_PJ

_



# OAR Box 1790 Prepped byKeeiaRichards



### Document

Number: 

# 216 ) ll-F- 5 Docket Number: 

# A-90-3 7

Printed 10/31/200812:43:16

PM Sheet 216 of 250P. 2

C T Ol

* 

# ISK I

'< • PflO-*" 0 UNITE D STATE S ENVIRONMENTA LPROTECTIO N AGENCY Offic e o fAi rQualit yPlannin g an d Standard s Researc h Triangl e Park , Nort h Carolin a2771 1 

## oy

MEMORANDUM DATE : SUBJECT : FROM : Octobe r 23 , 199 2 Propose d Rulemaking o nBes t Availabl e Contro l Technology(BACT

A//>

- ,-

. 

# / * -/JC'p Davi d Solomon/^*--/^^^^ ^ / Ne wSourc e Revie wSectio n (MD-15 ) TO : Ai r Docke t A-91- 3 0 Th e attache d revise d draf t propose d rulemaking o nBAC T wa s submitte d fo r interagenc yreviewt o th e Offic e o f Managemen t an d Budge t i n respons e t o comment s receive d fro m them , th e Departmen t o f Energy , th e Counci l o f Economi c Advisor s an d th e Counci l o n Competitivenes s regarding EPA' s origina l Octobe r 2 , 199 2 rulemakin g submittal . Attachmen t 

## {



# r77&^M 

# m 

# 0^ \<$ &P. 3

I v
• OCT-23-199 2 0 5 = 0 1 FRO MT O 8919541550 9 P . £' 2

Octobe r 22 , 199 2 NOT E TO : Ar t Fraa s FROM : Michae l Sha p 

# iro^ f

Enclose d i s a revise d cop yo f th e BAC T rulemakin g package , whic hincorporate s th e change s w e hav e discusse d and agree d upon . W e hav e mad e on e chang e t o th e agreed-upo n change s i n orde r t o mak e a footnot e bette r agre e wit hth e text : i n footnot e 11 , "affordabilit yanalysis " wa s change d t o "affordabilit y considerations. " Pleas e cal l m e i f yo u hav e an yquestion s regardin g thi s rule .P. 4

6560-5 0 ENVIRONMENTAL PROTECTIO NAGENC Y 4 0 CFRPART S 5 1 AN

D 5 2 [AD-FRL

- ] REQUIREMENT S FORPREPARATION , ADOPTION , AND SUBMITTAL O F IMPLEMENTATIO NPLANS ; APPROVAL AN

D PROMULGATIONO F IMPLEMENTATIONPLAN S AGENCY : Environmenta l Protectio n Agenc y(EPA ) ACTION : Propose d Rul e SUMMARY : T o improv e th e effectivenes s o f th e preventio no f significan t ai r qualit ydeterioratio nprogramrequire d b y titl e I , par t C , o f th e Clea nAi r Ac t (Act) , EPApropose s todayt o amend it s rule s t o clarif yth e regulatory definitio n o f bes t availabl e contro l technology(BACT ) b y addin g languag e tha t elucidate s th e lega l requirement s fo r a BAC T analysis . Th e newlanguag e specifie s tha t a BAC T analysi s mus t contai n the following tw o cor e requirements : 1 ) th e determinatio n mus t conside r a representativ e group o f th e rang e o f availabl e contro l system s fo r th e source , an

d 2 ) selectio n o f a particula r contro l systema s BAC T mus t b e justifie d b ya compariso n o f th e candidat e contro l system s i n term s o f th e statutorycriteri a an d supporte d b

y th e record . I n addition , EPApropose s t o amen d th e regulation s definin g BAC T t o reflec t th e chang e mad e b y§ 403(d ) o f titl e I V o fP. 5

2 th e Ac t Amendment s o f 199 0 (199 0 Amendments ) t o th e statutorydefinitio n o f BACT . Th e EPAi s soliciting publi c commen t o n thes e propose d clarification s t o th e regulatorydefinitio no f BACT . DATES : Comment s mayb e submitte d t o EPAa t th e addres s belo wo n o r befor e [6 0 day s fro mdat e o f publication] . A publi c hearing i s schedule d fo r [ ] . Th e hearing may b e cancele d i f n o speaker s hav e requeste d tim e t o presen t thei r comment s 1 5 day s prio r t o th e schedule d hearing date . Writte n comment s i n lie u o f testimon yar e encouraged . DOCKET : Supporting informatio nuse d i ndeveloping th e propose d rul e i s containe d i n Docke t No . A-91-30 . Thi s * , docke t i s availabl e fo r publi c inspectio nan d copying betwee n 8:3 0 a.m . an d 3:3 0 p.m. , MondaythroughFriday , a t th e addres s liste d below . Areasonabl e fe e mayb e charge d fo r copying . ADDRESSES : Comment s mus t b e maile d (induplicat e i f possible ) to : Th e EPAAi r Docke t (LE-131) , Attn : Docke t No , A-91-30 , RoomM-1500 , Watersid e Mall , 40 1 MStree t SW , Washington , D.C . 20460 . Th e publi c hearing wil l b e hel d [ ] . FO RFURTHE RINFORMATIONCONTACT : Th e EPA' s Ne wSourc e Revie wSectio n a t (919 ) 541-5591 . Person s intereste d i n attending th e hearing o r wishing t o presen t ora l testimon y shoul d contac t Ms . JoAnnAllman , i n writing , a t th e U.S . Environmenta l Protectio nAgency , Offic e o f Ai r Qualit yP. 6

3 Planning an

d Standards , Ai r Qualit yManagemen t Division , Mai l Drop 15 , Researc hTriangl e Park , Nort hCarolina 27711 .

SUPPLEMENTARYINFORMATIO N

I . Background Majo r stationarysource s an d majo r modification s ar e subjec t t o th e preventio n o f significan t deterioratio n(PSD ) revie wrequirement s o f th e Ac t (titl e I , par t C) . Asubjec t facilit ymayno t b e constructe d withou t a permi t tha t meet s th e requirement s o f § 16 5 o f th e Act . Th e curren t PS D programi s implemente d b ytw o set s o f regulations . Th e firs t se t o f regulations , 4 0 CFR51.166 , specifie s th e minimu mrequirement s tha t a PS D ai r qualit ypermi t program unde r par t C o f th e Ac t mus t contai ni n orde r t o obtai n approva l b

yEPAa s a revisio n t o a Stat e implementatio nplan (SIP) . Th e secon

d set , 4 0 CF R52.21 , delineate s th e Federa l PS D permi t program , whic hcurrentl yapplie s a s par t o f th e SI P fo r State s tha t hav e no t submitte d a PS D programmeeting th e requirement s o f 4 0 CFR51.166 . Roughl ytwo-third s o f th e State s ar e implementing thei r ow n PS D programwhic hha s bee n approve d b

yEPAunde r 4 0 CFR51.166 . Th e regulation s a t 4 0 CFR52.2 1 appl yi nth e remaining States , mos t o f whic h hav e bee n delegate d th e authorit yt o implemen t th e Federa l PS D program . Among othe r substantiv e requirements , th e facilit ymus t appl yBAC T pursuan t t o § 165(a)(4 ) [se e als oP. 7 4 4 0 CFR52.21(j ) (Federa l regulations) , 4 0 CFR51.166(j ) (regulation s setting fort hth e requirement s fo r SI P approva l o f a Stat e PS D program) , an d 4 0 CFRpar t 52 , subpar t A- subpar t FF F (variou s SI P requirements)]. 1 Emission s limitation s reflecting th e applicatio no f th e BAC T requiremen t mus t b e se t fort hi n th e PS D permi t [se e § 165(a)(1)] . T o obtai n a PS D permit , a napplican t must , among othe r requirements , conduc t ananalysi s i n accordanc e wit hEPAregulation s t o ensur e th e applicatio no f BAC T t o eac hne wo r modifie d emission s uni t [se e § 165(a)(2 , 4)] . Th e require d analysi s mus t addres s "the degre e o f continuou s emission s reductio n whic hcoul d b e achieve d b ysuc h facility " [se e § 165(e)(3)(B ) an d 4 0 CFR52.21(n)(1)(3)] . Th e ter m "bes t availabl e contro l technology " i s define d i n th e Ac t as : an emission s limitatio nbase d o n th e maximu m degre e o f reductio no f eac hpollutan t subjec t t o regulatio n unde r th e Ac t emitte d fro mo r whic h result s froman

ymajo r emitting facility , whic h th e permitting authority , on a case-by-cas e basis , taking int o accoun t energy , environmental , an d economi c impact s an d othe r costs , determine s i s achievabl e fo r suchfacilit ythroughapplicatio n o f productio n processe s an d availabl e methods , systems , an

d techniques , including fue l cleaning , clean fuels , o r treatmen t o r innovative fue l combustio n technique s fo r contro l o f eac hsuc h pollutant . I n n o even t shal l applicatio n o f "bes t availabl e contro l technology " resul t i nemission s o f an ypollutant s whic hwil l excee d th e emission s allowe d b

yan yapplicabl e standard establishe d pursuan t t o § 741 1 o r 741 2 o f thi s title . 'Unde r th e 199 0 Amendments , i ncertai n circumstances , BAC T i s als o a requiremen t fo r obtaining a permi t unde r Par t D o f th e Act .P. 8

