# Respondents Brief — Util. Air Regulatory Grp. v. Envtl. Prot. Agency, 135 S. Ct. 702 (2014) (No. 14-47) > Briefs, arguments, decisions, and more. URL: https://www.frixlaw.com/law-library/documents/brief%3Amicro_IA40385016_0332%3A14 ## Record - **Collection:** Supreme Court brief - **Document type:** Respondents Brief - **Published:** January 1, 2014 ## Text Nos. 14-46, 14-47 and 14-49 —— --— — Dis METS VAL, ws Fir FEB 25 2015 ‘Flee Bn the Supreme Court of the United States STATE OF MICHIGAN, ET AL., PETITIONERS ENVIRONMENTAL PROTECTION AGENCY, ET AL. UTILITY AIR REGULATORY GROU P, PETITIONER ‘ENVIRONMENTAL PROTECTION AGENCY, ET AL. NATIONAL MINING ASSOCIATION, PETITIONER ENVIRONMENTAL PROTECTION AGENCY, ET AL. ON WRITS OF CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR THE DISTRICT OF COLUMBIA CIRCUIT BRIEF FOR THE FEDERAL RESPONDENTS AVI 8. GARBOW « General Counse! BONJA L. RODMAN Paut oeenee mitted States E tal nvironmen Sind Sta ton Agency = Washington, D.C. 20460 DONALD B. VERRILLI, JR. Solicitor General Counsel of Record JOHN C. CRUDEN Assistant Attorney General MALCOLM L. STEWART Deputy Solicitor General ROMAN MARTINEZ Assistant to the Solicitor General = G. HOSTETLER Department of Justice Washington, D.C. 20530-0001 SupremeCtBriefa@ usdoj. gov (202) 514-2217 QUESTION PRESENTED Whether the Environmental Protection Agency un- reasonably refused to consider costs in determining whether it is appropriate to regulate hazardous air pollutants emitted by electric utilities. (I) TABLE OF CONTENTS Page CE I erccctsicercececsnesscntureencsctiitininntinesineattseisinmnanammnnestanas l TT a sce arepcuniednemnienenacenadioatiniseunsimilenisaesnmabapail 2 nen csssissesceticiuasiesienoeicderiiipmcesintoasiignanigueeniocssineanigtl 2 | __ ESRERETAE SSE Par Raves nsoon ven te eseeteite Mer ORE TIO 2 I IIIIIIID oss dccscienncenssetuinnenersasotinennsanishidecieminienstsdeinnens 17 Argument: EPA reasonably declined to consider costs when listing power plants for regulation under Section 7412 .................. 21 A. Under Section 7412(n)1)(A), EPA has substantial discretion to determine whether it is “appropriate” to list power plants as a source category subject to ET CIID ns icxnconsssanstnnnnpetnmeninnnenneideamnaniie 21 B. The text, structure, and history of the CAA establish that EPA’s interpretation of Section 7412(n){1)(A) is SE nentotsetianenecipainmtidninaiatiininen 23 1. EPA’s interpretation of Section 7412(n)(1)(A) is consistent with the criteria for listing all other sources of hazardous air pollutants under Section 2. EPA’s interpretation is consistent with the NESHAP delisting criteria that apply to power plants and all other stationary sources .................... 32 3. Congress’s express references to costs in other CAA provisions support EPA’s interpretation of Ss I ircsntnceiicceniietepniiinissinnnsaiiiabnemmceniacnitaas 35 4. EPA’s approach to power-plant regulation under the NESHAP program is consistent with the structure of the CAA’s other multistage regula- QO PRR coc ececsecesseseenscsssemssnsmnmnenncerntanemesevene 38 C. Petitioners’ arguments fail to establish that Section 7412(n)(1)A) unambiguously requires EPA to con- Ny thas cicsininnsteesecliedesuannicsnisumtasiantcnaibadaliied cseciscaiidenpuiiaisont 40 (11) IV Table of Contents—Continued: Page 1. The word “appropriate” does not unambiguously require EPA to consider costs when deciding ee i icinctittcenieicitittantinintcinnimmnis 40 2. Section 7412(n)(1)(B)’s express reference to costs does not support petitioners’ interpreta- tion of Section 7412(m)(1)(A) .........scccsccesscreeeeeceeereeseees 47 3. Neither this Court’s precedents nor the D.C. Circuit’s NRDC decision supports petitioners’ theory that silence requires agencies to consider 4. Whether or not Section 7412(n)(1)(A) is a “re- sidual risk” provision is irrelevant to whether EPA must consider Costs............c..sccssssssssscessseseeseenees 51 5. Petitioners’ objections to other aspects of the 2012 Final Rule are outside the scope of the I BI eicttctntnieirsiitiiisaniinintinncinimnmnin 52 D. In the RIA that accompanied the 2012 Final Rule, EPA reasonably concluded that the benefits asso- ciated with the rule will greatly exceed its costs ........... 53 I a ciiscsestinssiissirisiisniiicsinsiceiieeseiaiiaeahbiclinisteaniueiaepneepisiaiicieiiitenes 58 Appendix — Statutory provisions .................ccccsccecscssesseeeseeeeees la TABLE OF AUTHORITIES Cases: American Textile Mfrs. Inst., Inc. v. Donovan, ees IED cckinicersestiieittiiectnnsiccniecsiasineis 23, 37, 38, 49, 51 Chevron U.S.A. Inc. v. NRDC, 467 U.S. 837 SETI Un seissrntscechasiceinsieheiecaiieaesabibehioniedia 3, 17, 21, 23 EPA v. EME Homer City Generation, L.P., A EE 21, 23, 48, 49, 50 EPA v. New Jersey, 555 U.S. 1162 (2009) 0.0.0... ccccceceeeeeees 10 Entergy Corp. v. Riverkeeper, Inc., 556 U.S. 208 IED sacsich checsedislatveseeideanibasbubaisniataseieadiapuniaealacenniiaaliin 19, 20, 23, 49, 54 Cases—Continued: Page FDA v. Brown & Williamson Tobacco Corp., ree Be E wriccievtessenenceniinseccncunineimnnatinnipasetisiatitaniiin 23, 26 General Motors Corp. v. United States, 496 U.S. 530 SETI aschcb nescsihinabonsigandsnnennnaiinaenieaeieidinulenmamuiianiminintinianinismesinas 37 Massachusetts v. EPA, 549 U.S. 497 (2007) .000.......ccccccceseeees 39 Mims v. Arrow Fin. Servs., LLC, 132 S. Ct. 740 II sasiccntitiarsieuasdngieeagnatinaindabanmaleptiamseiiennpnaasatencainiiapiidasibiiena 29 NRDC v. EPA, 824 F 2d 1146 (D.C. Cir. STITT iacscisiedoensasidatintstsantullbensitiniateatalnedialediaiteinasammbioen 7, 20, 50, 51, 52 National Lime Ass'n v. EPA, 233 F.3d 625 eae as Sat eiecescobiicabdienbdasienhiceiaiesiainesionentinsiencdiodapnientninmnessniiancte 12 New Jersey v. EPA, 517 F.3d 574 (D.C. Cir. 2008), cert. dismissed, 555 U.S. 1162, and cert. denied, Se es IN I i iichanhcitatsinisstatiiiceniblesresbisabcsinianaslabe 4, 10, 32 Sossamon v. Texas, 131 S. Ct. 1651 (2011) ..................... 22, 41 Union Elec. Co. v. EPA, 427 U.S. 246 (1976)...0.....ccccccceeseeess 37 Utility Air Regulatory Grp. v. New Jersey, es Se EY esiasesincuisinlistiuniihencdiisciieniniesiuisiiaiinidiaiesineetnieciemes 10 Vermont Yankee Nuclear Power Corp. v. NRDC, Se TIT ciinice\citiesbenbinsbcneainisisitnnaesciindaishatlamesdcipaamcnaibaatbet 43 West v. Gibson, 527 U.S. 212 (1999) ............ccccccsesccessoccsrcncsers 20 Whitman v. American Trucking Ass’ns, 531 U.S. 457 EE ES I ROA Rate ae Pa 16, 18, 23, 36, 37 Statutes, regulations and rule: Clean Air Act, 42 U.S.C. 7401 ef 869. ..........00..cccccecsccseccessessovess 2 es, IIIT ic cciiciciecehicelseiclaniscicaenitiiniaia as dtndaiiaiia 3, 32 ae ee I iciicintiiactinsdtassansncibeestsisabisisissdciinotsitaabiaatabiateilagibai 42 de IIE vshiiatk coddcneseintnicdtanaaetlaatiipnntcietisalienddaiatel 35 es Se edhisieiasinsitciesbiieteccintinonsiniaensssisteninalinatanead 35 Ee jn ENE en ene 35 VI Statutes, regulations and rule—Continued: Page ESR Cee ree ere ema EE 35 A, FED ncscccnstinrnsitaeincntsisinntnastanneneas 35 a ei NU iceciiniestinsithviehscihsiiiesiea get 35 ae ie PD inisinsesisitssistinssiiialeindncsicisihcninsibeucigipasimeictiganse 35 ey WED peicdeitsninsisccistsscanissiibatinibinigieiicacintasidiaaasedions 35 Is RDS. 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FEED ectnisniinitsscintapeiapsictmmenmpeicane 35 OB UAL, FE crsesteretinisisinsineimonmmsmaieanioena 35 4B DEBE... THD ceetctnscssnnsitstemtiguamiaeiecee 42 GB URS, Fre eresinistinintvtssteionninmemaiagiiaiene 42 4B UBS. TRIO ceenesericscssaviinemnnniennseeininiaaamaaniad 35 IX Statutes, regulations and rule—Continued: Page 42 U.S.C. T611D(eM2SK BV) .......--.eccceceeseeserenrreseernrnsenrenees 35 Se es Sen G YD cxcescecssscscessaceserssssnsczsnecencteecesces 35 ree ecnpnemenenemmbanneenaseenemnnenen 35 rc 35 EE 59a ET 3 | Ee 3, 59a eee 39, 59a es SNEED ccienssncnecnencnscesvecsescsczcnnssnesneneee 35, 39, 59a 42 U.S.C. TEZ1(a SMAI) ........0-0cecererseressercersrecsesenenee 35, 59a I ID ss scicnennseanesnennssuenenenenntnasesnnasante 35 ee 35 i 35 eee 35 ee 35 ae, Se ccconcenedncscnsseessesssesecncnenencesnsenenses 35 ee 35 en 35 a 35 a 35 a 42 I 42 ce 35 A 35 a 35 or cersceerenesensscenneenneennsneneenenveee 35 42 U.S.C. TEAHOM2Z)(B)UV).....---cecererreesereerersereseeesensenens 35 ee 35 ricer cnrienierceeensenneineeienannsinamnenuates 3 ED sisi crreesiensssenneneinivnerenetanenenneetcennnennteens 35 X Statutes, regulations and rule—Continued: Page en aerials crpeinaiieetateteeeete eras 35 es Pe ccrsceereicssteacnssittoninincateestaentatytniestsintienempessmnnestal 35 I is Ce rcceniteicsnteecnrsicansnaitetcinaaniastetesiansenans 35 ae es HRI cicterrcsiccisssssinnsiinsssethederntanininainnninseiameinnats 35 ie CE caniceniiitesscasesienecnmiecienniamiamunattionsentsadesia 42 es ee ictecensetesittcntrssivasesrinienitscensitiacstashiaseinattiasiectaienianeiind 35 Ss TI icici ncorcieisarinstontinertenepntemenansemenuats 35 a ID censoccecsicctiteeerticrmatemssasiasiomnibtannmanaatia’ 35 Ge TE Ce ceteneirentnentnmenimniiammeneinnionl 35 es Ce eecccdctcecsontesntrantesicinentnnennnntiamentineme 42 eis I ceccenatiidssiicncciaietiineatihatiieeptaineniuenmunpenindel 35 is, Ce ciniscinticsdincsnshsantiachitdeanesbepanssinaieemaiempsionicdameaniaal 35 es, Te statistic circ coecenccnasheiesemepepsnanaimmanaine 35 ER ee ae 35 Se es i ccisinninssintinitinerreisternincgipereisnainieestaniatentantaties 35 Ee a Ce ieaainsintsittnstnecianintintantareatnniaineatiaeneniin — Ce es Ce ricieciceticiniaeaieiel apa aaseaeieertiapieaientecacirnteales 35 a i iteneaiessttenaniatiisabiitcteablensanistpeiadtaiaieteiduetanie 35 a, i ccrierrtes iesncssietinssistecniieieieshatiaatesintaasihastdntsesaninibiaal s es Se crecccsenteaniicstintientienstintaptteatinieaiinisteniieaiie 35 ks Pe ircierennntccncniinnmnemencdinmuimnntias 35 Clean Air Act Amendments of 1990, Pub. L. No. 101-549, 104 Stat. 2399: Wty GE, BO SRR, BG GRR. GIG cccccsecensnssasereemepnsseresenssmeensonns 4 Clean Air Amendments of 1970, Pub. L. No. 91-604, 84 Stat. 1676: Bo Ee eee nee 4 Or, 4 Clean Water Act, 33 U.S.C. 1251 et 869. .............cccccceseeoes 49, 54 GB DKS. BRI TID ccercsereserrasssennscecsernsnnsneesncsesnnesnmnennemnents 22 XI Regulations and rule—Continued: Page Exec. Order No. 12,866, 3 C.F.R. 639 (1994) .................. 14, 56 Exec. Order No. 13,563, 3 C.F.R. 215 (2012) ..........cccceeee sees 14 i Bie icttacceccmnannnintininnsnctiinntipseninniniimmemameas 8 i Te Tl Oe cqeeenenpesenterenseseniecemiinsctonstnnatvanseimsinntiieaian 10 Miscellaneous: Envtl. Protection Agency, Regulatory /mpact Analysis for the Final Mercury and Air Toxics I ecrerensetesecretctntmeesinememneninnmnsmenenen 55 54 Fed. Reg. 38,044 (Sept. 14, 1989) ...........ccccccccccecceecnnennnnes 7 65 Fed. Reg. (Dec. 20, 2000): Sh, TPO EED crccnsznsuniersnsemnnsqesnenenenquenasinenmnmnanemenanmnanin 8 I, HE cntnentenetinsenemsintiieinenianioapionpenieaianeiangeieinnpenrcaninnnmnanat SS) 1 FR evicxnvseestesetedenioniteneniisiensenntnnnonanemsenmneneesneenneumaneenenelanentnt: 9 i FD ecesasesnansenecseensmtoseesnscusmsasenmeunsrsimeammnnscnmnninsinn 8,9 ee 46 i Fa asestectensetenradharnernensincssputesinesinsiinbeniotallastateimsteanessesinnntaainstd 8, 9, 46 70 Fed. Reg.: ic ts SE I ceretecceniecnartenmnasecansanicantenmtasamonets 10 OE III creinscomisexinonetiomeuiateneciniensnionentestionses 10 76 Fed. Reg. (May 3, 2011): EE acnattscnseensriosaantconnessincninenniniendinnmanimneananteiatastencaeete 11 is nceerengeineeenenenenmmnniepennnennansemceeneemmnaninsemesnenminnintiets ll SD TR ND cenneecnimensencncinemeninmntenemnmnenenmatns 11 i IEE ecicisisesensenrsmowminennesmncnsienanictaameninentenaseeanianetiian 11 ee 12, 47 SD, PD cncnreesecsvennenmeennntememunnnnmenneenmmnattion 11, 45 ee iicetineiereicchinieniaetnidsiaseeaianngainieaninotiite 11, 12, 32, 34, 46 i, SD tencricientenicursmnivensinncnaunniivaniininnainiantiniats 47 a 47 XII Miscellaneous—Continued: Page ii TET idiibinieltigninsiseprmmnennddduieiennemetitenninianamnneate 46, 47 I cnerssrinicidinnninsimienentinetajuibgteendemainas 11 77 Fed. Reg. (Feb. 16, 2012) ih: Ti licnrastirestenmseneenmniopenseninatseniennimininsiineanidianmnntennauiintitin 12 ee En ER ee 14 SE ee en 2, 14, 20, 43, 55 dT os soncnecsencnmesaseameienecieceliampieanindsaniesasameesttibien 13, 14, 15, 53 1 RIES eeesrenesenserstemmeeessernsmmsemesnnnenimemannminenelinin 6, 13 Sis TE ineeitineieiemnnenemsnnenvnspeneestatinnnninimnnanmiennniunnnintatnies 57 SE iciesscsernesnsvsemenierennahiansnninnenansteneminimmmontnmans 47 SN, FE a elcrnsccenssconsniiannnsnentaveniscinninasenansbniigpemnimininnsnin 13 EN 46 CS ET ticomcucessnprorennsemniccunintnnitigianveiatinenmuimvtietitit 12 TE irapteassenpeanenpsneimenpinasierpenenisienmnanniueipianimenniassnin 14,15 is TET sinetiniibienianciamenenastncnentincmnnencenitaenieisinnendngibeninnannieniai 12 I iranencaseenisinstnineghnnienapniainnninimicainmeiidiei 13 ITI curbs dpeeieanrtobaiecenitanapdlaesitaasattaiaiadtisai 13, 15, 47 0, i nietannnierenentnnannssinuenscememnnnmmmimemninannanaiiiin 13 i, ee ceecseernnscenenaeninnnionsnnntsieniesinmeetemmeianienaninineneatin 13 Oo Re ieterdeniecmnssvavsaspecssemmnnctesessensenmetenesiinnaniennmeinnmaniats 13 i ientscnnsicaisennnivaieicicninnneneinipannenisienatecsinpnnpelacintuniats 13 i Ti ciienieiithesieennenernnienncernnreneanenstnnepreneieniennnceninenemensenenieiita 57 a 13 Se iesessicieerctanntecicsnineenimnerenenmminnnianiananinnt 14, 15 i Ti cihieenaspneniinenenaianstignuenmnmesennaeinnnnitnninmetants 55, 57 A cesnnictncseinnmsiciominnanteamativemaninascastasmmummcmmennencemmianainiti 14 78 Fed. Reg. 10,020-10,021 (Feb. 12, 2013) ...............cccccceoeee 54 79 Fed. Reg. (Oct. 6, 2014): i, Ga IES seneceertncstnasesecncnnmmcssniciennmunianiteneisnnaeisansomninians 54 XIII Miscellaneous—Continued: Page HLR. Rep. No. 490, 101st Cong., 2d Sess. (1990) ...........-.- 1 Michael A. Livermore & Richard L. Revesz, Rethinking Health-Based Environmental Standards, 89 N.Y.U. L. Rev. 1184 (2014) .............-.ccccee 56 Nat’ Ctr. for Envtl. Econ., Office of Policy, Envtl. Protection Agency, Guidelines for Preparing Economic Analyses (2014), http//yosemite. epa.gov/ ee/epa/eerm.nsf/vwAN/EE-0568-50.pdf/ $file/ EE-0668-50. pdf .......cscecssssoscsceceserssssserssnsnessnssssnessncssssscnsersnssees 56 Office of Mgmt. & Budget, OMB Circular A-4 (2003), http://www.whitehouse.gov/sites/default/files/ omb/assets/omb/circulars/a004/a-4. pdf...........