by the Regas Memorandum, as to whether the EPA’s perform

ance standard applies when the discharge qualifies as f ill material. In fact, the MOA’s prea mble suggests that wh en a discharge qualifies a s “fill material,” the Corps retains authority to regulate it under §404: “Dischar ges listed in the Corps definition of ‘discharge of fill material,’

. . . rem a in subject to section 404 even if they occur in association with discharges of wastes meeting the criteria in the agreement for section 402 discharges.” Id., at 887 1. The MOA is quite consistent with the agencies’ determi

nation that the Corps regulates alldischarges of fill mate

-25 Cite as: 55 7 U

. S. ____ (2009) Opinion of theCourt rial and that §306 does not apply to these discharges. 2 SEA CC d r aws our at tention to the preamble of the current fill material regulation. 67 Fed. Reg. 31129 (2002) (final rule). It cites the opening passages of the preamble, which state : “[T]oday’s rule is generallyconsistent with curren t agency practice and so it d oes not expand the types of discharges that will b e covered under section 404.” Id. , at 31133. In SEAC C’s view, this passage demonstrates that the fi ll rule was n o t intended to displace the pre-ex isting froth

flotation gold mine perf ormance standard, wh ich has been on the book s since 1982

. The preamble goes on to say, in a section enti tled “Efflu

ent Guideline Limitations and 402 Permits”: “[W]e emp hasize that today’s rule generall y is in

tended to maintain our existing approach to regulat

ing polluta nts under either section 402 or40 4 of the CWA. Effl uent limita t ion guidelines and new source performance standards (‘effluent guidelines’) promul

gated unde rsection 304 and 306 of the CWA establish limitations and standa r ds for specified wastestreams from industrial categories, and those limitations and standards a r e incorporated into permits issu ed under section 402 of the Act. EPA has never sought to regu

late fill material under effluent guidelines. Rather, effluent guidelines restrict disch a rges of pollutants from identified wastestreams based upon the pollut

ant reducti on capabilities of avail able treatment tech

nologies. Recognizing that some discharges (such as suspended or settleabl e sol i ds) can have the associ

ated effect, over time, of raising the bottom elevation of a water due to settling of waterb orne pollut ants, we26 COEUR ALA S KA, INC. v. S O UTHEAST ALASKA CONSERVAT ION COUNCI L Opinion of theCourt do not consider such pollutants to be ‘fill material,’ and nothing in today’s rule chan ges that view. Nor does today’s rule change any dete rmination we have made regarding discha rges that a r e subject to an ef

fluent limitation guidelin e and standards, which will continue to be regula ted under section 402 of the CWA. Sim ilarly, this rule does n o t alter the manner in which water quality standards currently a p ply un

der the section 402 or the section 404 progra ms.” Id. , at 31135. Although the preamble asserts itdoes not c hange agency policy withregard to EPA performance standards and §402 permitting decisions, it is explicit in noting that th e EPA has “never sought to regul a te fill ma terial under effluent guidelines.” Ibid

. The preamble, then, is consis

tent with th e Regas Memorandum. If a discharge does not qualify as fill material, the EPA’s new source performance standard applies. If the discharge qualifies as fill, th e performance standard does not apply; and there was no earlier agency pra ctice or policy to the contrar y . 3 SEA CC also cites remarks mad e by the agencies in response to public comments on the proposed fill material regulation. App. 22a– 127a. These remarks were incorpo

rated byref e rence into the ad ministrative record. 67 Fed. Reg. 31131. Responding to a qu esti on about w h ether “mine tailings ” would be “s ubject to se ction 404 regulation as opposed to section 402” under the 2002 fill regulation, the agencies stated: “Today’s final rule clari f ies that an y material that has the effect of fill is regulated under section 404 and further tha tthe placement of ‘overburden, slurry, or tailings or s i milar mini ng-related materials’ i s consid

-27 Cite as: 55 7 U

. S. ____ (2009) Opinion of theCourt ered a discharge of fillmaterial. Nevertheless, if EPA has previou s ly determined that certain materials are subject to an [effluent limita tion guideline] u n der spe

cific circum s tances, then that determination remains valid. Moreover,

. . . permits issu ed pursuant to sec

tion 402 are intended to regulate process water an d provide effluent limits that are protective of receiving water quali t y. This distinction provides the frame

work for today’s rule.” App. 48a. This statement is not conclusive of the issue. SEACC notes that this response, lik e the regulation’s preamble, pledges that EPA’ s “pr e viou[s]

. . . determination[s]” with regard to the application of performance standards “re

mai[n] valid.” But, as noted above, the Rega s Memoran

dum has followed this policy by applying th e EPA’s per

formance standard to the discharge of water from the lake into the downstream creek