Emission s froman

ysourc e utilizing clea nfuels , o r an yothe r means , t o compl ywit hthi s paragrap h shal l no t b e allowe d t o increas e abov e level s tha t woul d hav e bee n require d unde r thi s paragrapha s i t existe d prio r t o enactmen t o f th e Clea nAi r Ac t Amendment s o f 1990 . [se e § 169(3) , a s amende d b y§ 403(d ) o f th e 199 0 Amendments] . I n determining BAC T o n a case-by-cas e basis , th e reviewin g authorit yevaluate s th e energy , environmental , an d economi c impact s an d othe r cost s associate d wit heac ho f th e candidat e technologie s considere d i nth e analysis . Th e reviewin g authorit ythe n specifie s an emission s limitation , base d o n th e maximu mdegre e o f reductio no f eac hpollutan t subjec t t o regulation , taking int o accoun t energy , environmental , an

d economi c impact s an d othe r costs , i t determine s i s achievabl e fo r suc hfacility . I nn o even t may a technologyb e selecte d tha t woul d no t mee t an yapplicabl e standar d o f performanc e unde r 4 0 CFR6 0 [ne wsourc e performanc e standard s (NSPS) ] o r 6 1 [nationa l emissio n standard s fo r hazardou s ai r pollutant s (NESHAP)] . I n addition , i f th e reviewing authorit ydetermine s tha t ther e i s n o economically-reasonabl e o r technologically

feasibl e wayt o accuratel ymeasur e th e emissions , an d henc e t o impos e an enforceabl e emission s standard , i t mayrequir e th e sourc e t o us e design , alternativ e equipment , wor k practic e o r operationa l standard s t o reduc e emission s o f th eP. 9

6 pollutan t t o th e maximu mexten t [4 0 CFR52.21(b)(12) ; 4 0 CFR 51.166(b)(12)]. 2 I n January1979 , EPAissue d "Guidanc e fo r Determining BAC T Unde r PSD, " an d i n Octobe r 199 0 issue d a "PS D Worksho p Manual " (EP

A450/2-80-081) . Thes e document s outline d an approac ht o th e BAC T analysi s i nwhic hth e applican t wa s t o propos e a bas e cas e a s BACT , presen t mor e stringen t contro l alternatives , an

d defen d it s BAC T selectio n "demonstrating tha t eac halternativ e contro l system.. . woul d caus e unreasonabl e advers e energy , environmental , o r economi c impacts " (se e "Guidanc e fo r Determining BAC T Unde r PSD, " January4 , 1979) . Th e 197 9 guidanc e documen t note s EPA' s belie f tha t Congres s intende d tha t th e State s hav e broa d flexibilit yt o decid e o nth e relativ e weigh t t o assignt o eac ho f thes e factors . Further , BAC T wa s describe d a s a "flexibl e approac h[which ] allow s th e permitting authorit y t o conside r a numbe r o f loca l factor s (for exampl e th e siz e o f th e plant , th e amoun t o f ai r qualit yincremen t tha t woul d b e consumed , an

d desire d economi c growt hi nth e area ) i n deciding o n a weighing scheme. " Thi s methodologyi nth e

2 Fo r example , i f a coa l storag e pil e emit s coa l dus t t o th e atmosphere , i t woul d mak e littl e sens e t o impos e anemission s standard , sinc e measuring th e amoun t o f coa l dus t rising of f th e pil e mayb e nearl yimpossible . Amuc hmor e direc t approac ht o controlling emission s is , fo r example , requiring th e owne r t o we t th e coa l pil e periodicall yo r t o totall yenclos e it . Thi s typ e o f operationa l standar d o r wor k practic e woul d b e equivalen t t o an emission s limitatio n fo r th e purpos e o f th e BAC T requirement . I n some instances , i t mayb e appropriat e t o expres s BAC T fo r a particula r pollutan t a s an emission s limitatio n an d a wor k practic e o r operationa l standard .P.1 0

7 197 9 guidanc e i s commonl yreferre d t o a s th e "bottom-up " approach . I n Jun e 1986 , EP

Aestablishe d a Ne wSourc e Revie w(NSR ) Tas k Forc e t o addres s growing concern s abou t th e effectivenes s o f th e NS Rprogram s i nmeetin g th e statutory requirements , an

d t o recommend action s t o improv e EPA' s exercis e o f it s oversigh t an d enforcemen t responsibilitie s i n implementing th e NS Rprogram . Among th e Tas k Forc e findings , base d o n a comprehensiv e revie wo f numerou s PS D permit s issue d during th e previou s severa l years , wa s tha t PS D applicant s an

d State s frequentl ywer e conducting inadequat e BAC T determinations . I n numerou s instances , applicant s woul d propos e anemission s limitatio na t o r nea r a n applicabl e NSP S unde r § 11 1 o f th e Ac t a s th e bas e case , an d provid e littl e o r n o consideratio no f mor e stringen t contro l option s befor e settling o nth e propose d leve l a s BACT . State s typicall ywoul d accep t thes e determination s wit hlittl e o r n o independen t analysis , thereb yfailing t o fulfil l thei r responsibilitie s unde r th e Act . Th e Tas k Forc e pointe d ou t tw o basi c solution s t o th e problem o f inadequat e BAC T analysis . On e wa s t o improv e implementatio n o f th e existing metho d s o that , i n practic e a s wel l a s i n theory , th e statutoryrequirement s woul d b e fulfilled . Th e othe r optio n wa s t o cal l fo r a nalternat e approac ht o th e BAC T analyse s i n th e expectatio n tha t it s interna l dynamic s woul d achiev e mor e effectiv e implementatio no f th e BAC TP.1 1

8 requirement s (se e generall y"NewSourc e Revie wTas k Forc e Report, " Fina l Draft , Decembe r 1986) . I n th e meantime , i nanadjudicativ e decisio no nappea l o f a PS D permi t fo r a municipa l wast e combustor.(MWC) , th e Administrato r hel d tha t a PS D applican t ha s th e "burde n o f demonstrating tha t significan t technica l defects , o r substantia l loca l economic , energy , o r environmenta l factor s o r othe r costs , warran t a contro l technolog yles s efficien t tha n [the mos t stringen t technolog yavailable] " [se e Honolul u Resourc e RecoveryFacilit y("H-Power") , PS D Appea l No . 86-8 , a t 7 (Reman d Order , Jun e 22 , 1987)] . Shortl y thereafter , EPAissue d guidanc e calling fo r applicatio no f th e H-Powe r holding t o al l BAC T determination s fo r MWC s ("Operationa l Guidanc e o nContro l Technolog yfo r Ne wan

d Modifie d Municipa l Wast e Combustors, " Jun e 26 , 1987) . Subsequen t t o thes e events , EPAdecide d t o promot e wha t ha s come t o b e know n a s a "top-down " BAC T metho d fo r al l categorie s o f PS D sources . I n brief , th e top-dow n procedur e provide s tha t availabl e contro l technologie s b e ranke d i n descending orde r o f contro l effectiveness . Th e PS D applican t firs t examine s th e mos t stringen t alternative . Tha t alternativ e i s establishe d a s BAC T unles s th e applican t demonstrates , an

d th e permitting authorit yi nit s informe d judgmen t agrees , tha t technica l considerations , o r energy , environmental , o r economi c impact s o r othe r costs , justif ya conclusio n tha t thi s technolog yi s no t "achievable " o rP.1 2

9 appropriat e i n thi s cas e a s BACT . I f a particula r technologyi s deeme d no t t o b e BACT , the nth e nex t mos t stringen t alternativ e i s considered , an d s o on . I n a Decembe r 1 , 198 7 memorandum , EPAHeadquarter s requeste d it s Regiona l Office s t o us e a top-dow nmetho d i n thei r ow

n BAC T determinations , an d t o encourag e Stat e an d loca l PS D permitting authoritie s t o d o s o a s wel l (se e Decembe r 1 , 198 7 memorandu mfrom Crai g Potter , Assistan t Administrato r fo r Ai r an d Radiation , entitle d "Improving New Sourc e Review") . Th e memorandu mfurthe r directe d Regiona l Office s t o conduc t timel yreview s o f PS D application s submitte d t o Stat e permitting authorities , an d t o commen t adversel yo n propose d PS D permit s tha t faile d t o adequatel y conside r contro l option s mor e stringen t tha nNSPS , a s woul d b e require d a s a matte r o f cours e i nan yacceptabl e metho d o f determining BACT . I f fina l Stat e an d loca l permit s stil l faile d t o reflec t adequat e consideratio n o f th e relevan t BAC T factors , th e Region s wer e t o conside r suc hpermit s deficien t an

d conside r appropriat e enforcemen t actio n unde r § § 11 3 an

d 16 7 (in th e cas e o f State-issue d permits ) o r appeal s t o th e Administrato r unde r 4 0 CFR124.1 9 (i nth e cas e o f Federa l permits ) t o remed ysuc hdeficiencies . I n recommending th e us e o f th e top-dow napproach , EPA di d no t revis e it s existing PS D regulations , no r di d i t cal l fo r revisio n o f applicabl e SIP's . Rather , i nsetting fort h thi s polic yapproach , EPArelie d upo nth e existing statutoryP.1 3

