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# OAR Box 

# 1818 Prepped byOllie Stewart



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# 65 ) ll-F- 6 Docket Number: 

# A-87-1 1

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PM Sheet 65of 79P. 2



# A

- ffi.- M in-*-*«• »

6560-2 6 ENVIRONMENTA L PROTECTIO

NAGENCY 4 0 CFR Par t 8 6 [AMS-FRL

- ] Contro l o f Ai r Pollutio n fro mNewMoto r Vehicle s an

d NewMoto r Vehicl e Engines : Refueling Emissio n Regulation s for Gasoline-Fuele d Light-Dut yVehicles , Light-Dut yTrucks , an d Heavy-Dut yVehicle s AGENCY : Environmenta l Protectio n Agency(EPA) . ACTION : Notic e o f Propose d Rulemaking . SUMMARY : Thi s notic e contain s EPA' s propose d regulatory requirement s for a vehicle-base d progra mt o contro l refueling emission s fro mgasoline-fuele d light-dut y vehicles , light-dut ytrucks , an d heavy-dut yvehicles . Th e propose d standard i s 0.1 0 gram s o f vapo r pe r gallo n (g/gal ) o f dispense d fuel . For light-dut yvehicle s an d light-dut y trucks , a 0.1 0 g/ga l standard i s als o propose d for high-altitud e conditions . The propose d tes t procedur e for determining complianc e wit hth e standard use s th e Seale d Housing for Evaporativ e Determinatio n (SHED ) in a way simila r t o tha t currentl yused for testing evaporativ e hydrocarbo n emissions . Th e yea r o f implementatio n i s propose d t o b

e tw o or mor e mode l year s afte r promulgatio n o f the fina l rule .P. 3 Th e Agenc ybelieve s tha t th e propose d contro l o f refueling emission s i s warrante d fo r a numbe r o f reasons . I t can improve ambien t ozon e level s i n al l area s o f th e countryincluding thos e tha t ar e currently , or ar e projecte d t o be , in violatio n o f the Nationa l Ambien t Ai r Qualit yStandard for thi s pollutant . Also , the ' propose d vehicle-base d contro l progra mwil l provid e importan t ozone-relate d benefit s i n area s tha t ar e no wi n complianc e wit hth e ambien t standard . Further , th e propose d emissio n control s wil l hel p protec t the genera l publi c fro mth e risk s o f cance r du e t o exposur e t o benzene , a componen t o f gasolin e vapor , an d t o evaporate d gasolin e a s a whole . Thi s proposa l woul d reduc e emission s o f gasolin e refueling vapor s b

ynearl y9 0 percen t fro muncontrolle d levels . I n anothe r par t o f today' s Federa l Register , th e Agenc yi s proposing t o regulat e th e volatilit yo f commercia l gasoline . Du e t o th e interaction s betwee n tha t rulemaking an

d thi s actio n on refueling emissions , th e Agenc ysuggest s th e intereste d reade r consul t bot hnotice s fo r a bette r understanding o f today' s proposals . DATES : EPAwil l conduc t a three-daypubli c hearing o n thi s Notic e o f Propose d Rulemaking an d o n th e gasolin e volatilit yproposa l approximatel y6 0 day s afte r Federa l Registe r publication . Th e specifi c date s o f th e hearing wil l b e announce d in a subsequen t Federa l Registe r notice . -2

-P. 4 Comment s on thi s proposa l wil l be accepte d for 3 0 day s following the conclusio n o f th e hearing . Additiona l informatio n on th e publi c hearing an d th e submissio n o f comment s can b e foun d unde r "Publi c Participation " i n th e SupplementaryInformatio n sectio n o f today' s notice . ADDRESSES : Th e publi c hearing wil l b e hel d in Washington , DC . Th e exac t locatio n wil l b e announce d i n a subsequen t Federa l Registe r notice . Intereste d partie s maysubmi t writte n comment s (i n duplicat e i f possible ) t o Publi c Docke t No . A-87-n , at :

Centra l Docke t Sectio n (A-130 ) U.S . Environmenta l Protectio n Agenc y Attention : Docke t No . A-87-1 1 40 1 MStreet , SW Washington , D C 2046 0 Material s relevan t t o thi s propose d rulemaking hav e bee n place d i n Docke t No . A-87-1 1 b yEPA . Publi c Docke t No . A-84-07 , establishe d i n suppor t o f EPA' s assessmen t o f ai r pollutio n regulatorystrategie s for th e gasolin e marketin g industry , als o contain s considerabl e background informatio n an d ha s bee n incorporate d b yreferenc e int o A-86-11 . Th e docket s ar e locate d a t th e above addres s in th e Wes t Towe r Lobby , GalleryI , an d mayb e inspecte d betwee n 8 a.m . an d 4 p.m . MondaythroughFriday . Areasonabl e fe e mayb e charge d b

yEPAfor copying docke t materials .

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-P. 5 FOR FURTHE R INFORMATIO NCONTACT :

Mr . Richar d S . Wilco x Standard s Developmen t an d Suppor t Branc h Emissio n Contro l Technolog yDivisio n U.S . Environmenta l Protectio n Agenc y 256 5 Plymout hRoad An n Arbor , M I 4810 5 Telephone : (313 ) 668-439 0 SUPPLEMENTAR

Y INFORMATION :

I . Backgroun

d

A . Introductio n Question s regarding the nee d for contro l o f refueling emission s fro

m gasoline-fuele d vehicle s an d ho wsuc h contro l shoul d b e obtaine d hav e stimulate d considerabl e interest . T o facilitat e a n understanding o f th e complexit y o f th e issue s surrounding th e contro l o f refueling emissions , a shor t reviewo f th e historyo f thi s subjec t i s presente d i n th e remainde r o f thi s sectio n (Sectio n I) , including a brie f overvie wo f th e environmenta l issue s whic hhav e led t o presen t concern s abou t thes e emissions . Following tha t background information , Sectio n I I mor e full ydescribe s an d quantifie s th e environmenta l effect s associate d wit hrefueling emission s i n term s o f ambien t ai r qualit y(ozone) , th e huma n cance r risk s du e t o direc t persona l exposure , th e nee d for contro l o f thes e emissions ,

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an d th e decisionmaking proces s tha t ha s le d t o EPA' s conclusio n tha t requiring vehicle-base d vapo r recovery , or onboard systems, * i s th e preferre d contro l approach . Sectio n IV

discusse s potentia l challenge s t o EPA' s lega l authorit yfo r implementing onboard rathe r than Stag e I I refueling controls . Elsewher e i n today' s Federa l Register , EPAi s proposing t o reduc e th e volatilit yo f in-us e gasolin e fro m curren t levels . Thi s actio n wil l contro l excessiv e evaporativ e emission s fro mth e moto r vehicl e flee t an d als o reduc e evaporativ e VO C fro mcertai n stationarysource s (i.e. , storag e tanks) . However , th e analyse s containe d i n thi s refueling proposa l wer e performe d unde r the assumptio n tha t onboar d contro l system s woul d b e certifie d wit hfuel s representing curren t summertime commercia l fuel s (i.e. , wit hcertificatio n fue l having a Rei d Vapo r Pressur e (RVP ) o f 11. 5 pound s pe r squar e inch) . Thi s situatio n represent s the mos t difficul t cas e in term s o f moto r vehicl e manufacture r complianc e an d als o indicate s th e Agency' s inten t t o adop t onboard control s regardles s o f wha t decisio n i s eventuall ymad e wit hrespec t t o fue l volatility . Th e effec t o f volatilit ycontro l a s i t regard s th e decisio n t o contro l refueling vapor s wil l b e highlighte d

Onboar d vapo r recoverycontrol s ar e self-containe d system s locate d entirel ywithi n th e vehicle . Se e Sectio n II.D . o f thi s notice . -5

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a t appropriat e point s i n thi s notice . Th e effec t o f fue l volatilit yon the benefits , cost , an d cos t effectivenes s o f refueling contro l i s als o separatel ydiscusse d i n Sectio n V . Th e las t sectio n o f thi s preambl e (Sectio n VI ) present s a complet e descriptio n o f today' s proposa l an d othe r relevan t information . Thi s include s th e derivatio n o f th e propose d standard , a reviewo f th e propose d tes t procedur e an

d it s integratio n wit hth e existing test protocols , leadtime , enforcemen t protocols, , safet yan d economi c impacts . Sectio n VI als o describe s severa l propose d tes t procedur e change s tha t ar e relate d t o evaporativ e emission s control . Theyar e being propose d primaril yt o ensur e tha t evaporativ e emission s ar e appropriatel ymeasure d in determining complianc e wit h emissio n standard s an d t o clarif yth e definitio n o f evaporativ e emissions . Th e revision s ar e intende d t o paralle l th e same propose d change s include d i n EPA' s proposa l t o regulat e fue l volatility , whic happear s elsewher e i n today' s Federa l Register . Whil e theyar e describe d furthe r late r i n thi s refueling proposal , th e principa l rational e fo r thes e change s i s foun d i n th e fue l volatilit yproposal . Finally , i t shoul d b e note d tha t th e cos t an d benefi t analyse s whic har e describe d i n today' s proposa l wer e base d on th e assumption s tha t Stag e I I control s woul d begi n t o b e -6

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implemente d a s earl ya s mid-198 8 o r a s lat e a s 1990 , depending on th e contro l scenario , an d tha t onboard control s woul d b e implemente d beginning wit hth e 199 0 mode l year . Depending o n th e time require d t o complet e thi s rulemaking , differen t effectiv e date s than thes e coul d be promulgated . However , thi s fac t doe s no t significantl y affec t th e decisio n t o propos e a n onboar d vapo r recovery standard , becaus e the cost s an d benefit s o f th e two contro l technologie s ar e essentiall yunaffecte d an d th e relativ e ranking o f th e alternative s i s unchange d b yth e exac t effectiv e date s ultimatel ychosen . (Mor e detaile d description s o f th e potentia l leadtime requirement s an d th e effectiv e dat e o f th e standard ar e presente d i n th e safet y an d leadtime discussion s foun d in Sectio n V. )

B . Historyo f Refueling Control s Th e contributio n o f hydrocarbo n emission s fro m gasolin e refueling operation s t o ambien t ozon e level s ha s bee n o f concer n fo r some time. * Thi s concer n led EPAt o promulgat e regulation s unde r Sectio n 110(c ) o f th e Clea n Ai r Ac t (CAA ) i n th e mid-1970 s tha t woul d hav e require d th e installatio n o f gasolin e vapo r recoverysystem s a t servic e stations , o r Stag e I I systems,* * i n al l or par t o f eleve n

* Diese l refueling operation s hav e no t bee n a concer n du e t o th e lo

wvolatilit yand , hence , lo wemission s potentia l o f diese l fue l relativ e t o gasoline . * * Stag e I I vapo r recoverysystem s ar e integrate d wit h th e fue l dispensing equipment . Se e Sectio n II.D . -7

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Ai r Qualit yContro l Region s (AQCRs ) i n eigh t state s [e.g. , 3 8 FR 3052 4 (Novembe r 7 , 1973) , 3 9 FR 488 1 (Februar y8 , 1974) , an

d 3 9 FR 2105 3 (June 18 , 1974)] . Th e Agenc y propose d amendment s t o thos e regulation s in Octobe r 197 5 (4 0 FR 47668 ) and , base d on th e comment s receive d an d informatio n develope d during tha t rulemaking , ne w regulation s wer e propose d i n Novembe r 197 6 (4 1 FR 48043) . On May31 , 1977 , EP Adeferre d unti l furthe r notic e the require d Stag e I I complianc e date s fo r thes e eleve n AQCR s (4 2 FR 27674) . Actio n o n th e propose d revision s t o th e earlie r Stag e I I regulation s wa s neve r completed , no r wer e the previou s complianc e date s reinstated . Also , i n Augus t 197 7 th e CA

Awa s amende d t o ad d severa l specifi c provision s pertaining t o th e contro l o f refueling emissions . Sectio n 202(a)(6 ) o f th e CAA , adde d i n 1977 , direct s th e Administrato r o f EPAt o "determin e th e feasibilit yan d desirabilit yo f requiring ne wmoto r vehicle s t o utiliz e onboard hydrocarbo n contro l technolog ywhic hwoul d avoi d th e necessit yo f gasolin e vapo r recoveryo f uncontrolle d emission s emanating fro mth e refueling o f moto r vehicles. " Thi s sectio n furthe r provides , that , "[if ] th e Administrato r find s tha t i t i s feasibl e an d desirabl e t o employsuc htechnology , h e shall...prescribe , b y regulation , standard s requiring th e us e o f onboar d hydrocarbo n technology.... " I n respons e t o thi s statutory

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-P.1 0 requirement , . EPAundertoo k a reviewan d analysi s o f availabl e informatio n in th e late-1970's , an d tentativel y determine d tha t onboar d contro l fo r light-dut yvehicle s wa s technicall yfeasible.[1 ]

However , in ligh t o f th e seriou s financia l difficultie s faced b yth e automotiv e industr yin 198 0 an

d 1981 , EPAconducte d a reviewo f it s regulatoryprogram s t o identif ypossibl e change s tha t coul d reduc e th e regulatory burde n on th e industry . A s a resul t o f tha t review , EPA decide d i n 198 1 tha t th e us e o f onboard technolog yfo r th e contro l o f refueling emission s wa s undesirabl e a t tha t time . Thus , th e Agenc yannounce d tha t onboar d control s wer e no t being require d (4 6 FR 21629 , Apri l 13 , 1981) . No w tha t th e economi c crisi s withi n th e automotiv e industryha s passed , an

d in ligh t o f ne winformatio n concerning th e nee d for ozon e reductio n measure s an d the potentia l advers e healt heffect s fro minhaling gasolin e vapors , EPAi s reevaluating possibl e actio n unde r Sectio n 20 2 (a)(6 ) o f th e CAA . Althoughn o onboar d standard or revise d fina l regulation s fo r Stag e I I control s hav e bee n promulgate d b y EPA , refueling emissio n contro l ha s bee n achieve d in limite d geographica l area s o f th e country . Stag e I I contro l system s ar e being use d i n 2 6 countie s o f Californi a an d i n th e Distric t o f Columbi a a s a mean s o f improving -9

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ozon e ai r quality . Thes e requirement s hav e bee n in effec t sinc e th e mid-1970s , an d hav e demonstrate d th e feasibilit y o f Stag e I I controls .