. The response do es not state that the EPA will apply its performance s t andards to discharges of fill materi al. 4 The agencies’ published statements indicate adherence to the EPA’s previous application and interpr e tation of its performance standards. SEACC cannot sh ow that th e agencies have changed their inter p retation or application of their regulations. SEACC cite s no instance inwhich the EPA has applied one of its performance standards to a disc harge of fill material. B ycontras t , Coeur Alaska cites t w o instances in which the Corps issued a §404 pe rmit authorizing a min e to discharge solid was t e (tailings) as fill ma terial. See Brief for Petitioner Coeur Alaska 40–42. S EACC objects that those two §404 permits authorized dis c harges th at used the tailings to construct use f ul structures—a dam in one case, atailings pond in another. Here, by contras t , SEACC contends that the primary purpose of the dis

-28 COEUR ALA S KA, INC. v. S O UTHEAST ALASKA CONSERVAT ION COUNCI L Opinion of theCourt charge is to use anavigable water to dispose of waste. Ibid. But t hat objection misses the point. The two §404 permits cited by Coeur Alaska illus trate that the agencies did not hav e a prior pr actice of applying EPA performance standards to discharges of mining wastes that qualify as fill material

. SEA CC ha s not demonstrated th at the agencies have changed th eir policy, and it cann ot show th at the Regas Memorandum is contrar yto the agencies’ published statements. * * * We accord deference to the agencies’ reasonab le decision to continue their prior practice. The judgment of the Court of Appeals is reversed, and these cases are remanded for further proceedings consis

tent with th is opinion. It is so orde red._________________

_________________ 1 Cite as: 55 7 U

. S. ____ (2009)
B REYER , J ., concu rrin g 

## SUPREME CO URT O FTHE UNI TED STATES

Nos. 07– 98 4 a n d 07–9 90
COE U R ALASKA, INC ., PETITIONER 07–984 v. SOU T HEA S T ALASKA CONSERVATION C O UN CIL ET AL

. ALASKA, P E TITIONER 07–990 v. SOU T HEA S T ALASKA CONSERVATION C O UN CIL ET AL

. ON WRITS OF CERTIORARI TO THE UNITED STAT ES COURT OF APPEAL S FOR THE NINT H CIRCUIT [Ju n e22, 2009 ] J USTICE B RE YE R , concu rring. As I understand the Court’s opi n ion, it recognizes a legal zone within which the regulating agencies might reasonably classify material ei ther as “dredged or fill material” subject to § 404 of the Clean Water Act, 33 U. S. C. §13 44(a), or as a “pollutant,” subject to §§402 an d 306, 33 U. S. C. §§1342(a), 1316(a). Within this zone, the law author i zes the environmental agencies to classify material as the one or the other, so long as they act within the bounds of relevant regulations, and provided that the classification, consider ed in terms of the purposes of the statutes and relevant regulations, is reasonable. This appro a ch reflects the difficu lty of ap plying §§402 and 306 literally to ever ynew-source-related discharge of a “pollutant.” The Environmental P r otection Agency (EPA) applies §30 6new sou rce “performance standards” to a wide variety of discharges, ranging, for example, from2 COEUR ALA S KA, INC. v. S O UTHEAST ALASKA CONSERVAT ION COUNCI L B REYER , J ., concu rrin g those involv ed in the processing of apples in to apple juice or apple cider, 40 CFR §407.10 (20 08); to the manufactur

ing of cement, §411.1 0 ; to the production of fresh meat cuts by a m e at cutter, §432.60; an d to the manufacture of pharmaceutical products by ferm entation, §439.10. See generally 40 CFR pts. 405–471 (containing more than 800 pages of “n ew source performance” and effluent limitation regulations). At the same ti me the regulations for any one point sourc e often regu late numerous chemicals, minerals, and other s ubstances produced by that point s o urce; in th e case of fermentation products, for example, the regulations provide performance standards fo r roughly 30 different chemicals. §439.15. These “standards of performance” “reflect the greatest de gree of effluent reducti on which th e Administra tor determines to be a c hievable through appli

cation of the best availabl e demonstrated con trol technol

ogy . . . including, wh ere practicable, a sta n dard permit

ting no discharge of pollutants.” 33 U. S. C. §1316(a)(1). To literally apply thes e performance standards so as to forbid the use of any of these substances as “fill,” even when, say, they constitute no mor ethan trace elements in dirt, crushed rock, or sand that i s clearly being used a s “fill” to build a levee or to re place dirt remove d from a lake bottom may prove unnecessarily strict, cf. §13 62(6) (defin

ing “pollut ant” to include “roc k”), to the point thatsuc h application would undermine the objective of §404, which foresees th e use of “dredged or fill material” in certai n circumstan ces and with approval of the relevant agencies. §1344. At minimum, the EPA mi ght reasonab ly read th e statute and the applica b le regulations as allowing the use of such ma terial, say crushed rock, as “fill” in som eof these situations. Cf. Chev ron U. S. A. Inc. v. Na tural Resource s Defen se Co uncil, Inc. , 467 U. S. 837, 842–8 44 (1984); Auerv. Robbins , 519 U. S. 452, 461 (1997). At the same time, I recognize the danger th at J USTIC E G INSBURG warns agai nst, namely, that “[w]h o le categories3 Cite as: 55 7 U