1 0 an d regulatorydefinition s fo r determining BACT . I n s o doing , i t wa s EPA' s vie wa t tha t time tha t th e top-dow n approac hannounce d i n decision s an d memorand a constitute d a reasonabl e metho d fo r implementing th e existing provisions . Th e approac h"represent[ed ] EPA' s judgmen t tha t existing BAC T requirement s can bes t b e accomplishe d througha particula r analytica l methodology " [se e lette r fromEPA Administrato r WilliamK . Reill yt o America n Pape r Institut e an d th e Nationa l Fores t Product s Associatio n (collectivel y "API") , May12 , 1989] . I nothe r words , EPAbelieve d tha t utilizatio n o f th e top-dow napproac hwoul d ensur e tha t th e tw o cor e criteria , a s discusse d below , woul d b e adhere d t o b ypermitting authorities . O n Marc h29 , 198 9 (supplemente d o n May3 an d 10 , 1989) , AP I petitione d EPAt o rescind th e top-dow npolic yan

d initiat e a rulemaking on BAC T determinations . Th e EPA denie d thi s reques t on May12 , 198 9 (supplemente d o nJun e 13 , 1989) , explaining tha t th e top-dow napproac hwa s no t a t varianc e with , no r a revisio n of , th e PS D regulations , an d tha t n o rulemaking wa s required . Subsequently , AP I file d sui t i n th e D.C . Circui t an d i n th e U.S . Distric t Cour t fo r D.C . AP I v . Reillv , D.C . Cir . No . 89-142 8 (filed 7/10/89) ; AP I v . Reillv . D.C . Cir . No . 89-203 0 (filed 7/18/89) . A consortiu

mo f utilitie s als o file d a petitio nfo r revie wo f EPA' s actions , [Alabam a Powe r Co . v . EPA , D.C . Cir . No . 89

- 142 9 (filed 7/11/89 ) , an d th e cas e wa s consolidate d wit hth eP.1 4

1 1 AP I case] . Th e same consortiu mfile d a n administrativ e petitio n wit hEPAo n February1 , 1990 . Finally , AP I als o challenge d th e 199 0 EPAdraf t guidanc e documen t o ntop-dow n BACT , AP I V . Reillv , D.C . No . 90-136 4 (filed 7/13/90) . A settlemen t agreemen t ha s bee n entere d int o fo r thes e case s (se e 5 6 FR34202) . Th e EPAha s decide d a s a matte r o f polic yt o conduc t thi s propose d rulemaking t o facilitat e greate r publi c participatio n concerning thes e issues .

II . Lega l Requirement s fo r a PS D Analysi s I n adopting th e PS D program , Congres s emphasize d th e importanc e o f thoroughan d publi c analyse s i n PS D decisio n making , stating tha t on e o f th e purpose s o f PS D i s t o assur e tha t an ydecisio n t o permi t increase d ai r pollutio ni n an y are a t o whic hPS D applie s i s mad e onl yafte r carefu l evaluatio n o f al l th e consequence s o f suc ha decisio nan d afte r adequat e procedura l opportunitie s fo r informe d publi c participatio n i n th e decisio n making proces s [se e § 160(5)] . A s note d above , § 16 5 specifies , an d EPAregulation s reflect , th e requiremen t t o conduct , among othe r PS D permi t revie wrequirements , a BAC T analysis . Th e statutory emphasi s o n procedura l rigo r i s accompanie d b yexpression s o f congressiona l inten t tha t State s hav e wid e discretio ni n setting fina l emission s limit s reflecting BACT . State s als o hav e considerabl e discretio n i nothe r aspect s o f th e PS D program , suc ha s allocatio n o f th e availabl e increment . Fo rP.1 5

1 2 example , State s coul d choos e t o allocat e th e incremen t o na first-come , first-serve d basis , preserv e a portio n o f th e incremen t t o accommodat e futur e growth , o r allocat e incremen t througha market-base d approach . Th e legislativ e historyo n BAC T make s i t clea r tha t Congres s mean t th e Stat e t o mak e th e fina l substantiv e decisio n o n th e appropriat e leve l o f technolog yfo r th e sourc e an

d are a i n question . Th e keypassage s o f th e Senat e repor t showtha t th e Stat e ha s broad flexibilit yt o exercis e it s judgmen t i n implementing BACT . Th e repor t states :

Th e decisio nregarding th e actua l implementatio n o f bes t availabl e contro l technologyi s a keyone , an d th e committe e place s thi s responsibilit ywit hth e State , t o b e determine d i n a case-by-cas e judgment . I t i s t o b e recognize d tha t th e phras e ha s broad flexibilit yi n howi t shoul d an d ca n b e interpreted , depending o nsite . I n makin g thi s keydecisio n o n th e technology t o b e used , th e Stat e i s t o tak e int o accoun t energy , environmental , an d economi c impact s an d othe r cost s o f th e applicatio no f bes t availabl e contro l technology . Th e weigh t assigne d t o suc h factor s i s t o b e determine d b yth e State . Suc ha flexibl e approac hallow s th e adoptio no f improvement s i n technologyt o become widesprea d fa r mor e rapidl ythanwoul d occur wit ha uniform Federa l standard (emphasi s added) . [se e S.R . 95-217 , 95t hCong. , 1s t Sess . 3 1 (1977)] . Th e Senat e repor t languag e suggest s tw o importan t bound s on th e exercis e o f th e discretio nafforde d t o th e permittin g authorit yi n determining BACT . First , i t i s clea r tha t i n adopting BACT , Congres s intende d PS D permitting authoritie s t o exercis e informe d discretio n t o weighenergy ,P.1 6

**- 3 environmental , and economi c impact s i ndetermining BAC T fo r a particula r source , whil e leaving t o th e State s th e flexibilit yt o decid e o n th e relativ e weight s t o assign eac h o f thes e factor s i n deciding among options. 3 Second , i t i s als o clea r tha t Congres s believe d tha t on e o f th e advantage s o f Stat e flexibilit ywoul d b e t o speed up th e adoptio no f advance s i n contro l technology. 4 Th e exercis e o f discretio nwithi nthes e bound s ca nb e fulfille d b

ymor e than on e metho d o f determining BACT . Regardles s o f th e specifi c methodologyuse d fo r determining

3 "Th e decisio n regarding th e actua l implementatio no f BAC T i s a ke yone , an

d th e committe e place s thi s responsibilit ywit h th e State , t o b e determine d i n a case-by-cas e judgment . I t i s recognize d tha t th e phras e ha s broa d flexibilit yi nho wi t shoul d an d ca n b e interpreted , depending o n site . I n makin g thi s ke ydecisio no nth e technolog yt o b e used , th e Stat e i s t o tak e int o accoun t energy , environmental , an d economi c impact s an d othe r cost s o f th e applicatio n o f BACT . Th e weigh t assigne d t o suc hfactor s i s t o b e determine d b yth e State . Suc ha flexibl e approac hallow s th e adoptio no f improvement s i n technologyt o becom e widesprea d fa r mor e rapidl ytha nwoul d occu r wit ha uniformFedera l standard . Th e onl yFedera l guideline s ar e th e EPAne wsourc e performanc e an d hazardou s emission s standards , whic hrepresen t a floo r fo r th e State' s decision . Thi s directiv e enable s th e Stat e t o conside r th e siz e o f th e plant , th e incremen t o f ai r qualit ywhic hwil l b e absorbe d b yan y particula r majo r emitting facility , an d suc hothe r consideration s a s anticipate d an

d desire d economi c growt hfo r th e area . Thi s allow s th e State s an d loca l communitie s t o judg e ho wmuc ho f th e define d incremen t o f significan t deterioratio nwil l b e devote d t o an ymano r emitting facility . If , unde r th e designwhic ha majo r facilit ypropose , th e percentag e o f th e incremen t woul d effectivel ypreven t growt hafte r th e propose d majo r facilit ywa s completed , th e Stat e o r communit ycoul d refus e t o permi t construction , o r limi t it s size . Thi s i s strictl ya Stat e and loca l decision " (emphasi s added ) [se e Sen . Rep . No . 95-217 , 95t h Cong. , 1s t Sess . 3 1 (1977)] .