I n addition , EPAan d certai n state s continu e t o vie w the contro l o f refueling emission s a s a desirabl e ozon e reductio n strategy . Fo r example , severa l state s committe d in thei r 198 2 ozon e stat e implementatio n plan s (SIPs ) t o conside r Stag e I I regulations . Thes e state s wer e amon g a numbe r o f state s that , a s o f February1983 , containe d ozon e non-attainmen t area s an d had bee n grante d extension s b yEPA beyon d th e statutoryattainmen t dat e o f Decembe r 31 , 1982 , a s provide d for unde r Sectio n 11 0 o f th e CAA . Further , resolution s wer e passe d in 198 2 an d agai n i n 198 5 b ybot h the Stat e an

d Territoria l Ai r Pollutio n Progra m Administrator s (STAPPA ) an d th e Associatio n o f Loca l Ai r Pollutio n Contro l Official s (ALAPCO) . Thes e resolution s requeste d tha t EPArevie wStag e I I contro l technolog yan d publis ha contro l technique s guidelin e documen t fo r us e b y the variou s stat e ai r pollutio n contro l agencie s tha t woul d defin e Stag e I I control s a s "reasonabl yavailabl e contro l technology " unde r Sectio n 17 2 o f th e CAA . Suc ha n actio n woul d hav e th e effec t o f promoting th e us e o f suc hcontrol s i n ozon e non-attainmen t areas . Simila r resolution s wer e als o passe d i n 1986 , an d include d th e reques t tha t EPA promulgat e onboar d contro l requirement s a s a long-ter m emissio n reductio n strategy . -10

-P.1 2 Th e relationshi p betwee n refueling emission s an d ozon e ai r qualit yha s bee n . carefull yconsidere d b yEPAozon e experts . A s describe d mor e full ylate r i n today' s notice , th e ozon e attainmen t problemfacing th e natio n i s no w extremel yserious , an d it s solutio n wil l requir e a well-coordinated , aggressiv e effor t aime d a t bringing al l area s o f th e countryint o complianc e wit hth e ozon e NAAQS . Thi s effor t wil l includ e a mixtur e o f stat e an d Federa l actions . Among th e potentia l Federa l action s tha t EP Aha s considere d a s possibl e nationwid e emissio n contro l measure s i s th e reductio n o f refueling emission s throughth e us e o f onboar d o r Stag e I I technology . EPAanticipate s publishing a propose d comprehensiv e ozon e strateg yin th e nea r futur e an d refueling control s almos t certainl ywil l playa significan t rol e i n tha t strategy . Whil e th e lin

k betwee n refueling emission s an d ozon e formatio n ha s bee n recognize d fo r some time , ther e i s als o evidenc e tha t exposur e t o gasolin e vapo r resulting fro m refueling emission s pose s direc t risk s t o publi c health . Gasolin e an

d it s vapor s ar e a comple xmixtur e o f volatil e organi c compound s (VOC) . On e o f th e mos t importan t constituent s i n gasoline , fro ma publi c healt heffect s perspective , i s benzene . Epidemiologica l studie s strongl y sugges t tha t benzen e i s a huma n carcinogen . Also , laboratorystudie s hav e show n thi s compound t o caus e

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-P.1 3 multipl e cancer s i n animals . Base d o n thi s evidence , benzen e wa s liste d b yth e Agenc yin Jun e 1 9 7 7 a s a hazardou s ai r pollutan t unde r Sectio n 11 2 o f th e Ac t (4 2 FR 29332) . (Additiona l informatio n regarding EPA' s decisio n t o lis t benzen e a s a hazardou s ai r pollutan t can b e foun d in Docke t Numbe r OAQPS-79- 3 (Par t I). )

Mor e recently , carcinogeni c concern s wit hrefueling emission s hav e focuse d no t jus t on benzene , bu t gasolin e vapor s i n general . Laboratorytest s conducte d b yth e America n Petroleu mInstitut e (API ) hav e show n wholl y vaporize d gasolin e cause s cance r i n animals . Th e AP I an d othe r studie s wer e independentl yreviewe d b yEPA' s Scienc e AdvisoryBoar d (SAB ) an d b yth e Healt hEffect s Institut e (HEI). * Afte r carefull yconsidering th e availabl e evidence , EPAha s conclude d tha t gasolin e vapor s ar e a probabl e huma n carcinoge n unde r EPA' s Cance r Ris k Assessmen t Guideline s (5 1 FR 33992 , Septembe r 24 , 1986) .

Th e SA B i s a grou

p o f expert s fro

mvariou s scientifi c organization s tha t advise s th e Administrato r o n th e scientifi c validit yan d usefulnes s o f informatio n develope d i n suppor t o f regulatoryactivities . HE I i s a non-profi t researc horganizatio n establishe d an d sponsore d jointl yb yEPAan

d th e automotiv e industr y t o provid e an

d evaluat e dat a o n th e healt heffect s o f emission s fro

m moto r vehicles .

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Thi s conclusio n i s share d b ySA B an d HEI . Th e basi s o f EPA' s decisio n an d accompanying ris k estimate s ar e discusse d furthe r i n Sectio n II.C . o f today' s notice . C . EPA' s Stud

yo f Refueling Emission s

O n Augus t 8 , 1984 , EPAannounce d the publi c availabilit yo f a n extensiv e analysi s o f th e gasolin e marketing industry(4 9 FR 31706) . Thi s draf t study, * "Evaluatio n o f Ai r Pollutio n RegulatoryStrategie s for Gasolin e Marketing Industry,"[2 ] (hereafte r referre d t o a s "the draf t gasolin e marketing study" ) wa s prepare d b yEPA' s Offic e o f Ai r Qualit yPlanning an d Standard s an

d th e Offic e o f Mobil e Sources . Th e analyse s include d i n tha t documen t quantifie d th e emission s an d healt hrisk s associate d wit h al l component s o f th e gasolin e distributio n an d marketing network , fromth e deliveryo f gasolin e fro mrefineries , t o th e refueling o f vehicle s at servic e stations . Th e analyse s als o estimate d th e costs , emissio n reductions , ris k reductions , an d economi c impact s associate d wit hth e man ycontro l strategie s considered . Implici t in thi s draf t stud ywa s EPA' s desir e t o reevaluat e th e 198 1 decisio n no t t o requir e onboar d controls .

I n makin g th e draf t gasolin e marketing stud ypublicl y available , EPAsolicite d comment . o n th e document' s methodology , assumptions , an d conclusions . A t tha t time , -13

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EPAstate d tha t al l suc hcomment s woul d b e considere d i n determining th e nee d fo r an d natur e o f an

yregulatory strategie s fo r thi s industry . Ove r 18 0 writte n comment s fro m individuals , stat e an d loca l governments , an d industr

y wer e received . Th e submission s range d fro mone-pag e letter s t o detaile d analytica l document s consisting o f hundred s o f page s fro msuc hindustr

ygroup s a s the America n Petroleu

mInstitut e (API ) an d th e Moto r Vehicl e Manufacturer s Associatio n (MVMA) . Th e comment s wer e broad in scope , covering al l aspect s o f th e Agency' s analyses .

A s a resul t o f th e comment s an d th e availabilit yo f ne wor update d information , th e Agenc yundertoo k a thorough an d length

yreviewo f th e gasolin e marketing study . Thi s effor t ha s culminate d i n a revise d analysis . Base d o n th e content s o f thi s fina l stud yan d othe r supporting analyses , whic har e containe d in th e draf t RegulatoryImpac t Analysi s (RIA),[3 ] EPAbelieve s tha t th e contro l o f vehicl e refueling emission s i s appropriate , an d tha t onboard control s ar e feasibl e an d desirable . Thus , EPApropose s t o requir e onboar d controls . Th e following section s reviewkeyfinding s o f EPA' s analyse s an

d presen t th e decisio n rational e tha t support s today' s proposal . Reader s wishing t o obtai n mor e detaile d technica l informatio n shoul d consul t th e draf t RIA , whic h i s availabl e i n th e publi c docke t fo r inspection . -14

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II . Environmenta l Concern s an d Evaluatio n o f Contro l Strategie s A . Introductio n Thi s sectio n quantifie s th e environmenta l effect s associate d wit hrefueling vapor s an d describe s th e need for contro l o f thes e emissions . I t als o contain s a n overview o f th e alternativ e refueling emissio n contro l technologies , an d present s th e Agency' s rational e fo r choosing onboard vapo r recoverysystem s a s th e mos t desirabl e an d appropriat e mean s o f addressing th e environmenta l concerns . A s a prelud e t o thes e discussions , th e nex t sectio n present s a brie f characterizatio n o f th e emission s associate d wit hth e refueling process .

B . Source s an

d Compositio n o f Refueling Emission s Abou t 9 0 percen t o f al l refueling emission s consis t o f vapor s displace d fromth e vehicl e fue l tank b yth e incoming gasoline . Th e mas s o f thes e emission s depend s o n th e volume o f vapo r displace d an d it s density , whic hi n turn ar e determine d b yth e temperatur e o f th e fue l being dispense d an

d o f tha t alread

yin th e tank , th e tan k siz e an d geometry , th e volatilit yo f th e fuel , an d a numbe r o f othe r mino r factors . (The determinant s o f mas s refueling emission s ar e discusse d i n greate r detai l i n "Refueling Emission s fro

mUncontrolle d Vehicles,"[4 ] an EPAtechnica l repor t availabl e fo r reviewi n th e publi c docket. ) -15

-P.1 7 Les s significan t source s o f refueling emission s ar e spillag e an

d undergroun

d tan k emptying losses . Spillag e occur s a s a resul t o f "splas hback " fro mthe fil l pip e or th e escap e o f gasolin e fro mth e dispensing nozzle . Underground tan

k emptying losse s represen t the escap e o f vapo r fro

mth e ven t o f th e servic e statio n undergroun d storag e tank . Thi s emptying los s occur s becaus e a s fue l i s pumpe d int o th e vehicl e fue l tank , ambien t ai r i s ingeste d int o th e servic e statio n tan k throughit s tan

k vent . Thi s "fresh " ai r cause s liqui d fue l t o evaporate , in th e tan k unti l a

n equilibriu

mconcentratio n betwee n the vapo r an d liqui d phase s i s reestablished . A s thi s proces s occurs , th e pressur e withi n th e tan k maytemporaril ybecome greate r than th e atmospheri c pressure . Th e exces s pressur e withi n th e underground tan k i s relieve d whe n a smal l volum e o f gasolin e vapo r i s emitte d fro mthe vent . Th e spillag e an d emptying los s source s eac haccoun t for abou t 5 percen t o f th e tota l emission s associate d wit hth e refueling process.[3 ]

Th e compositio n o f refueling vapor s depend s o n thei r sourc e (e.g. , fue l tan k displacemen t o r spillage) , th e fue l typ e (e.g. , leade d o r unleaded) , an d th e volatilit yo f th e fuel . Gasoline , i n general , i s a comple xmixtur e containing varying amount s o f hydrocarbon s belonging t o four mai n groups , an d muc hsmalle r amount s o f variou s additives . Th e hydrocarbon s i n gasolin e ar e classifie d a s

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paraffin s (alkanes) , olefin s (alkenes) , naphthene s (cycloparaffin s o r cyclanes) , an d aromatic s (benzen e o r benzen e derivatives) . Gasolin e als o contain s certai n additives , whic har e generall ypresen t i n ver ylimite d amounts , t o provid e specifi c produc t qualities . Th e compositio n o f th e liqui d gasolin e an d tha t o f it s vapo r ar e no t necessaril yth e same . Fo r example , th e larges t sourc e o f refueling emissions , tha t portio n resulting fro

mvapo r displacemen t i n th e vehicl e fue l tank , doe s no t consis t o f full yvolatilize d gasoline . Al l availabl e informatio n show s tha t th e "light-end " hydrocarbon s generall yevaporat e mor e readil ytha n th e highe r molecula r weigh t hydrocarbons , an d s o refueling emission s ar e primaril ylight-en d hydrocarbons . I n general , dat a showtha t 7 0 percen t or mor e o f th e emission s b ymas s ar e comprise d o f hydrocarbo n molecule s containing 5 o r fewe r carbo n atom s (e.g. , butane s an d pentanes) . Further , dat a showtha t paraffin s (alkanes ) ar e th e larges t constituen t among th e othe r majo r hydrocarbo n group s i n refueling emissions . Th e portio n o f refueling emission s tha t result s fro m spilling gasoline , on th e othe r hand , reflect s th e compositio n o f th e liqui d fuel . Thi s i s du e t o th e tota l evaporatio n o f liqui d fue l tha t i s spilled . However , a s rioted above , EPAestimate s tha t no mor e than 5 percen t o f

-17

-P.1 9

tota l refueling emission s currentl yresul t fro mfue l spillag e an

d evaporation . Thus , th e statement s mad e wit h respec t t o th e compositio n o f refueling emission s du e t o vapo r displacemen t ar e essentiall yvali d for tota l refueling emission s a s well . Whil e th e majorit yo f refueling emission s ar e th e light-en

d hydrocarbons , the othe r component s o f liqui d gasolin e ar e als o represente d in th e vapo r emission s generate d during the refueling event . Benzen e i s o f particula r concer n t o EPA , a s previousl ynoted . Arecen t EPAstud

ysuggest s tha t unde r averag e conditions , a liqui d fue l containing 1. 6 weigh t percen t benzen e woul d generat e refueling vapor s containing 0. 8 weigh t percen t benzene.[5 ]

C . Environmenta l Nee d fo r Contro l

Th e principa l environmenta l concern s associate d wit h refueling emission s focu s o n thei r contributio n t o ozon e formatio n i n th e atmospher e an d o n thei r direc t healt h effects . Eac ho f thes e area s i s discusse d separatel ybelow . 1 . Refueling Emission s a s a n Ozon e Precurso r

A s note d above , refueling emission s consis t almos t entirel yo f hydrocarbons . I n the presenc e o f sunlight , thes e volatil e organi c compound s (VOC ) combin e wit hothe r -18

-P.2 0

pollutants , in a serie s o f chemica l reactions , t o produc e ozon e (an

d othe r photochemica l oxidants) . Th e myriad o f advers e effect s tha t mayresul t fro mexposur e t o ozone , ar e thoroughl ydescribe d elsewher e an d ar e no t repeate d i n detai l here.[6 ] In summary , ozon e an d othe r oxidant s ar e pulmonaryirritant s tha t adversel yaffec t pulmonary membranes , lun

g tissues , an

d lun g function . Anima l studie s als o indicat e tha t ' ozon e maylea d t o an increase d susceptibilit yt o bacteria l infection . Thes e detrimenta l healt heffect s ma

yaggravat e existing illnes s or lea d t o a n lun g disease . In additio n t o human healt hconcerns , ozon e mayadversel yaffec t vegetatio n an d caus e damag e t o variou s type s o f material s (e.g. , elasti c compounds) . I n accordanc e wit hSectio n 10 9 o f th e CAA , EPA promulgate d an

d revise d primaryan d secondaryNationa l Ambien t Ai r Qualit yStandard s (NAAQS ) for ozon e i n th e 1970's . Th e primarystandard i s intende d t o protec t th e publi c healt hwit ha n adequat e margi n o f safety. * Th e secondarystandard i s aime d a t protecting th e publi c welfare . Th e curren t NAAQ S (i.e. , bot hprimaryan d secondary ) for ozon e require s tha t th e expecte d numbe r o f day s i n a calenda r yea r wit hone-hou r measure d

Th e curren t primarystandard i s principall ybase d o n wel l documente d studie s o f acut e healt heffects .

-19

-P.2 1

concentration s above 0.1 2 part s pe r millio n (ppm ) b e les s than or equa l t o one . Sectio n 17 2 o f the CA Agenerall yrequire d al l state s t o submi t Stat e Implementatio n Plan s (SIPs ) tha t provide d fo r attainmen t o f the nationa l primarystandard b yDecembe r 31 , 1982 . Thi s deadlin e wa s extende d t o Decembe r 31 , 198 7 for state s tha t showe d attainmen t b y198 2 t o b e impossibl e despit e th e applicatio n o f al l reasonabl yavailabl e contro l measures . Th e SIP s fo r thes e "extension " area s wer e t o includ e certai n specifi c measure s (e.g. , vehicl e inspectio n an d maintenanc e programs ) and , lik e th e SIP s for area s wit h a 198 2 attainmen t date , wer e t o contai n stationarysourc e emissio n control s reflecting reasonabl yavailabl e contro l technology . Also , thi s sectio n o f th e statut e mandate s tha t SIP s provid e fo r attainmen t o f th e nationa l secondary standard a s expeditiousl ya s practicable . Sectio n 109(d ) o f th e CA Arequire s EPAt o periodicall y reasses s eac hNAAQS , including th e ozon e standards , t o ensur e tha t th e publi c healt han d welfar e continue s t o b e protecte d withi n th e statutoryguidelines . Base d o n th e result s o f suc hreviews , including a n independen t assessmen t b

yth e Clea n Ai r Scientifi c AdvisoryCommitte e (CASAC) , EPAmayrevis e th e applicabl e ambien t ai r qualit y standard s a s appropriate . I n th e las t severa l years , EPA a"n d numerou s independen t researc horganization s launche d a massiv e effor t t o bette r understand an d quantif yth e environmenta l effect s o f ozon e ai r pollution . Th e NAAQ S -20

-P.2 2 fo r ozon e i s currentl ybeing reassesse d b yth e Agenc yan

d CASAC i n ligh t o f resulting healt han d welfar e effect s research . Non-Attainmen t Areas . Despit e th e impositio n o f variou s H C controls , man yarea s o f th e natio n continu e t o violat e th e ozon e NAAQS . Base d o n th e lates t three-yea r perio d fo r whic hcomplet e ai r qualit ymonitoring dat a ar e availabl e (1982-84) , EP Aha s determine d tha t mor e than 7 0 urba n area s ar e currentl yexceeding th e ambien t standard . Twelv e o f thes e area s ar e locate d i n California . Th e significanc e o f th e nationwid e non-attainmen t problemi s clearl yindicate d b yconsidering th e fac t tha t wel l ove r 10 0 millio n peopl e live in th e area s whic har e know n t o excee d th e ozon e standards .