. S. ____ (2009)
B REYER , J ., concu rrin g of regulated industries” might “ g ain immunity from a variety of pollution-control standards,” if, s a y, a §404

- permit applicant simply adds “suff i cient solid matter” to a pollutant “to raise the bottom of a water body,” thereb y turning a “pollutant” governed by §306 into “fill” governed by §404. Post , at 7 (diss e nting opinion). Yet there are safeguards against that occurring. For one thing, as the Court recognizes, see ante , at 11, it is n o t the case that any material that has the “ ‘effect of .

. . [c]hanging the bottom elevation’ ” of the bod yof wa ter is automatically subject to §404, not§402. The EPA has never sugg ested that i twould int e rpret the r e gulations so as to turn §404 into aloophole, permitting evasion of a “performan ce standard” simply because a polluter dis

charges enough pollutant to raise the bottom elevation of the body of water. For another thing, even wh ere a matter is determined reasonably to be“fill” and consequently falls within §404, the EPA can retain an important role in the permitting process. That is because the EPA may veto any §404 plan that it finds has an “unaccepta b le adverse effect on municipal water supplies, sh ellfish beds and fishery areas . . . , wildlife, or recreational areas.” §1344(c). Finally, EPA’s decision not to apply §306, but to allow permitting to pro c eed under §404, must be a reason

able decision; and court review wil lhelp assur ethat is so. 5 U. S. C. §706. In these cases, it seems to me that the EPA’ s i n terpreta

tion of the statute as permitting the EPA/Co rps of Engi

neers “fill” definition to apply to the cases at hand is rea

sonable, hence lawful. Lower Slate Lake, located roughl y three miles from the Kensington Gold Min e , is 5 1 fe et deep, 800 feet wide, and 2,000 feetlong; downstream from the lake is Slate Cre e k. Facedwith a di fficult choice between creating a huge pile of s l u rry on nearby wetlands or using p a rt of the lake as a s t orage facil i ty for min e tailings, see App. 294a–298a; see also ante , at 5–8, the4 COEUR ALA S KA, INC. v. S O UTHEAST ALASKA CONSERVAT ION COUNCI L B REYER , J ., concu rrin g EPA arrive d at a compromise. On the one ha nd, it would treat mine tailings pla c ed directly into the l a ke as “fill” under the §404 permitting program. App. 144a. The tailings, the EPA recognized, would have the “immedia te effect of filling the areas of water into whi c h they are discharged. ” Ibid. But it would also treat any spillover of the tailings, or chemicals from the tailings, into any nearby waterway, most particularly Slate Creek (running out of Slate Lake) as requiring a §402 permit. The EPA’s §306 “performance sta n dard” wou l d apply an d that stan

dard insists upon no dischar ge of proce ss wastewa t e r a t all. Id. , at 145a; see also 40 CFR §440.104(b). The EPA reached this result because it recognized that, even though pollutants discharged into the cr eek might come “in the form of sus p ended and settleable s o lids,” such solids woul d “have, at most, an incidental filling effect.” App. 145a. The EPA thereby sought to apply the distinction it had previously recognized between discharges th at have the immediate effect of raising the bottom elevation of water, and those that only have the “associated effe ct, over time, of raising the bottom elevation of a water due to settling of waterborne pollutants.” See 67 Fed. Reg. 31135 (200 2) (concluding that §402 applies toth e latter); s ee also Brief for G. Tracy Mehan III as Amicus Curiae22– 23. I cannot say whether the EPA’s compromise represents the best ov erall enviro nmental re sult; but I do beli eve i t amounts to the kind of detailed decision that the statute s delegate authority to t h e EPA, n o t the cour ts, to make (subject to the bounds of reasonab leness). I believe th e Court’s views are consistent wit hthose I here expre ss. And with that understa n ding, I join its opinion._________________

_________________ 1 Cite as: 55 7 U

. S. ____ (2009) Opinion of S CALIA , J. 