4 Se e als o statemen t o f Senato r Muskie , 12 3 Cong . Rec . S917 1 (June 8 , 1977) .P.1 7

1 4 BACT , b e i t top-down , th e metho d embodie d i n th e 197 9 guidance , o r otherwise , EPAinterpret s th e relevan t Ac t provision s a s embodying tw o cor e lega l criteri a tha t mus t b e satisfie d i n an

yBAC T analysis. 5 First , th e permi t applican t mus t conside r a representativ e grou p o f availabl e contro l technologie s [i.e. , technologie s tha t ar e representativ e o f th e rang e o f availabl e control s tha t ar e a t leas t a s effectiv e a s th e minimu mpermissibl e (NSP S limit , § 11 2 limit , o r SI P limit)] . Second , selectio no f a particula r contro l systema s BAC T mus t b e justifie d b ya compariso n o f th e candidat e contro l system s i n term s o f th e statutorycriteri a an d supporte d b

yth e recor d i nsuc ha way tha t th e basi s fo r th e choic e o f BAC T fro mamong th e othe r

Applicatio n o f EPA' s earlie r top-dow nguidanc e mayhav e had th e unintende d effec t o f constraining Stat e discretio n i nmaking BAC T determination s an d absolutel yprecluding consideratio n o f certai n cos t an

d environmenta l factor s (e.g. , incrementa l cos t effectivenes s an

d incrementa l ambien t impacts) . Als o th e Administrator' s decisio n i nUnio nCount yResourc e Recovery Facility , PS D Appea l No . 90- 1 (Nov . 28 , 1990 ) a t 8 , coul d b e improperl yconstrue d a s precluding an ycompariso no f candidat e contro l technologie s i n ligh t o f th e applicabl e statutory factors . Together , thi s mayhav e create d an undul ystrong presumptio n tha t th e mos t stringen t leve l o f contro l i s BACT . Permitting authoritie s wishing t o followa top-dow nmetho d i nth e futur e shoul d b e sur e tha t th e metho d i s consisten t wit hth e cor e criteri a an

d doe s no t ignor e relevan t factors .P.1 8

1 5 candidat e system s i s apparen t an d consisten t wit hstatutory criteria. 6 Th e EPAi s todayproposing guidanc e consisten t wit hth e PS D regulations . Th e EPAcontinue s t o recogniz e tha t th e Ac t an d existing regulation s fo r BAC T mandat e applicatio n o f th e tw o cor e criteri a discusse d above . Rathe r tha nfurthe r advocating adherenc e t o th e top-dow n methodology , th e Agenc y i s instead emphasizing th e broa d flexibilit ywhic h permitting authoritie s hav e i n conducting th e requisit e BAC T analysis . Indeed , EPAi s todayproposing t o codif yth e cor e criteri a int o it s regulatorydefinitio n o f BACT . A t th e same time , however , th e legislativ e historyt o th e Ac t

, ; demonstrate s tha t Congres s favore d broad flexibilit yfo r State s i n applying th e statutoryfactor s (i.e. , energy , environmental , an

d economi c impacts ) i ndetermining BACT . Wit hthi s purpos e i n mind , EPAbelieve s tha t s o long a s th e cor e criteri a ar e applie d a s describe d herein , Congress ' interest s i n stimulating advance s i n pollutio ncontro l technologyan

d preserving th e flexibilit yo f th e permitting

6 I n thi s regard , t o th e exten t tha t a rational e fo r th e rejectio n o f th e nex t mor e stringen t alternativ e tha nth e on e propose d als o provide s th e basi s fo r rejectio no f othe r mor e stringen t alternatives , ther e i s n o nee d t o conduc t a separate , detaile d analysi s fo r eac hmor e stringen t option . T o giv e a n example , assume tha t afte r examining a contro l optio ni n detail , th e permitting authorit yaccept s a napplicant' s proposa l t o rejec t a contro l optio n du e t o a n advers e economi c impac t afte r considering th e energy , environmental , an d othe r economi c impact s o f tha t option . Th e permitting authorit ynee d no t conside r th e othe r mor e stringen t contro l option s i n detail , i f i t conclude s tha t thei r associate d energy , environmental , an d economi c impact s d o no t diffe r meaningfull yfro mth e contro l optio n rejected .P.1 9

1 6 authorit yar e bes t accomplishe d withou t requiring utilizatio n o f th e top-dow n methodology . I n thi s way , permittin g authoritie s ar e fre e t o develop thei r ow n BAC T implementatio n policie s an d conside r factor s tha t exis t fo r a propose d facilit yona case-by-cas e basi s withi nth e statutoryan

d regulatoryframewor k fo r a BAC T analysis . I n ligh t o f this , t o th e exten t th e Agency' s earlie r top-down guidanc e efforts , including th e Honolul u Powe r an d Pennsauke n Count yPS D appeals , appl ya top-dow napproac h tha t coul d b e rea d t o restrai n Stat e discretio n i n weighin g th e statutoryfactor s an d coul d b e read a s being inconsisten t wit hcongressiona l inten t tha t th e Stat e retai n broa d discretio n t o weighth e statutoryfactor s o r t o preclud e comparing candidat e control s using anincrementa l impac t analysi s an

d applying othe r statutorycriteria , thos e decision s n o longe r reflec t EPApolicy . A s state d above , th e primarybenefi t t o th e top-dow n methodologywa s tha t i t woul d ensur e applicatio n o f th e BAC T cor e criteri a b y permittin g authorities . However , earlie r effort s ha d th e potentia l t o chil l the ful l exercis e o f a State' s discretio n b yannouncing cor e criteri a tha t coul d b e construe d t o creat e a n undul ystrong presumptio ni n favo r o f th e mos t stringen t pollutio n contro l alternativ e available . By proposing t o promulgat e th e cor e criteri a (a s reformulate d today ) b

yregulation , EPAbelieve s i t ha s adequatel yP.2 0

1 7 implemente d th e Act , including th e congressiona l inten t tha t broa d discretio n remai n wit hth e permitting authority . I n th e contex t o f earlie r appeal s t o th e Administrator , question s hav e arise nove r Stat e discretio nt o conside r th e incrementa l ambien t an d cos t impact s associate d wit hcertai n pollutio n contro l options , relativ e t o th e othe r availabl e options , i n determining BAC T [se e Columbi a Gul f Transmissio n Co. , PS D Appea l No . 88-1 1 (Order , Jun e 2 1 1989) ; Worl d Colo r Press . Inc. , PS D Appea l No . 88- 4 (Reman d Order , Decembe r 13 , 1990)] . I n thos e decisions , i n contras t t o earlie r EPA guidanc e (e.g. , th e 198 0 PS D Workshop Manua l pag e I-B-35) , th e Administrato r determine d tha t th e environmenta l impact s pron g o f th e BAC T analysi s preclude d analysi s a s t o whethe r us e o f th e mor e stringen t contro l alternativ e woul d benefi t ambien t ai r quality , o r whethe r th e additiona l benefi t wa s wort hth e expense . However , th e Administrato r di d recogniz e that , unde r certai n circumstances , suc hconsideration s may b e appropriat e unde r th e economi c impact s prong o f th e BAC T analysis . Underlying thes e decision s wa s th e vie wthat , unde r th e Act , ther e i s a distinctio n betwee n BACT , whic hi s concerne d wit hpollutio n contro l technology , an d ambien t impacts , whic hrelate s t o overal l ai r qualit y[se e 4 2 U.S.C . 7475(a)(3 ) an d (4)] . Whil e th e EPAcontinue s t o recogniz e tha t BAC T i s primaril ydirecte d t o technolog yselection , an

d tha t thi s i s somewha t distinc t fro mimpact s upo n ambien t ai r quality , EPAP.2 1

1 8 doe s no t believ e th e Ac t o r implementing regulation s mandat e absolut e separatio n o f th e tw o concepts . Rather , th e selectio n o f an appropriat e technologya s BAC T i s sufficientl yrelate d t o th e Act' s overriding concer n wit h ai r qualit ytha t a permitting authorit ymay , i nit s discretio n an

d a s par t o f it s overal l BAC T analysis , conside r th e relativ e ambien t impact s o f th e availabl e contro l alternatives . Althoughthi s typ e o f analysi s may occu r unde r eithe r th e economi c o r environmenta l pron g o f th e BAC T analysi s (thu s modifyin g recen t decision s b yth e Administrator , albei t i n a manne r consisten t wit hstatement s i n EPA' s 198 0 Worksho p Manual) , th e permitting authorit y

; mus t continu e t o conside r th e ful l rang e o f statutory factor s befor e issuing th e fina l permit . Thi s approac hi s consisten t wit hEPA' s 198 0 Worksho p Manua l an d recognize s Congressiona l inten t tha t th e State s retai n broad discretio n an

d flexibilit yi n making BAC T determinations. 7 Eve n thoughState s hav e discretio nt o conside r incrementa l ambien t an

d economi c impacts , theymus t als o consider , i n accordanc e wit hthei r overal l BAC T policy , al l o f th e othe r statutoryfactor s i nth e BAC T analysis . Thes e can , fo r example , includ e consideratio no f sourc e specifi c factors , suc ha s locall ysensitiv e environmenta l resources ; proximit y

7 I n suc hcases , th e analysi s shoul d rel yo nth e mode l an d mode l input s use d i n conducting th e requisit e PS D ambien t ai r qualit yanalysi s (i.e. , th e determinatio n tha t ne wemission s wil l no t caus e o r contribut e t o a violatio n o f th e applicabl e NAAQ S o r PS D increments) .P.2 2

1 9 t o Clas s I areas ; overal l incremen t management ; acidification ; o r visibilit yimpairment. 8 Thus , a Stat e may no t rel ysolel yupo n pre-se t ambien t impac t o r cost
effectivenes s level s i nselecting BACT , bu t mus t justif yit s selectio n i n term s o f al l th e statutoryfactor s (althoug h suc hlevel s mayb e utilize d b ya Stat e t o assis t i t i n makin g it s determination) . I n a BAC T analysis , th e representativ e grou p o f contro l technologie s initiall yconsidere d shal l includ e th e mos t