I n additio n t o reviewing th e presen t stat e o f ozon e ai r quality , EPAha s als o assesse d th e nee d fo r additiona l futur e hydrocarbo n contro l b ymaking projection s o f futur e ai r qualit ytrends . Fo r thi s rulemaking , estimate s o f futur e ai r qualit ywer e mad e fo r 6 1 non-Californi a urba n area s tha t ar e currentl yi n non-attainmen t status. * Californi a area s wer e exclude d fro m th e modelin g projection s becaus e tha t stat e alread ycontrol s refueling emission s wit hStag e I I vapo r recoverysystem s in non-attainmen t areas . Curren t attainmen t area s wer e als o

Thi s represent s the estimate d numbe r o f non-attainmen t area s a t th e time thi s analysi s wa s performed . -21

-P.2 3 exclude d fro

m th e analysis , althoug hi t shoul d b e note d tha t a numbe r o f thes e area s ar e ver yclos e t o th e standard . I f thes e area s had bee n include d i n EPA' s analysis , i t i s possibl e tha t some o f them woul d hav e bee n projecte d t o become non-attainmen t area s i n th e futur e du e t o the effect s o f growth . Thus , th e tota l numbe r o f non-attainmen t area s i n th e futur e mayb e greate r than show n below .

A s wit han

yprojectio n o f futur e events , ai r qualit y model s rel yon a variet yo f assumption s regarding suc h thing s a s emissio n rates , growt hrates , contro l technologies , emissio n standards , an d contro l efficiencies . Amor e detaile d descriptio n o f thes e input s for th e variou s mobil e an d stationarysourc e categorie s i s containe d i n th e draf t RIA.[3 ] I t i s sufficien t her e t o not e tha t for mobil e sources , the mode l reflect s th e continuing gain s in emission s contro l tha t accru e fro mth e Federa l Moto r Vehicl e Contro l Program , unde r whic h increasingl ystringen t exhaus t an d evaporativ e emissio n standard s hav e bee n promulgated . Fo r stationarysources , the mode l account s fo r th e emissio n reduction s tha t hav e bee n achieve d a s o f th e bas e yea r (i.e . , 1983 ) fro mwhic h the projection s begin. *

* Thi s represent s a conservativ e assumptio n for some o f th e urba n area s modeled , becaus e some state s may furthe r contro l existing stationarysources . Th e degre e o f suc hcontrol , however , i s currentl yunknown . -22

-P.2 4 Figur e 1 illustrate s EPA' s genera l projection s o f non-methan e hydrocarbo n (NMHC ) emission s an d ozon e NAAQ S attainmen t statu s for th e year s 1988 , 1995 , 2000 , an d 201 0 assuming n o additiona l VO C contro l measure s ar e promulgate d in th e future . Th e result s for 198 8 indicat e tha t a substantia l numbe r o f urban area s (5 1 o f th e 6 1 modeled ) mayfai l t o compl ywit hthe NAAQ S b yth e statutory deadline . Beyon

d that , the mos t obviou s tren d betwee n no w an d 199 5 i s tha t onl ya verysmal l improvemen t in ai r qualit yi s projecte d t o occur a s a resul t o f the emissio n standard s tha t alread yhav e bee n promulgate d for bot h stationaryan

d mobil e sources . Sinc e mos t o f th e majo r urban area s modele d (i.e. , thos e wit hth e greates t populations ) remai n in non-attainmen t statu s throughou t th e projectio n period , th e smal l improvemen t show n thr u 199 5 become s eve n smalle r whe n viewe d in term s o f populatio n expose d t o highozon e levels . Figur e 1 als o illustrate s tha t i n th e mor e distan t future , growt hwil l caus e th e problemt o worse n withou t furthe r controls . Mor e specifically , thes e projection s indicat e tha t b

yearl yi n th e nex t century , emissio n inventorie s wil l agai n b e rising steadily . B yth e en

d o f th e projectio n perio d (i.e. , 2010) , emissio n inventorie s in th e area s modele d apparentl ywil l b e wors e than in 1988 .

-23

-

# RGURE 1

NMHC Inventories an d Ozon e NAAQ S Attainmen t Statu s for6 1 Urba n Non-Attainmen t Area s - Bas e Case 1000 0 W 

## c



# _ g o o o c

. 2 Cfl 

# I

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• M M 

# B Q

_ 

### 9000 H 800 0 7000 - 6000 - 5000 - 4000 - 3000 - i 2000 - 1000 - 5 5 6 0 

## o 0 ) 

### 5 0 

## c a > 

# E c 4 0 [O <

## I c 

# 30 5 -2 0

-1 0 

# E

a ) -•"•- - 

## o ( D m— 

# e a . - 0 

# 198 8 199 5 200 0 201 0P.2 6

Th e numbe r o f area s violating th e ozon e NAAQ S follow s thi s trend. *

Th e magnitud e o f th e ozon e ai r qualit yproblemfacing th e natio n i s furthe r illustrate d b yadditiona l estimate s mad e b yEPA . Th e result s o f thi s analysi s showth e emissio n reduction s tha t ar e neede d relative t o th e 198 3 base-yea r NMH C inventor yt o eliminat e the projecte d non attainmen t problem . A s show n i n Tabl e 1 , reduction s o f u p t o abou t 9 0 percen t appea r necessaryt o bring al l area s o f th e countryint o compliance . Base d on estimate s b yth e Tabl e 1 EFFEC T O F VO C INVENTOR Y REDUCTION S ON OZONE NAAQ S COMPLIANC E SITUATIO N (6 1 NON-CALIFORNI AAREAS ) % Reductio n fro

mBaselin e No . o f Non-Attainmen t Area s VO C Emission s Inventory* * 10 % 20 % 30 % 40 % 50 % 60 % 70 % 80 % 90 % 198 8 4 2 3 2 2 4 1 6 9 3 1 1 0 199 5

3 8 2 8 2 4 1 4 9 4 2 1 0 200 0

4 2 3 1 2 4 1 7 1 0 5 3 1 0

* Give n th e uncertaintie s inheren t i n projecting absolut e value s fo r emissio n inventorie s an d attainmen t statu s int o th e nex t century , i t i s mor e appropriat e t o emphasiz e th e trend s i n thes e measures . * * Beyond thos e tha t wil l alread yaccru e fro

mth e existing Federa l Moto r Vehicl e Contro l Progra mi n th e 6 1 non-attainmen t area s modeled .

-25

-P.2 7

Agency' s Ozon e Tas k Force , ther e i s a clea r nee d t o implemen t al l reasonabl e control s o n volatil e organi c compound s (VOC ) i f progres s toward attainmen t o f the ozon e NAAQ S i s t o b e assured . Further , EPAha s conclude d tha t refueling controls , eithe r Stag e I I or onboard , coul d provid e par t o f the neede d VO C reductions . Othe r Areas . Whil e th e benefit s associate d wit h controlling VO C emission s i n non-attainmen t area s are readil yapparent , reducing thes e emission s i n attainmen t area s i s als o beneficial . Th e benefit s accruing fro m thes e reduction s can b e groupe d int o thre e categories . First , ozon e i s a regiona l concer n becaus e VO C emission s originating i n on e are a mayb e transporte d throughth e atmospher e an

d adversel yaffec t ai r qualit yi n anothe r area . Thi s phenomeno n allow s VO C emission s i n attainmen t area s t o exacerbat e problem s in complying wit hth e ozon e NAAQ S i n non-attainmen t areas . Thus , th e Agenc ybelieve s tha t reducing suc hattainmen t are a emission s i s o f valu e in terms o f non-attainmen t are a reductions . Second , Sectio n 11 0 o f th e CA

Amake s i t clea r tha t i n additio n t o attaining the NAAQS , a primarypurpos e o f th e statut e i s t o maintai n complianc e wit hth e ambien t standard s i n orde r t o preven t th e advers e healt han d welfar e effect s associate d wit h exces s concentration s o f pollutant s suc ha s ozone . Similarily , Sectio n 101(b)(1 ) provide s that

- a keypurpos e o f th e Ac t i s t o "protec t an d enhanc e th e qualit yo f th e Nation' s ai r resource s s o a s t o promot e th e publi c healt h -26

-P.2 8

an d welfar e ...." * Thes e goal s appl yt o al l area s o f the country , including attainmen t areas . Thus , VO C contro l measure s tha t hel p maintai n th e ozon e NAAQS , or preven t th e deterioratio n o f ai r quality , i n attainmen t area s hav e valu e fo r thos e purposes . Therefore , the benefit s o f VO C reduction s i n attainmen t areas , a s wel l a s non-attainmen t areas , ar e a

n importan t consideratio n i n th e overal l evaluatio n o f refueling controls . 2 . Refueling Emission s a s a Carcinogeni c Ris k

I n additio n t o the healt han d welfar e risk s pose d b y ozone , o f whic hrefueling emission s ar e a precursor , EPA ha s foun

d tha t gasolin e vapo r i s probabl ycarcinogeni c t o humans . Generally , quantifying th e cance r ris k pose d b yan environmenta l threa t i s a n inexac t scienc e that , b y necessity , relie s on a variet yo f estimate s an d assumptions . Du e t o th e complexit yo f th e subject , i t i s importan t t o understand th e basi s o f EPA' s carcinogeni c ris k assessmen t for refueling emission s befor e describing th e result s o f th e analysis . Therefore , an overvie wo f th e basi s o f EPA' s ris k analysi s wil l preced e th e presentatio n o f th e actua l cance r incidenc e estimates . Fo r a mor e detaile d discussio n o f th e result s o f th e ris k assessment , th e intereste d reade r i s referre d t o th e draf t RIA.[3 ]

Se e Sierr a Clu

bv . EPA , 54 0 F.2 d 111 4 (D.C . Cir.) , vacate d (on othe r grounds ) su bnomMontan a Powe r Compan yv . EPA , 43 4 U S 80 9 (1977) .

-27

-P.2 9 Th e ambien t concentration s o f benzen e an d gasolin e vapor s generate d fro mrefueling operation s ar e quit e low , especiall ycompare d t o anima l exposure s i n laborator y studies . Moreover , i t i s impossibl e t o directl ymeasur e th e ris k o f contracting cance r using the analytica l technique s whic har e currentl yavailable . A s a n alternative , EPAha s estimate d th e cance r ris k a t thes e concentration s b

yextrapolating fro mestimate s o f ris k du e t o highe r concentration s in th e studie s o f workplac e an d laborator

yexposure . Thus , th e estimate d risk s fro mthes e lo wconcentration s represen t plausibl e uppe r limit s o n th e actua l risk . Using thi s approach , th e assessmen t o f carcinogeni c ris k can b e separate d int o two verybroad categories . Th e firs t i s estimating th e potenc yo f th e activ e agen t i n causing a particula r carcinogeni c en d point . Th e mor e poten t th e agent , th e mor e probabl e i t i s tha t a perso n may contrac t cance r afte r being expose d t o th e substanc e ove r a perio d o f time . Th e secon d broad categoryinvolve s estimating th e degre e o f exposur e t o th e substance . Thi s include s suc hvariable s a s th e numbe r o f individual s exposed , i n additio n t o th e concentratio n an d duratio n o f th e exposure . O f th e two broad categories , estimating th e potenc yo f a suspecte d carcinoge n i s ofte n th e mos t critica l an

d difficul t t o quantify . Hence , i n assessing

-28

-P.3 0 th e carcinogeni c ris k associate d wit hrefueling emissions , i t i s especiall yimportan t t o acknowledg e th e principa l uncertaintie s i n thi s area .

A s alread

ymentioned , th e carcinogeni c concern s associate d wit hthe refueling proces s hav e historicall y focuse d o n benzene , a norma l constituen t o f gasoline , an d gasolin e vapor s a s a whole . Th e cance r ris k associate d wit hbenzen e ha s bee n widel yevaluate d i n bot h epidemiologica l an d anima l studies . Th e epidemiologica l studie s hav e show

n a n increase d incidenc e o f leukemi a among worker s expose d t o benzene . Bot hrat s an d mic e hav e show

n a statisticall ysignifican t increas e i n carcinogenesi s associate d wit hrelativel yhighbenzen e exposure s through inhalatio n an

d ingestion . Additionally , th e dose-respons e relationship s derive d fro mth e huma n an

d anima l studie s wer e similar . Th e Agenc ybelieve s thi s evidenc e provide s an adequat e basi s fo r classifying benzen e a s a huma n carcinoge n an

d fo r estimating th e carcinogeni c potenc yo f thi s compoun

d a t th e lowe r exposur e level s tha t ar e typica l o f refueling operations , becaus e th e studie s ar e o f goo d qualit yan

d theyshowconsisten t results .

A s discusse d earlier , th e Agenc yliste d benzen e a s a hazardou s ai r pollutan t unde r Sectio n 11 2 o f th e CA Ai n 197 7 (4 2 F R 29332) , base d on th e result s o f th e occupationa l studie s an d EPA' s finding tha t "ambien t

-29

-P.3 1 exposure s [t o benzene ] mayconstitut e a cance r ris k an d shoul d b e reduced. " i n 1984 , th e potenc yestimat e derive d fro mthes e studie s wa s use d b yEPAt o establis hstandard s fo r "fugitive " benzen e ' emission s fro mstationarysourc e equipmen t leak s (4 9 FR 23513) . Th e quantitativ e estimat e o f ris k fro mbenzen e exposur e ha s bee n update d base d on a recen t reviewo f the scientifi c literature.[7 ] Th e cance r potenc yestimat e wa s increase d slightl y(i.e. , 1 7 percent) , an d thi s update d estimat e i s use d i n th e ris k analysi s accompanying thi s proposal . Lik e benzene , th e carcinogeni c ris k associate d wit h exposure s t o gasolin e vapor s a s a whol e ha s als o bee n assesse d b

yevaluating existing epidemiologica l an d anima l studies . Th e availabl e epidemiologica l studie s o f worker s i n th e petroleu

m industryar e considere d t o b e suggestiv e o f increase d cance r incidence . However , du e t o methodologica l difficultie s in distinguishing betwee n gasolin e exposure s an d othe r chemicals , th e Agenc y consider s thes e studie s t o b e inconclusiv e concerning th e casua l rol e o f gasolin e vapor s at thi s time . A s a result , th e carcinogeni c ris k o f exposur e t o gasolin e vapor s ha s bee n estimate d largel yo n th e basi s o f anima l studie s conducte d b

yth e America n Petroleu m Institut e (API) . I n th e AP I work , rat s an d mic e wer e expose d t o relativel yhigh

-30

-P.3 2

concentration s o f wholl yvaporize d unleade d gasolin e fo r two years . Thes e wel l designed , chroni c inhalatio n studie s showe d evidenc e o f significantl yincrease d kidneycance r i n mal e rat s an

d live r cance r i n femal e mice . Th e Agency' s refueling ris k assessmen t i s base d on th e potenc yestimate s fro mthe mal e ra t tests . However , th e quantitativ e ris k estimate s derive d b yEP Afro mbot hanima l specie s wer e i n clos e agreement . Th e carcinogeni c activit yobserve d i n . thes e anima l test s i s though t t o b e induced b yactiv e agent s containe d i n th e fue l othe r than benzene . Thi s i s a reasonabl e assumption , sinc e th e site s o f carcinogeni c activit yar e generall yobserve d t o b e differen t fo r benzen e than fo r gasolin e vapor s (i.e. , circulatorysysteman d bon e marro w vs . live r an

d kidney) , an

d sinc e th e concentratio n o f benzen e during th e anima l experiment s wa s to o smal l t o induc e th e observe d response . I n estimating human risk s t o gasolin e vapor , th e ris k o f th e benzen e componen t itsel f i s added t o th e human-equivalen t gasolin e vapo r ris k determine d fro

m th e anima l experiments , sinc e th e two effect s ar e apparentl yindependen t o f eac hothe r an d additive a t lo

wconcentrations . Suc ha n approac hfo r estimating th e potentia l risk s pose d b ya mixtur e o f carcinogen s i s suggeste d i n EPA' s Carcinoge n Ris k Assessmen t Guideline s (5 1 FR 33992) .