## SUPREME CO URT O FTHE UNI TED STATES

Nos. 07– 98 4 a n d 07–9 90
COE U R ALASKA, INC ., PETITIONER 07–984 v. SOU T HEA S T ALASKA CONSERVATION C O UN CIL ET AL

. ALASKA, P E TITIONER 07–990 v. SOU T HEA S T ALASKA CONSERVATION C O UN CIL ET AL

. ON WRITS OF CERTIORARI TO THE UNITED STAT ES COURT OF APPEAL S FOR THE NINT H CIRCUIT [Ju n e22, 2009 ] J USTICE S CALIA , concu rring in pa rt and conc urring i n the judgme nt. I join the o p inion of th e Court, except for its protesta

tion, ante , at 20, that it is not according Chevro ndeference to the reasonable inter p retation set forth in the memoran

dum sent by the Direct or of the E nvironmental Protection Agency’s (EPA) Office of Wetla nds, Oceans and Water

sheds, to the Director o f the EPA’ s regional Office of Water with responsibility over the Coeur Alaska mine—an inter

pretation consistently followe d by both EPA a n d the Corp s of Engineers, and adop ted by both agencies in the proceed

ings before this Court. See Chev ron U. S. A. I n c. v. Natu

ral Resour c es Defen se Council, Inc. , 467 U. S. 837 (1984). The opinionpu rpor ts t ogivethis agenc yin te rp retation“ a measure of deference ” because it i nvolves an i n terp reta tio n of “the age n cies’ own regulatory scheme,” and “ ‘the regu latory regi me,’ ” an te, at 20 (citi n g Auer v. Robbins , 5192 COEUR ALA S KA, INC. v. S O UTHEAST ALASKA CONSERVAT ION COUNCI L Opinion of S CALIA , J. U. S. 452, 4 61 (1997)). Auer , howe ver, stands only for the principle th at we deferto an agen cy’s inter p r e tation of its own ambiguous regulation

. But i tbecomes obvious from the ensuing discussion that the referenced “regulator y scheme,” and “regulat o ry re gime” for which the Cour t accepts the agency interpreta tio nincludes not just the agencies’ own regulati ons but als o(and indeed primarily) the conformity of tho s e regulations with t h e ambiguous governing s t atute, which is the primary dispu t e here. Surely the Court is not addi ng to our already inscruta

ble opini o n in United S t ates v. Mead Corp. , 5 33 U. S. 218 (2001), the irrational fillip that an agency position which otherwise does not qualify for Chevron de ference does receive Che v ron deference if it clarifies not just an am

biguous sta t ute but also an ambiguous regulation. On e must conclude, then, that if today’s opinion i s notaccor d

ing the agencies’ reasonable and a u thoritative interpreta

tion of the Clean Water Act Ch e v ron deference, it is ac

cording some new ty p eof deference—perhap s to be called in the future Coeur Al aska deference—which is identica l to Chevron deference except for th e name. The Court’s deference to the E PA and th e Corps of Engineers in today’s cases is eminently reasonable. It is quite impossible to a c hieve predictable (and relativel y litigation-free) adminis tration of the vast body of comple x laws committed to the charge of executive agencies with

out the ass u rance that reviewing courts will accept rea

sonable an d authorita tive agency interpreta tion of am

biguous provisions. If we mus tnot call that practi ce Chevron de ference, then we have to rechrist en the rose. Of course the only reason a new name is required is our misguided opinion in Mead , whose incomprehensib le criteria for Chevron deference have produced so much confusion inthe lowe r courts * that there has no w appeare d

——————

* Compare, e.g., Krusev. W e lls Fargo Hom eMortgage, Inc

. , 383 F. 3d3 Cite as: 55 7 U

. S. ____ (2009) Opinion of S CALIA , J. the phenomenon of Chevron avoidance—the practice of declining to opine whether Chev ron applies or not. Se e Bressman, How MeadHas Muddled Judicial Review of Agency Acti on, 58 Vand. L. Rev. 1443, 1464 (2005). I favor overruling Mead. Failing that, I am pleased to join an opin ion that effectively ignores it.

—————— 49, 61 (CA 2 2 004) ( a c c o r d ing Chevro n def e rence to policy statements issu ed byDep a r tmen tof Ho u s in gan d UrbanDev e lopm en t) an d Schu

etz v. Banc One Mo rtga geCorp. , 292 F. 3d 100 4, 1 012 (CA 92 0 0 2 ) (s ame), with Krzalicv. Re public Title Co. , 314 F. 3d 875, 8 81 (CA 7 200 2) (den y i n g Chev ron defer e nc e to same polic ystate m ents). Comp ar e Am erica n Fe deratio nof Govt. Em ploy ees, AFL–CIO, Local 4 4 6 v. Nicholson , 475 F. 3d 34 1, 353 –3 54 (C AD C 200 7) (ac c or din g Chevron defer e nc e to i n for m al adjud i c a tion byDepar tment of Veter a ns Affair s) , withA m e r i c a nFed e ra tionof Govt. Employe e s, AFL–CIO, Loc a l 2152 v. Principi , 464 F. 3d 1049, 1 0 57 (CA 920 06) (den y i ng Chevron defe rence to si mil a rac ti on). It i s notev en c l earthat notic e -and- c omment r u le

making will a ssure Chevron deference to agency interp retation of an ambiguous statute. See Rub i e’sCostum eCo. v. Unit ed S t ates , 337 F. 3d 135 0, 135 5 (C A Fed. 2003) ( c u s toms c l as si fic a tion)._________________