8 I n some cases , th e lac k o f comprehensiv e informatio n o r modelin g tool s limit s th e applicatio no f suc hanalyses . However , i n makin g it s fina l BAC T determination , th e Stat e i s no t constraine d b

ylimitation s t o modeling technolog yo r th e difficult yi n assessing environmenta l impacts . I f a Stat e lack s th e abilit yt o definitivel yquantif yth e impact s upo n ai r qualit y o r ai r qualit yrelate d values , o r prefer s t o no t rel yupo nsuc h measures , i t nevertheles s retain s discretio n t o manag e it s ai r resource s throughrelianc e upo n qualitativ e determinatio n o r reasonabl e approximatio n i nmakin g it s fina l BAC T selection .P.2 3

2 0 stringen t contro l technolog yavailable. 9 However , ther e i s n o requiremen t tha t eac halternativ e b e evaluate d i nequa l depth . Unde r th e statutorydesign , PS D permitting authoritie s fo r eac hjurisdictio n hav e broad discretio n t o reflec t loca l condition s an d preference s i nweighin g th e energy , environmental , an d economi c factor s tha t ente r int o a BAC T determination . Fo r example , State s coul d adop t a pre screening process . An initial , limite d analysi s may conclud e tha t certai n alternative s ar e unlikel yt o b e considere d BAC T base d upo nth e mos t recen t informatio n availabl e concerning cost , feasibility , an d othe r relevan t factor s pertainin g t o thos e alternatives , an d upo n th e : permitting authority' s genera l approac ht o weighing th e

'Whethe r a technologyi s "available " fo r purpose s o f BAC T i s a practical , factua l determination , using conventiona l notion s o f whethe r th e technologycanb e pu t int o us e [se e Pennsauke n County , Ne wJerse yResourc e RecoveryFacility . PS D Appea l No . 88- 8 (Reman

d Order , Nov . 10 , 1988 ) a t 8] . Th e permi t applican t shoul d refe r t o th e BACT/LAE RClearinghous e whe n identifying a representativ e grou p o f availabl e contro l technologies . Eac htyp e o f selecte d contro l system(e.g. , a baghouse , a n electrostati c precipitator , a dryscrubber , a we t scrubber , a carbo n absorber ) o r combinatio no f contro l system s shoul d b e analyze d a t th e technicall yachievabl e leve l o f contro l a s i t coul d b e applie d a t th e propose d facility . Majo r alternative s withi n a give n typ e o f contro l systemshoul d als o b e considere d whe n suc halternative s woul d produc e meaningfull y differen t energy , environmental , o r economi c impac t o r othe r cost s tha n th e initia l leve l o f contro l analyzed . O nth e othe r hand , analyse s o f numerou s mino r variation s i n a contro l system (or combination s thereof ) i s no t required . I nEPA' s experience , typicall yther e ar e onl ya t mos t four o r fiv e BAC T option s tha t nee d b e reviewe d i n detai l fo r an ypropose d sourc e i norde r t o ensur e tha t a representativ e sampl e o f alternative s i s considered .P.2 4

2 1 statutoryfactors . Suc ha screening o f potentia l BAC T option s t o identif yth e mos t likel yan d promising maysav e th e sourc e an

d permitting authorit ytime an d moneyan

d provid e a degre e o f predictabilit yt o al l concerned . Wher e th e permitting authorit ydecide s afte r considering an

ysource-specifi c factor s tha t th e screened

ou t option s woul d no t b e BACT , the n th e evaluatio n proces s woul d shif t i n th e nex t step t o th e remaining "live " option s fo r furthe r analysis . Fo r example , wher e a permitting authorit yha s mad e explici t statement s through , guidelines , prio r BAC T determinations , o r otherwise , tha t base d o n th e availabilit yo f on e o r mor e technologie s an d a weighin g o f relevan t factors , a particula r emissio nrang e i s appropriat e a s a BAC T limit , an d i f source-specifi c factor s d o no t lea d t o a conclusio n tha t anothe r emissio n rang e woul d b e mor e appropriate , the n th e mor e detaile d aspec t o f th e BAC T analysi s coul d b e limite d t o technologie s capabl e o f performing i n th e initia l rang e considered . I f a Stat e decide s t o adop t a screening proces s fo r BACT , source s applying fo r a BAC T determinatio n can focu s analytica l attentio n o n thos e alternative s likel yt o b e considere d BAC T b ytha t authority . O f course , a s always , th e BAC T analysi s an d decisio n mus t stil l b e mad e o n a case-by-cas e basis . Moreover , today' s actio n doe s no t requir e a Stat e t o follow th e proces s a s discusse d above . I f thi s approac hi s followed , however , th e State' s initia l criteri a shoul d b eP.2 5

2 2 se t i n an ope n publi c proces s an d update d regularly . Also , i n n o cas e doe s a n initia l screening o f option s preclud e th e Administrato r o r an yothe r perso nfro

m questioning th e appropriatenes s o f th e criteri a i ngenera l o r th e applicatio n o f thos e criteri a i na specifi c permit . Th e tw o cor e criteri a clarifie d i n today' s actio nar e consisten t wit hdetermination s i n th e administrativ e appeal s decision s subsequen t t o th e H-Powe r decisio n tha t applicatio n o f th e tw o cor e criteri a relating t o consideratio n o f availabl e technologie s an d t o justif yth e chose n technologyunde r th e statutoryfactor s ar e essentia l requirement s o f a BAC T analysis . Th e Administrator' s subsequen t PS D appea l decision s hav e require d tha t State s us e suc hcor e criteri a i nmakin g BAC T determinations . Thus , i n Unio n Count yResourc e RecoveryFacility . PS D Appea l . No . 90- 1 (11/28/90) , th e Administrato r cite d complianc e wit h th e tw o cor e criteri a i nupholdin g a BAC T determinatio nfo r a resourc e recoveryfacility . Th e Administrato r relie d on th e same tw o cor e criteri a i n upholding a permi t determinatio n i n Mecklenbur g Cogeneratio n Limite d Partnership , Clarksville , VA . PS D Appea l No . 90- 7 (12/21/90) . AlthoughEPAbelieve s tha t th e curren t statutoryan d regulatorydefinition s o f BAC T implicitl yrequir e th e consideratio n o f th e tw o cor e criteri a se t fort hi n thi s notice , a s fundamenta l t o an yadequat e BAC T determination ,P.2 6

2 3 th e criteri a announce d i n earlie r decision s nee d t o b e clarifie d t o ensur e tha t the yd o no t restric t Stat e discretion . Th e EP Ai s toda yproposin g t o mak e thes e requirement s explici t byinsertin g int o th e regulator y definitio n o f BAC T th e followin g tw o cor e requirement s fo r a BAC T analysis : 1 ) th e determinatio n mus t conside r a representativ e grou p o f availabl e contro l system s fo r th e source , and , 2 ) selectio n o f a particula r contro l syste ma s BAC T mus t b e justifie d bya compariso n o f th e candidat e system s i n term s o f th e statutor ycriteri a an d supporte d byth e record .

III . Impact s Analysi s i n a BAC T PS D Determinatio n I n evaluatin g th e alternativ e candidat e contro l systems , a n applican t mus t conside r an d compar e th e expecte d energy , environmental , an d economi c impact s o f th e alternatives . Thi s sectio n discusse s som e specifi c impact s whic hma yaffec t th e fina l technolog yultimatel yselected , an d present s a se t o f potentia l factors , anynumbe r o f whic h ma yb e addresse d i n a permi t applicatio n dependin g o n th e individua l situation . Th e energy , environmental , an d economi c impact s discusse d belo war e illustrativ e onl yan d ar e no t intende d a s a n exclusiv e lis t o f consideration s fo r BACT . Som e o f thes e factor s ma yno t b e appropriat e i n al l cases , whil e i n othe r instances , factor s whic har e no tP.2 7

2 4 include d her e ma yb e relevan t t o th e BAC T determination . Fo r example , i f a contro l systemproduce s a knownquantit y o f soli d wast e a s a by-produc t inheren t t o it s design an d operatio n unde r norma l conditions , sucha nimpac t shoul d b e note d i n th e PS D permi t application . However , thi s facto r nee d no t b e analyze d i ndetail , unles s th e applican t wishe s t o us e soli d wast e impact s a s anargumen t fo r o r agains t selectio n o f a particula r contro l alternativ e a s BACT . Th e discussio n doe s no t addres s th e evaluatio no f eac hfacto r no r th e weighin g o f an yfacto r relativ e t o another . Suc h determination s shoul d b e mad e o n a case-by-cas e basi s b yth e permitting authority . Fo r th e purpos e o f thi s discussion , th e term s "emissio n contro l system " o r "BAC T system " refe r t o th e "applicatio n o f productio n processe s an d availabl e methods , systems , an d techniques , including fue l cleaning , clea n fuels , o r treatmen t o r innovative fue l combustio n techniques " [se e § 169(3) , a s amende d b y§ 403(d ) o f th e 199 0 Amendments] . I n general , th e BAC T analysi s shoul d addres s th e direc t impact s o f alternativ e contro l systems . Usually , direc t impact s ar e experience d on-sit e [e.g. , scrubbe r sludg e disposa l sites] ; however , the ycoul d als o b e off-site . Fo r example , ammoni a sli p i s no t limite d t o th e plan t boundary . Duplicativ e analyse s generall yar e no t require d i n preparing th e BAC T permi t application . An ystudie s previousl yperforme d fo r Environmenta l Impac t Statements ,P.2 8