-31

-P.3 3 Th e us e o f anima l dat a in carcinogeni c ris k assessment s i s a generall yaccepte d practic e whe n epidemiologica l evidenc e i s inconclusive . In thi s particula r case , th e Agencyfind s th e inductio n o f tumor s in two anima l specie s provide s adequat e evidenc e t o conside r gasolin e vapo r a s a probabl e human carcinoge n unde r bot hEPA' s Carcinoge n Ris k Assessmen t Guideline s an d th e criteri a establishe d b yth e Internationa l Agenc yfo r Researc ho n Cancer . Also , th e EPAbelieve s th e evidenc e i s sufficien t t o justif ya quantitativ e estimat e o f human ris k fro mexposure s t o gasolin e vapor s i n orde r t o gaug e th e magnitud e o f th e potentia l publi c healt hproblem . Nevertheless , extrapolating tes t result s fro m highl y expose d animal s t o human s tha t ar e expose d t o muc hlowe r concentration s i n the ambien t ai r i s inherentl yuncertain , an d th e Agency' s analysi s recognize s thes e uncertainties .

Du e t o th e importanc e o f th e issue s involved , th e basi s o f EPA' s ris k assessmen t ha s bee n independentl y reviewe d b

yth e Agency' s Scienc e AdvisoryBoard (SAB ) an d th e Healt hEffect s Institut e (HEI) . Bot ho f thes e scientifi c group s generall yagre e tha t gasolin e vapor s ar e probabl e huma n carcinogens ; however , theyals o hav e recognize d th e uncertaintie s inheren t in extrapolating anima l dat a t o quantif yhuman risk .

-32

-P.3 4 I n reviewing EPA' s ris k assessment , SA B conclude d tha t th e degre e o f scientifi c uncertaint yi n th e resulting quantitativ e estimat e o f human ris k shoul d b e clearl y acknowledged . HE I expresse d a mor e cautiou s vie wregarding th e actua l quantificatio n o f carcinogeni c risk , stating tha t i t i s no t presentl ypossibl e t o drawaccurat e conclusion s concerning th e degre e o f human risk .

I n SAB' s opinion , th e two area s o f greates t uncertaint yi n EPA' s analysi s o f gasolin e vapor s are : 1 ) th e relevanc e o f using a quantitativ e ris k facto r base d o n the mal e ra t kidneyrespons e in human quantitativ e ris k estimates , an

d 2 ) th e differenc e i n chemica l compositio n betwee n th e gasolin e exposure s i n th e AP I laboratory studie s an

d tha t typica l o f actua l populatio n exposur e during refueling emissions . Simila r opinion s hav e als o bee n expresse d b

yHE I an

d API . Regarding th e firs t are a o f uncertainty , some investigator s hav e argue d tha t the mal e rat s use d i n th e chroni c inhalatio n studie s mayb e uniqu e in thei r susceptibilit yt o kidneycance r afte r bein g expose d t o gasolin e vapors . Th e mal e ra t ha s bee n show n t o b e susceptibl e t o rena l toxicit y(i.e. , kidne ycel l damage ) fro mgasolin e vapors , an d some scientist s postulat e tha t suchdamag e ultimatel ylead s t o the , developmen t o f tumors . Further , th e mechanis mo f thi s toxi c respons e i s though t t o -33

-P.3 5 b e uniqu e t o the mal e ra t specie s use d i n th e laborator y studies . Suc ha finding o f uniquenes s i n th e mal e ra t woul d weaken , bu t no t eliminate , th e presumptio n o f a carcinogeni c respons e i n humans . Th e Agenc yfind s severa l reason s t o questio n th e conjectur e tha t th e mal e ra t respond s uniquel yt o gasolin e vapors . First , the lin k betwee n acut e or chroni c hydrocarbon-induce d kidneydamag e an d carcinogenicit yi s no t clear , no r ha s i t bee n proven . Second , the kidneyo f experimenta l animal s ha s bee n demonstrate d t o b e the targe t organ o f ove r 10 0 carcinogeni c compounds . Third , a statisticall ysignifican t increas e i n live r tumor s wa s detecte d fo r femal e mic e i n th e AP I studies , wit hn o repor t o f accompanying tissu e damage . Finally , othe r type s o f malignan t tumor s hav e appeare d i n othe r strain s o f animal s whe n expose d t o syntheti c fuels . Overall , mos t scientist s agre e wit hEPAtha t th e rol e o f acut e kidne ytoxicit yin th e inductio n o f kidne ytumor s i n mal e rat s an d it s relevanc e t o huma n cance r ar e currentl yunresolve d issues . However , i t i s importan t t o not e tha t a carcinogeni c respons e t o gasolin e vapor s wa s als o demonstrate d in th e AP I laboratorystudie s o f femal e mice . Furthe r th e Agency , HEI , an d SA B al l agre e tha t th e carcinogeni c effec t o f gasolin e vapor s i n animal s i s rea l an d can no t b e ignore d a s a potentia l huma n hazard . -34

-P.3 6 Regarding th e secon d are a o f uncertaint yraise d b ySA B an d HEI , EPAagree s ther e mayb e a differenc e betwee n th e vapo r compositio n t o whic hanimal s wer e expose d i n th e chroni c inhalatio n stud yan d tha t t o whic hhuman s mayb e expose d unde r ambien t conditions . A s previousl ydiscussed , refueling emission s consis t o f a greate r proportio n o f "light-end " hydrocarbo n molecule s than doe s wholl y vaporize d gasoline . Du e t o th e obviou s difference s in chemica l composition , i t i s possibl e tha t th e carcinogeni c potentia l o f gasolin e vapor s emitte d during refueling i s no t wel l represente d b yth e tes t result s derive d from wholl yvaporize d gasoline . API , among others , ha s specificall ymad e thi s claim .

I n suppor t o f it s position , AP I ha s performe d short-ter

mbioassayscreening test s usin g differen t fraction s o f vaporize d gasolin e t o identif yth e hydrocarbo n compound s tha t initiat e th e rena l toxicit yobserve d i n th e mal e ra t kidney . Thes e test s showe d branch-chai n paraffin s wit h6 t o 9 carbo n atom s (i.e . , _ > C 6 compounds ) t o b e th e primarycausa l agent s o f th e toxi c effects . A s a result , AP I ha s conclude d tha t becaus e th e percentag e o f _ > c « compound s i n wholl yvaporize d gasolin e i s substantiall y mor e tha n i n refueling vapors , EPA' s estimat e o f th e potentia l cance r ris k fromgasolin e vapor s i s overl y conservative . Specifically , th e refueling vapo r fractio n compose d o f _

> C 6 hydrocarbon s molecule s ha s bee n show n t o

-35

-P.3 7

b e 2 5 percen t o r les s o f tha t i n wholl yvaporize d gasoline . Thus , i f AP I i s correct , EPA' s quantitativ e assessmen t o f populatio n ris k t o gasolin e vapor s woul d b e to o highb

ya t leas t a facto r o f four . Th e Agenc yha s considere d API' s argument , bu t note s tha t th e crucia l evidenc e demonstrating th e associatio n betwee n kidneytoxicit yan d kidneytumor s i s lacking . Also , SA

B conclude d ".. . tha t th e issu e o f th e representativenes s o f th e inhale d vapors , whil e certainl ya complicating facto r i n th e AP I bioassayshoul d no t b e regarde d a s a majo r flaw. " I n addition , EPAcoul d fin d n o dat a t o indicat e whic hfractio n o f th e gasolin e vapo r i s responsibl e fo r th e inductio n o f live r tumor s i n femal e mice . Fo r thes e reasons , th e Agenc ybelieve s i t woul d b e unwis e t o bas e th e quantitativ e ris k assessmen t o n a n assumptio n tha t maysignificantl yunderestimat e th e potentia l healt hproblem . Instead , EPAfind s i t pruden t t o interpre t th e result s o f th e ris k assessmen t a s plausibl e uppe r limits , wit hth e actua l risk s being a t o r belo wth e estimates . Nonetheless , t o illustrat e th e effect s o f th e assumptio n tha t th e heavie r molecula r weigh t compound s ar e responsibl e fo r th e carcinogeni c propertie s o f refueling emissions , EPAha s include d a n estimat e o f th e incidence s attribute d t o th e >C 6 fractio n o f gasolin e vapor s i n it s ris k assessment .

-36

-P.3 8 Using th e potenc yestimate s fo r benzen e an d gasolin e vapor s describe d above , th e ris k assessmen t analysi s focuse d o n four exposur e scenarios : occupational , self-service , community , an d exces s evaporativ e emissions . Eac ho f thes e exposur e scenario s can b e characterize d i n term s o f the intensity , frequency , an d duratio n o f exposure ; th e numbe r o f peopl e affected ; an d th e geographi c rang e o f emissions . Th e occupationa l exposur e scenario , in term s o f refueling emissio n control , i s a roug hestimat e o f th e potentia l ris k t o servic e statio n attendant s expose d t o gasolin e vapor . Th e purpos e o f thi s analysi s wa s t o giv e EPAa n approximatio n o f potentia l risk s pose d t o individual s chronicall yexpose d t o gasolin e vapo r i n th e occupationa l setting . Self-servic e exposur e refer s t o th e exposur e person s ar e subjecte d t o i n refueling thei r ow n vehicles . Lik e occupationa l exposure , i t i s characterize d b yhighgasolin e vapo r concentration s fo r relativel ybrie f durations . However , th e frequenc yo f exposur e i s muc hlowe r than tha t t o whic hservic e statio n attendant s ar e subjected . Th e rapi d expansio n o f self-serv e gasolin e outlet s mean s that , toda yan d fo r th e foreseeabl e future , th e majorit yo f th e populatio n experience s suc hexposure .

-37

-P.3 9 Communit yexposur e refer s t o th e exposur e experience d b yperson s residing i n th e immediat e vicinit yo f servic e stations . A s such , i t ha s a wide r geographi c rang e than do th e occupationa l o r self-servic e scenarios . Th e dispersio n o f gasolin e vapo r int o the atmospher e in th e vicinit yo f servic e station s mean s tha t th e concentratio n o f gasolin e vapor s i s muc hlowe r than tha t o f th e preceding scenarios . However , th e duratio n o f suchexposure s i s muc hlonger , approaching constan t exposur e i n th e cas e o f 24-hour

stations . Fo r eac hscenario , th e estimate d annua l incidence s ar e summarize d i n Tabl e 2 . Th e colum n heade d "Bz " refer s t o incidence s resulting fro mexposur e t o benzene . Th e colum n heade d "GV " refer s t o incidence s resulting fro mexposur e t o gasolin e vapo r a s a whole . Whil e th e benzen e exposur e occur s a s par t o f th e exposur e t o ga s vapor , EPAi s treating thes e ris k an d incidenc e estimate s a s additive , fo r reason s alread youtlined . Thus , adding th e "Bz " an d "GV " estimate s give s th e estimate d tota l incidence s b y scenario . I n ligh t o f th e uncertaintie s associate d wit h thes e values , th e Agenc yagai n believe s theyshoul d b e interprete d a s plausibl e uppe r bound s o f ris k for possibl e effects .

-38

-P.4 0 Tabl e 2 ESTIMATE D TOTA

L CANCE R INCIDENCE S RESULTIN

GFROMUNCONTROLLE D REFUELIN GEMISSION S

Scenari o Occupationa l Self-serv e Communit y (Annua l

B z 2 5 1 Incidenc e



### > c s 4 8 3 198 7 -

G V 1 7 3 3 1 0 - 2020 ) Total *

(B z + GV ) 1 9 3 8 1 0 Tota l * 7 1 5 6 0 6 7 Column s an

d row s mayno t ad

d exactl yt o total s du e t o rounding . Th e colum

n in Tabl e 2 heade d "K V refer s t o th e estimate d incidence s resulting fro mexposur e t o tha t fractio n o f ga s vapo r compose d o f "heavy-end " hydrocarbo n compounds . Thes e value s ar e presente d t o illustrat e th e effect s o f using onl ythes e heavie r compound s t o evaluat e th e carcinogeni c ris k associate d wit hexposure s t o gasolin e vapors . I n additio n t o th e annua l incidences , whic har e base d on "average " exposures , EPAals o estimate d th e lifetime ris k fo r individual s highl yexpose d t o gasolin e vapor s for eac ho f th e refueling-relate d exposur e scenarios . Th e lifetime risk s ar e 4 x10" J , 8 x10" s , an d 1 x10" 4 fo r occupational , sel f service , an d communit yexposures , respectively .

-39

-P.4 1 Th e result s o f EPA' s assessmen t showtha t th e highes t lifetime ris k o f cance r i s incurre d b yservic e statio n attendants . Th e lowes t lifetime ris k i s fo r individual s using self-servic e pumps . Thes e individual s may potentiall yb e expose d t o significan t vapo r concentration s fro mth e fillneck , bu t th e numbe r o f refueling event s i s far lowe r than fo r th e occupationa l category . Nonetheless , a s show

n in Tabl e 2 , self-servic e exposur e show s th e greates t annua l cance r incidenc e becaus e o f th e larg e numbe r o f peopl e tha t pum p thei r ow

n gasoline . Th e uppe r boun d o f annua l incidence s (i.e . , B z plu s GV ) fo r al l refueling categorie s i s estimate d t o b e abou t 67 . O f this , abou t 9 0 percen t ar e attributabl e t o gasolin e vapors , wit h th e remainde r attribute d t o benzene .