--..----e0eceeees 56 Samuel J. Rascoff & Richard L. Revesz, The Biases of Risk Tradeoff Analysis: Towards Parity in Environmental and Health-and-Safety Regulation, 69 U. Chi. L. Rev. 1763 (2002).........-----0-s+00 56 S. Rep. No. 228, 10ist Cong., 1st Sess. (1989)............ 4, 26, 57 Staff of the Senate Comm. on Environment and Public Works, 103d Cong., Ist Sess., 1 A Legislative History of the Clean Air Act Amendments of 1990 (Comm. Print 1993) .............c--c.esscsssssesecesseerenssorenssoressensess 8, 28 Cass R. Sunstein, Cost-Benefit Default Principles, 99 Mich. L. Rev. 1651 (2001) ..........c-c-ccenceseereeeneensneersnnennnens 39 Cass R. Sunstein, Essay, The Real World of Cost- Benefit Analysis: Thirty-Siz Questions (and Almost as Many Answers), 114 Colum. BO ee 56 The New Oxford American Dictionary (2d ed. DIOG) ....00ccecccecsesccesessseneseccscensseccsecnosonsessovenessssasesscsssonssssosees 22, 41 In the Supreme Court of the Anited States No. 14-46 STATE OF MICHIGAN, ET AL., PETITIONERS vz. ENVIRONMENTAL PROTECTION AGENCY, ET AL. No. 14-47 UTILITY AIR REGULATORY GROUP, PETITIONER vz. ENVIRONMENTAL PROTECTION AGENCY, ET AL. No. 14-49 NATIONAL MINING ASSOCIATION, PETITIONER v. ENVIRONMENTAL PROTECTION AGENCY, ET AL. ON WRITS OF CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR THE DISTRICT OF COLUMBIA CIRCUIT BRIEF FOR THE FEDERAL RESPONDENTS OPINIONS BELOW The opinion of the court of appeals (Pet. App. la- 98a) is reported at 748 F.3d 1222.’ The final rule promulgated by the Environmenta] Protection Agency ' Citations to Pet. App. are to the appendix to the petition for a writ of certiorari filed by the National Mining Association in No. 14-49. (1) 2 (Pet. App. 196a-1160a) is published in 77 Fed. Reg. 9304. JURISDICTION The judgment of the court of appeals (Pet. App. 99a-100a) was entered on April 15, 2014. The three petitions for writs of certiorari were filed on July 14, 2014. Those petitions were granted on November 25, 2014, limited to the following question: “Whether the Environmental Protection Agency unreasonably re- fused to consider costs in determining whether it is appropriate to regulate hazardous air pollutants emit- ted by electric utilities.” The jurisdiction of this Court rests on 28 U.S.C. 1254(1). STATUTES INVOLVED Pertinent provisions of the Clean Air Act, 42 U.S.C. 7401 et seg., are reprinted in the appendix to this brief. App., infra, la-60a. STATEMENT This case involves the determination of the Envi- ronmental Protection Agency (EPA) that it is “appro- priate and necessary” to regulate emissions of haz- ardous air pollutants from coal- and oil-fired power plants under the Clean Air Act (CAA or Act), 42 U.S.C. 7412(n)(1)(A). EPA concluded that costs are not relevant to the decision whether to regulate such emissions, but that costs should instead be taken into account when setting emission standards under 42 U.S.C. 7412(d). When EPA promulgated those standards, it issued a Regulatory Impact Analysis (RIA) estimating that the total quantifiable benefits of those standards would exceed their total costs by between $27 billion and $80 billion (measured in 2007 dollars) each year. 77 Fed. Reg. 9305-9306 (Feb. 16, 3 2012) (2012 Final Rule). The court of appeals upheld EPA’s decision not to consider costs when making the threshold listing decision as “clearly permissible” under Chevron U.S.A. Inc. v. NRDC, 467 U.S. 837 (1984). Pet. App. 25a. 1. a. The CAA’s core purpose is “to protect and enhance the quality of the Nation’s air resources so as to promote the public health and welfare and the pro- ductive capacity of its population.” 42 U.S.C 7401(b)(1). To that end, the Act establishes a compre- hensive set of regulatory programs to control air pol- lution from both stationary and mobile sources. Such programs include the National Ambient Air Quality Standards (NAAQS) program, see 42 U.S.C. 7408- 7410; the New Source Performance Standards (NSPS) program, see 42 U.S.C. 7411; the National Emissions Standards for Hazardous Air Pollutants (NESHAP) program, see 42 U.S.C. 7412; and the Motor Vehicle Emission and Fuel Standards program, see 42 U.S.C. 7521-7544, 7547-7554. For each of those programs, the Act establishes a multistage regulatory process in which first EPA makes a determination about the dangers posed to public health or welfare by certain types of pollution, and then EPA or the States promulgate emission standards that sources must meet to address those dangers. See 42 U.S.C. 7408(a), 7409(a), (b) and (d)(1), 7410, 7411(b), 7412(c) and (d), 7521(a). EPA does not consider costs when assessing the dangers at the first stage, but it does consider costs, in accord- ance with the relevant provisions, when setting stand- ards at the second stage. See tbid. b. This case involves the NESHAP program, under which EPA regulates stationary-source emissions of 4 more than 180 “hazardous air pollutants” specifically identified in 42 U.S.C. 7412(b). Such pollutants cause serious health impacts, such as cancer, neurological disorders, reproductive dysfunctions, and death. H.R. Rep. No. 490, 101st Cong., 2d Sess. 315 (1990) (1990 House Report).” As originally established in 1970, the NESHAP program required EPA to generate the list of hazard- ous air pollutants and to establish health-based emis- sion standards for each one. Clean Air Amendments of 1970, Pub. L. No. 91-604, § 112(b)(1)(A) and (B), 84 Stat. 1685. By 1990, however, EPA had set stand- ards for only seven pollutants, and those standards applied only to a handful of source categories. New Jersey v. EPA, 517 F.3d 574, 578 (D.C. Cir. 2008), cert. dismissed, 555 U.S. 1162, and, cert. denied, 555 U.S. 1169 (2009); 1990 House Report 322; S. Rep. No. 228, 101st Cong., 1st Sess. 131 (1989) (1989 Senate Report). Frustrated by the slow pace of regulation, Con- gress completely overhauled the NESHAP program in the Clean Air Act Amendments of 1990 (1990 Amendments), Pub. L. No. 101-549, Tit. III, § 301, 104 Stat. 2531. In doing so, Congress eliminated much of EPA’s discretion under the original statute. First, the 1990 Amendments included a list of more than 180 hazardous air pollutants to be regulated. 42 U.S.C. 7412(b)(1) (Supp. II 1990). Congress also directed EPA to publish and revise “a list of all cate- 2 The CAA distinguishes hazardous air pollutants from “criteria air pollutants”—ozone, particulate matter, nitrogen oxides, sulfur dioxide, lead, and carbon monoxide—which are regulated under the NAAQS program. 1990 House Report 196, 315; see 42 U.S.C. 7408-7410. D gories and subcategories of major sources” of the listed pollutants. 42 U.S.C. 7412(ce)(1). A “major source” is any stationary source or group of stationary sources at a single location and under common control that emits or has the potential to emit ten tons per year or more of any single hazardous air pollutant, or 25 tons per year or more of any combination of haz- ardous air pollutants. 42 U.S.C. 7412(a)(1). The 1990 Amendments also required EPA to list any category or subcategory of “area sources”—defined to include stationary sources of hazardous air pollution that are not “major source[s]”—that the agency concludes “presents a threat of adverse effects to human health or the environment * * * warranting regulation under this section.” 42 U.S.C. 7412(a)(2), (c)(1) and (3). EPA's decision to list a source category imposes no direct obligation on any regulated entity and is not “final agency action” subject to judicial review. 42 U.S.C. 7412(e). The listing decision does, however, require EPA to promulgate emission standards for listed hazardous air pollutants emitted by sources within that category. 42 U.S.C. 7412(d)(1). Those standards generally must “require the maximum de- gree of reduction in emissions of the [listed] hazard- ous air pollutants * * * that [EPA] * * * deter- mines is achievable for new or existing sources in the category or subcategory to which such emission standard applies.” 42 U.S.C. 7412(d)(2); see 42 U.S.C. 7412(d)(5) (authorizing alternative standard for area sources). Congress prescribed a specific methodology for identifying the “maximum degree of reduction” that is “achievable” by sources within a particular category. 6 42 U.S.C. 7412(d)(3). In general, for existing plants, the emission standard “shall not be less stringent, and may be more stringent than” the average emission limitation that is already being achieved by the best- performing 12% of existing sources. 42 U.S.C. 7412(d)(3)(A); see 42 U.S.C. 7412(d)(3)(B) (requiring EPA to set standards that are at least as stringent as the average emission limitations of the five best performers for source categories with fewer than 30 sources). The practical effect of that requirement is to create an irrebuttable presumption that a particular degree of emission reduction is “achievable” by sources within a category if it is actually being achieved by a significant percentage of such sources. In determining whether more stringent standards should be imposed on sources within a particular category—i.e., whether greater emission reductions are “achievable” by such sources—EPA must consider such factors as cost, energy requirements, and other health and environmental impacts. 42 U.S.C. 7412(d)(2). EPA refers to standards set at the mini- mally stringent level as “floor” standards, and to more stringent standards as “beyond-the-floor” standards. 77 Fed. Reg. at 9307. Section 7412 authorizes EPA to delete particular source categories from the list in specified circum- stances. See 42 U.S.C. 7412(c)(9)(B)(i) and (ii). Sec- tion 7412 does not authorize EPA to consider the costs of complying with the Section 7412(d) emission stand- ards in determining whether to delist a particular source category.° * The 1990 Amendments also require EPA to review Section 7412(d) standards within eight years after they are promulgated to ensure that they are sufficient to protect public health with an 7 e. This case involves one source category of haz- ardous air pollutants—coal- and oil-fired “electric utility steam generating unit[s],” ie., power plants. 42 US.C. 7412(aX(8). The 1990 Amendments estab- lished a special procedure that EPA must follow be- fore deciding whether to list power plants for regula- tion under the NESHAP program. If EPA deter- mines that power plants should be listed, however, it must set emission standards in accordance with the same statutory provisions that apply to other listed source categories. See 42 U.S.C. 7412(n)(1)(A) (stat- ing that EPA “shall regulate [power plants] under [Section 7412], if [EPA] finds such regulation is ap- propriate and necessary”); Pet. App. 36a-38a. Congress required EPA to perform, within three years of the 1990 Amendments, “a study of the haz- ards to public health reasonably anticipated to occur as a result of emissions” of listed hazardous air pol- lutants from power plants “after imposition of the requirements” set forth elsewhere in the Act. 42 U.S.C. 7412(n)(1)(A). That provision reflects the fact that Title IV of the Act established a new program to control power-plant emissions of two “criteria pollutants”—sulfur dioxide and nitrogen oxide—that ample margin of safety. 42 U.S.C. 7412(f2). That “residual risk” review tracks the two-step process that was in place before the 1990 Amendments were enacted. See 42 U.S.C. 7412(fK2B) (preserving EPA interpretation set forth in 54 Fed. Reg. 38,044 (Sept. 14, 1989)); NRDC v. EPA, 824 F.2d 1146, 1164-1166 (D.C. Cir. 1987) (en banc). Under that residual-risk review, EPA first evaluates health factors alone and determines the “safe[]” level of risk. 42 U.S.C. 7412(fX2A). EPA then determines whether more stringent standards are necessary to protect public health with an “ample margin of safety,” taking into account costs and other relevant factors. /bid. 8 contribute to the phenomenon of acid rain. 42 U.S.C. 7408(f)(1)(A); see 42 U.S.C. 7651-7651f. Congress understood that the controls used to meet the new acid-rain requirements and other requirements of the Act could have the ancillary benefit of reducing hazardous-air-pollutant emissions from power plants. See Staff of the Senate Comm. on Environment and Public Works, 103d Cong., 1st Sess., 1 A Legislative History of the Clean Air Act Amendments of 1990 1416 (Comm. Print 1993) (1990 CAA Legislative History); Nat'l Mining Ass’n (NMA) Br. 5-8; Util. Air Regulatory Grp. (UARG) Br. 9-10. Because the hazardous-air-pollutant reductions associated with implementation of the other CAA programs were not yet known, Congress concluded that EPA should study the risks remaining after implementation of those programs before deciding whether to list power plants for regulation under the NESHAP program. See 42 U.S.C. 7412(n)(1)(A). 2. a. After the 1990 Amendments became law, EPA listed, and promulgated Section 7412 emission standards for, scores of source categories, cover- ing virtually the full range of American industry. See 40 C.F.R. Pt. 63. In 1998, EPA completed the statutorily-required study of the health effects of power-plant emissions. 65 Fed. Reg. 79,825-79,826 (Dec. 20, 2000). In December 2000, EPA determined that regula- tion of coal- and oil-fired power plants under Section 7412 was “appropriate and necessary.” 65 Fed. Reg. at 79,830. EPA therefore added such power plants to the list of source categories to be regulated under Section 7412. Jd. at 79,831. EPA also determined that it was “not appropriate or necessary” to regulate 9 natural-gas-fired power plants, and it accordingly chose not to list those plants. /bid. As part of its 2000 determination, EPA found that coal- and oil-fired power plants are the largest source of domestic anthropogenic mercury emissions, and that “[mJercury is highly toxic, persistent, and bioac- cumulates in food chains.” 