2 5 wate r pollutio n permits , o r othe r program s mayb e use d whe n appropriat e t o demonstrat e advers e energy , environmental , o r economi c impacts . Th e same consideration s ar e generall yapplicabl e t o bot hnewan

d modifie d sources . Wher e appropriate , however , th e permi t revie wmayconside r an yspecia l economi c o r physica l constraint s whic hmigh t limi t th e applicatio no f certai n contro l technique s t o a modifie d emission s unit , suc ha s retrofitting cost s tha t woul d no t b e born e b ya new unit , o r th e remaining usefu l lif e o f th e modifie d facility . Th e resul t mayb e tha t th e leve l o f contro l require d fo r an emission s uni t undergoing modificatio nmayno t b e a s stringen t a s tha t whic hwoul d b e require d i f th e same uni t wer e being newl yconstructe d a t an existing plan t o r a t a "greenfield " facility . Thi s observatio ni s mean t onl yt o illustrat e tha t th e BAC T decisio nmus t b e mad e o na case-by

cas e basi s b

yth e permitting authorit yconsidering th e relevan t energy , environmental , an d economi c impacts . A . Energ

yImpact s Energ yimpact s shoul d addres s energ yus e i nterm s o f penaltie s o r benefit s associate d wit ha contro l system an d th e direc t effect s o f suc henerg yus e o nth e facility . A sourc e may , fo r example , benefi t fro mth e combustio n o f a concentrate d ga s strea mric hi nvolatil e organi c compounds ; o n th e othe r hand , extr a fue l o r electricit yi s frequentl y require d t o powe r a contro l devic e o r incinerat e a dilut eP.2 9

2 6 ga s stream . I f suc hbenefit s o r penaltie s exist , they shoul d b e quantifie d t o th e exten t possible . I n quantifying energ yimpacts , th e applican t coul d estimat e th e direc t energ yimpact s o f th e contro l alternativ e i n unit s o f energ yconsumptio na t th e sourc e (e.g. , Btu , Kwh , barrel s o f oil , ton s o f coal) . Th e energ y requirement s o f th e contro l option s coul d b e show n i nterm s o f tota l and/o r incrementa l energ ycost s pe r tota l and/o r incrementa l to n o f pollutan t remove d i n compariso n t o th e nex t highe r an

d lowe r contro l options . I nman ycases , becaus e energ

ypenaltie s o r benefit s ca nusuall yb e quantifie d i n term s o f additiona l cos t o r income t o th e source , th e energ

yimpact s analysi s canb e converte d int o dolla r cost s and , wher e appropriate , b e factore d int o th e economi c impact s analysis . Indirec t energ

yimpact s (sucha s energ yt o produc e raw material s fo r constructio no f contro l equipment ) ar e usuall y no t considered . However , i f th e permi t authorit y determines , eithe r independentl yo r base d o n a showing b y th e applicant , tha t an indirec t energ yimpac t i s unusua l o r significant , th e indirec t impac t mayb e considered . Th e energ yimpac t shoul d still , however , relat e t o th e applicatio n o f th e contro l alternativ e an d no t t o a concer n ove r energ

yimpact s associate d wit hth e projec t i ngeneral . Th e energ

yimpac t analysi s ma yals o addres s th e concer n ove r th e us e o f locally-scarc e fuels . Th e designatio no f aP.3 0

2 7 scarc e fue l mayvaryfro mregio nt o region , bu t i n genera l a scarc e fue l i s on e whic hi s i n shor t suppl ylocall yan d can b e bette r use d fo r alternativ e purposes , o r on e whic hmay no t b e reasonabl yavailabl e t o th e sourc e eithe r a t th e presen t tim e o r i n th e nea r future .

B . Environmenta l Impacts . Th e environmenta l impact s analysi s i n th e BAC T evaluatio n proces s concentrate s o n collatera l environmenta l impact s du e t o contro l o f emission s o f th e pollutan t i n question , suc ha s soli d o r hazardou s wast e generation , discharge s o f pollute d wate r fro ma contro l device , visibilit yimpact s (e.g . visibl e stea m plume) , o r emission s

• o f toxi c pollutants , and , i n th e State' s discretion , ambien t ai r qualit yimpact s o f th e contro l systemunde r consideration . Th e applican t shoul d identif yan y environmenta l impact s associate d wit ha contro l alternativ e tha t hav e th e potentia l t o affec t th e selectio no r rejectio n o f tha t contro l alternative . Potentiall ysignificant , secondaryenvironmenta l impact s mus t als o b e evaluated . Scrubbe r effluent , fo r example , mayaffec t wate r qualit yan d lan d use , and , similarly , technologie s using cooling tower s mayaffec t visibility . Othe r example s o f secondaryenvironmenta l impact s coul d includ e hazardou s wast e discharges , suc ha s spen t catalyst s o r contaminate d carbon . Generally , thes e type s o f environmenta l concern s become importan t whe nP.3 1

2 8 sensitiv e site-specifi c receptor s exis t o r whe n th e incrementa l emission s reductio n potentia l o f on e contro l optio n i s onl ymarginall ygreate r thanth e nex t mos t effectiv e option . Th e BAC T decisio ncan conside r Stat e polic ydecision s regarding us e o f th e availabl e ai r qualit yincremen t fo r futur e growt han

d th e weighing o f thi s factor . A s discusse d above , th e direc t impac t o f th e control s o n ambien t concentration s mayals o b e identifie d an d considere d i n th e BAC T analysis . Incrementa l change s i n ambien t impact s o f alternativ e contro l system s mayb e assesse d an d compared , along wit hcos t dat a oncontrols , t o determin e whethe r a differen t leve l o f contro l i s justifiabl e i n ligh t o f th e relate d environmenta l benefit s o r i s neede d t o carryou t a State' s decisio n o n th e allocatio no f th e availabl e increment. 1 0 Th e procedur e fo r conducting ananalysi s o f environmenta l impact s shoul d b e mad e base d o nconsideratio n o f site-specifi c circumstances . I n general , th e analysi s o f environmenta l impact s start s wit hth e identificatio n an d quantificatio n o f th e solid , liquid , an d gaseou s discharge s fromth e contro l devic e (o r devices ) unde r review .
10 I n today' s rulemaking , EPAaffirm s tha t an yapplican t may provid e an incrementa l ambien t analysi s a s par t o f it s BAC T submissions , an

d i f so , th e Stat e shoul d conside r i t i n makin g a BAC T determinatio n (se e e.g. , footnot e 3 above) . Likewise , a Stat e mayreques t suc hanalysi s o f an yapplican t a s par t o f it s BAC T process . Moreover , EPAintend s t o provid e guidanc e o nho w thes e issue s mayb e addresse d b ystate s an

d applicants .P.3 2
2 9 Regarding secondaryeffects , a qualitativ e o r semi

quantitativ e screening ca n b e performe d t o narrowth e analysi s t o discharge s wit hpotentia l fo r causing advers e environmenta l effects . Next , th e mas s an d compositio n o f an ysuc hdischarge s shoul d b e assesse d an d quantifie d t o the exten t possible , base d o nreadily-availabl e information . A s previousl ymentioned , th e analysi s nee d onl yaddres s thos e contro l alternative s wit han yenvironmenta l impact s tha t hav e th e potentia l t o affec t th e selectio n o r rejectio no f a contro l alternative . Pertinen t informatio nabou t th e publi c o r environmenta l consequence s o f releasing thes e material s shoul d als o b e assembled . Thus , th e relativ e environmenta l impact s (bothpositiv e an d negative ) o f th e variou s alternative s ca n b e compare d wit heachother . Als o th e generatio no r reductio no f toxi c an d hazardou s emission s using th e variou s BAC T alternatives , including compound s no t regulate d unde r th e Ac t o r th e PS D program , ar e considere d a s par t o f th e environmenta l impact s analysis . Pursuan t t o th e EPAAdministrator' s decisio ni n Nort hCountyResourc e RecoveryAssociates . PS D Appea l No . 85- 2 (Reman

d Order , Jun e 3,1986) , a PS D permitting authorit yshoul d tak e int o accoun t th e abilit yo f a give n contro l alternativ e fo r regulate d pollutant s t o affec t emission s o f pollutant s no t subjec t t o regulatio nunde r th e Ac t o r th e PS D programi n makin g BAC T decisions . Consequently , th e affec t o f a give n contro l alternativ e upo nP.3 3