_________________ 1 Cite as: 55 7 U

. S. ____ (2009)
G IN SB U R G , J., dis s e nting 

## SUPREME CO URT O FTHE UNI TED STATES

Nos. 07– 98 4 a n d 07–9 90
COE U R ALASKA, INC ., PETITIONER 07–984 v. SOU T HEA S T ALASKA CONSERVATION C O UN CIL ET AL

. ALASKA, P E TITIONER 07–990 v. SOU T HEA S T ALASKA CONSERVATION C O UN CIL ET AL

. ON WRITS OF CERTIORARI TO THE UNITED STAT ES COURT OF APPEAL S FOR THE NINT H CIRCUIT [Ju n e22, 2009 ] J USTICE G IN S B UR G , wi th whom J USTICE S TE VENS an d J USTICE S OUTERjoin, dissenting. Petitioner Coeur Alask a , Inc., proposes to discharge 210,000 gallons per day of mining waste into Lower Slate Lake, a 23-acre subalpine lake in Tongass National For

est. The “tailings slurry” would contain concentrations of aluminum, copper, lead, and mercu ry. Over th e life of the mine, roughly 4.5 mill ion tons of solid tailing s would enter the lake, raising the bottom elev ation by 50 feet. It is undisputed that the di scharge would kill all of the lake’s fish and nearly all of its other aquatic life. 1 Coeur Alask a ’s proposal is prohib ited by the Environ

mental Protection Age n cy (EPA) performan c e standard

——————

1 Whether aquatic life w ill eventually be able to inhabit the lake ag ainis u n c er tain

. Com p ar e ante , at 5, with App. 2 01a–2 02a; an d Southeas t Alas k aConservat ion Councilv. United Stat esArmyCorps of Eng i neers , 486 F. 3d 638, 642 (CA9 20 07).2 COEUR ALA S KA, INC. v. S O UTHEAST ALASKA CONSERVAT ION COUNCI L G IN SB U R G , J., dis s e nting forbidding any discharge of process wastewater from ne w “froth-flotation” mills i n to wa ters of the United States. See 40 CFR §440.104(b)(1) (2008). Section 306 of the Clean Water Act direct s EPA to pr omulgate such perfor m ance standards, 33 U. S. C. §1316(a), and declares it unlawful for any discharger to violate them, §1316( e). Ordinarily, that would be the end of the inquiry. Coeur Alaska contends, however, that its discharge is not subject to EPA’s regulato ry r e gime, but is governed, instead, by the mutually exclusive permitting authority of the Army Corps of E n gineers. The Corps has authority, under §404 of the Act, §1344(a), to issue per m its for dis

charges of “dredged or fill material.” By regulation, a discharge that has th e effect of raising a water bod y ’s bottom elevation qualif ies as “fill material.” See 33 CFR §323.2(e) (2 008). Discharges properly withi nthe Corps’ permitting authority, i tis undisp u ted, are n o t subject t o EPA performance standards. See ante , at 20; Brief for Petitioner Coeur Alask a26; Brief for Respondent South

east Alaska Conservation Council et al. 37. The litigation before the Court thus presents a single question: Is a pollutant dischar ge prohibited under §306 of the Act eligible for a §404 permit as a discharge of fill material? In agreement withthe Court of Appeals, I would answer no. The statute’s text, s tructure, and pur

pose all mandate adherence to EPA pol l ution-control requiremen t s. A discharge covered by a performance standard m u st be authorized, if at all, by EPA. I A Congress enacted the Clean Water Act in 1 972 “to re

store and maintain the chemical, physical, and biological integrity” o f the waters of the United States. 33 U. S. C. §1251(a). “The use of any river, l a ke, stream or ocean as a waste treat ment system,” the Act’s drafters stated, “is3 Cite as: 55 7 U

. S. ____ (2009)
G IN SB U R G , J., dis s e nting unacceptabl e.” S. Rep. No. 92–414, p. 7 (1971). Congress announced in the Act itself an ambitious objective: to eliminate, b y1985, the discharge o f all pollutants into the Nation’s navigable waters. 33 U. S. C. §1251(a). In service of its goals, Congress issued a core command: “[T]he discharge of an y pollutant by an y pe rson shall be unlawful,” except in compliance with the Act ’ s terms