65 Fed. Reg. at 79,827. EPA found that mercury emitted by power plants falls into water bocies and then becomes concentrated in the bodies of predatory fish, which absorb the methy]- mercury contained by their food sources. When hu- mans eat those contaminated fish, they too are ex- posed. The methylmercury from the fish poses an especially great risk to children born to women ex- posed to high levels of methylmercury during preg- nancy. J/bid. EPA explained that methylmercury “readily passes * * * to the fetus and fetal brain,” and that children exposed to methylmercury during pregnancy have exhibited developmental neurological abnormalities and delays. Jd. at 79,829. EPA esti- mated that approximately seven percent of American women of childbearing age—.e., millions of women— were being exposed to methylmercury in amounts that exceed a health-protective level. bid. Although EPA’s 2000 finding focused primarily on the hazards posed by mercury emissions, the agency also found that the cancer-related risks posed by oth- er metals emitted by power plants presented a poten- tial public-health concern, and that acid-gas and dioxin emissions likewise warranted further evaluation. 65 Fed. Reg. at 79,827. EPA also identified a number of available emission controls that are effective at reducing emissions of mercury and other hazardous air pollutants. /d. at 79,830. 10 b. As a result of the 2000 listing decision, EPA was required to promulgate Section 7412(d) emission standards for all hazardous air pollutants emitted by power plants within two years. See 42 U.S.C. 7412(c)(5) and (e). EPA did not meet that deadline. In 2005, EPA attempted to reverse the 2000 determi- nation, to remove power plants from the Section 7412(c) list, and instead to regulate power-plant mer- cury emissions under the NSPS program, 42 U.S.C. 7411. 70 Fed. Reg. 16,004 (Mar. 29, 2005) (2005 Delisting Rule). In a related rulemaking, EPA prom- ulgated Section 7411 standards of performance for mercury emissions. 70 Fed. Reg. 28,606 (May 18, 2005). Numerous parties petitioned for judicial review of the 2005 Delisting Rule and the accompanying Section 7411 standards. The D.C. Circuit granted the peti- tions and vacated both rules. New Jersey, 517 F.3d at 583. The court held that the 2005 Delisting Rule “vio- lated the [Act’s] plain text” by failing to comply with the delisting requirements set forth in 42 U.S.C. 7412(c)(9). New Jersey, 517 F.3d at 582. The govern- ment filed, but later moved to dismiss, a petition for a writ of certiorari seeking review of the D.C. Circuit’s decision. See EPA v. New Jersey, 555 U.S. 1162 (2009) (No. 08-512) (petition filed Oct. 17, 2008; mot. to dismiss filed Feb. 6, 2009). This Court dismissed the government’s petition under Sup. Ct. R. 46, New Jer- sey 555 U.S. at 1162, and it denied an industry group’s petition for a writ of certiorari, Utility Air Regulatory Grp. v. New Jersey, 555 U.S. 1169 (2009) (No. 08-352). 3. As a result of the D.C. Circuit’s ruling, power plants remained on the Section 7412(c) list pursuant to EPA’s 2000 listing decision. In 2011, EPA solicited 1] public comments on a proposed rule establishing emission standards for listed hazardous air pollutants emitted by such plants. 76 Fed. Reg. 24,976 (May 3, 2011) (2011 Proposed Rule). EPA proposed to reaf- firm its 2000 “appropriate and necessary” deter- mination and listing decision. /d. at 24,993-25,020. It also relied on robust new technical analyses confirm- ing the health and environmental hazards posed by power-plant emissions of hazardous air pollutants. /d. at 24,986, 24,993-25,020. The preamble to the 2011 Proposed Rule also set forth EPA’s proposed interpretation of Section 7412(n)(1)(A)’s directive to regulate power plants “if [EPA] finds such regulation is appropriate and neces- sary.” 76 Fed. Reg. at 24,986 (emphasis omitted); see id. at 24,986-24,993. EPA observed that Section 7412(n)(1)(A) “provides no clear standard to govern EPA’s analysis,” and that the broad phrase “appropri- ate and necessary” therefore “convey[s] considerable discretion to [EPA] in determining what is appropri- ate and necessary in a given context.” Jd. at 24,987. EPA then proposed that it is “appropriate” to regu- late power plants under Section 7412(n)(1)(A) if, at the time of the finding, (1) hazardous-air-pollutant emis- sions from those plants pose a hazard to either public health or the environment, and (2) controls are availa- ble to reduce such emissions. 76 Fed. Reg. at 24,988- 24,989. EPA also stated that, although the term “ap- propriate” is ambiguous, it is best interpreted in the present statutory context not “[to] allow for the con- sideration of costs in assessing whether hazards to public health or the environment are reasonably antic- ipated to occur based on [power-plant] emissions.” /d. at 24,989. EPA observed that its approach was “con- 12 sistent with the overall structure of the CAA,” and that Congress had not allowed the agency to consider costs when listing any other source category for regu- lation or when evaluating whether any source catego- ry should be delisted. Ibid. EPA further proposed that it may find regulation to be “appropriate” based “on a finding that any single {hazardous air pollutant] emitted from [power plants] poset a hazard to public health or the environment.” 76 Fed. Reg. at 24,988. It noted that Section 7412 does not mandate distinct “appropriate and neces- sary” findings for each individual pollutant, and that EPA must promulgate standards for all hazardous air pollutants emitted by major-source categories subject to regulation. Jd. at 24,989 (citing National Lime Ass'n v. EPA, 233 F.3d 625, 633 (D.C. Cir. 2000)). EPA also proposed that regulation of power plants is “necessary” under Section 7412(n)(1)(A) if public- health or environmenta) hazards posed by power-plant emissions will not be addressed through the imple- mentation of other CAA requirements. /d. at 24,990- 24,992. 4. In February 2012, EPA issued a final rule promulgating emission standards for power plants. 77 Fed. Reg. at 9304. a. The preamble to the final rule set forth EPA’s final interpretation of Section 7412(n)(1)(A)’s “appro- priate and necessary” standard. 77 Fed. Reg. at 9320- 9329. The preamble explained that costs do “not have to be read into the definition of ‘appropriate,’” and that “it is reasonable to assess whether to list [power plants] * * * without considering costs.” /d. at 9327. b. The preamble also reaffirmed EPA’s December 2000 “appropriate and necessary” finding and listing 13 decision, as well as the additional analyses of the health and environmental hazards posed by power- plant hazardous-air-pollutant emissions that the agen- cy had discussed when it issued the 2011 Proposed Rule. 77 Fed. Reg. at 9310-9364. EPA ultimately found it “appropriate” to regulate coal- and oil-fired power plants under Section 7412 because, inter alia: (1) such plants remain by far the largest domestic source of mercury emissions and of many other listed hazardous air pollutants; (2) mercury and other emit- ted pollutants pose hazards to public health and the environment; and (3) effective controls remain availa- ble to reduce emissions. /d. at 9362-9363, 9366 (noting that various findings provided independent bases for regulation). EPA separately reaffirmed that it is “necessary” to regulate power-plant emissions be- cause, inter alia, implementation of other CAA re- quirements would not eliminate the identified hazards to public health. /d. at 9363. c. Pursuant to Section 7412(d), the 2012 Final Rule established emission standards for listed hazardous pollutants emitted by power plants. 77 Fed. Reg. at 9366-9376. EPA explained that those standards could be met—and, in fact, were in many cases already being met—by existing power plants using proven and available control technologies. /d. at 9307, 9366-9376. With respect to almost every pollutant, EPA set the emission standard at the least stringent “floor” level allowed by Congress. /d. at 9367 (Tbl. 3), 9369; see 42 U.S.C. 7412(d)(3)(B). EPA noted that those stand- ards would dramatically reduce power-plant emissions of mercury and other pollutants. 77 Fed. Reg. at 9306, 9424-9425. 14 d. In accordance with Executive Orders 12,866 and 13,563, EPA also issued an RIA that estimated the costs and benefits of the new power-plant emission standards. 77 Fed. Reg. at 9305-9306, 9426-9432; 4 J.A. 904-956 (RIA excerpts). That analysis project- ed that the standards, once fully implemented in 2016, would yield annual monetized benefits of between $37 billion and $90 billion (measured in 2007 dollars), as compared to annual costs of $9.6 billion. 77 Fed. Reg. at 9305-9306. The RIA explained that the rule would achieve sig- nificant reductions of emissions of mercury and other listed hazardous air pollutants, and that the technolo- gies used to reduce those emissions would also have the significant ancillary benefit of reducing emissions of two criteria pollutants—particulate matter (specifi- cally PM,,) and sulfur dioxide (a precursor to PM,,). 77 Fed. Reg. at 9305; 4 J.A. 954-955. Although those criteria pollutants are not listed as hazardous air pollutants, they are directly regulated by the final rule as surrogates for listed hazardous air pollutants. See 77 Fed. Reg. at 9305. EPA explained that the “great majority” of the quantifiable benefits identified in the RIA are “attributable to co-benefits from reductions in PM,,-related mortality.” /bid. Those quantifiable benefits include the prevention of up to 11,000 prema- ture deaths each year. Jd. at 9306, 9445; see id. at 9426-9432. EPA made clear that the RIA played no role in its finding that regulating power plants was “appropriate and necessary” under Section 7412(n)(1)(A). See 77 Fed. Reg. at 9323. It also explained that only one of the direct health and environmental benefits from reducing emissions from hazardous air pollutants 15 could even be partially quantified. /d. at 9306, 9323, 9363, 9426-9432; see 4 J.A. 905, 918, 921-922, 940-953. * EPA ultimately concluded, however, that, “[u]pon con- sidering these limitations and uncertainties, it re- mains clear that the benefits of this rule * * * are substantial and far outweigh the costs.” 77 Fed. Reg. at 9306. 4. Petitioners filed consolidated petitions for judi- cial review of the 2012 Final Rule in the D.C. Circuit. Other power producers and other States intervened in support of the rule. As relevant here, petitioners argued that EPA must consider costs when determin- ing whether regulation of power plants is “appropri- ate” under Section 7412(n)(1)(A). Pet. C.A. Br. 41; see Pet. App. 24a-25a. Petitioners also challenged numer- ous other aspects of the 2012 Final Rule, including EPA’s factual) findings with respect to the harmful effects of exposure to mercury, acid gases, and other pollutants. Pet. C.A. Br. 48-55. a. The court of appeals upheld EPA’s “appropriate and necessary” finding and its accompanying decision to list power plants. Pet. App. 16a-54a. The court explained that the Act “does not evince unambiguous congressional intent on the specific issue of whether * The RIA explained that there are “daunting” obstacles to suc- cessfully quantifying, in monetary terms, the direct public-health benefits from reducing emissions of hazardous air pollutants. 4 J.A. 951. Those obstacles include (1) gaps in toxicological data; (2) uncertainties in extrapolating results from high-dose animal experiments to estimate human effects at lower doses; (3) limited ambient and personal exposure monitoring data; (4) difficulties in tracking diseases, such as cancer, that have long latency periods; and (5) insufficient economic research to support the valuation of the health impacts often associated with exposure to individual air toxics. /bid. 16 EPA was required to consiier costs in making its ‘appropriate and necessary’ determination under [Section 7412(n)(1)(A)].” Jd. at 25a. It found EPA’s interpretation to be “clearly permissible” under Chev- ron, stating that the agency had “reasonably conclud- ed it need not consider costs in making its ‘appropri- ate and necessary’ determination under [Section 7412(n)(1)(A)].” Jd. at 25a, 33a. The court of appeals relied in part on Whitman v. American Trucking Ass’ns, 531 U.S. 457 (2001), in which this Court highlighted its longstanding “re- fus[al] to find implicit in ambiguous sections of the [CAA] an authorization to consider costs that has elsewhere, and so often, been expressly granted.” /d. at 467; see Pet. App. 25a-26a; see also id. at 31a n.2. The court of appeals also noted that Congress (1) has required EPA to regulate other sources of pollution without considering cost; (2) has not allowed EPA to consider costs when deciding whether to delist a source category under the NESHAP program; and (3) has required EPA to take account of costs when setting the level of regulation of power-plant hazard- ous-air-pollutant emissions. See id. at 27a-29a, 31a; see also 42 U.S.C. 7412(c) and (d)(2). The court unan- imously rejected all other aspects of petitioners’ chal- lenges to the 2012 Final Rule. Pet. App. 16a-22a, 33a- 54a. b. Judge Kavanaugh concurred in part and dis- sented in part. Pet. App. 68a-98a. Judge Kavanaugh agreed with petitioners that, in order to determine whether it is “appropriate” to list power plants for regulation under the NESHAP program, EPA must consider the costs associated with such regulation. /d. 17 at 73a-84a. Judge Kavanaugh joined all other aspects of the panel’s per curiam opinion. SUMMARY OF ARGUMENT EPA properly declined to consider costs in decid- ing that it was “appropriate and necessary” to list power plants for regulation under the NESHAP pro- gram. 42 U.S.C. 7412(n)(1)(A). With respect to all other source categories, the CAA unambiguously directs EPA to consider costs only in setting the proper level of regulation, not in making the threshold determination whether a particular source category should be listed. Petitioners have identified no textual or practical justification for requiring a different ap- proach to the listing and subsequent regulation of power plants. Because EPA’s interpretation comports with the Act’s text, structure, and purposes, the court of appeals correctly upheld the agency’s decision un- der Chevron U.S.A. Inc. v. NRDC, 467 U.S. 837 (1984). A. In the 1990 Amendments, Congress directed EPA to conduct a study of the health hazards posed by the emission of hazardous air pollutants from pow- er plants. 