D . Overvie wo f Alternativ e Contro l Technique s

A s mentione d earlie r i n thi s notice , ther e ar e two basi c alternative s fo r th e contro l o f refueling emissions . Thes e ar e generall yreferre d t o a s "Stag e II " an d "onboard. " Th e two vapo r recoverysystem s ar e vastl y different , wit hStag e I I equipmen t installe d at th e servic e statio n an

d onboar d equipmen t installe d i n th e vehicle . Thi s differenc e make s a basi c understanding o f th e two contro l technique s especiall yimportan t i n facilitating th e subsequen t discussio n o f EPA' s decisio n rationale . Wit h thi s goa l i n mind , th e following discussio n present s a -40

-P.4 2

brie f descriptio n o f th e Stag e I I an d onboard systems , an d explore s a fe wo f th e mor e importan t feature s associate d wit heac htechnology . 1 . Basi c Descriptio n o f Stag e I I an d Onboard Stag e I I vapo r recover ysystems , a s note d earlier , ar e installe d at th e servic e station . Wit hthes e systems , th e vapo r i n th e vehicl e fue l tan k tha t i s displace d b yliqui d gasolin e being dispense d i s prevente d fro mescaping t o th e atmospher e b

ya flexibl e rubbe r "boot " a t th e junctur e o f th e fillnec k an

d the dispensing nozzle . Thi s boo t i s fitte d ove r th e nozzle' s spout , an d i s attache d t o a hos e simila r t o (but generall ysmalle r than ) th e liqui d dispensing hose . Thi s hose , in turn , i s connecte d t o piping whic hroute s th e vapor s t o th e underground fue l tank . Avapor-for-liqui d exchang e i s mad e a s liqui d gasolin e displace s gasolin e vapo r fromth e vehicl e fue l tan k t o th e underground storag e tank . Recovering th e vapo r i n thi s manne r eliminate s th e ingestio n o f ai r b yth e underground tan k tha t woul d normall yoccu r a s fue l i s pumpe d out . This , i n turn , prevent s gasolin e fro mevaporating insid e th e storag e tan k t o reestablis hth e vapor-liqui d equilibrium , a s discusse d earlier . Th e servic e statio n owne r realize s a n economi c benefi t fro

mthi s recovere d vapor , sinc e liqui d fue l tha t

-41

-otherwis e woul d b e evaporate d can instead b e sold . Thi s i s referre d t o a s th e vapo r recoverycredit, * an d wil l b e cite d b ytha t ter

mi n th e economi c impac t discussio n late r i n thi s notice . Stag e I I system s can b e subdivide d int o two broad type s o n th e basi s o f th e metho d use d t o return th e displace d vapo r t o th e undergroun d storag e tank . Th e firs t type , know

n a s th e "balanc e system, " i s th e simpler , les s expensive , an

d mor e widel yuse d o f th e two (Figur e 2) . (Abou t 8 0 percen t o f curren t Stag e I I systeminstallation s ar e balanc e systems. ) Vapo r transfe r t o th e storag e tank i s accomplishe d b

yexploiting th e sligh t pressur e create d i n th e vehicl e fue l tan k b yth e incoming flowo f gasoline . Thi s systemi s "passive, " an d operate s on th e basi s o f very smal l difference s i n pressure . Therefore , a tigh t sea l i s require d a t th e junctur e o f th e dispensing nozzl e an d th e fillneck . I n orde r t o ensur e a goo d seal , th e dispensing nozzl e i n a balanc e systemi s equippe d wit ha "no-seal , no-flow " feature , consisting o f a spring-loade d bellow s an d a n interloc k mechanism . Fo r fue l t o b e dispensed , enough Similarly , i f Stag e I I i s i n place , th e vapo r fro m th e underground tan

k tha t normall ywoul d b e los t a s thi s tank i s refille d can b e recycle d bac k t o th e carg o truc k vi a a vapo r return line for subsequen t reprocessing .

-42

-Figur e2 

### STAG E I I VAPO R RECOVER YBALANC E SYSTE M

METE R

GASOLIN E FIL L LIN E

GASOLIN E STORAG E TAN KP.4 5 pressur e mus t b e applie d t o th e nozzl e b yth e operato r t o sufficientl ycompres s th e bellow s an d thu s deactivat e th e interloc k mechanism . Th e othe r broad typ e o f Stag e I I systemi s know n a s "vacuu massist. " Suc hsystem s enhanc e th e recoveryo f gasolin e vapo r b

yemploying a devic e (i.e. , a blowe r o r a n aspirator ) t o creat e a sligh t vacuu m a t th e nozzle . Thi s vacuu mact s t o activel ydraw(assist ) th e gasolin e vapo r int o th e rubbe r boo t for return t o th e storag e tank . Thi s vacuu massis t i s advantageou s i n tha t i t obviate s th e nee d for a tigh t sea l at th e fillneck/nozzl e juncture , bu t ha s th e disadvantag e tha t ambien t ai r i s draw n int o th e vapo r return hos e along wit hth e vapor . Fo r blower-assiste d systems , thi s result s i n th e tota l volume o f th e returning vapor-plus-ambien t ai r bein g greate r tha n th e volum e o f liqui d gasolin e withdraw n fro mth e underground tank . Th e exces s vapor , whic hcanno t b e accommodate d b yth e storag e tank , thu s require s some for mo f secondaryprocessing (e.g. , incineration) . Th e complexit yan d adde d hardwar e associate d wit hth e vacuu massis t systemmak e i t mor e expensiv e tha n th e balanc e system , an d i t i s significantl y les s popula r fo r thos e area s currentl yemploying Stag e I I vapo r recovery .

-44

-P.4 6 Th e secon

d basi c alternativ e fo r th e contro l o f vehicl e refueling emission s i s th e onboard vapo r recover y system(Figur e 3) . A s implie d b yth e name , th e requisit e contro l hardwar e i s locate d o n th e vehicle . Consequently , no discernibl e modification s t o th e fue l dispensing equipmen t ar e required , an d consumer s perceiv e no differenc e whe n dispensing fuel . Onboard system s functio n during th e refueling o f th e vehicl e b ysealing th e vehicl e fillneck , the n routing th e displace d vapo r fro mth e fue l tan k t o a storag e canister . Thi s caniste r i s loaded wit h granule s o f activate d carbon , an d th e hydrocarbo n molecule s i n th e vapo r ar e absorbe d ont o th e surface s o f thes e granules . Whe n th e vehicle' s engin e i s started , fres h (ambient ) ai r i s draw n throughth e caniste r t o desorb , o r purge , th e hydrocarbon s fro mth e activate d carbon . . Th e resulting mixtur e o f ai r an d hydrocarbo n vapor s i s transferre d t o th e fue l metering systeman d the n burne d i n th e engine . Thi s provide s th e onboard systemwit ha fue l recoverycredi t simila r t o tha t previousl ydescribe d i n connectio n wit hStag e II , becaus e gasolin e vapor s tha t woul d normall yb e los t t o th e atmospher e ar e instead use d t o powe r th e vehicle . Th e Agenc ywoul d lik e t o add , however , tha t although th e onboar d vapo r recoverysystemmos t widel ydiscusse d a t th e presen t time i s base d o n th e us e o f a charcoa l storag e canister , othe r alternativ e contro l technologie s do exist . -45

-Figur e3 

## OnboardVapor

Contro lSystem

FUE LCA P NOZZL EACTUATE

D ROLLOVER/VEN

TVALV E

^J-TUB ESEA

L \ DESIGNE D SLO WLEA K VAPO

RLIN E / LIMITIN GORIFICE PURG EVALV E

CARBO N CANISTE R T O PURG

E INDUCTION POINT

VEHICL EFUE LTAN KP.4 8 On e suc halternative , whic hi s describe d in mor e detai l in Sectio n V I o f thi s notice , i s a flexibl e fue l tan k bladder . Th e us e o f a bladder-base d systemi s a n attractiv e possibilit yno t onl ybecaus e o f it s effectivenes s in controlling refueling vapors , bu t als o becaus e thi s typ e o f technolog ycan improve vehicl e safet y beyon d presen t level s in th e even t o f a crash . EPA encourage s the ful l exploratio n o f thi s an d an yothe r alternativ e contro l technologies . Specifically , comment s ar e requeste d on th e advantage s an d disadvantage s o f alternative s t o canister-base d onboar d controls , including th e area s o f technica l feasibility , contro l effectiveness , an d cost . 2 . Salien t Feature s o f Eac hContro l Techniqu e Onboar d Refueling Control s an d Evaporativ e Emissions . A n issu e closel yassociate d wit hreducing emission s during th e refueling proces s i s th e interactio n betwee n th e requisit e onboar d contro l technology , fue l volatility , an d th e potentia l fo r reduction s i n evaporativ e emission s fro m moto r vehicles . Recen t dat a fro mEPA' s in-us e surveillanc e program * indicat e tha t man yvehicle s fai l t o compl ywit h

* Thi s tes t progra mi s conducte d b

yEPAt o determin e i f vehicle s tha t ar e certifie d t o b e in complianc e wit h specifi c emissio n standard s continu e t o mee t th e applicabl e requirement s i n day-to-dayservice . -47

-P.4 9 th e applicabl e evaporativ e emissio n standard s i n custome r service.[8 ] Acontributing caus e o f thes e failure s i s tha t in-us e fue l typicall yi s mor e volatil e than fue l used i n emission s certificatio n testing an d generate s a greate r volume o f evaporativ e emissions . Evaporativ e emissio n contro l systems , i f designe d solel yfo r us e wit h certificatio n fuel , mayb e undersize d an d insufficientl y purge d whe n use d t o contro l in-us e fue l o f a highe r volatilit ytha n th e fue l specifie d fo r certification , resulting i n exces s evaporativ e emissions . Th e Agenc yha s identifie d severa l way s t o hel p assur e in-us e complianc e wit hth e evaporativ e emissio n standards . Th e possibl e solution s generall yreflec t EPA' s inten t t o hav e th e volatilit yo f certificatio n fue l represen t tha t o f in-us e fuel . In particular , in a separat e propose d rulemaking , containe d elsewher e i n today' s Federa l Register , EPApropose s t o reduc e th e Rei d Vapo r Pressur e (RVP ) ( a volatilit ymeasure ) o f commerciall yavailabl e gasolin e i n Clas s C area s (a s define d b yth e America n Societ yo f Testing Materials ) in two stages , fro mth e curren t recommende d summertime maximu mo f 11. 5 pound s pe r squar e inch(psi ) t o 9. 0 ps i (the volatilit yleve l fo r certificatio n tes t fuel ) b y1992. * Volatilit ylevel s in

* Th e Agency' s volatilit yrulemaking consider s RVP change s a s lo

wa s 8. 0 psi .

-48

-P.5 0 othe r area s o f th e countrywoul d b e reduce d proportionally . Thi s woul d hel p assur e tha t evaporativ e contro l systems ar e designe d an

d teste d t o handl e fue l volatilit y representativ e o f wha t theywil l encounte r in-use . Anothe r approac ht o attaining th e evaporativ e standard s woul d b e t o increas e th e volatilit yo f th e certificatio n tes t fue l t o matc htha t o f commercia l fuel . I f don e i n conjunctio n wit hrelativel ysimpl e revision s to * th e curren t tes t procedure , thi s revisio n woul d basicall y requir e th e us e o f large r storag e canister s and/o r highe r purg e rate s t o contro l exces s evaporativ e emissions . Thi s las t approac hi s als o evaluate d i n EPA' s volatilit yproposa l an d i s assume d i n th e bas e analyse s i n suppor t o f today' s refueling proposal . I n particular , th e refueling analyse s presume a certificatio n tes t fue l RVP o f 11. 5 psi , rathe r than th e curren t certificatio n requiremen t o f 9. 0 psi . Th e Agenc ychos e thi s approac hfo r analyzing th e impac t o f volatilit ycontrol s on refueling control s becaus e a certificatio n RV P o f 11. 5 ps i no t onl yrepresent s th e highes t in-us e volatilit yleve l currentl yuse d in th e vas t majorit yo f non-attainmen t area s a s specifie d b yth e America n Societ yfor Testing an d Material s during th e summe r ozon e season , bu t als o i s a worst-cas e situatio n wit hrespec t t o th e cos t an d design , o f onboar d controls .

-49

-P.5 1

I n it s fina l rulemaking , th e Agenc ywil l ensur e tha t th e volatilit yo f th e certificatio n fue l fo r onboar d refueling control s i s full yconsisten t wit hth e fina l decision s mad e abou t tes t fue l in the volatilit yrulemaking .

I f EPAreduce s th e volatilit yo f commercia l fuel , th e cost s an

d benefit s o f refueling control s woul d change , althoug hth e effec t i s relativel ysmall . EPAha s analyze d thes e effect s for th e rang e o f volatilit ylimit s propose d i n th e volatilit yrulemaking . Thes e effect s an d thei r interaction s wit hth e Agency' s decisio n t o contro l refueling emission s ar e full ydiscusse d in Sectio n V o f thi s proposal . Th e analyse s accompanying th e fina l onboar d rul e wil l reflec t th e actua l in-us e volatilit yo f commercia l fue l a s specifie d b yth e fina l volatilit yrule .

I n th e contex t o f solving th e evaporativ e emission s problem , i t i s als o importan t t o understand tha t onboar d refueling control s woul d generall yb e designe d wit hth e inheren t abilit yt o contro l exces s evaporativ e emissions . Thi s i s possibl e becaus e thes e system s ar e simila r i n design an

d functio n t o evaporativ e contro l systems . I f onboard wer e combine d wit hth e contro l o f exces s evaporativ e emission s in thi s manner , th e resulting cos t effectivenes s o f th e reduction s o f exces s H C emission s woul d b e mor e attractiv e than th e contro l o f onl yrefueling emissions . Th e Agency' s draf t gasolin e marketing stud y -50

-P.5 2

use d thi s approach . However , becaus e EPAi s proposing t o addres s th e exces s evaporativ e emission s problemb y controlling fue l volatility , th e Agenc ybelieve s i t i s mos t appropriat e t o determin e th e bes t refueling contro l strateg yexclusiv e o f exces s evaporativ e emission s control . Therefore , the cost s an d benefit s o f eliminating exces s evaporativ e emission s ar e exclude d fro mEPA' s analysi s o f refueling control s an d th e associate d decisio n rational e (i.e. , onboard i s analyze d incrementall yt o th e contro l o f exces s evaporativ e emissions) . Instead , they ar e considere d in th e separat e EPArulemaking actio n o n fue l volatilit yan d exces s evaporativ e emission s containe d elsewher e i n today' s Federa l Register . Use r Convenience . Regardles s o f thei r design , al l Stag e I I system s shar e a commo n drawbac k in tha t th e recover ynozzle s an

d hose s ar e somewha t heavier , bulkier , an d mor e awkward than thei r conventiona l counterparts . Eve n thoughth e overal l inconvenienc e associate d wit hStag e I I system s o f mor e recen t design ha s bee n greatl yreduce d fro m earl ysystems , th e Agenc ybelieve s tha t some smal l inconvenienc e facto r is , an d wil l continu e t o be , associate d wit hth e consume r us e o f Stag e I I equipment .

-51

-P.5 3 Th e inconvenienc e o f using Stag e I I equipmen t can b e especiall ysignifican t fo r balanc e systems , whic har e th e dominan t typ e o f installation . Th e spring-loade d bellow s an d interloc k mechanis massociate d wit hth e "n o seal , n o flow " featur e o f thes e system s ha s some potentiall y inconvenien t characteristics . Th e operato r mus t exer t pressur e on the nozzl e whe n inserting i t int o th e fillpip e i n orde r t o compres s th e bellows , disengag e th e interloc k system , an

d allowfue l t o b e dispensed . Th e interloc k itsel f add s a possibl e failur e mod e t o th e refueling operation . In addition , for prope r operation , th e perso n conducting th e refueling mus t wai t severa l second s afte r stopping th e flowo f fue l befor e removing th e nozzle , i n orde r t o allowth e pressur e withi n th e systemt o equalize . I f th e nozzl e i s remove d to o soo n (a s ofte n happens ) vapo r los s mayoccur . O f course , th e exten t t o whic hthes e characteristic s o f Stag e I I system s ar e perceive d t o b e a n inconvenienc e wil l varyb y individual . Onboar d vapo r recoverysystems , b ycontrast , remai n unnotice d b

yth e consume r during th e refueling process . Th e requisit e hardwar e i s an integral , self-containe d par t o f th e vehicle , an

d ther e i s n o direc t huma n involvemen t i n th e contro l process , sinc e n o specia l actio n or attentio n i s require d in orde r t o dispens e th e fuel . Finally , -52

-P.5 4

contraryt o some vehicl e manufacturers ' claims , onboard system s ar e expecte d t o b e integrate d withi n th e vehicl e i n a waytha t wil l no t interfer e wit hoccupan t o r trun k space . Hence , onboard systems avoi d th e consume r inconvenienc e ofte n associate d wit hStag e I I systems .