3 0 th e emissio n o f toxi c o r hazardou s ai r contaminant s mus t b e evaluate d i n conducting th e BAC T analysis . C . Economi c Impact s Thi s analysi s shoul d addres s th e economi c impact s associate d wit hth e cost s (includin g incrementa l costs ) o f installing an

d operating alternativ e contro l systems . Normall yth e submitta l o f verydetaile d an d comprehensiv e projec t cos t dat a i s no t necessary . I n th e economi c impact s analysis , consideratio nshoul d b e give n firs t t o quantifying th e cos t o f th e variou s contro l options . Th e revie wshoul d includ e a complet e explanatio n o f procedure s fo r assessing economi c impact s an d
: an ysupporting data . Onc e th e contro l technolog yalternative s an

d emission s performanc e level s hav e bee n identified , capita l an d annua l cost s ar e developed . Th e direc t cos t fo r eac hcontro l alternativ e shoul d b e presente d bot ho na n incrementa l an d a n overal l basis . Investmen t costs , operatio nan d maintenanc e costs , an d annualize d cost s shoul d b e presente d separately . Annualize d cost s ar e operatio n an d maintenanc e cost s plu s depreciatio nan d interes t charge s onth e investment . Cost s shoul d b e itemize d an d explained . Credi t shoul d b e include d fo r produc t recoverycost s an d by-produc t sale s generate d fromth e us e o f contro l systems , including th e sal e o f sulfu r dioxid e allowance s unde r th e aci d rai n programan

d othe r emissio n reductio ncredits . Th e lifetimeP.3 4

3 1 o f th e investmen t shoul d b e stated . Wher e possible , cost s shoul d b e broke n dow n int o proces s chang e cost s (cost s o f les s polluting productio nprocess ) an d direc t pollutio n abatemen t cost s (cos t o f pollutio n contro l equipment) . Th e cost s o f ai r treatment , wate r treatment , an d soli d wast e disposa l shoul d b e presente d separately . Th e objectiv e o f th e analysi s i s t o provid e a realisti c estimat e o f th e cost s o f th e alternativ e technologies . A s a guid e i n determining whe ncontro l cost s becom e excessive , alternativ e contro l system s ca n b e compare d i n term s o f th e incrementa l cos t effectivenes s o f th e availabl e alternatives . Thus , a s an example , ananalysi s focusing o n I a compariso n o f th e incrementa l economi c an d corresponding environmenta l (e.g. , ai r quality ) impact s o f th e BAC T candidate s an

d tha t addresse s al l o f th e relativ e statutory factor s woul d b e sufficient . State s canevaluat e whethe r th e incrementa l cos t effectivenes s o f a mor e stringen t optio n i s appropriat e i nligh t o f othe r relevan t experienc e (e.g. , recen t BAC T determinations ) an d othe r factor s involve d i n th e BAC T decisio nan d th e State' s weighing o f thes e factors . Incremental , cost-effectivenes s calculation s ar e generall yperforme d o nth e basi s o f incrementa l dollar s pe r to n o f additiona l pollutan t removed . I n additio n t o th e type s o f economi c impact s discusse d above , EPAi s todaysoliciting commen t o nwhethe r th e economi c impact s analysi s shoul d conside r a s impact s th eP.3 5

3 2 affordabilit yo f control s b yth e fir

mi n respons e t o alternativ e level s o f control . Fo r example , a mor e costl y BAC T alternativ e coul d b e presente d a s altering th e economic s o f a projec t t o th e poin t wher e a decisio nwoul d b e mad e t o cance l th e constructio n o r expansio n o f a facility , t o relocat e a plant , t o reduc e th e scal e o f operation , o r t o chang e th e productio nmix . I nsuc hcases , th e loca l economi c impact s o f suc hdecision s (e.g. , loca l employmen t effects , including numbe r o f jobs , dollar s pai d i n salaries , and change s i nemploye e skil l level s required ) woul d b e evaluate d an d factore d int o th e economi c analysis . Comment s shoul d addres s th e reasonablenes s an d practicalit y o f including suc hconsideration s i n th e BAC T analysis. 1 1

IV . Purpos e o f th e Propose d Chang e Th e approache s se t fort hi n th e variou s EPAfina l an d draf t guidanc e document s hav e bee nintende d t o guid e permi t applicant s an

d permitting official s i nthos e area s subjec t t o th e Federa l PS D regulation s a t 4 0 CFR52.21 . The yhav e no t establishe d binding regulatoryrequirements , whic har e containe d i n th e Federa l regulation s an d SIP's . Rathe r tha n specifying a precis e approac ht o th e BAC T analysis , EPAi s proposing todayt o clarif ytw o cor e lega l requirement s tha t

"Th e EPA' s 197 9 guidanc e discusse d th e us e o f affordabilit y considerations . However , i n1987 , EPAadopte d a polic ytha t affordabilit yshoul d no t b e a facto r i n BAC T analyses . Th e EPA i s no wrevisiting th e issue .P.3 6

3 3 ar e necessaryfo r an adequat e BAC T analysi s unde r existing law . I n reviewing ne wo r revise d Stat e PS D rules.submitte d fo r SI P approval , th e Agenc ywil l deemth e progra m t o b e adequate.i f i t specifie s tha t thes e tw o requirement s ar e necessaryfo r a n adequat e BAC T analysis . Likewise , i n fulfilling it s oversigh t an d enforcemen t responsibilities , th e Agencywil l continu e it s policyo f reviewing specifi c permitting action s fo r conformit ywit hth e cor e criteria . S o long a s th e Stat e ha s carefull yevaluate d eac hcandidat e system , justifie d th e choic e o f on e ove r eac ho f th e other s i n term s o f th e statutorycriteria , otherwis e followe d th e procedura l norm s embodie d i n th e cor e criteria , an d ensure d

; , th e decisio n woul d no t violat e an yobjectiv e standard s tha t mayappl y(sucha s NSP S o r SI P limits) , EPAwil l conside r a State' s BAC T analysi s t o b e adequat e an d wil l no t second

gues s the State' s substantiv e BAC T decision . Thus , unde r today' s proposal , adherenc e t o an yspecifi c BAC T approach , suc ha s top-dow

n o r bottom-up , i s no t required . Rather , today' s proposa l i s intende d t o ensur e adherenc e t o th e cor e criteri a suc htha t State s mak e reasone d an d informe d BAC T determination s i n a publicly-accountabl e manner . Further , th e State s hav e wid e discretio ni nsetting th e weigh t assigne d t o eac hstatutoryfacto r (energy , environmental , economi c an

d othe r costs ) i ncomparing an d balancing th e relativ e effect s o f th e variou s BAC T options . Whicheve r approac hi s selected , th e BAC T analysi s shoul d includ e aP.3 7

3 4 complet e explanatio n o f th e procedure s use d b yth e Stat e t o asses s th e energy , environmental , an d economi c impact s an d an ysupporting data . Permit s containing BAC T determination s tha t d o no t conform t o th e PS D requirement s o f th e Act , EPA regulations , an

d applicabl e SIP's , a s reflecte d i nth e cor e criteria , wil l b e considere d deficien t b yEPA . Instance s o f procedura l irregularitie s o r arbitrarydecisio nmaking wil l remai n ground s fo r SI P calls , permi t appeals , o r enforcemen t action , a s appropriate . Th e EPAi s todaysoliciting commen t o nth e propose d clarificatio n t o th e BAC T definitio nfo r th e purpos e o f clarifying an

d delineating th e regulatorystandard b ywhic h th e adequacy.o f a BAC T determinatio nshoul d b e judged . A s note d above , EPAalread yrecognize s tha t ther e ar e a variet y o f permissibl e methods , including th e top-dow n method , fo r determining BACT . Stat e permitting authoritie s ar e fre e t o appl yth e cor e lega l criteri a withou t referenc e t o an y exclusiv e metho d i n making BAC T determination s tha t satisf y th e Act . O f course , th e BAC T analysi s an d selectio nproces s i s bu t on e par t o f a complet e PS D review , an d th e BAC T emission s limitation s mus t b e consisten t wit hal l othe r PS D requirements .

V . CleanFuel s Th e definitio n o f BAC T i n§ 169(c ) o f th e Ac t i s change d b

y§ 403(d ) d f th e 199 0 Amendments . T o maintai nP.3 8

3 5 conformit ywit hth e statutorydefinition , EPApropose s t o amend th e regulatorydefinitio no f BAC T a t 4 0 CF R52.21(b)(12 ) an d 51.166(b)(12 ) b

yinserting "clean fuels " afte r "including fue l cleaning, " an d b yadding th e following a t th e en d thereof : "Emission s froman ysourc e utilizin g clea n fuels , o r an yothe r means , t o compl ywit h thi s paragraphshal l no t b e allowe d t o increas e abov e level s tha t woul d hav e bee n require d unde r thi s paragrapha s i t existe d prio r t o enactmen t o f th e CleanAi r Ac t Amendment s o f 1990. " VI . Miscellaneou s A . Docket . Adocke t ha s bee nestablishe d fo r thi s actio nunde r § 307(d)(1)(I ) and (N ) o f th e Act , 4 2 U.S.C . 7607(d)(1)(I ) and (N) . Th e docke t i s an organize d an d complet e fil e o f al l informatio n considere d i nth e developmen t o f thi s ruling . Th e docke t i s intende d t o allowth e publi c t o identif yan

d locat e document s relate d t o thi s ruling . Th e docke t numbe r fo r thi s ruling i s A-91-30 .

B . Paperwor k Reductio nAct . N o additiona l publi c reporting burde nwil l resul t fro m thi s ruling . Al l informatio ncollectio nrequirement s o f th e Federa l NS Rregulation s hav e bee n approve d b yth e Offic e o f Managemen t an

d Budge t (OMB ) unde r th e provision s o f th e Paperwor k Reductio nAct , 4 4 U.S.C . 3501 , et* . seq. , and hav e bee n assigne d OM B contro l numbe r 2060-0003 . Th e effec t o fP.3 9

3 6 thi s rul e woul d b e n o chang e i npaperwor k relate d t o complying wit hNS Rrequirements , sinc e thi s ruling onl y provide s additiona l clarificatio n regarding th e regulatory definitio n o f BACT . C . Th e E.O . 12291 . Unde r E.O . 12291 , EPAmus t judg e whethe r a rul e i s "major " an

d therefor e subjec t t o th e requiremen t o f a regulatoryimpac t analysis . Thi s ruling i s no t a majo r rul e becaus e i t wil l no t chang e th e economi c cost s o f meetin g th e requirement s o f th e Act . However , thi s ruling wa s submitte d t o OMB fo r review . Writte ncomment s fro mOMB t o EPAan

d an y EPArespons e ar e include d i nDocke t A-91-30 .