42 U.S.C. 7412(n)(1)(A). It instructed EPA to regulate such emissions under Section 7412 if the agency concluded that doing so was “appropriate and necessary after considering the results of the study.” Ibid. That open-ended phrasing gives EPA discretion to interpret Section 7412(n)(1)(A) in accordance with Section 7412’s broader text, structure, and purposes. B. EPA’s approach to the listing of power plants for NESHAP regulation is consistent with the CAA provision that governs the listing of other stationary- source categories. See 42 U.S.C. 7412(c). That provi- sion requires EPA to list sources based on either the 18 volume of their hazardous-air-pollutant emissions (major sources) or the risks posed by such emissions to health or the environment (area sources). Thus, with respect to all other stationary sources of hazard- ous air pollutants, EPA’s decision whether to list a particular source category must be made without regard to cost. Petitioners rely heavily on Congress’s enactment of a separate provision that is specific to the listing of power plants. See 42 U.S.C. 7412(n)(1)(A). But neither the text of that provision, nor Congress’s reasons for enacting it, suggest that Congress wished to encourage (much less to require) EPA to consider costs in making the threshold listing decision. The reasonableness of EPA’s approach is rein- forced by the statutory provision that governs EPA’s delisting of previously listed source categories. See 42 U.S.C. 7412(c)(9). Under that provision, which applies equally to power plants and all other station- ary sources, costs are irrelevant to EPA’s determina- tion whether a particular source category should be delisted. EPA reasonably concluded that, if costs are not relevant to the delisting decision, they should also be irrelevant when the agency decides whether to include power plants on the list in the first place. Other textual and structural aspects of the CAA confirm the reasonableness of EPA’s conclusion that costs are irrelevant to the listing determination. Although the Act directs EPA to take account of costs when making many other regulatory decisions, Section 7412(n)(1)(A) imposes no such requirement. Cf. Whitman v. American Trucking Ass’ns, 531 U.S. 457, 467-468, 471 (2001). EPA’s interpretation of Section 7412(n)(1)(A) is also consistent with various 19 other CAA regulatory programs involving multistage decisionmaking in which (1) EPA makes a threshold decision to regulate based exclusively on health and environmental factors, and (2) EPA or the States then consider costs (among other relevant factors) in choosing the proper level of regulation. The CAA’s repeated use of that approach refutes petitioners’ contention that it is inherently irrational, and/or pre- sumptively inconsistent with Congress’s intent, to ignore costs in making the threshold decision whether to regulate. C. Petitioners’ contrary arguments lack merit. First, they emphasize the breadth of the term “appro- priate,” as well as the common sense point that it is often reasonable to consider costs in determining whether particular regulatory burdens should be imposed. But petitioners fail to acknowledge the basic congruence between EPA’s approach to power-plant regulation under the NESHAP program—which treats costs as relevant only to the formulation of specific emission standards, not to the threshold list- ing decision—and the approach that Congress man- dated for all other source categories. In attacking EPA’s interpretation of Section 7412(n)(1)(A) as “ut- ter{ly] irrational[],” NMA Br. 19, petitioners impugn the very cost-blind listing methodology that Congress unambiguously mandated for all other types of sta- tionary sources. Petitioners also lean heavily on mischaracteriza- tions of relevant precedent. For example, they cite decisions like Entergy Corp. v. Riverkeeper, Inc., 556 U.S. 208 (2009), to support their argument that EPA must consider costs when making regulatory deci- sions. In fact, those decisions show that statutory 20 silence with respect to costs is typically “meant to convey nothing more than a refusal to tie the agency’s hands as to whether cost-benefit analysis should be used, and if so to what degree.” Jd. at 222. Petition- ers also invoke the D.C. Circuit’s decision in NRDC v. EPA, 824 F.2d 1146 (1987) (en banc). They fail, how- ever, to acknowledge the court of appeals’ statement in that case that EPA could reasonably have inter- preted the statute at issue to prohibit the considera- tion of costs. See id. at 1165-1166 & n.11. Petitioners’ other arguments are equally unavail- ing. They highlight 42 U.S.C. 7412(n)(1)(B), which requires EPA to conduct a study of mercury emissions and the costs of reducing them. But Congress did not require EPA to consider the Section 7412(n)(1)(B) study when deciding whether to regulate power plants, and the study Congress did make relevant was not required to consider costs. See 42 U.S.C. 7412(n)(1)(A). Petitioners’ proffered analogy between Section 7412(n)(1)(A) and Section 7412(f) likewise does not support their argument, since Section 7412(f)(2) forbids EPA from considering costs when making the threshold determination whether addi- tional regulation is warranted. D. Petitioners rely heavily on EPA’s analysis of the costs and benefits of the 2012 Final Rule. But the RIA simply confirms that EPA’s ultimate decision to regulate power plants would be reasonable even if the agency were required to take costs into account using a cost-benefit test. The RIA reflects EPA’s judgment that the rule’s quantifiable benefits will exceed its costs by between $27 billion and $80 billion each year. 77 Fed. Reg. at 9305-9306. In attacking that conclu- sion, petitioners argue that EPA must both (1) consid- 21 er all of the costs that NESHAP regulation of power plants entails and (2) ignore most of the rule’s bene- fits. That result-oriented theory is inconsistent with the basic logic of petitioners’ principal statutory ar- gument, and it defies common sense. ARGUMENT EPA REASONABLY DECLINED TO CONSIDER COSTS WHEN LISTING POWER PLANTS FOR REGULATION UNDER SECTION 7412 Under Chevron U.S.A. Inc. v. NRDC, 467 U.S. 837 (1984), this Court must uphold EPA’s interpretation of Section 7412(n)(1)(A) unless that provision unambigu- ously requires the agency to consider costs when deciding whether it is “appropriate” to regulate power plants under the NESHAP program. See id. at 842- 844; see also EPA v. EME Homer City Generation, L.P., 134 S. Ct. 1584, 1603 (2014) (noting that the Court “routinely accord[s] dispositive effect to an agency’s reasonable interpretation of ambiguous stat- utory language”). The text, structure, context, and history of Section 7412(n)(1)(A) support EPA’s deci- sion to consider costs only in setting the proper level of NESHAP regulation, not in making the threshold listing determination. A. Under Section 7412(n)(1)(A), EPA Has Substantial Discretion To Determine Whether It Is “Appropriate” To List Power Plants As A Source Category Subject To NESHAP Regulation Section 7412(n)(1)(A) requires EPA to “perform a study of the hazards to public health” that are “rea- sonably anticipated to occur” as a result of power- plant hazardous-air-pollutant emissions after imposi- tion of other CAA requirements. The provision fur- 22 ther directs the agency to regulate power plants if it “finds such regulation is appropriate and necessary after considering the results of the study.” 42 U.S.C. 7412(n)(1)(A) (emphasis added). The central issue in this case concerns the meaning of the word “appropri- ate” in that provision. Standard dictionaries define “appropriate” in broad terms, to mean “specially suitable,” “fit,” or “proper,” Webster’s Third New International Dictionary 106 (1993) (capitalization omitted), or “suitable or proper in the circumstances,” The New Oxford American Dictionary 76 (2d ed. 2005). As those definitions make clear, the application of any “appropriate[ness]” requirement depends on the particular context in which the term appears. This Court has likewise recognized that “the word ‘appropriate’ is inherently context-dependent,” holding that the phrase “[a]ppro- priate relief” in 42 U.S.C. 2000cc-2(a) is “open-ended and ambiguous about what types of relief it includes.” Sossamon v. Texas, 131 S. Ct. 1651, 1659 (2011); see West v. Gibson, 527 U.S. 212, 217-218 (1999) (holding that the term “appropriate” is flexible and depends on statutory context). Section 7412(n)(1)(A) does not explicitly address whether EPA must or should consider costs in decid- ing whether it is “appropriate” to regulate power plants under the NESHAP program. Neither the broad statutory term “appropriate,” nor Congress’s failure expressly to forbid consideration of costs, sug- gests that costs must be considered. This Court has never held that statutory silence is a basis for requir- ing agencies to consider costs. Rather, the determi- nation whether costs are germane to a particular agency decision ultimately depends on the details of 23 the particular statutory scheme at issue and the agen- cy’s views of how to resolve any ambiguity.° Under Chevron, agencies have discretion to inter- pret open-ended and ambiguous statutory terms, and courts must give those interpretations dispositive effect so long as they are reasonable. 467 U.S. at 842- 844; EME Homer City, 134 S. Ct. at 1603. By declin- ing to set forth an exclusive list of factors relevant to the decision whether to list power plants as a NESHAP source category, Congress implicitly au- thorized EPA to determine the “appropriate[ness]” of such listing in light of the CAA’s text, structure, histo- ry, and purposes. As explained below and by the court of appeals, EPA properly exercised that interpretive authority here. B. The Text, Structure, And History Of The CAA Establish That EPA’s Interpretation Of Section 7412(n)(1)(A) Is Reasonable A “fundamental canon of statutory construction” is that “the words of a statute must be read in their context and with a view to their place in the overall statutory scheme.” FDA v. Brown & Williamson 5 See Entergy Corp. v. Riverkeeper, Inc., 556 U.S. 208, 223 (2009) (“{S]ometimes statutory silence, when viewed in context, is best interpreted as limiting agency discretion.”); see also, ¢.g., EME Homer City, 134 S. Ct. at 1603, 1606-1607 (permitting EPA to consider costs when allocating emission contributions among upwind States under 42 U.S.C. 7410(aX2)(D)(i)); Whitman v. American Trucking Ass’ns, 531 U.S. 457, 467-468, 471 (2001) (holding that EPA may not consider costs when setting NAAQS); American Textile Mfrs. Inst., Inc. v. Donovan, 452 U.S. 490, 510- 512 (1981) (holding that the Department of Labor was not required to engage in cost-benefit analysis in absence of statutory com- mand). 24 Tobacco Corp., 529 U.S. 120, 133 (2000) (citation omit- ted). Consistent with that interpretive canon, EPA construed Section 7412(n)(1)(A) in a way that best harmonizes regulation of power-plant emissions with the rules that govern other source categories. The court of appeals correctly upheld EPA’s interpretation as “clearly permissible.” Pet. App. 25a; see id. at 18a, 32a-33a. 1. EPA’s interpretation of Section 7412(n)(1)(A) is consistent with the criteria for listing all other sources of hazardous air pollutants under Section 7412 Section 7412 requires EPA to make two basic de- terminations when regulating stationary sources of hazardous air pollutants. First, EPA must decide whether any particular source category should appear on the list of categories subject to regulation. 42 U.S.C. 7412(c). Second, the agency must promul- gate emission standards for any categories appearing on that list. 42 U.S.C. 7412(d). With respect to all source categories other than power plants, the ex- pected costs are relevant to EPA’s choice of specific emission standards, but not to the threshold listing decision. EPA acted reasonably in applying the same approach to NESHAP regulation of power-plant emis- sions. a. Section 7412(c) generally precludes EPA from considering costs when deciding whether to list par- ticular source categories for NESHAP regulation. Section 7412(c) requires the agency to list and regu- late (1) all “major” sources of pollution, defined as those sources emitting more than ten tons of a single hazardous air pollutant (or 25 tons of any combination of such pollutants) per year, 42 U.S.C. 7412(a)(1) and 25 (c)(1); and (2) any “area” sources of pollution that EPA determines present “a threat of adverse effects to human health or the environment,” 42 U.S.C. 7412(c)(1) and (3). Those statutory directives do not authorize EPA to consider the costs associated with regulating either type of source when making the initial listing decision. Rather, they reflect Congress’s determinations that major sources pose an inherent risk warranting regulation; that area sources should be listed based on EPA’s judgment of the threat posed by their emissions; and that the risk alone is a suffi- cient justification for listing under the NESHAP pro- gram. The CAA directs EPA to consider the anticipated costs only in devising the specific emission standard that will apply to sources within a listed category. Each major source emission standard must “require the maximum degree of reduction in emissions” that EPA “determines is achievable” for sources within the relevant category. 42 U.S.C. 7412(d)(2). For existing sources, the Act requires EPA to promulgate stand- ards at least as stringent as a statutorily-defined “floor,” defined by reference to the emission reduc- tions actually achieved by the best-performing sources within the category. 