. §1311(a). The Act’s subst antive requirements—housed primarily in Subchapter III, “Standards and Enforce

ment”—est ablish “a c o mprehensive regulato ry progra m supervised by an ex pert administrative agency,” EPA

. Milwaukeev. Illinois , 451 U. S. 304, 317 (19 81). See also 33 U. S. C. §1251(d) (“Except as otherwise expressly pro

vided

. . . , the Administrator of [EPA] shall administer this [Act].”). The Act instructs E PA to establish various technology

based, increasingly stringent e fflu e nt limitations for cate

gories of point sources. E.g., §§1311, 1314. These limit a tions, formulated as restrictions “on quantities, rates, and concentrati ons of chemical, physical, biological, and other constituents,” §1362(1 1 ), were im posed to ac hieve national uniformity among cate gories of sources. See , e.g., E

. I. du Pont de Nemours & Co. v. Train , 430 U. S. 112, 129–1 30 (1977). Th e lim itation s for agiven discharge depend on the type of pollutant and source at issue. 2 Of ke y importance, n e w sources must meet stringen t “standards of performance” adopte d by EPA under §306. That section makes it “unlawful for any . . . new source to operate .

. . in violation of” an applicable performance

——————

2 In addition, the Ac t r e quir es St at es to institute comprehensive wa

terqu alitys t an dar d s fori n tr asta te wat e r s , subjec t to EPA ap pr ov al. See §1313. Th is program supplemen ts the tec hnology - based s t andar d s, serving to “prevent water q u ality from fa lling below ac ceptable level s ” even when p o int sources complywith effluent limita t ions

. EPAv. California ex rel. State Wat e r Resources Control Bd. , 426 U. S. 200, 205, n . 12 (1976).4 COEUR ALA S KA, INC. v. S O UTHEAST ALASKA CONSERVAT ION COUNCI L G IN SB U R G , J., dis s e nting standard. 33 U. S. C. §1316(e) (emphasis added). In line with Congr e ss’ aim “to insure .

. .‘ maximum feasible con

trol of new sources,’ ” duP o n t , 430 U. S., a t1 38, the pre

ferred standard for a new source is one “ ‘permitting no discharge of pollutants,’ ” id. , a t137–138 (quoting 33 U. S. C. §1 316(a)(1) (emphasis added)). M o reover, new sources, unlike existing source s, are not eligib le for EPA

granted variances from applicable limitations. 430 U. S., at 138. 3 In 1982, EPA promulgated new source performance standards for facilities engaged in mining, incl uding those using a froth-flotation milling process. See Ore Mining and Dressing Point So urce Ca teg o ry Effluent Limitations Guidelines and New Source Performance Sta n dards, 4 7 Fed. Reg. 5 4598 (1982). Existing mills, the Agency found, were already achieving zero discharge; it was therefore practicable, EPA concl u ded, fo r new mills to do as well

. Id., at 5460 2. Accordingly, under 40 CFR §440.104(b)(1), new mines using the froth-flotation method, as Coeur Alask aproposes to do, may not discharge wastewate r directly int owaters of the United States. B The nationwide pollution-control requirements just described are implemented thro ugh the National Pollution Discharge EliminationSys t em (NPDES), a permitting scheme set forth in §402 and administered by EPA and th e States. The NPDES is the linchpin of the Act, for it trans

forms generally applicable effluent limitations into the individual obligations of each discharger. EPAv. Califor

-

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3 Even theprovision allowing the Pr esident to exempt federal instal

lations from compliance with the Act’ s requ irements—“if he determines it to be in the par a mount inter e st of the United States to do so”—does not ex tend to new sourc estandar d s: “[N] o ex emption maybe gr anted fr om th e r e qu ir emen ts of sec t ion[306] or[307] of t h is [Ac t].” 3 3 U. S. C. §1323 (a).5 Cite as: 55 7 U

. S. ____ (2009)
G IN SB U R G , J., dis s e nting nia ex rel. Sta t e Wa te r Resourc e sControl B d

. , 426 U. S. 200, 205 (1 976). The discharge of a pollutan tis generall y prohibited unless the source has obtained a NPDES per mit. E.g., EPAv. National Crush e d Stone Assn. , 449 U. S. 64, 71 (198 0) (“Section 402 authorizes the establishment of the [NPDES], under which ev ery discharger of pollutants is required to obtain a permit.”). The Act also establishes a separate permitting scheme, administered by the Corps, for di scharges of “dredged or fill materia l .” 33 U. S. C. §1344(a)