D . Economi c Impac t Assessment . Th e requiremen t fo r performing anEconomi c Impac t Assessmen t unde r § 31 7 o f th e Ac t (4 2 U.S.C . 7617) , doe s no t appl yt o th e amendment s EPAi s promulgating today . Sectio n 31 7 applie s onl yt o "revision s whic hth e Administrato r determine s t o b e substantia l revisions. " Th e ,proposed clarifying languag e i s no t a substantia l revisio nbecaus e i t doe s no t chang e curren t regulatoryburdens .

E . RegulatoryFlexibilit yAct . Thi s actio n i s no t subjec t t o the certificatio n provision s o f § 605(b ) o f th e RegulatoryFlexibilit yAc t becaus e thi s rul e wil l no t resul t i na chang e i n administrativ e cost s o r a n increas e i n contro l costs ,P.4 0

3 7 therefor e having n o significan t impac t o nindustr yo r smal l communities . F . Effectiv e Date . Sectio n 4(d ) o f th e Administrativ e Procedure s Act , 5 U.S.C . 553(d) , require s a 30-da ywaiting perio d befor e makin g a substantiv e rul e effective . Althoughth e regulatoryrevision s being propose d todayar e no t considere d substantive , the yar e being subjec t t o notice-and-commen t an d wil l become effectiv e onl yafte r publi c comment s hav e bee n receive d and considered , an d fina l actio nha s bee n taken . ••List o f Subject s 4 0 CFRPart s 51 , 5 2 Administrativ e practice s an d procedure , Intergovernmenta l relations , Ai r pollutio ncontrol , NSR , BACT , Sulfur oxides , Nitroge ndioxide , Particulat e matter , Carbo n monoxide , Hydrocarbons , Lead , Ozone , Reporting an d recordkeeping requirements , Volatil e organi c compounds , NSPS , NESHAP . Authority : 4 2 U.S.C . 7401(b)(1) , 7410 , 7411 , 7470

- 7479 , 7491 , 7501-7508 , 760 1 an d 7602 , a s amende d b yth e 199 0 Amendments , Pub . L . No . 101-549 , 10 4 Stat . 239 9 (Nov . 15 , 1990) ; 402 , 409 , 41 5 o f th e Ac t a s amended , 10 4 Stat . 2399 ; 4 2 U.S.C . 7401-764 2 a s amende d b yth e 199 0 Amendments , Pub . L . No . 101-549 , 10 4 Stat . 239 9 (Nov . 15 , 1990) ; 4 2 U.S.C .P.4 1

3 8 7401 , 7411 , 7414 , 7416 , an d 760 1 a s amende d b yth e 199 0 Amendments , Pub . L . No . 101-549 , 10 4 Stat . 239 9 (Nov . 15 , 1990) ; 402 , 409 , 41 5 o f th e Ac t a s amended , 10 4 Stat . 2399 , unles s otherwis e noted .
Dated :

WilliamK . Reill y Administrato rP.4 2

3 9 Fo r th e reason s se t fort hi n th e preamble , Par t 5 1 o f Chapte r I o f Titl e 4 0 o f th e Cod e o f Federa l Regulation s i s propose d t o b e amende d a s follows :

Par t 5 1 - REQUIREMENT S FORPREPARATION , ADOPTION , AND SUBMITTAL O F IMPLEMENTATIONPLANS . 1 . Sectio n 51.16 6 i s propose d t o b e amende d b y revising paragrap h(b)(12 ) t o read a s follows : 51.16 6 Preventio n o f significan t deterioratio no f ai r qualit y.

* * * * * (b ) * * * (12 ) Bes t availabl e contro l technolog ymean s a n

. emission s limitatio n(includin g a visibl e emission s standard ) base d o n th e maximu mdegre e o f reductio nfo r eac h pollutan t subjec t t o regulatio nunde r th e Act , whic hwoul d b e emitte d froman ypropose d majo r stationarysourc e o r majo r modificatio n whic hth e reviewing authority , o na case by-cas e basis , taking int o accoun t environmental , energy , and economi c impact s an d othe r costs , determine s i s achievabl e fo r suc hsourc e o r modificatio nthrough applicatio n o f productio n processe s o r availabl e methods , systems , an

d techniques , including fue l cleaning , clea n fuels , o r treatmen t o r innovativ e fue l combustio ntechnique s fo r contro l o f suc hpollutant . Two criteri a mus t b e satisfie d i n an

yBAC T analysis :P.4 3

4 0 1 ) th e determinatio n mus t conside r a representativ e grou p o f th e rang e o f availabl e contro l system s fo r th e source ; an d 2 ) selectio n o f a particula r contro l syste ma s BAC T mus t b e justifie d bya compariso n o f th e candidat e contro l system s i n term s o f th e statutor ycriteri a an d supporte d by th e record . I n n o even t shal l applicatio n o f BAC T resul t i n emission s o f anypollutan t whic hwoul d excee d th e emission s allowe d byanyapplicabl e standar d unde r 4 0 CF R6 0 an d 61 . I f th e Administrato r determine s tha t technologica l o r economi c limitation s o n th e applicatio n o f measuremen t methodolog yt o a particula r emission s uni t woul d mak e th e impositio n o f a n emission s standar d infeasible , a design , equipment , wor k practice , operationa l standard , o r combinatio n thereof , ma yb e prescribe d instea d t o satisf y th e requiremen t fo r th e applicatio n o f BACT . Suc hstandar d shall , t o th e degre e possible , se t fort hth e emission s reductio n achievabl e b yimplementatio n o f suc hdesign , equipment , wor k practice , o r operation , an d shal l provid e fo r complianc e bymean s whic hachiev e equivalen t results . Emission s fro m

anysourc e utilizin g clea n fuels , o r any othe r means , t o compl ywit hthi s paragrap hshal l no t b e allowe d t o increas e abov e level s tha t woul d hav e bee n require d unde r thi s paragrap ha s i t existe d prio r t o enactmen t o f th e 199 0 Amendments .P.4 4

4 1 Par t 5 2 - APPROVAL AN D PROMULGATIONO F IMPLEMENTATIO NPLANS . 1 . Sectio n 52.2 1 i s propose d t o b e amende d b yrevising paragrap h(b)(12 ) t o read a s follows : 51.2 1 Preventio no f significan t deterioratio no f ai r quality .

* * * * * (b ) * * * (12 ) Bes t availabl e contro l technolog ymean s an emission s limitatio n (includin g a visibl e emission s standard ) base d o n th e maximu mdegre e o f reductio nfo r eac h pollutan t subjec t t o regulatio nunde r th e Ac t whic hwoul d b e emitte d fro

man ypropose d majo r stationar ysourc e o r majo r modificatio n whic hth e Administrator , o na case-by-cas e basis , taking.int o accoun t environmental , energy , an d economi c impact s an d othe r costs , determine s i s achievabl e fo r suc hsourc e o r modificatio nthroughapplicatio no f productio n processe s o r availabl e methods , systems , an d techniques , including fue l cleaning , cleanfuels , o r treatmen t o r innovativ e fue l combustio ntechnique s fo r contro l o f suc hpollutant . Tw o criteri a mus t b e satisfie d i n an yBAC T analysis : 1 ) th e determinatio n mus t conside r a representativ e grou p o f th e rang e o f availabl e contro l system s fo r th e source ; an

d 2 ) selectio n o f a particula r contro l systema s BAC T mus t b e justifie d b ya compariso n o f th e candidat e contro lP.4 5

I * , 4 2

system s i n term s o f th e statutorycriteri a an d supporte d b

y th e record . I n n o even t shal l applicatio no f BAC T resul t i n emission s o f an

ypollutan t whic hwoul d excee d th e emission s allowe d b yan yapplicabl e standard unde r 4 0 CF R6 0 and 61 . I f th e Administrato r determine s tha t technologica l o r economi c limitation s o n th e applicatio no f measuremen t methodologyt o a particula r emission s uni t woul d mak e th e impositio n o f a n emission s standard infeasible , a design , equipment , wor k practice , operationa l standard , o r combinatio n thereof , ma yb e prescribe d instead t o satisf y th e requiremen t fo r th e applicatio no f BACT . Suc hstandar d shall , t o th e degre e possible , se t fort hth e emission s reductio n achievabl e b yimplementatio no f suc hdesign , equipment , wor k practice , o r operation , an d shal l provid e fo r complianc e b

ymean s whic hachieve equivalen t results . Emission s from

an ysourc e utilizing clean fuels , o r an y othe r means , t o compl ywit hthi s paragraphshal l no t b e allowe d t o increas e above level s tha t woul d hav e bee n require d unde r thi s paragrapha s i t existe d prio r t o enactmen t o f th e 199 0 Amendments .