42 U.S.C. 7412(d)(3); see pp. 5-6, supra. That requirement reflects an apparent con- gressional judgment that, if a particular level of emis- sion reduction has actually been accomplished by a significant percentage of comparable sources, it is ipso facto “achievable.” In identifying the minimum level of stringency that the statute requires, EPA does not explicitly consider costs. But the method by which the floor is calculated ensures that the minimum standard is “achievable” in 26 the sense of economically feasible for at least a signifi- cant number of sources. See Pet. App. 27a, 29a-30a; cf. 1989 Senate Report 168-169 (noting that “[c]Jost considerations are reflected in the selection of emis- sions limitations which have been achieved in prac- tice”). The possibility remains, however, that particu- lar sources may find achievement of the minimum standards prohibitively expensive; and the Act does not allow EPA to treat that possibility as a ground for promulgating emission standards less stringent than the statutory floor. EPA must explicitly consider costs (along with other factors) when it decides whether to impose emission standards that are more stringent than the minimum level required by Section 7412(d)(3). b. EPA’s interpretation of Section 7412(n)(1)(A) renders Section 7412 a “symmetrical and coherent regulatory scheme,” Brown & Williamson, 529 U.S. at 133, under which anticipated costs are considered at the same stage of the regulatory process for power plants as for other stationary sources. For stationary sources other than power plants, EPA’s NESHAP listing decision turns either on an explicit agency finding of potential harm (for area sources) or on sources’ emission of hazardous air pollutants in quan- tities above a statutory threshold (for major sources). The agency reasonably construed the Section 7412(n)(1)(A) term “appropriate” to turn on a compa- rable harm-based inquiry. Although the specific trig- gers for regulation differ slightly depending on wheth- er the source at issue is a major source, area source, or power plant, see pp. 5, 24-25, supra, the basic crite- ria shaping EPA’s threshold decision to regulate focus on the potential for harm and exclude consideration of 27 cost. EPA’s interpretation likewise ensures that, when costs are taken into account in fashioning specif- ic emission standards, they are considered in the same manner for power plants as for other stationary sources. c. EPA’s decision to harmonize the treatment of power plants and other stationary sources with re- spect to costs is plainly reasonable. Although Con- gress enacted a special listing provision that applies only to power plants, neither the text of Section 7412(n)(1)(A) nor Congress’s reasons for enacting it suggest that EPA must consider costs when making the threshold listing determination. Rather, Congress established the special requirements of Section 7412(n)(1)(A) to reflect the unique—and at that point still undetermined—impact that the Title IV acid-rain program and other CAA requirements would have on power-plant emissions of hazardous air pollutants. See pp. 7-8, supra. The text of Section 7412(n)(1)(A) supports that in- terpretation. Section 7412(n)(1)(A) departs from the scheme governing other source categories only by requiring EPA (1) to conduct a study “of the hazards to public health reasonably anticipated to occur as a result of emissions by [power plants] of pollutants listed under [Section 7412(b)] after imposition of the requirements of th{e] [CAA]J”; and (2) to regulate power plants “under this section, if [EPA] finds such regulation is appropriate and necessary after consid- ering the results of the study.” 42 U.S.C. 7412(n)(1)(A) (emphases added). Section 7412(n)(1)(A) thus requires EPA to conduct a new study of the risks created by power-plant emis- sions of hazardous air pollutants, and to consider that 28 study in making its listing decision, rather than simply basing the decision on whatever information was al- ready available.* Section 7412(n)(1)(A) further pro- vides that, in assessing such risks, the study should take into account any emission reductions that other CAA provisions could reasonably be anticipated to produce. The 1990 Amendments thus imposed a de- gree of structure on the agency’s assessment of poten- tial harms. None of those requirements suggests, however, that Congress intended the agency to depart from the basic harm-based approach to listing deci- sions that the Act mandates with respect to all other source categories.’ ®° The State petitioners (Br. 33-34) argue that the Section 7412(n)(1A) study requires EPA to consider costs insofar as it directs the agency to address “alternative control strategies for emissions which may warrant regulation.” That is not correct. Section 7412(n)(1)(A) does not require the study to consider the costs of alternative control strategies, but merely to identify and describe available and effective control technologies. See 4 J.A. 850 ’ The State petitioners argue (Br. 29-30) that the legislative history of Section 7412(n)(1A) evidences Congress’s intent that EPA must consider costs when deciding whether regulation of power plants is “appropriate.” But the only support they cite for that proposition is Representative Oxley’s general statement that a purpose of that provision was to “avoid[] the imposition of exces- sive and unnecessary costs on residential, industrial, and commer- cial consumers of electricity.” States Br. 30 (emphasis omitted) (quoting 1 1990 CAA Legislative History 1417); see Pet. App. 8la (Kavanaugh, J., concurring in part and dissenting in part) (relying on same statement). Representative Oxley’s statement does not specifically indicate that EPA must consider costs when determin- ing whether NESHAP regulation of power plants is “appropriate.” See 1 1990 CAA Legislative History 1416-1417. Rather, it is consistent with the view that Section 7412(n\1)(A) avoids unneces- sary costs by allowing EPA to regulate power plants only after 29 d. Three other points deserve emphasis. First, pe- titioners make no effort to demonstrate that listing power plants for NESHAP regulation without consid- eration of costs creates a greater danger of overregu- lation, or is otherwise more objectionable from a poli- cy standpoint, than a similar cost-blind listing decision for any other source category. Rather, petitioners suggest that a threshold decision to regulate without consideration of costs is an inherently unreasonable practice that Congress could not plausibly be thought to have countenanced. See, eg., States Br. 24 (“[WJhen deciding whether it is appropriate to impose regulation, a reasonable person would consider both the pros and cons—in other words, the benefits and costs—of regulation.”). The dissenting judge below articulated the putatively applicable principle in simi- larly general terms, stating that, “as a matter of com- mon sense, common parlance, and common practice, determining whether it is ‘appropriate’ to regulate requires consideration of costs.” Pet. App. 74a (Ka- vanaugh, J., concurring in part and dissenting in part). That view is flatly inconsistent with the basic struc- ture of the NESHAP program and its treatment of other source categories. Second, Section 7412(n)(1)(A) does not authorize EPA to apply to power plants whatever specific emis- sion standards the agency deems “appropriate and necessary.” Rather, it authorizes EPA to determine conducting the required study and finding that power-plant emis- sions will continue to pose public-health hazards even after imposi- tion of other CAA requirements. See Pet. App. 25a & n.1. In any event, “the views of a single legislator, even a bill’s sponsor, are not controlling.” Mims v. Arrow Fin. Servs., LLC, 132 S. Ct. 740, 752 (2012). 30 whether it is “appropriate and necessary” to regulate power plants “under this section,” i.e., under Section 7412. 42 U.S.C. 7412(n)(1)(A). As the court below unanimously recognized, once EPA decided that pow- er plants should be listed for regulation as a NESHAP source category, the agency was required to devise emission standards in accordance with the generally- applicable methodology, see 42 U.S.C. 7412(d), that governs other listed source categories, see Pet. App. 36a-38a. That fact reinforces the propriety of EPA’s decision to apply listing criteria that preserve the integrity of the overall statutory scheme.’ Third (and more generally), when Congress enacts a comprehensive regulatory scheme, and directs an agency to devise an “appropriate” response to some interstitial problem, the agency would not be expected * Notably, Section 7412 contemplates a two-step process in which EPA first places power plants on the list of source categories established by Section 7412(c), and then promulgates specific stan- dards for hazardous air pollutants emitted by such plants in ac- cordance with Section 7412(d). See Pet. App. 36a-38a. Congress thus plainly envisioned that EPA would set the standards (at the second step) well after making the threshold listing determination (at the first step). See 42 U.S.C. 7412(e)(3) and (4). But Congress would not have expected EPA to consider—at the listing stage— the cost of complying with emission standards that had not yet been formulated. Here, of course, the idiosyncratic procedural history resulted in EPA making its initial “appropriate and neces- sary” finding in 2000, and then reaffirming that finding in 2012 at the same time that it promulgated power-plant emission stand- ards. But there is no reason to believe that when Congress en- acted the 1990 Amendments, it expected EPA to consider the threshold listing determination twice. EPA’s view that Section 7412(n1)A) does not require consideration of costs as the thresh- old listing stage is consistent with Congress’s understanding of how the statutory scheme would operate. 31 to approach the matter as though it were writing on a blank slate. Nor would it be usual for the agency to base its interstitial decision on the perceived unwis- dom of general congressional policy choices reflected in the statute. Rather, the agency would be expected to make interstitial choices that are logically con- sistent with, and promote the effective implementa- tion of, the larger congressional design. In making the listing decision at issue here, it therefore would have been inappropriate for EPA either to ignore or to second-guess Congress’s determination that con- sideration of costs under the NESHAP program should be deferred until the emission-standard-setting stage. EPA articulated a fully adequate rationale for its listing decision by explaining that (1) Congress’s general approach of deferring cost consideration in that manner is an integral feature of the statutory scheme, and (2) no sound textual or practical reason had been identified to treat power plants differently. e. In determining whether costs are relevant to the listing decision for power plants under Section 7412(n)(1)(A), EPA thus faced a simple choice. The agency could either interpret that provision to har- monize with the criteria that govern analogous NESHAP listing determinations for other stationary sources, or it could conclude that Congress intended to depart from those criteria—without saying so ex- plicitly, and despite the fact that doing so could poten- tially leave a major source of hazardous air pollution outside the NESHAP program. EPA’s choice of the former approach reflects the more natural reading of the statutory text, and it advances the CAA’s core goal of “protect{ing] and enhanc{ing] the quality of the Nation’s air resources so as to promote the public 32 health and welfare.” 42 U.S.C. 7401(b)(1). In any event, it is farfetched to suppose that, by directing EPA to determine whether NESHAP regulation of power plants is “appropriate,” Congress required the agency to use listing criteria fundamentally different from those that Congress had mandated for all other stationary-source categories. See pp. 40-45, infra. 2. EPA’s interpretation is consistent with the NESHAP delisting criteria that apply to power plants and all other stationary sources EPA’s interpretation of Section 7412(n)(1)(A) is al- so consistent with 42 U.S.C. 7412(c)(9)(B), which em- powers EPA to delist power plants and other station- ary sources in specified circumstances. That provision makes clear that Congress intended such sources to remain subject to regulation under Section 7412 so long as they continue to pose dangers to public health or the environment, regardless of the costs of comply- ing with such regulation. Section 7412(c)(9) illumi- nates Congress’s understanding of when regulation of power plants is appropriate, and EPA reasonably relied on that provision when interpreting Section 7412(n)(1)(A). See Pet. App. 31a. a. Section 7412(c)(9)(B) sets forth criteria under which EPA may remove “any source category”— including power plants—from the list of categories subject to regulation. See New Jersey v. EPA, 517 F.3d 574, 582 (D.C. Cir. 2008), cert. dismissed, 555 U.S. 1162, and, cert. denied, 555 U.S. 1169 (2009). Like the provisions that establish the general criteria governing EPA’s initial listing decisions, Section 7412(c)(9) does not authorize consideration of costs as a basis for delisting. 76 Fed. Reg. at 24,989. Rather, EPA is authorized to delete a source category from 33 the list in two limited situations, both of which relate exclusively to health and welfare considerations. First, EPA may delist a source category if (1) the “sole reason” for initially including the category on the list was its emission of a “unique chemical sub- stance,” and (2) that substance is subsequently delet- ed from the separate list of hazardous air pollutants because EPA concludes that it will not cause adverse effects to human “health” or the “environment{].” 42 U.S.C. 7412(c)9)(A) (cross-referencing 42 U.S.C. 7412(b)(3)(C) and (D)). Second, EPA may delist a source category if two other conditions are both satisfied. To the extent that sources within the category emit pollutants thit may cause cancer in humans, EPA must determine that no source in the category (or group of sources in the case of area sources) emits such hazardous air pollutants in quantities which may cause a lifetime risk of cancer greater than one in one million to the individual in the population who is most exposed to emissions of such pollutants. 42 U.S.C. 7412(c)(9)(B)G). In addition, if sources with- in the category emit pollutants that result in adverse health effects other than cancer, or in adverse envi- ronmental effects, EPA must determine that “emis- sions from no source in the category or subcategory concerned (or group of sources in the case of area sources) exceed a level which is adequate to protect public health with an ample margin of safety and no adverse environmental effect will result from [such] emissions.” 