I t shoul d als o be note d tha t bot hStag e I I an d onboar d vapo r recover

ysystem s maypresen t some benefi t t o th e consume r in term s of : 1 ) persona l discomfor t du e t o breathing gasolin e vapors , an d 2 ) fue l spitbac k an d spillag e during th e dispensing process . Stag e II , o f course , remove s gasolin e vapor s fro mth e breathing zone, * an d th e mor e recen t generatio n o f equipmen t appear s t o reduc e th e frequencyo f spitback . Similarly , onboar d mitigate s th e inhalatio n o f gasolin e vapors . I t als o shoul d reduc e spitback , sinc e th e system s wil l b e require d t o contro l thi s phenomeno n at highdispensing rate s a s par t o f th e certificatio n process , whic hi s discusse d late r i n today' s notice . I n fact , becaus e o f thi s specifi c

Genera l Motor s ha s examine d th e cost s an d benefit s o f using Stag e I I control s i n California . Althoughth e Agenc ydoe s no t endors e th e conclusion s o f th e study , th e result s sugges t tha t consumer s perceiv e a significan t benefi t associate d wit hbreathing fewe r vapor s whe n using Stag e I I equipment . I f thi s i s th e case , EPAbelieve s tha t onboar d woul d als o b e perceive d a s providing thi s typ e o f benefit , becaus e i t als o reduce s vapo r inhalation .

-53

-P.5 5 regulatoryrequirement , i t i s possibl e tha t onboar d may provid e a somewha t greate r benefi t t o th e consume r i n avoiding thi s particula r annoyanc e than Stag e II . Th e differenc e betwee n onboard an d Stag e I I i n term s o f use r convenienc e i s a significan t distinction . Th e fac t tha t consumer s perceiv e no differenc e in refueling a vehicl e equippe d wit honboard control s relative t o a vehicl e withou t suchcontrol s (o r perhap s eve n some advantages) , mean s tha t on e o f th e primaryincentive s fo r tampering wit hemissio n contro l system s doe s no t exis t fo r onboard . Thi s i s no t the cas e wit hStag e I I system s wher e tampering (e.g. , substitutio n o f conventiona l nozzle s an d hose s b

ystatio n owners ) mayoccur i n an attemp t t o mitigat e potentiall yannoying characteristic s associate d wit hth e dispensing equipment . A s discusse d below , thi s differenc e ha s an impac t o n th e projecte d relativ e in-us e contro l efficiencie s for th e two systems . Th e inconvenienc e associate d wit hth e us e o f Stag e I I systems , a s compare d t o onboard control , als o can b e assigne d a certai n economi c value . I f consumer s woul d willingl ypaymor e fo r thei r gasolin e simpl yt o avoi d th e us e o f Stag e I I dispensing equipment , the n ther e exist s a relative cos t betwee n th e two contro l approache s whic hi s define d a s th e Stag e I I "inconvenienc e cost. " Du e t o th e wid e variatio n in whic hconsumer s mayvalu e Stag e I I

-54

-P.5 6 inconvenience , i t i s impossibl e t o specificall yquantif y thi s cost . However , t o provid e a n indicatio n o f th e importanc e o f thi s factor , the effec t o f smal l inconvenienc e cost s wil l b e indicate d i n the analyse s presente d below . Contro l Efficiency . Bot hStag e I I an d onboar d vapo r recover ysystems hav e th e potentia l t o contro l nearl yal l refueling emissions . Certificatio n test s o f ne wStag e I I installation s b

yth e Stat e o f Californi a indicat e tha t th e system s initiall yar e abou t 9 5 percen t efficient . Tes t dat a for experimenta l onboard system s hav e show n contro l efficiencie s a s higha s 9 9 percent . O f course , i t i s th e in-us e effectivenes s tha t i s importan t i n assessing th e environmenta l benefit s associate d wit heac hcontro l technology . Thi s i s determine d b

ycombining th e theoretica l efficienc yo f eac h syste mwit hestimate s o f th e losse s in contro l frequenc y an d effectivenes s resulting fro msuc hfactor s a s misinstallation , imprope r maintenance , an d tampering . Th e Agency' s analysi s o f dat a fro mexisting Stag e I I program s indicate s tha t th e frequencyo f th e abov e events , an d therefor e th e resulting in-us e efficienc yo f th e contro l technology , i s highl ydependen t on th e leve l o f enforcemen t (e.g. , inspection s b ystat e o r loca l authorities) . Base d on thes e data , nationa l averag e Stag e I I in-us e efficiencie s

-55

-P.5 7

wer e estimate d b

yEPAt o rang e fro

m6 2 percent , i n area s o f minima l enforcemen t (i.e. , essentiall yn o inspections) , t o 8 6 percent , in area s wit hannua l enforcemen t programs . EPA woul d expec t enforcemen t t o varybetwee n thes e extreme s throughou t th e country . Unlik e Stag e I I systems , whic hhav e bee n i n us e i n certai n area s o f the countr yfor severa l years , onboard system s hav e ye t t o b e use d in productio n vehicles . Consequently , ther e ar e n o extensiv e in-us e dat a o n th e performanc e o f productio n version s o f thi s technology . However , EPAnote s tha t prototyp e onboard system s hav e bee n installe d in in-us e vehicle s an d hav e successfull y accumulate d mor e than 50,00 0 mile s o f servic e a t th e theoretica l maximu

mleve l o f control , providing evidenc e o f successfu l in-us e performance .

I n suc hcases , wher e specifi c in-us e dat a i s lacking , in-us e dat a fro

msimila r contro l technolog yi s ofte n use d a s a surrogat e for the purpos e o f analysis . Thi s approac h i s particularl yusefu l here , i n tha t EPAha s a significan t amoun t o f surveillanc e surveydat a fo r evaporativ e emissio n contro l systems , whic har e verysimila r i n design an d functio n t o onboard vapo r recoverysystems . Becaus e o f thes e similarities , EPAanticipate s tha t th e in-us e performanc e o f onboard system s i n capturing vapor s displace d fro

mthe vehicle' s fue l tan k shoul d b e verymuc h

-56

-P.5 8

lik e tha t o f evaporativ e emissio n contro l system s tha t have bee n properl ydesigned . In particular , littl e or n o deterioratio n i n performanc e ove r the usefu l lif e o f th e vehicl e woul d b e expecte d for properl ymaintaine d systems . Hence , using th e rate s o f malmaintenance , defect , an d tampering foun

d fo r in-us e evaporativ e storag e canisters , EPAha s estimate d th e in-us e efficiencyo f onboar d system s t o b e abou t 9 3 percent . Thi s in-us e efficienc yi s no t directl ycomparabl e t o the Stag e I I value s discusse d above , however , becaus e onboard doe s no t contro l th e emptying losse s fro

m th e servic e station' s undergroun d tan k a s Stag e I I control s do . I f thes e losse s ar e include d in expressing th e overal l syste

mefficiencyfor onboard , EPAestimate s thes e control s captur e abou t 8 3 percen t o f al l refueling emissions . Exemptions . Th e installatio n o f Stag e I I contro l system s require s a sizeabl e capita l investmen t b yservic e statio n owners . Fo r man ystations . Stag e I I contro l coul d b e prohibitivel yexpensive , resulting i n significan t economi c hardshi p o r eve n statio n closure . Sectio n 32 4 o f th e CA Aaddresse s thi s issu e fo r smalle r servic e station s b ymandating tha t an yindependen t facilit ywit ha throughpu t les s than 50,00 0 gallon s pe r mont h(gal/mo ) b e exemp t fro

man yFedera l Stag e I I requirement s promulgate d b yEPA . Additionally , th e Agency' s analysi s o f thi s issu e showe d tha t coupling the Congressionally-mandate d 50,00 0

-57

-P.5 9

gal/mo exemptio n limi t for independent s wit ha 10,00 0 gal/mo exemptio n limi t for non-independents , whic ha s a byproduc t o f thei r affiliatio n wit hpetroleu mcompanie s may hav e greate r economi c resources , appeare d t o provid e th e mos t cost-effectiv e Federa l Stag e I I program . Thi s exemptio n scenari o wa s use d extensivel yi n the draf t RIA , an d result s in abou t 7 5 percen t o f al l publi c an d privat e outlet s (representing abou t 2 5 percen t o f th e tota l gasolin e consumption ) being uncontrolled.[3 ] Althoughth e CA

Amandate s tha t an yFederall yrequire d Stag e I I progra

mincorporat e a 50,00 0 gal/mo exemptio n limi t for independen t station s (an d althoughEPAcoul d adop t a 10,00 0 gal/mo limi t fo r non-independent s t o maximiz e cos t effectiveness) , i f Stag e I I wer e selectivel y implemente d i n non-attainmen t areas , Stat e government s coul d impos e mor e stringen t exemptio n level s tha n specifie d b yEP Aor simpl yno t allowexemptions . A s an exampl e o f othe r possibl e exemptio n levels , man yarea s o f Californi a wit hStag e I I program s exemp t station s wit hthroughput s o f les s than 2,00 0 gal/mo. * Lowe r exemptio n level s hav e th e advantag e o f providing greate r emissio n reductions . On e o f th e primarydisadvantage s i s tha t th e margina l cos t o f

* Exemptio n level s i n Californi a non-attainmen t area s rang e fro

m0 - 30,00 0 gal/mo .

-58

-P.6 0 contro l increase s significantl ya s smalle r an d smalle r station s ar e added t o th e program . Also , th e numbe r o f facilitie s escalate s rapidl ya s the exemptio n limi t i s reduced , wit ha concomitan t increas e i n th e scop e an d difficult yo f implementing , an d the n administering suc h programs . Th e Agency' s sensitivit yanalysi s o f thi s issu e showe d tha t th e incrementa l cos t effectivenes s o f contro l rapidl y escalate s fo r station s wit hthroughput s les s than 10,00 0 gal/mo . Fo r example , VO C reduction s fro mstation s pumping betwee n 2,00 0 an

d 10,00 0 gal/mo woul d cos t mor e than nin e time s mor e on a

n incrementa l basi s than th e reduction s provide d unde r th e 10,000/50,00 0 gal/mo Federa l exemptio n scenario . Give n th e potentia l advers e economi c effect s o f lowe r exemptio n levels , th e Agenc ycan no t rul e ou t th e possibilit ytha t man yState s woul d declin e adopting substantiall ylowe r exemptio n level s tha n migh t b e require d b yEPA . Therefore , th e Agenc yha s assume d th e 10,000/50,00 0 gal/mo Federa l exemptio n scenari o i n analyzing th e cost s an d emissio n benefit s o f Stag e II , whil e a t th e same time acknowledging that , i f selectivel y implemente d i n non-attainmen t areas , individua l State s may prefe r mor e stringen t Stag e I I programs .

•59

-P.6 1 Th e existenc e o f an yStag e I I exemption s effectivel y decrease s th e overal l efficienc yo f th e progra m wit hregard t o reducing al l the potentiall ycontrollabl e refueling emissions . I f th e exemption s provide d unde r th e 10,000/50,00 0 gal/mo Federa l limit s ar e include d i n expressing th e overal l systemefficienc yfo r Stag e II , EPA estimate s thes e control s captur e abou t 50-7 0 percen t o f al l refueling emissions . Th e basi s for thi s estimat e i s discusse d mor e full yi n Sectio n II.E . o f today' s notice .

B ycontrast , n o analogou s exemption s ar e necessary , or contemplated , for th e classe s o f vehicle s subjec t t o onboard requirements. * Uni t Cost . Th e estimate d tota l capita l cos t o f a Stag e I I vapo r recoverysystemfo r th e moderately-size d nonexemp t servic e statio n i s $12,200 . Whe n thi s i s amortize d ove r th e expecte d lifetime o f th e equipment , an d th e annua l operating expense s an d fue l recoverycredi t ar e included , suc ha nonexemp t servic e statio n wil l spen d approximatel y$2,60 0 pe r yea r fo r vapo r recoverycontrols . I n th e cas e o f onboard control , whe n expresse d a s an Motorcycle s an

d some off-road vehicle s ar e th e onl y vehicle s potentiall ycontrolle d b yStag e I I system s tha t woul d b e exemp t fro monboar d requirements . Off-roa d vehicle s ar e no t subjec t t o contro l unde r Sectio n 20 2 o f th e Act , whil e EPAwoul d exemp t motorcycle s du e primaril yt o eithe r economi c o r technica l feasibilit yconsiderations . -60

-P.6 2 incremen t t o th e cos t o f reducing exces s evaporativ e emissions , th e vapo r recoverysystemi s estimate d t o increas e th e purchas e pric e o f th e averag e vehicl e b y$19 . I f th e anticipate d fue l recoverycredi t fo r a well-maintaine d vehicl e i s discounte d t o th e yea r o f purchas e an

d added t o the above hardwar e cost , the averag e buye r wil l incu

r a ne t cos t o f abou t $1 4 pe r vehicle . Decisio n Rational e an d Selectio n o f Contro l Technolog

y Thi s sectio n explain s th e Agency' s overal l rational e for proposing refueling control s in general , an d fo r proposing onboard contro l technolog yi n particular . I n discussing whethe r refueling control s shoul d b e adopted , th e cost s an

d benefit s o f othe r strategie s tha t hav e eithe r bee n adopte d or ar e unde r seriou s consideratio n wil l b e use d a s comparativ e benchmarks . I n choosing betwee n th e alternativ e contro l technologies , severa l importan t factor s affecting th e decisio n wil l b e evaluated : emissio n reductions , cance r incidenc e reductions , timing o f th e benefits , cost , cos t effectiveness , enforcemen t burden , use r convenience , equity , an d competitiv e effects . Some o f thes e topic s wer e introduce d in th e previou s section s o f today' s notice , th e other s wil l b e describe d wher e appropriat e i n th e analysi s whic hfollows .