. Section 404 hews to the Corps’ established expertise in matters of navigabilit y and construction. The §404 program does not implement the uniform, technology-based pollution-control standards set out, int er alia , in §306. Inst ead, §404 permits are subject to regulatory guidelines based generally on the impact of a discharge on the receiving environment. See §1344(b); ante , at 4–5. As the above-described statutory background indicates , Coeur Alaska’s claim to a §404 permit carries weighty implications. If eligible for thatp e rmit, Coeur Alaskaca n evade the exacting pe rform ance standard prescribed by EPA for froth-flotation mills. It may, instead, use Lower Slate Lake “as the sett ling pond a n d disposal site for th e tailings.” App. 360a (Corps’ Record of Decision). II Is a pollutant discharge pr ohibited under §306(e) eligi

ble to receiv e a §404 permit as a discharge of fill materia l ? All agree on prelimina r y matters. Only one agency, the Corps or E PA, can issue a permit for the discharge. S ee ante , at 10, 22. Only EPA, throu gh the NPDES progra m, issues permits that implement §306. See supra , at 2. Further, § 306(e) and EPA’s fro t h-flotation performan c e standard, unless ina p plicable h e re, bar C oeur Alaska’s proposed discharge. Se e ante , at 1 4–15. No part of the statuto r y scheme, in my view, calls into6 COEUR ALA S KA, INC. v. S O UTHEAST ALASKA CONSERVAT ION COUNCI L G IN SB U R G , J., dis s e nting question the governance of EPA’s performan c e standard. The text of §306(e) stat es a clear p r oscription: “[I]t shall b e unlawful for any owne r or operator of any n e w source to operate such source in violation of any stan dard of per

formance applicable to such source.” 33 U. S. C. §1316(e). Under the standard of performance relevant here, “there shall be no discharge of proc ess wastewater to navigab le waters fro mmills tha tuse the froth-flotation process” for mining gold. 40 CFR §440.104 (b)(1). The Act imposes these requirements without qualification. Section 404, stating th at the Corps “may issue permits ” for the discharge of “dredged orfill material,” does not create an exception to §306( e)’s plain command. 33 U. S. C. §1 344(a). Cf. ante , at 1 2

. Section404 neither mentions §306 nor sta t es a contra ry requirem e nt. The Act can be home to both provisions, with no wo rds added or omitted, so long as the category of “dredged or fill mate

rial” eligible for a §404 perm it is read in h a rmony with §306. Doing so yields a simp le rule: Discharges governe d by EPA performance standards are subject to EPA’s ad

ministration and receive permits under the NPDES, no t §404. This reading accords with the Act’s structure and objec

tives. It retains, through the NPDES, uniform applicati o n of the Act ’ s core pollution-control requirements, and i t respects Congress’ spec ial conc ern for new sou rces. Leav

ing pollutio n -related decisions to EPA, moreover, is consis

tent with C o ngress’ delegation to that agencyof primary responsibility to admi nister the Act. Most fundamental, adhering to §306(e)’s instruction honors th e overriding statutory goal of elim inating wa ter pollution, and Con

gress’ parti cular rejecti on of the use of navigable waters as waste disposal sites

. See supra , at 2–3. See also 3 3 U. S. C. §1324 (creating “cle an lakes” program requiring7 Cite as: 55 7 U

. S. ____ (2009)
G IN SB U R G , J., dis s e nting States to identify and restore pollu ted lak e s). 4 The Court’s reading, in contrast, strains cr edulity. A discharge of a pollut ant, otherwise prohibited by firm statutory command, becomes lawful if it contains suffi

cient solid matter to r a ise the bottom of a water body , transformed into a waste disposalfacility. Whole catego

ries of regulated industries can thereby gain immunity from a variety of pollution-control standards. The loophol e would swal low not only standa r ds governing mining ac

tivities, see 40 CFR pt. 440 (efflu e nt limitations and new source performance standards for ore minin gand dres s ing); id. , pt. 434 (coal mining); id. , pt. 436 (mineral min

ing), but also standards for dozen s of other categories of regulated point sourc e s, see, e.g., id. , pt. 411 (cement

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4 The Court asserts that “numerous difficulties ” will ensue if a dis

cha r ge gove rn ed b yanew s o urce pe rform a nce s t a n da rd is ineligib le for a §404 per m i t

. An t e , at 12. Namely , the Cour t notes, the disc har g er will have to d e termine whether a performance st anda rd applie s to i t

. Ante , at 13. Tha tis not only the us ua l inquiry under th e Clean Wat e r Act; it is one Coeur Al aska answered, without a pparent difficulty, whe n it s o ught a n d ob ta ined a nEPA perm it for the proposed discharge fro m the lake into a downs t ream creek. S ee an t e , at 6.