42 U.S.C. 7412(c)(9)(B)(ii). b. EPA reasonably relied on Section 7412(c)(9)’s delisting criteria when declining to consider costs as part of the decision to add power plants to that list. 34 See 76 Fed. Reg. at 24,989; Pet. App. 3la. The deci- sions to list or delist a stationary source are two sides of the same coin: Both address the same fundamental issue Of whether a source category will appear on the Section 7412 list and therefore be subject to regula- tion. EPA reasonably concluded that, since the CAA unambiguously precludes consideration of costs as a basis for delisting, Congress did not likely intend for costs to be considered at the initial listing stage ei- ther. A contrary approach would produce a strange and asymmetric scheme, under which EPA could consider expected costs at the outset in deciding whether power plants should be placed on the list, but could not revisit an initial listing decision if the costs of regulation change or turn out to be much higher than anticipated. The delisting criteria also make clear that Con- gress intended the NESHAP program to protect those individuals most exposed and most sensitive to the harms caused by hazardous air pollutants. Section 7412(c)(9)(B)(i) forbids EPA to delist a source that may cause a lifetime risk of cancer “greater than one in one million to the individual in the population who is most exposed to emissions of such pollutants.” 42 U.S.C. 7412(c)(9)(B)(i) (emphasis added). That provision reflects Congress’s intent to protect the most vulnerable members of the population, regard- less of the costs. It thereby undermines petitioners’ conclusory assertion (States Br. 24) that, for a regula- tion to be “reasonable” under the CAA, it must be based on an assessment of both costs and benefits.° * Other provisions of Section 7412 likewise evince Congress's concern for the most vulnerable. See 42 U.S.C. 7412(f2\A) (requiring regulation to address cancer risks “to the individual 35 3. Congresas’s express references to costs in other CAA provisions support EPA’s interpretation of Section 7412(n)(I)(A) As explained above, Congress unambiguously re- quired EPA to consider costs at the second stage of the regulatory process, when EPA calculates the proper level of regulation under Section 7412(d)(2). See p. 6, supra. Congress also directed EPA to con- sider costs when implementing dozens of other CAA provisions. ° Those statutory directives support EPA’s decision not to consider costs in determining whether power plants should be regulated under the NESHAP program. 42 U.S.C. 7412(n)(1)(A). most exposed to emissions from a source”), (n)(1XC) (requiring study of health effects of mercury, with special focus on “consump- tion by sensitive populations”). '° For other provisions in Section 7412 requiring EPA to consid- er costs, see 42 U.S.C. 7412(d)2) (setting level of emission stand- ards generally), (8A)(i), (B)(i) (same with respect to coke oven batteries), (f (1)(B) (report to Congress on need for further legis- lation on air pollution), (2)(A) (establishing additional emission standards), (nX1)(B) (study of mercury emissions) and (s)(2) (report to Congress on compliance with EPA standards under the CAA). For provisions elsewhere in the CAA that require EPA to con- sider costs in various ways, see 42 U.S.C. 7403(eX6), (g)(1), (iX1), (3) and Q\3)(BXiii), 7404(aX1), (2), (4) and (b)(1), 7408(b)(1), 7411(a)(1), (gX4XB), (h)(1), (2) and G)1)(A)(ii), 7419(b)(3) and (dX(2), 7425(b), 742% aX2), 747H3), 7491(g)1) and (2), 7509%d)(2), 7511 b(eX2BXiv), (v), (f)(1)(A) and (B), 7521(a)(2), (3 Ai), (BX), (D), (bX1XC), (i2)(AMD, (ii), (3)(AXiii), (B)(iii), (C)iii), (k) and (D(2), 7545(c)(2)(B), (kX 1)(A), (3)(B)(i), (ii), (02)(B)ii)(V) and (4XC), 7547(a)(3)-(5) and (b), 7554(a), (bX2) and (3), 7571(b), 7586(a)(4), 7689(e)(2), 7590(a), 7612(a), (c) and (d)(1), 7617(c)(1), (4) and (g), 7628(a) and (b), 7651c(f2)(B), 7651f(b)(2). 36 a. In determining that costs were irrelevant to the decision whether to list power plants for NESHAP regulation, EPA principally relied on the fact that the CAA unambiguously precludes consideration of costs in making closely analogous decisions—i.e., the decision whether to list other source categories, and the decision whether to delist a previously listed category—under the NESHAP program. EPA reasonably .concluded that, if Congress had wanted the agency to apply fundamentally different criteria in deciding whether to list power plants, it would have explicitly mandated that approach. Petitioners suggest (e.g., States Br. 23-24) that an express statutory reference to costs was unnecessary because Section 7412(n)(1)(A) requires EPA to determine whether listing of power plants is “appropriate,” and consideration of costs is an inherent component of any “appropriate” decision to regulate. Section 7412(d)(2) and the other provisions cited above refute that line of argument by showing that, when Congress intended to require EPA to consider costs in implementing the NESHAP program, Congress expressed that intent in clear and specific ways. b. This Court’s decision in Whitman v. American Trucking Ass’ns, 531 U.S. 457 (2001), supports EPA’s conclusion. There, the Court agreed with EPA that costs are irrelevant when establishing air quality standards under 42 U.S.C. 7409(b), as part of the NAAQS program. 531 U.S. at 467. The Court noted that Section 7409(b)(1) requires EPA to set standards under that program at the level “requisite to protect the public health,” allowing an “adequate margin of safety.” Jd. at 465 (citation omitted). The Court con- trasted that language with various other CAA provi- 37 sions that specifically directed EPA to consider costs. Id. at 467-468 (citing General Motors Corp. v. United States, 496 U.S. 530, 538, 541 (1990); Union Elec. Co. v. EPA, 427 U.S. 246, 257 & n.5 (1976)). In agreeing with EPA that costs are irrelevant when setting NAAQS, the Court made two points that are directly relevant here. First, the Court empha- sized its refusal “to find implicit in ambiguous sections of the CAA an authorization to consider costs that has elsewhere, and so often, been expressly granted.” American Trucking, 531 U.S. at 467-468. Second, the Court emphasized that Congress’s silence with re- spect to costs was especially telling in light of Section 7409(b)(1)’s express emphasis on health hazards. The Court explained that, even if EPA may consider fac- tors other than health when setting NAAQS, the agency may not consider costs. /d. at 469. It noted that cost “is both so indirectly related to public health and so full of potential for canceling the conclusions drawn from direct health effects that it would surely have been expressly mentioned * * * had Con- gress meant it to be considered.” /bid. Both of those observations support EPA’s decision here. Congress’s failure to direct EPA to consider costs in Section 7412(n)(1)(A) is especially significant in light of the CAA’s numerous express references to costs. And costs are far removed both from the crite- ria that EPA considers in determining whether other source categories should be listed, and from the only criterion (potential “hazards to public health”) that Section 7412(n)(1)(A) specifically directs the agency to consider in deciding whether to list power plants. In these circumstances, EPA reasonably relied on Amer- ican Trucking in concluding that Congress did not 38 intend the agency to consider costs under Section 7412(n)(1)(A). 4. EPA's approach te power-plant regulation under the NESHAP program is consistent with the struc- ture of the CAA’s other multistage regulatory pro- grams In addition to Section 7412 (see pp. 4-6, supra), the CAA establishes several other regulatory programs involving multistage decisionmaking in which EPA (1) makes a threshold decision to regulate based ex- clusively on health and environmental factors, and (2) considers costs (among other relevant factors) when choosing the proper level of regulation. EPA reasonably construed Section 7412(n)(1)(A) to estab- lish that same approach here. The NAAQS program for controlling criteria pollu- tants involves a multistage process in which EPA does not consider costs for purposes of two key threshold decisions. Under that program, EPA first decides whether emissions of a criteria pollutant “may reason- ably be anticipated to endanger public health or wel- fare.” 42 U.S.C. 7408(a). If EPA makes such an en- dangerment finding, it must establish NAAQS for that pollutant which are “requisite to protect the public health and * * * welfare,” again without any consid- eration of potential regulatory costs. 42 U.S.C. 7409; American Trucking, 531 U.S. at 471 n.3. States may consider costs, however, when they later craft plans containing actual controls to achieve the air quality standards. 42 U.S.C. 7407(a), 7410; American Truck- ing, 531 U.S. at 470. The NSPS program for stationary sources estab- lishes a multistage process that is even more closely analogous to the NESHAP program at issue here. 39 Under the NSPS program, EPA must first publish a list of categories of stationary sources that “cause[], or contribute[] significantly to, air pollution which may reasonably be anticipated to endanger public health or welfare,” without any consideration of costs. 42 U.S.C. 7411(b)(1)(A). If EPA concludes that emis- sions from a particular source category are danger- ous, that finding triggers a nondiscretionary duty to promulgate emission standards for new sources within the category, applying the “best system of emission reduction.” 42 U.S.C. 7411(a)(1); see 42 U.S.C. 7411(b)(1)(B). The statute directs EPA to “tak[e] into account the cost of achieving such reduction” when identifying that “best system.” 42 U.S.C. 7411(a)(1). Similarly, the Motor Vehicle Emission and Fuel Standards program requires EPA first to determine, without considering potential costs, whether certain motor-vehicle emissions “cause, or contribute to, air pollution which may reasonably be anticipated to endanger public health or welfare.” 42 U.S.C. 7521(a)(1). If EPA concludes that such dangers exist, it must promulgate standards for emissions from that class of engines, and it may consider costs when fash- ioning those standards. 42 U.S.C. 7521(a)(2); see Massachusetts v. EPA, 549 U.S. 497, 533 (2007). Those programs reflect Congress’s view that chan- neling cost considerations to the later stage of a multi- stage regulatory process is a sensible way to achieve the CAA’s purposes. Prominent academic commenta- tors agree that agencies act reasonably when they take account of costs in accordance with a multi- stage process. See, eg., Cass R. Sunstein, Cost- Benefit Default Principles, 99 Mich. L. Rev. 1651, 1695-1696 (2001). EPA permissibly construed Section 40 7412(n)(1)(A) to mandate the same regulatory ap- proach that Congress repeatedly embraced through- out the CAA. C. Petitioners’ Arguments Fail To Establish That Sec- tion 7412(m)(1)(A) Unambiguously Requires EPA To Consider Costs Under Chevron, petitioners can prevail only by showing that EPA’s interpretation of the statute is unreasonable. Petitioners thus must establish that Section 7412(n)(1)(A) unambiguously compels EPA to consider costs when determining whether NESHAP regulation of power plants is “appropriate.” Petition- ers have not satisfied that standard. 1. The word “appropriate” does not unambiguously require EPA to consider costs when deciding whether to regulate Petitioners argue (NMA Br. 18-23; UARG Br. 25- 36) that Section 7412(n)(1)(A)’s use of a facially broad term (“appropriate”), coupled with statutory silence with respect to costs, necessarily requires EPA to consider costs when deciding whether to list power plants for regulation. They also assert (States Br. 33- 37) that EPA’s interpretation renders that term su- perfluous. Neither contention has merit. a. Petitioners argue that Congress’s use of the word “appropriate” to guide a regulatory decision necessarily requires agencies to consider costs when making that decision. See, e.g., NMA Br. 19-23; States Br. 23-24; UARG Br. 25-29, 36-40. Petitioners assert that, under the ordinary meaning of the term “appropriate,” EPA must take into account the sur- rounding “circumstances” in order to determine whether regulation is “suitable or proper.” States Br. 41 23 (emphasis omitted); UARG Br. 25 (both quoting The New Ozford American Dictionary at 76). They further contend (States Br. 24) that, in light of the “common meaning” of “appropriate,” it is clear that (1) “Congress wanted EPA to consider the circum- stances that would normally inform the decision whether or not to regulate,” and (2) “when deciding whether it is appropriate to impose regulation, a rea- sonable person would consider both the pros and cons—in other words, the benefits and costs—of regu- lation.” Petitioners are correct that “appropriateness” in- quiries are “inherently context-dependent,” Sossa- mon, 131 S. Ct. at 1659, and that particular conduct may be “appropriate” in some circumstances but in- appropriate in others. But petitioners ignore the most salient contextual evidence of Congress’s intent with respect to the specific question presented here. As explained above, the CAA precludes EPA from con- sidering costs in deciding whether any other type of stationary source should be listed for NESHAP regu- lation. The Congress that enacted the 1990 Amend- ments presumably believed that the basic Section 7412 framework, under which costs are not considered in listing major or area sources, but are instead taken into account in determining the stringency of regula- tion, was an “appropriate” means of regulating those stationary sources. Congress’s use of that term in Section 7412(n)(1)(A) therefore provides no colorable basis for inferring that Congress intended to preclude EPA from applying the same approach to power plants. b. Other CAA provisions further undermine peti- tioners’ contention that consideration of costs is an 42 essential prerequisite to an “appropriate” decision to regulate. At least 19 different CAA provisions author- ize EPA to take some form of action based on its de- termination that doing so is “appropriate.”’' Under many of those provisions, costs are clearly irrelevant to the agency’s analysis. For example, it is not plausi- ble that Congress intended EPA to consider costs when deciding whether it is “appropriate” (1) to invite the participation of “the Under Secretary of Com- merce for Oceans and Atmosphere, the Director of the Fish and Wildlife Service, [or] the Secretary of Agri- culture” when conducting a study of pollution damage to ecosystems, 42 U.S.C. 7403(e); or (2) to receive assurances that a state or local air pollution control agency has provided for adequate representation of “international” interests in the air quality control region before providing a grant to the agency, 42 U.S.C. 7405(a)(2). Similarly, when Congress instructed EPA to re- vise, “where appropriate,” the list of hazardous air pollutants set forth in Section 7412(b), it plainly did not want the potential for high costs to bar the agency from adding pollutants that present “a threat of ad- verse human health effects * * * or adverse envi- ronmental effects.” 