-61

-P.6 3 Th e overal l presentatio n o f EPA' s decisio n rational e begin s b

yfocusing on refueling contro l a s a strateg yt o reduc e ozon e precurso r emission s i n non-attainmen t areas . Th e presentatio n the n focuse s on th e valu e o f reducing VO C emission s i n attainmen t area s an d th e reductio n i n carcinogeni c ris k tha t result s fro ma refueling contro l program . 1 . Refueling Control s fo r Ozon e NAAQ S Attainmen t

T o asses s refueling control s a s a n ozon e reductio n strateg yi n non-attainmen t areas , th e Agency' s analysi s include s onl yth e cost s an d benefit s o f implementing Stag e I I contro l technolog yi n 6 1 urba n non-attainmen t areas * outsid e o f California , becaus e Stag e I I i s alread yi n plac e there , a s discusse d previously . Fo r onboard , th e cost s o f a nationwid e progra mar e use d (sinc e onboar d canno t b e implemente d solel yi n non-attainmen t areas) , whil e th e benefit s ar e restricte d t o onl ythos e tha t woul d occu r in the same 6 1 areas . Evaluating th e tw o contro l technologie s i n thi s manne r doe s no t reflec t th e possibl e reductio n i n cance r incidence s or th e reductio n i n ozon e level s in attainmen t

* , Thi s i s th e estimate d numbe r o f non-attainmen t area s a t th e time thi s analysi s wa s performed . -62

-P.64 _

area s associate d wit honboard contro l requirements . I t i s clear , fo r example , tha t i n additio n t o reducing th e ozon e healt heffect s associate d wit hnon-attainmen t areas , essentiall yal l reduction s i n ozon e precurso r emission s hav e potentia l value , eve n thos e occurring outsid e o f non-attainmen t areas . Including thes e potentia l effect s i n th e analysi s woul d improve th e estimat e o f onboard cos t effectiveness . Th e additiona l benefit s o f a nationwid e onboard program , an d th e effect s o f suc hbenefit s o n cost effectiveness , ar e furthe r discusse d i n Sectio n II.E.3 . o f today' s notice . Tabl e 3 summarize s th e result s o f EPA' s non-attainmen t are a analysis . I t ca n b e see n fromthi s tabl e tha t implementing eithe r Stag e I I or onboar d can provid e a significan t degre e o f VO C contro l i n non-attainmen t areas . Th e rang e o f potentia l emissio n reduction s using Stag e I I i s jus t les s than o r equa l t o abou t tw o percen t o f th e tota l bas e yea r VO C inventory , whil e fo r onboard i t i s abou t two percen t o f th e bas e yea r inventory . Fe wo f th e remaining VO C contro l strategie s know n t o EPAcan provid e significantl ymor e emissio n reductio n i n non-attainmen t areas , sinc e th e large r source s ar e alread ysubjec t t o emissio n contro l requirements .

-63

-P.6 5 Tabl e 3 VO C RESULT S FOR REFUELIN GCONTROL S IN6 1 URBA

NNON-ATTAINMEN

T AREA S Annua l VO C Annualize d Cos t Reductio n Cost s Effectivenes s Strateg y(100 0 Mg/Yr ) ($MM/Yr ) ($/Mg ) Stag e II * 66-10 0 58-9 2 850-110 0 (195-295** ) (2700-3600** ) Onboar d no** * 18 0 2200*** *

* Stag e I I value s ar e base d o n th e 10,000/50,00 0 gal/mo Federa l exemptio n scenario . * * T o illustrat e th e importanc e o f eve n a smal l inconvenienc e cost , thes e number s includ e a n averag e inconvenienc e cos t o f abou t 1 0 cent s pe r refueling event . Thi s represent s a cos t o f $13 7 t o 20 3 MM/yr . An inconvenienc e cos t o f onl yabou t on e hal f a cen t pe r gallo n ( 5 cent s pe r fill-up ) woul d mak e Stag e I I an d onboard cost-effectivenes s value s similar.[3 ] ** * Include s onl yreduction s i n 6 1 urba n N Aareas ; nationwid e reduction s ar e 280,00 0 Mg/yr . *** * A s discusse d late r i n thi s section , whe n th e othe r benefit s o f a

n onboar d progra

mar e included , th e cos t effectivenes s become s substantiall ybetter . T o pu t th e cos t effectivenes s o f refueling contro l in perspective , th e cost-effectivenes s value s in Tabl e 3 can b e compare d t o thos e o f othe r contro l option s tha t ar e availabl e fo r non-attainmen t areas . I n thi s regard , refueling emission s contro l remain s withi n th e cost-effectivenes s rang e represente d b yothe r VO C reductio n strategies , an

d appear s significantl yles s expensiv e tha n some o f th e option s whic hhav e bee n identified . (Fo r example , controlling VO C emission s fro mmeta l rolling

-64

-P.6 6

operation s ha s a cos t effectivenes s ranging u p t o $9,500/Mg. ) Furthermore , a s mentione d earlier , the othe r contro l program s ar e generall ymor e difficul t t o implemen t relative t o a refueling contro l program . Fromthi s information , i t no t onl yappear s tha t th e contro l o f refueling emissions , whethe r b yStag e I I or b

y onboard , represent s a significan t reductio n i n VO C emissions, * bu t can b e achieve d wit ha cos t effectiveness , i n th e rang e o f othe r availabl e contro l alternatives . I f refueling emission s ar e t o b e controlle d t o obtai n non-attainmen t are a VO C emission s reductions , EPAmus t choos e betwee n th e two alternativ e contro l technologies . Leaving asid e th e effec t o f inconvenienc e costs , th e cost-effectivenes s value s i n Tabl e 3 favo r Stag e II . However , ther e ar e a numbe r o f othe r relevan t factor s whic h mus t b e considere d tha t mak e onboar d control s mor e desirabl e overal l than Stag e II . First , viewing th e expecte d emissio n benefits , Tabl e 3 show s onboar d ha s th e potentia l t o provid e greate r emissio n

Reduction s in potentia l cance r ris k ar e proportiona l t o VO C reductions . Thi s topi c i s furthe r discusse d i n Sectio n II.E.3 .

-65

-P.6 7

reduction s than Stag e I I i n the lon g run. * Thi s advantag e o f onboard stems fro mbot hth e likelihoo d o f somewha t highe r in-us e contro l efficiencyan d th e lack o f significan t exemptions , relativ e t o Stag e II.* * A s show n i n Figur e 4 , onboard reduce s refueling emission s b y8 3 percen t fro

muncontrolle d level s afte r ful l implementation . Onboard' s long-ter mcontro l capabilit yfar exceed s th e rang e o f 4 8 t o 6 6 percen t reductio n (depending on leve l o f enforcement ) achieve d b yStag e I I systems wit hth e Federa l exemptio n levels . Thi s advantag e i s especiall ysignifican t whe n i t i s recalle d tha t th e non-attainmen t problemi s projecte d t o become mor e sever e afte r the mid-1990' s an d tha t fewothe r currentl yavailabl e strategie s identifie d b y th e Agenc yappea r capabl e o f providing a significan t degre e o f VO C control .

I n th e short-term , th e compariso n i s les s clea r cut . Figur e 4 show s tha t Stag e I I system s coul d provid e greate r emissio n reduction s than onboard i n th e initia l year s afte r implementation , depending o n wha t assumption s ar e mad e wit h respec t t o th e implementatio n schedul e o f suc hsystems .

Fo r mor e stringen t exemptio n scenario s than th e 10,000/50,00 0 gal/mo Federa l exemptio n leve l assume d i n th e analysis , th e averag e annua l emissio n reduction s fo r onboard ar e a t the mid-poin t i n th e rang e o f possibl e value s fo r Stag e II.[3 ] Onboar d appear s t o retai n thi s long-ter m advantage , excep t whe n Stag e I I exemption s ar e allowe d onl yfo r station s wit hthroughput s o f les s than 2,00 0 gal/mo an d annua l enforcemen t i s assumed . Thi s exemptio n leve l i s no t consisten t wit hSectio n 32 4 o f th e CAA . -66

-JU N 0 o ^8 7

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m. advantag e occur s unde r th e assumptio n tha t Stag e I I system s coul d b e full yinstalle d i n al l non-attainmen t area s withi n a three-yea r period . B y contrast , onboard control s woul d b e phased-i n ove r a longe r perio d o f time a s ne wvehicle s displac e existing vehicle s i n th e fleet . Ther e i s a degre e o f uncertaint yassociate d wit hthe 3-year phase-i n schedul e for Stag e II . Th e logistic s and* resourc e requirement s o f equipping th e larg e numbe r o f servic e station s i n non-attainmen t area s wit hStag e I I systems , an

d th e potentia l for loca l resistanc e t o suc han extensiv e progra

m mak e i t verydifficul t t o judg e whe n ful l implementatio n woul d actuall yoccur . Th e uncertai n natur e o f an yshort-ter

madvantag e tha t mayb e associate d wit h Stag e I I system s i n term s o f emissio n reduction s i s readil y illustrate d i f a somewha t longe r implementatio n schedul e i s assumed . Fo r example , Figur e 4 indicate s tha t a seven-yea r implementatio n schedule , whic hha s bee n suggeste d b yAPI , a s a reasonabl e schedul e an d whic hcoul d occu r i n conjunctio n wit hth e minima l enforcemen t scenario , woul d eliminat e an

yshort-ter

mbenefi t o f Stag e II . Th e Agenc ybelieve s ther e ar e two othe r consideration s pertaining t o VO C reduction s tha t ar e importan t i n choosing betwee n onboard an d Stag e I I i n non-attainmen t areas . Th e firs t involve s th e fac t tha t th e nationwid e scop e o f a n -68

-P.7 0 onboard progra

mwoul d provid e automati c coverag e for margina l attainmen t area s whic hmayotherwis e violat e th e standard i n th e futur e du e t o populatio n o r industria l growth . Th e secon d consideratio n involve s th e broad geographi c natur e o f ozon e ai r qualit yproblems . Thi s pollutan t generall yi s a regiona l concer n becaus e VO C emission s in attainmen t area s mayb e transporte d through th e atmospher e int o adjacen t non-attainmen t areas . Turning fro

mth e immediat e issu e o f emissio n reductions , ther e ar e a numbe r o f practica l area s wher e Stag e I I an

d onboard ar e quit e different . Adopting Stag e I I in non-attainmen t area s acros s th e countrywoul d resul t in a n extensiv e ne wai r pollutio n contro l program . Fo r example , unde r th e Federa l exemptio n criteri a assume d b y EPA , th e 6 1 non-attainmen t area s hav e abou t 43,00 0 servic e station s tha t woul d b e affected . I f individua l state s adopte d mor e stringen t requirements , thi s numbe r woul d escalat e rapidly . I n mos t cases , Stag e I I program s woul d b e implemente d throughactio n b yeac haffecte d stat e government . I n some cases , stat e legislativ e approva l may b e required . Individua l state s woul d the n b e primaril y responsibl e fo r administration , inspection , an d enforcemen t afte r implementation . Whil e th e existenc e o f suc h complication s i s not , i n itself , sufficien t reaso n no t t o implemen t Stag e I I controls , i t i s anothe r facto r t o b e considere d in th e decision . -69

-P.7 1 I n a relate d area , an effectiv e enforcemen t o f Stag e I I program s woul d requir e annua l inspection s i n orde r t o ensur e maximu

m in-us e effectiveness . Hence , th e increas e in enforcemen t staf f fo r state s an d loca l area s associate d wit ha Stag e I I progra mwoul d b e quit e significant . Whe n th e scop e o f thes e programs , th e implementatio n an d continuing enforcemen t costs , an d th e inconvenienc e associate d wit hth e dispensing equipmen t ar e al l take n int o consideration , EPAbelieve s tha t Stag e I I vapo r recover y coul d prov e t o b e a n unpopula r contro l strateg yat bot hth e stat e an

d loca l governmen t level s in man yarea s o f th e country , a s numerou s comment s on EPA' s gasolin e marketing stud yten d t o confirm . Th e numbe r o f differen t partie s involve d i n th e successfu l us e o f Stag e I I control s a s a n ozon e reductio n strateg ycoul d als o hav e significan t advers e impact s o n th e rat e o f implementatio n an d in-us e effectivenes s o f Stag e II . I t likel ywoul d lea d t o delay s i n th e implementatio n o f Stag e I I contro l system s i n some areas , an d eve n afte r implementation , ther e coul d b e pressure s operating agains t th e concurren t establishmen t o f strong provision s fo r inspection s an

d enforcement . Onboar d ha s non e o f thes e practica l disadvantages . Onboard avoid s th e establishmen t o f a multitud e o f ne w stat e an

d loca l program s wit hpotentiall ylarg e enforcemen t

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-P.7 2

burdens . Rather , thi s contro l technolog ywoul d represen t th e additio n o f a ne wmobil e sourc e emissio n standard t o th e existing Federa l Moto r Vehicl e Contro l Progra mtha t ha s demonstrate d it s success . I n addition , i t woul d b e implemented , managed , an d enforce d i n conjunctio n wit hth e existing administrativ e an d enforcemen t function s tha t alread yexis t a s par t o f the curren t moto r vehicl e program . Therefore , onboard hold s a clea r advantag e ove r Stag e I I i n term s o f th e implementatio n an d enforcemen t aspect s o f a progra mt o contro l vehicl e refueling emissions . Ther e ar e certai n economi c consideration s tha t ar e als o importan t in choosing betwee n onboar d an d Stag e II . Thes e concern th e distributio n o f cost s an d resultan t effect s o n competition . Th e installatio n an d maintenanc e o f Stag e I I contro l system s clearl yimpose s a significan t cos t burde n o n servic e statio n owners , particularl ythos e nea r th e exemptio n leve l selected . Further , increase d operating cost s associate d wit h maintaining Stag e I I system s coul d adversel yaffec t competitio n betwee n some controlle d an d uncontrolle d stations . Thi s coul d occur for station s locate d jus t withi n th e boundaryo f a non-attainmen t are a relativ e t o thei r uncontrolle d counterparts , or fo r controlle d station s jus t abov e th e exemptio n cutof f leve l relativ e t o thei r * uncontrolle d competitio n belo wth e exemptio n level . -71

-P.7 3 Suc heconomi c disruption s ar e avoide d throughth e us e o f onboard systems , sinc e th e cost s o f contro l ar e spread acros s a muc hgreate r numbe r o f economi c entitie s (i.e. , al l th e purchaser s o f ne wautomobile s an d trucks) . EPA believe s tha t thi s distributio n o f cost s i s inherentl ymor e equitabl e than tha t fo r Stag e II . Indeed , i t i s likel y tha t becaus e o f thi s basi c characteristi c o f onboar d controls , Sectio n 202(a)(6 ) o f th e CA Adirecte d EP

At o specificall yconside r th e "equitabl e distributio n o f costs " i n evaluating onboar d contro l systems .