J US TI CE B REY ERfears that “li t era[l] app l [ication]” of performance s t a n da rds would int e rfere wit heffort s “to build a leve e or to replace dirt removed from ala ke b o ttom,” a n d th us “ma y prove unne ces s a rily s t rict .” Ante , at 2 (concurring opinion). His concerns are imaginati v e, bu t it i s qu es tion able wh ether they are real. Apple juice processors, meatc u tter s , c e ment manufac tur e r s , and phar mac e utic al pr oduc er s d o not ordinarily build levees —and it is al most inconceivable that th ey would do s ous ing the wa s t e genera ted b ytheir high lys p ecific indus

trial processe s. See, e.g., 40 C F R § 411. 10 (per for m an c estan dar df o r pa rticula rcement ma nufa c turing p r oces s )

. Levee cons truction ge ner allyis under taken bydev e l o per s org o v e rnment, entities not subjec t t o perform a nce s t a n da rds for such aproj ec t. This lit igatio n, furthe rmore, does not illus t rate the “diffic u lty” J US TI CE B REYER perceives. See ante , at 1. Coeu r Alask adoe s n o t seek tob u ild a levee or ret u rn dirtt oa lake; it s i mply wants to us e Lower S l ate Lake as a was t e disposa lsite.8 COEUR ALA S KA, INC. v. S O UTHEAST ALASKA CONSERVAT ION COUNCI L G IN SB U R G , J., dis s e nting manufacturing); id. , pt. 425 (leather tanning and finish

ing); id. , pt. 432 (meat and poultry produ cts processing). See also Brief for American Rivers et al. as Amici Curi ae 26–27 (observing that discharges i nthese categories “typi

cally contain high volu mes of solids”). Providing an escape hatch for polluters whose dischar ges contain solid matt er, it bears noting, is particularly perverse; the Act specifi

cally focuses on solid s as harmful pollutan t s. See 3 3 U. S. C. §1314(a)(4) (requiring EPA to publish information regarding “conventional pollutants,” including “suspended solids”); Brief for American Rivers , supr a , at 28–29, and n. 18 (ident ifying over 50 effluent limitations that restrict total suspended solids)

. 5 Congress, we have recognized, does not “alt er the fun

damental details of a r e gulatory s c heme in vague terms or ancillary provisions—i t does not, one might say, hide elephants in mouseholes.” Whitm a nv. American Trucking Assns., Inc. , 531 U. S. 4 57, 467–46 8 (2001). Ye t an altera

tion of that kind is just what to day’s decision imagines. Congress, a s the Courtreads the Act, silently upended, in an ancillary permitting provision, its painst aking pollu

tion-control scheme. S ee ante , at 17. Congress did so, th e Court holds, notwithstanding th e lawmak ers’ stated effort “to restore and mainta in the che m ical, phys ical, and bi o logical integrity” of the waters of the United States, 33

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5 The “safeguards” J US TI CE B REYERidentifi es are hardly reassuring. See ante , a t3 (con cu rrin go p inion). Give n today’s deci sion, it is opti

mist ic to expect that EPA o rthe co urts will act vigoro usly to prevent evasion of pe rformance standards. Nor is E PA’s vet opower unde r §404(c ) of th e CleanWa ter Ac t anade q u a te subs titu te f o radh e r e n c e t o §306. Th at power—ex er c i sed on lyadozentimes ov er3 6y e ar s en c o m pass ing more than one milli on permitapp lications, see Brief for Ameri

ca n Rivers 1 4

—hinges ona finding of “unacceptable adverse effect,” 33 U. S. C. §1344 (c ). Destr u c t ionof n e ar ly all a q u a ticlif e ina pr istin e lake app a rently does not qualify as “ una ccept ab le.” Reliance on a d ho c v e toes, mor eov er , under mines Congr e ss’ aim to inst all unifor mwater

pollution regul a tion.9 Cite as: 55 7 U

. S. ____ (2009)
G IN SB U R G , J., dis s e nting U. S. C. §1251(a); their assignment to EPA of the Hercu

lean task of setting strict effluent limitations for many categories of industrial source s; and their insistence that new sources meet even more am bitious sta n dards, not subject to e x ception or varianc e. Would a ra tional legisla

ture order exacting po llution limits, yet call all bets off if the pollutant, discharged into a lake, will raise the water body’s elevation? To say the lea s t, I am persuaded, that is not how Congress intended t h e Clean Water Ac tto operate. In sum, it is neither necessary nor proper t oread th e statute as allowing mines to bypa ss EPA’s ze ro-discharge standard by classifying slurry as “fill material.” The use of waters of the Uni t ed States as “settli n g ponds” for harmful mining waste, the Co urt o f Appeals correctly held , is antithetical to the text, struc t u r e, and pur p ose of the Clean Water Act.

* * * For the reasons stated, I would affirm the judgment o f the Ninth C i rcuit.