42 U.S.C. 7412(b)(2). A neighbor- ing provision states that EPA “shall” grant a petition to list a pollutant if the petitioner can show that the pollutant will cause “adverse effects to human health or adverse environmental effects.” 42 U.S.C. 7412(b)(3)(B). The CAA thus treats costs as irrele- " See, eg., 42 U.S.C. 7403(e), 7405(aX(2) and (3), 7407(c), (dX3)(A), (C) and (4)(AXii), 740% d)(1), 7411(b)(1)(B), 7412(b)(2) and (c)(1), 742%c)(1) and (2), 7502(aX2) and (d), 7525(a)(1) and (4B), 7571(aX(3), 7601(d)(2). 43 vant to EPA’s decision whether to list additional haz- ardous pollutants, despite Congress’s use of the word “appropriate” in Section 7412(b)(2).” c. Petitioners argue (e.g., NMA Br. 19) that EPA’s approach is irrational because it creates the theoreti- cal possibility of power-plant regulation whose costs dramatically exceed its benefits... Because EPA must consider costs before promulgating an emission standard that is more stringent than the statutory floor (see pp. 6, 25-26, supra), the agency’s failure to consider costs at the listing stage could produce that outcome only if the floor standard itself entailed costs 2 Qutside the CAA, a quick Westlaw search reveals literally hundreds of statutory provisions that condition agency action on a finding that the action is either “appropriate and necessary” or “necessary and appropriate.” Interpreting such language to require agencies to consider costs in every such circumstance— regardless of context—would destabilize longstanding administra- tive practice and impose new and burdensome constraints on agency decisionmaking that Congress surely did not intend. Cf. Vermont Yankee Nuclear Power Corp. v. NRDC, 435 U.S. 519, 543-548 (1978) (forbidding courts from requiring agencies to follow procedures beyond those mandated by statute). 'S The NMA’s hypothetical bears no relation to this case, in which EPA concluded that the total quantifiable benefits of regula- tion outweigh the total costs by between $27 billion and $80 billion (measured in 2007 dollars) each year. 77 Fed. Reg. at 9305-9306; see pp. 14-15, supra. There is likewise no danger that the hypo- thetical might arise in the future, because EPA’s decision to list power plants under Section 7412(n)(1)(A) was a one-time judgment that will never again be repeated. And while EPA may some day be asked to determine whether power plants should be delisted as a NESHAP source category, consideration of costs would play no role in that determination. See pp. 32-34, supra. 44 that greatly exceeded its benefits.’ But to the extent there is a realistic danger that costs will exceed bene- fits, it exists equally with respect to all other catego- ries of major sources, which are listed without regard to cost and (once listed) are subject to the same statu- tory floor. The premise underlying petitioners’ argument—i.e., that Congress could not have intended for EPA to list power plants based on criteria that create any risk that costs will exceed benefits—is thus directly at odds with the regime that Congress enact- ed for all other stationary sources. If Congress had viewed the avoidance of such a result as a paramount objective, it could have declined to establish any minimally stringent emission stand- ard (i.e., floor), and instead could have granted EPA plenary authority to craft whatever emission stand- ards the agency deemed appropriate, based on any and all relevant factors including costs. That ap- proach would have eliminated any concern about NMA’s hypothetical, and it would have eliminated any serious argument that EPA must consider costs when deciding whether to list power plants under Section 7412(n)(1)(A). But Congress did not take that ap- proach. Instead, Congress made the policy judgments that (1) all major stationary sources within each listed '‘* Judge Kavanaugh’s dissent specifically focused on that possi- bility, observing that, “once EPA determines that it is appropriate to regulate electric utilities under the [NESHAP] program, costs are not relevant at the first, ‘setting the floor’ stage of the [emission-standard-setting process]. And meeting that floor will be prohibitively expensive, particularly for many coal-fired electric utilities, regardless of whether EPA decides to go further and set a “‘beyond-the-floor’ standard.” Pet. App. 79a. 45 category should be required to achieve “the maximum degree of reduction in emissions” that EPA deter- mines to be “achievable,” 42 U.S.C. 7412(d)(2); and (2) EPA’s emission standards should “not be less stringent than” the emission limitation actually achieved by the best-performing sources, 42 U.S.C. 7412(d)(3). Congress evidently regarded category- wide achievement of the emission reductions already achieved by the best-performing sources as a more important policy objective than avoidance of any pos- sibility that costs would exceed benefits. That con- gressional policy choice is an integral feature of the statutory design, not an obstacle to be circumvented. If Congress had viewed the hypothetical possibility of excessive costs as acceptable for other source catego- ries, but unacceptable for power plants, it could have exempted power plants from the “floor” emission standards mandated by Section 7412(d). As explained above, however, the CAA makes clear that, if EPA lists power plants for NESHAP regulation pursuant to Section 7412(n)(1)(A), those facilities will be subject to the same standard-setting provisions that govern stationary sources within all other listed categories. See pp. 29-30, supra. d. The State petitioners assert (Br. 22-23, 33-37) that EPA's interpretation of “appropriate” fails to give that term any independent meaning. That is incorrect. Under EPA’s interpretation, it is “appro- priate” to regulate power plants under Section 7412(n)(1)(A) if, at the time the finding is made, (1) hazardous-air-pollutant emissions from _ those plants pose a hazard to either public health or the environment; and (2) controls are available to reduce such emissions. 76 Fed. Reg. at 24,988-24,989. Both 46 of those requirements give meaningful content to the statutory text. First, as the court of appeals recognized, EPA’s in- terpretation ensures that the agency will not only conduct the study mandated by Section 7412(n)(1)(A), but also “apply its judgment in evaluating the results of th[at] study” to determine whether health or envi- ronmental hazards exist. Pet. App. 28a. At the time Congress enacted Section 7412(n)(1)(A), it was unclear whether EPA would ultimately conclude that power- plant emissions can reasonably be anticipated to cause hazards to public health.” EPA’s interpretation of the term “appropriate” ensures that the agency exercises judgment in assessing those hazards.” Second, as the court of appeals also explained, EPA “did not focus exclusively on health hazards in consid- ering whether regulation would be ‘appropriate,’” but also considered “the availability of controls to address [hazardous-air-pollutant] emissions from [power plants}.” Pet. App. 28a (quoting 76 Fed. Reg. at 24,989; citing 77 Fed. Reg. at 9311). Although the State petitioners assert (Br. 36) that the availability of controls was “immaterial” to EPA’s final determina- tion to regulate power plants, they ignore EPA’s un- ambiguous statement to the contrary in the preamble ' Indeed, EPA eventually found that it was not “appropriate or necessary” to regulate emissions from natural-gas-fired plants because of the “negligible” dangers posed by such emissions. 65 Fed. Reg. at 79,831. And petitioners themselves disputed be- low that any such health or environment hazards exist with respect to power-plant emissions. See Pet. App. 40a-42a, 48a. ‘© Contrary to the State petitioners’ contention (Br. 34-35), EPA evaluated the “severity” of anticipated health effects as part of its hazard analysis. See, e.g., 76 Fed. Reg. at 24,992; 65 Fed. Reg. at 79,830-79,831; see also, e.g., Pet. App. 40a-42a. 47 to the 2012 Final Rule. See 77 Fed. Reg. at 9363 (“The availability of controls to reduce [hazardous-air- pollutant] emissions from [power plants] only further supports the appropriate finding.”). Finally, the State petitioners are wrong in contend- ing (Br. 34-36) that EPA’s interpretation of “appro- priate” entirely overlaps with its interpretation of “necessary.” Although both terms require an inquiry into the health dangers posed by power-plant emis- sions, the “appropriate” prong of the inquiry considers those dangers as they exist “at the time” the finding is made, whereas the “necessary” prong considers how those dangers will be affected by the imposition of the Title IV acid-rain program and other CAA require- ments. 76 Fed. Reg. at 24,988; see id. at 24,990, 24,992. And, unlike the “appropriate” prong, the “nec- essary” prong does not involve any analysis of the availability of controls to address power-plant emis- sions. See 77 Fed. Reg. at 9310-9311; 76 Fed. Reg. at 24,989-24,990. 2. Section 7412(n)(1)(B)’s express reference to costs does not support petitioners’ interpretation of Sec- tion 7412(n)(1)(A) Congress instructed EPA, in making its power- plant listing determination, to consider the study of potential public-health hazards that was mandated by Section 7412(n)(1)(A). Separately, in Section 7412(n)(1)(B), Congress also required EPA to conduct a different study into various issues relating specifi- cally to mercury emissions from power plants and other sources, including “the costs of * * * technol- ogies” that might be used to control such emissions. 42 U.S.C. 7412(n)(1)(B). The State petitioners argue (Br. 24, 42-43) that this latter requirement “confirms” 4x Congress’s expectation that EPA would consider costs when determining whether regulation is “appropriate” under Section 7412(n)(1)(A). Petitioners are mistak- en. By its terms, Section 7412(n)(1)(A) required EPA to consider the study mandated by that provision, not the separate study referenced in _ Section 7412(n)(1)(B), when making the listing determination. The State petitioners imply (Br. 24-25) that the Sec- tion 7412(n)(1)(B) study would be pointless if EPA treated costs as irrelevant to the power-plant listing decision. But the Section 7412(n)(1)(B) study was not limited to either power plants or costs. In any event, the study can still inform EPA’s application of the NESHAP program to mercury emissions from power plants and other sources, because EPA recognizes (and the CAA clearly directs) that cost is relevant at the second stage of the regulatory process, when EPA sets the proper emission standard. See p. 6, supra. 3. Neither this Court’s precedents nor the D.C. Cir- cuit’s NRDC decision supports petitioners’ theory that silence necessarily requires agencies to con- sider costs Petitioners cite various decisions of this Court and the D.C. Circuit to support their argument that Sec- tion 7412(n)(1)(A)’s silence with respect to costs un- ambiguously requires EPA to consider such costs in deciding whether to list power plants for NESHAP regulation. Petitioners’ reliance on those decisions is misplaced. a. In arguing that EPA must consider costs when deciding whether to impose regulation, petitioners invoke EME Homer City and Entergy Corp. v. River- keeper, Inc., 556 U.S. 208 (2009). NMA Br. 37; States 49 Br. 30-31; UARG Br. 31, 37. In both of those cases, however, the Court simply upheld EPA’s conclusion that the particular statutory provisions at issue al- lowed the agency to consider costs. See EME Homer City, 134 S. Ct. at 1607 (holding that EPA could choose to consider costs when allocating responsibility for cross-state air pollution among contributing States); Entergy, 556 U.S. at 217-226 (holding that EPA could choose to utilize cost-benefit analysis in establishing regulation under the Clean Water Act). Neither case involved a situation where EPA had concluded that a statutory provision that was silent with respect to costs was best construed to prohibit consideration of costs. This Court’s only precedent addressing that scenario is American Trucking, 531 U.S. at 467-471, in which the Court agreed with EPA that costs could not be considered under the relevant CAA provision. Far from supporting the claim that statutory si- lence necessarily requires EPA to consider costs, the decisions on which petitioners rely stand for the very different proposition that silence counsels deference to the agency. In Entergy, the Court declared that the statutory “silence” in that case was “meant to convey nothing more than a refusal to tie the agency’s hands as to whether cost-benefit analysis should be used, and if so to what degree.” 556 U.S. at 222. And in EME Homer City, the Court noted that the statute was silent with respect to costs. 134 S. Ct. at 1604. The Court then identified several potential interpreta- tions of the statute (some of which did not require consideration of costs) and held that “{uJnder Chevron we read Congress’ silence as a delegation of authority to EPA to select from among reasonable options.” 50 Ibid. The Court should apply similarly deferential review here. b. The State petitioners also heavily rely (Br. 27- 32) on the D.C. Circuit’s unanimous decision in NRDC v. EPA, 824 F.2d 1146 (1987) (en banc). Petitioners read (States Br. 29) that decision to hold that “Con- gress would have to clearly express an intent * * * to preclude EPA from considering costs if it wanted that outcome.” They argue (id. at 29-30) that Con- gress was presumably aware of NRDC when it enact- ed the 1990 Amendments, and that Section 7412(n)(1)(A)’s silence with respect to costs therefore “shows that Congress intended EPA to consider costs under [that provision] when deciding whether it is appropriate to regulate.” In NRDC, the court of appeals interpreted the pre-1990 version of Section 7412(b)(1)(B), which re- quired EPA to set emission standards for hazardous air pollutants “at the level which in [EPA’s] judgment provides an ample margin of safety to protect the public health.” 42 U.S.C. 7412(b)(1)(B) (1982); see NRDC, 824 F.2d at 1147. The court first held that the statute required EPA to make an initial determination of what level of emissions is “safe,” which the court described as the level necessary to achieve an “ac- ceptable” risk to health. /d. at 1164-1165. The court emphasized that EPA “cannot under any circumstanc- es consider cost and technological feasibility at this stage of the analysis.” /d. at 1165. The NRDC court then held that EPA could impose more stringent standards in order to provide an “am- ple margin” of safety, and that it could choose to con- sider costs and feasibility at this second stage of the analysis. 824 F.2d at 1165-1166. The court empha- 51 sized that its holding did not “bind [EPA] to any spe- cific method of determining what is ‘safe’ or what constitutes an ‘ample margin,” and it acknowledged that EPA could adopt a different mode of analysis under which cost would not be considered. /d. at 1165-1166 & n.11. The State petitioners misread NRDC in two signif- icant ways. First, they ignore the D.C. Circuit’s con- clusion that costs are irrelevant to the agency’s threshold determination of what level of emissions is “safe.” NRDC, 824 F.2d at 1164-1165; see 1990 House Report 322. Second, they ignore the court’s recogni- tion that EPA could lawfully have interpreted the pre- 1990 Section 7412(b) to prohibit the consideration of costs altogether, even when determining what consti- tutes an “ample margin” of safety. NRDC, 824 F.2d at 1165 n.11. Neither of those statements is compatible with petitioners’ description of NRDC (States Br. 27, 29) as holding that EPA may ignore costs only if the relevant statute says so expressly. Cf. American Trucking, 531 U.S. at 467-469 (holding that statutory silence can bar EPA from considering costs). 4. Whether or not Section 7412(n)(1)(A) is a “residual risk” provision is irrelevant to whether EPA must consider costs UARG asserts (Br. 30-35) that Section 7412(n)(1)(A) is a “residual risk” provision analogous to 42 U.S.C. 7412(f) and 7412(m). See note 3, supra. Those provisions address situations in which EPA must determine whether entities that are already regulated under Section 7412 should be subject to additional regulation in order to further protect public health or the environment. UARG reasons that, be- cause EPA may consider costs in implementing those 52 other provisions, it must also consider costs under Section 7412(n)(1)(A). That argument is a non sequitur. The fact that a particular CAA provision requires EPA to take ac- count of existing regulatory requirements when decid- ing whether to impose further regulation has no bear- ing on whether or how the agency should consider costs in making that decision. Indeed, the statutory analogue on which UARG primarily relies refutes its contention that any “resid- ual risk” provision necessarily permits EPA to consid- er costs when deciding whether to impose further regulation. As UARG acknowledges (Br. 30), Section 7412(f) incorporates the same “ample margin of safe- ty” standard that the D.C. Circuit considered in its 1987 NRDC decision. But that standard prohibits EPA from considering costs when determining the “safe” level of emissions at the first stage of the anal- ysis. NRDC, 824 F.2d at 1164-1166; pp. 50-51, supra. EPA may consider such costs only when deciding whether to adopt a more stringent emission standard that provides an additional margin of safety. /bid. Thus, to the extent that Section 7412(f) is relevant here at all, it supports EPA’s conclusion that the costs associated with power-plant emission standards under the NESHAP program are properly considered only when the agency decides how stringent those stand- ards will be, not when it decides whether power plants will be regulated under the program at all. 5. Petitioners’ objections to other aspects of the 2012 Final Rule are outside the scope of the question presented NMA and UARG both challenge (NMA Br. 42-44; UARG Br. 40-43) EPA’s determination that, once it 53 decided to regulate power-plant emissions under Sec- tion 7412(n)(1)(A), it was required to set emission standards for all hazardous air pollutants. NMA also challenges (Br. 37-42) the factual basis of EPA’s con- clusion that acid-gas emissions from power plants pose hazards to public health and the environment. Those legal arguments are not fairly encompassed within the question on which this Court granted certi- orari, and they should not be considered. In any event, both arguments lack merit and were correctly (and unanimously) rejected by the court of appeals. See Pet. App. 38a-44a; Gov’t Br. in Opp. 29-32. D. In The RIA That Accompanied The 2012 Final Rule, EPA Reasonably Concluded That The Benefits Asso- ciated With The Rule Will Greatly Exceed Its Costs Throughout their briefs, petitioners repeatedly in- voke the RIA in an effort to show that the 2012 Fina! Rule will impose costs that far exceed its benefits to society. Those arguments reflect a fundamental mis- understanding of the RIA. In fact, the RIA reflects EPA’s considered judgment, based on the same sort of cost-benefit analysis that petitioners appear to em- brace, that the benefits of the rule “are substantial and far outweigh the costs.” 77 Fed. Reg. at 9306. Although EPA did not rely on the RIA when deciding to regulate power plants under Section 7412(n)(1)(A), the RIA further refutes petitioners’ contention that EPA’s refusal to consider costs at the listing stage led the agency to adopt irrational power-plant regulation. 1. For the reasons explained above, EPA reasona- bly declined to consider costs when deciding that regulation of power plants is “appropriate” under Section 7412(n)(1)(A). Even if EPA had considered costs, it would not necessarily have adopted either the 54 approach set forth in the RIA or a more rigid form of cost-benefit analysis that petitioners at times appear to advocate. This Court has recognized that there are a variety of different reasonable methods by which an agency may consider costs in making regulatory deci- sions.’ The question presented in this case does not directly implicate the choice between potential meth- ods of considering costs in circumstances where such consideration is required by statute or an agency deems it to be appropriate. 2. The RIA estimated that the 2012 Final Rule would produce annual quantifiable benefits of between $37 billion and $90 billion (measured in 2007 dollars), as compared to estimated annual costs of $9.6 billion. In Entergy, for example, the Court identified at least three “plausible” ways in which EPA could consider costs when applying a “best technology available” standard within the Clean Water Act. 556 U.S. at 217-218. Those included (1) determining whether the standards’ costs can be reasonably borne by the regulated indus- try; (2) identifying the technology that most efficiently produces some degree of environmental benefit; and (3) comparing the costs and benefits of various approaches. /d at 218. In setting emis- sion standards for hazardous air pollutants, EPA has often consid- ered the cost-effectiveness of controls when determining whether to set standards at a level beyond the minimally stringent level required by 42 U.S.C. 7412(d)(3). See, e.g., 79 Fed. Reg. 60,262- 60,263, 60,272-60,273 (Oct. 6, 2014); 78 Fed. Reg. 10,020-10,021 (Feb. 12, 2013). Under that approach, EPA evaluates the costs per unit of pollutant emissions reduced or prevented ana compares that to costs per unit incurred by other industries reducing the same pollutant. If Section 7412(n1\A) were construed to require consideration of costs at the listing stage of EPA’s regulatory process, the agency would have substantial discretion to determine how cost considerations should be taken into account. See, ¢.9., Pet. App 77a (Kavanaugh, J., concurring in part and dissenting in part) (acknowledging agency discretion as to methodology). 55 77 Fed. Reg. at 9305-9306. As EPA explained, imple- mentation of the emission standards included in the rule “is expected, based purely on economic efficiency criteria, to provide society with a significant net gain in social welfare, even given the limited set of health and environmental effects we were able to quantify.” EPA, Regulatory Impact Analysis for the Final Mer- cury and Air Toxics Standards 8-1 (2011). Thus, even if Section 7412(n)(1)(A) required EPA to consider costs in deciding whether to list power plants for NESHAP regulation, the analysis contained in the RIA would have provided a fully sufficient basis for concluding that such regulation was “appropriate.” 3. Petitioners describe (NMA Br. 1, 18-19; States Br. 4, 32, 46-47; UARG Br. 3, 23, 42-43) the RIA as demonstrating that the costs of regulating power plants substantially outweigh the benefits. Petition- ers focus narrowly on the quantifiable benefits direct- ly associated with the rule’s reduction of Section 7412(b) pollutants, which the RIA estimates at $4 million to $6 million each year. As EPA explained, however, “these calculated benefits are a small subset of the benefits of reducing [mercury] emissions” un- der the 2012 Final Rule. 77 Fed. Reg. at 9428; see pp. 14-15, supra (noting RIA’s conclusion that virtually all of the direct benefits from reducing emissions of haz- ardous air pollutants are unquantifiable); see also 4 J.A. 914-923 (listing dozens of examples of unquanti- fied benefits). Petitioners offer no reason to suppose that EPA would or should have simply ignored the unquantified benefits if the agency had viewed costs as relevant to the power-plant listing decision. Petitioners also dismiss (NMA Br. 41-42; States Br. 47-48), as irrelevant to the listing decision, the tens of 56 billions of dollars in ancillary benefits that the 2012 Final Rule will achieve by reducing emissions of par- ticulate matter and sulfur dioxide. But considering such co-benefits is an accepted practice in cost-benefit analysis, the whole purpose of which is to measure the net impact that a regulation will have on social wel- fare.* Considering the co-benefits is also consistent with petitioners’ basic theory of this case, which is that “when deciding whether it is appropriate to im- pose regulation, a reasonable person would consider both the pros and cons—in other words, the benefits and costs—of regulation.” States Br. 24. Indeed, Section 7412(n)(1)(A) itself reflects Congress’s judgment that co-benefits are a valid basis ’ See, e.g., Exec. Order No. 12,866, 3 C.F.R. 639 (1994) (direct- ing EPA to assess “all costs and benefits of available regulatory alternatives”); Nat’] Ctr. for Envtl. Econ., Office of Policy, EPA, Guidelines for Preparing Economic Analyses, 11-2 (2014), http-//yosemite.epa.gov/ee/epa/eerm.nsf/vwAN/E E-0568-50.pdf/Sfi- le/EE-0568-50.pdf (requiring consideration of “ancillary (or co-) benefits and costs”); Office of Mgmt. & Budget, OMB Circular A-4 26 (2003), http-//www.whitehouse.gov/sites/default/files/omb/ assets/omb/circulars/a004/a-4.pdf (instructing agencies to “look beyond the direct benefits and direct costs of your rulemaking and consider any important ancillary benefits,” specifically including any “favorable impact of the rule that is typically unrelated or secondary to the statutory purpose of the rulemaking”); see also, e.g., Michael A. Livermore & Richard L. Revesz, Rethinking Health-Based Environmental Standards, 89 N.Y.U. L. Rev. 1184, 1250-1251 (2014) (endorsing consideration of ancillary benefits); Samuel J. Rascoff & Richard L. Revesz, The Biases of Risk Tradeoff Analysis: Towards Parity in Environmental and Health-and-Safety Regulation, 69 U. Chi. L. Rev. 1763, 1823-1824, 1831-1833 (2002) (same); Cass R. Sunstein, Essay, The Real World of Cost-Benefit Analysis: Thirty-Six Questions (and Almost as Many Answers), 114 Colum. L. Rev. 167, 190 (2014) (same). 57 for making regulatory decisions under the CAA. Section 7412(n)(1)(A) requires EPA to evaluate how the Act’s other provisions—+.e., provisions designed to limit emissions of pollutants other than the hazard- ous air pollutants at which the NESHAP program is directed—will impact power-plant emissions of hazardous air pollutants listed in Section 7412(b). 42 U.S.C. 7412(n)(1)(A). In other words, Section 7412(n)(1)(A) requires EPA to consider the co-benefits of the Act’s other regulatory programs. There is no sound reason to construe the same provision as prohibiting agency consideration of the co-benefits associated with regulation authorized by Section 7412(n)(1)(A) itself.’ Even apart from the co-benefits, power plants are responsible for approximately 50% of total anthropo- genic mercury emissions and 82% of total anthropo- genic hydrogen chloride (a listed hazardous acid gas) emissions in the United States. 77 Fed. Reg. at 9310. The 2012 Final Rule will reduce emissions of those pollutants from coal-fired plants by approximately 75% and 88%, respectively. Jd. at 9424. It is not pos- sible to quantify, in monetary terms, many of the benefits to be achieved frorn reducing such emissions. See, e.g., id. at 9428; 4 J.A. 940-944. But petitioners are wrong to imply that no such benefits exist. 4. Petitioners’ challenge to the 2012 Final Rule is ultimately self-contradictory. To prevail in this Court, petitioners must establish that Section 7412(n)(1)(A) required EPA to fully consider, at the listing stage, '® The CAA’s legislative history also reflects Congress’s expecta- tion that EPA would consider co-benefits when setting standards for hazardous pollutants for area sources. See 1989 Senate Report 172. 58 the costs and benefits of regulating power plants un- der the NESHAP program. But their argument that the 2012 Final Rule is substantively irrational, and that an “appropriate” consideration of costs would have produced a different result, depends on their view that EPA must ignore a huge portion of the ben- efits that the rule is likely to produce. Those argu- ments are not compatible with one another. In light of Section 7412(n)(1)(A)’s text and purpos- es, and of the larger statutory context in which that provision appears, EPA reasonably concluded that Congress did not intend the agency to consider costs when deciding whether to list power plants for NESHAP [Text truncated at 120,000 characters. The full text is on the page linked above.] --- Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/brief%3Amicro_IA40385016_0332%3A14. Public record. Not legal advice.