I t migh t b e als o argued , however , tha t a n onboar d progra mi s no t equitabl e becaus e vehicl e owner s residing outsid e o f non-attainmen t area s woul d b e require d t o shar e th e cos t o f a programdirecte d primaril ya t non-attainmen t are a benefits . A s wil l b e discusse d below , th e equitie s i n thi s cas e ar e no t s o clear-cut , becaus e ther e ar e potentiall ysignifican t benefit s fro monboar d control s i n attainmen t areas . Finally , turning onc e agai n t o th e questio n o f inconvenienc e costs , EPAbelieve s tha t whil e i t mayb e very difficul t t o assign a specifi c valu e t o eithe r th e operato r inconvenienc e attributabl e t o Stag e I I o r th e variou s implementatio n an

d competitiv e disadvantage s o f Stag e I I jus t described , theyclearl yhav e some value . Referring

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-bac k t o Table . 3 , i t can b e see n tha t eve n a smal l valu e for

suchinconvenienc e radicall yworsen s Stag e I I cos t effectivenes s compare d t o onboard . I n fact , a n inconvenienc e cos t o f abou t on e hal f a cen t pe r gallo n (multiplie d b

ya larg e numbe r o f gallon s pe r year ) make s th e Stag e I I an d onboard cost-effectivenes s value s equal.[3 ] Hence , eve n ignoring th e nationwid e benefit s inheren t i n a

n onboard program , EP Abelieve s tha t onboard ha s man yadvantage s ove r Stag e I I a s a VO C contro l strategy for non-attainmen t areas . 2 . Overal l Benefit s o f Onboar d Contro l Thi s sectio n provide s EPA' s overal l assessmen t o f th e benefit s o f alternativ e refueling emission s contro l programs . Onboard , a s a nationa l refueling emission s contro l strategy , woul d provid e additiona l ambien t ai r qualit ybenefit s an d direc t healt hbenefit s throughou t th e country . Th e benefit s o f reducing emission s o f ozon e precursor s i n non-attainmen t area s ar e relativel yobvious , an d hav e bee n examine d i n detai l i n th e preceding section . Whil e th e potentia l benefit s o f simila r emissio n reduction s i n area s currentl ymeeting th e ozon e NAAQ S mayno t b e a s readil yapparent , theyar e stil l important . I n addition , benefit s i n term s o f direc t healt heffect s (cance r ris k reductions ) occu r i n bot hattainmen t an d non-attainmen t area s a s a resul t o f controlling refueling emissions . -73

-P.7 5 Th e potentia l valu e o f controlling ozon e precurso r emission s in attainmen t area s hav e bee n discusse d earlie r in thi s preamble . Suc hpotentia l effect s includ e th e atmospheri c transpor t o f VO C emission s fro mattainmen t t o non-attainmen t areas , making i t mor e difficul t t o compl y wit hth e ozon e NAAQ S in region s wit hexisting ai r qualit y problems . Ther e ar e als o a considerabl e numbe r o f area s which , whil e i n attainmen t o f th e ozon e NAAQS , ar e very clos e t o th e standard . VO C reduction s i n thes e area s can b e expecte d t o hav e a valu e simila r t o non-attainmen t are a reduction s i f theyar e necessaryt o maintai n compliance . Thes e fact s sugges t tha t ther e i s a benefi t fro ma refueling emission s contro l progra mtha t achieve s emissio n reduction s in attainmen t area s a s wel l a s non-attainmen t areas . Reducing huma n exposure s t o refueling vapor s als o directl yreduce s th e potentia l cance r ris k associate d wit h thes e emissions . EPA' s estimate s o f thes e reduction s ar e give n i n Tabl e 4 . Again , th e number s give n her e fo r Stag e I I reflec t th e fac t tha t Stag e I I woul d b e implemente d i n non-attainmen t area s only , sinc e i t ha s alread ybee n show

n tha t o n a nationwid e basi s onboar d i s mor e desirabl e than Stag e II . Stag e I I incidenc e reductio n benefit s could , o f course , b e increase d b yimplementing a nationwid e program . However , unde r th e Federa l exemptio n limits , overal l Stag e

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-P.7 6

I I benefit s woul d no t b e a s grea t a s thos e for onboard , becaus e o f it s lowe r overal l efficienc yan d th e fac t tha t incidenc e reduction s ar e proportiona l t o emissio n reductions . Tabl e 4 INCIDENC E REDUCTION S FROMSTAG E I I AN D ONBOARD (Annua l Incidenc e 198 8 - 2020 ) Scenari o B z yC sG

V Stag e I I l 2- 4 10-1 5 Onboar d 4 i o 3 8 O n th e basi s o f overal l contro l effectiveness , onboar d produce s large r cance r incidenc e reductions , becaus e contro l i s no t confine d t o non-attainmen t area s only . Therefore , th e number s i n Tabl e 4 strongl yfavo r a n onboar d program . Thes e additiona l effect s ar e certainl yo f valu e t o society , jus t a s ar e ozon e reduction s i n non-attainmen t areas . Theyaccru e withou t an yadde d expens e an d can b e viewe d a s partiall yoffsetting th e cost s o f ozon e reductio n i n non-attainmen t areas . Therefore , giving some reasonabl e valu e t o thes e effect s wil l mor e accuratel yreflec t th e overal l cost.effectivenes s o f refueling control . Assigning exac t monetaryvalue s t o ozon e reduction s in attainmen t area s an d t o th e numbe r o f cance r incidence s avoide d i s problematic , give n th e numbe r o f variable s involve d an

d th e way s variou s segment s o f th e societ ymay

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-P.7 7

valu e th e two type s o f benefits . Estimate s for thes e value s can b e identified , however . Fo r example , fo r VO C reduction s i n attainmen t areas , a valu e o f $250/M g ha s bee n cite d b

yGenera l Motor s i n a previou s evaluatio n o f hydrocarbo n contro l benefits.[9 ] Althoughth e Agenc yha s no t ye t complete d it s ow n analysi s o f th e bes t valu e t o us e for attainmen t are a benefits , $250/Mg ha s bee n use d i n th e analysis . Similarly , a rang e o f $0. 5 t o $7. 5 millio n pe r incidenc e avoide d ha s sometime s bee n use d b yEP Aan d other s t o evaluat e th e benefit s o f reduce d cance r risks . Whil e th e Agenc ydoe s no t endors e thes e specifi c values , theyar e usefu l whe n combine d i n variou s way s t o evaluat e th e cos t effectivenes s o f adopting refueling contro l a s a n ozon e reductio n strateg

yi n th e 6 1 urba n non-attainmen t areas . I f th e value s cite d above fo r emissio n reduction s i n attainmen t area s an d cance r incidence s averte d ar e combine d wit hth e cost-effectivenes s analysi s previousl ysummarize d i n Tabl e 3 , th e result s show n i n Tabl e 5 ar e obtained . Th e firs t valu e ($2200/M g fo r onboard ) i s take n directl yfro m Tabl e 3 , an

d represent s th e cas e wher e cost s ar e applie d onl yt o th e VO C reduction s occurring i n th e 6 1 non-attainmen t areas . Subsequen t entrie s i n Tabl e 5 presen t th e resulting cost-effectivenes s for onboard VO C contro l i n non-attainmen t area s i f credit s fo r othe r benefit s ar e include d a s indicated .

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-P.7 8 Tabl e 5 VO C COS T EFFECTIVENES S IN6 1 URBA

NNON-ATTAINMEN

T AREAS * Onboar d Stag e Quantit yBeing Value d ($/MG ) ($/MG ) VO C reduction s i n non-attainmen t (NA ) area s onl y220 0 850-110 0 VO C reduction s i n N Aareas , wit hbenzen e incidenc e reduction s value d a t $7. 5 M M190 0 740-97 0 VO C reduction s i n N Aareas , wit h$250/Mg benefi t for VO C reduction s i n attainmen t area s (AA ) an d benzen e incidenc e reduction s value d a t $7. 5 M M150 0 740-97 0 VO C reduction s i n N Aareas , wit h$250/M g benefi t fo r VO C reduction s i n A Aan d benzen e an

d _>C 6 incidenc e reduction s value d a t $7.5M

M85 0 460-64 0 VO C reduction s i n N Aareas , wit h$250/Mg benefi t for VO C reduction s i n A Aan d benzen e an

d al l G V incidenc e reduction s value d a t $7.5M

MNeg . Neg . I n viewing th e progressio n o f cost-effectivenes s value s a s variou s benefit s ar e include d i n Tabl e 5 , not e tha t th e cos t effectivenes s o f onboar d rapidl yimproves . In fact , i f al l th e potentia l benefit s ar e include d i n th e analysis , th e VO C cos t effectivenes s i n non-attainmen t area s become s negative . Thi s simpl ymean s tha t th e valu e o f al l th e benefit s i s greate r than th e cos t o f th e onboar d program .

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-P.7 9 However, , a s discusse d earlier , i t i s particularl y difficul t t o accuratel yestimat e th e magnitud e o f the toxi c impac t o f gasolin e vapor s give n th e scientifi c uncertaintie s involved . Thi s uncertaint ysuggest s tha t th e non-attainmen t are a VO C cos t effectivenes s for onboar d i s i n th e rang e fro

mnegativ e t o $1500/Mg . EPAbelieve s suc h cost-effectivenes s value s ar e wel l withi n th e rang e o f an d generall ylowe r than othe r availabl e VO C contro l measures . Indeed , th e overal l desirabilit yo f onboar d relative to * Stag e I I coul d mak e i t preferabl e eve n i f it s cos t effectivenes s wer e substantiall ywors e than tha t for Stag e II . 3 . Conclusion s Th e abov e analysi s ha s presente d th e reasonablenes s an d nee d fo r refueling contro l an d th e compariso n betwee n onboar d an

d Stag e I I fro

ma numbe r o f perspectives . EPA believe s tha t th e result s showrefueling contro l t o b e a cost-effectiv e strateg yfo r reducing VO C emission s an d th e potentia l cance r ris k associate d wit hrefueling vapors . Moreover , th e Agenc ybelieve s tha t onboar d i s mor e desirabl e tha n Stag e I I a s a mean s t o attai n thos e reductions .

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-P.8 0 Propose d Polic yConcerning th e Rol e o f Stag e I I Control s in Nonattainmen t Area s A s describe d above , th e Agenc ybelieve s tha t onboard i s th e preferre d strateg yt o limi t moto r vehicl e refueling emission s an

d i s proceeding wit hth e accompanying regulatoryproposal . I t shoul d be note d tha t choosing a refueling contro l strateg ypresent s a

n unusua l issu e i n tha t on e contro l measur e (Stag e II ) coul d b e employe d an d eventuall ymad e obsolet e b ya mor e effectiv e syste m (onboard) . Thi s introduce s th e nee d t o evaluat e th e effectivenes s ove r time o f requiring essentiall yredundan t systems . Ther e are , however , a variet yo f reason s fo r choosing onboard ove r Stag e II , bot ha s a nationwid e strateg yan d a s a contro l strateg yfo r helping non-attainmen t area s ultimatel yt o attai n th e ozon e standard . Compare d t o requiring Stag e I I control s i n non-attainmen t area s only , onboard' s advantage s include : (1 ) greate r long-ter memissio n reductio n potential , (2 ) th e fac t tha t th e consume r doe s no t hav e t o handl e ne wan d possibl yinconvenien t refueling equipment , (3 ) ozon e reductio n benefit s i n attainmen t areas , including helping t o maintai n th e standard , an d (4 ) nationwid e benefit s fro m reduce d exposur e t o know n an d probabl e carcinogen s i n refueling vapors .

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-P.8 1 Congres s clearl yintende d unde r Sectio n 20 2 (a)(6 ) o f th e Clean Ai r Ac t tha t onboard control s potentiall ycoul d b e a substitut e fo r requiring Stag e I I controls . I n comparing onboard control s t o Stag e II , EP Abelieve s tha t onboard i s th e mos t effectiv e refueling contro l technolog y an d woul d provid e th e greates t overal l benefit s for publi c healt han

d welfare . Thus , EPAbelieve s tha t onboar d woul d b e a n effectiv e substitut e for Stag e I I controls . Accordingly , thi s proposa l t o requir e onboard refueling control s i s als o a propose d determinatio n tha t the Agency wil l no t regard Stag e I I control s a s a "reasonabl y availabl e contro l measure " withi n th e meaning o f Sectio n 172(b)(2 ) o f th e Clean Ai r Act . Th e effec t o f thi s determinatio n woul d b e tha t EPAwoul d no t requir e tha t al l SIP s fo r ozon e non-attainmen t area s subjec t t o Par t D o f th e Ac t contai n Stag e I I control s a s a minimu mattainmen t measure . AlthoughEPAbelieve s onboar d i s th e preferabl e refueling contro l approach , th e time neede d for onboar d t o become effectiv e raise s th e questio n o f whethe r refueling shoul d als o b e controlle d i n th e nea r ter mb ymean s o f Stag e I I implemente d a s a n interi mmeasur e i n some (or all ) ozon e nonattainmen t areas . Th e Agenc yha s examine d suc ha dua l strategy , a s describe d in Volume 1 o f th e accompanying draf t RIA . Tha t analysi s examine d thre e hypothetica l

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# JP.8 2

implementatio n schedule s for Stag e II , i n th e contex t o f a decisio n having bee n mad e t o requir e onboar d control s o n moto r vehicles . Th e analysi s indicate d tha t the valu e an d reasonablenes s o f Stag e I I a s an interi m measur e wa s largel ydependen t on th e spee d wit hwhic hStag e I I coul d b e implemente d i n practice . Th e longe r i t takes , th e mor e th e Stag e I I implementatio n woul d overlap tha t o f onboard , an d thu s Stag e I I a s a n interi mmeasur e woul d resul t i n rapidl y diminishing benefit s at essentiall yconstan t cost . An importan t facto r tha t can affec t th e reasonablenes s o f th e interi mus e o f Stag e I I i s th e degre e o f progres s i n th e developmen t o f Stag e I I regulation s a t th e Stat e level . Stag e I I i s clearl ymor e feasibl e a s an interi m refueling contro l measur e wher e i t ha s bee n installe d (or i s i n th e proces s o f installation ) than i n a situatio n wher e regulation s woul d hav e t o b e develope d an d approve d unde r Stat e procedures , an d the n g o throughth e EPArevie w an d approva l proces s prio r t o implementation . Afacto r relate d t o th e spee d wit hwhic hStag e I I rule s coul d b e developed , approve d an d implemente d woul d b e th e leve l o f controvers ysurrounding implementatio n a t th e loca l level . A s discusse d earlie r in thi s notice , judging b yth e correspondenc e receive d b yEPAo n th e refueling issue , suc h controvers ywoul d likel yb e substantia l an d th e likelihoo d o f delay s an

d litigatio n woul d b e great .

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-P.8 3

I n ligh t o f th e above , EPAbelieve s tha t th e decisio n a s t o whethe r State s mus t implemen t Stag e I I control s for th e interi m

perio d befor e onboard control s become full y effectiv e shoul d depen d ohth e exten t t o whic hState s hav e alread yplanne d fo r an

d implemente d Stag e II . Accordingly , area s wher e Stag e I I ha s alread ybee n installed , o r i s now i n th e proces s o f being installed , mus t continu e t o us e thes e system s whil e onboard control s ar e phase d in . In thes e circumstances , th e continue d us e o f existing Stag e I I woul d provid e interi menvironmenta l benefit s a t littl e additiona l cost . Suc harea s could , however , phas e ou t thes e system s a s onboar d i s phase d in . Suc hchanges , o f course , woul d nee d t o b e incorporate d i n revision s t o th e applicabl e SIP .

Area s tha t hav e no t begun implementatio n o f Stag e I I control s bu t whos e SIP s contai n commitment s t o do so , shoul d procee d wit himplementatio n o r submi t SI P revision s providing adequat e substitut e reductions . I n othe r non-attainmen t areas , interi mStag e I I control s woul d remai n a contro l measur e tha t State s coul d conside r including a s a par t o f th e area' s overal l ozon e attainmen t strategy .

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-Ill . KeyAnalytica l Issue s Affecting EPA' s Decisio n Th e above discussio n ha s attempte d t o full yse t fort h th e analyse s an

d interpretation s use d b yEPAin arriving a t it s decisio n t o propos e the onboard contro l progra m containe d in today' s notice . Th e Agenc yha s expende d considerabl e effor t in it s analyse s an d ha s considere d th e man yissue s an

d uncertaintie s involved . A t th e sam e time , EPAi s cognizan t tha t ther e i s controvers yregarding th e refueling contro l issu e an d i s desirou s o f obtaining th e fulles t degre e o f publi c participatio n i n th e rulemaking process . T o assis t commenters , thi s sectio n wil l agai n revie wth e mai n option s considere d b yth e Agenc yan

d the n presen t a discussio n o f th e analytica l issue s whic hmayb e mos t importan t i n affecting th e outcome o f EPA' s fina l decision .

A . Option s

EPA' s firs t mai n issu e concerning refueling wa s t o conside r whethe r t o contro l or no t contro l refueling emissions . A s describe d earlie r in thi s preamble , th e Agenc ybelieve s tha t contro l i s appropriate . Refueling contro l i s importan t fo r reducing th e generatio n o f ozon e precursor s i n non-attainmen t areas . I n addition , today' s proposa l wil l provid e additiona l benefit s i n term s o f

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-P.8 5

cance r incidenc e reduction s an d in term s o f ozon e reduction s i n attainmen t areas . Give n th e apparen t nee d for refueling control , Agenc y analyse s indicat e tha t bot honboard an d Stag e I I ar e cos t effectiv e approaches . Thus , th e secon d issue facin

g th e Agenc ywa s t o evaluat e competing technologie s for control . A s alread

yindicated , th e onboard contro l approac hha s bee n selecte d fo r proposal . Stag e I I ha s a potentia l advantag e i n term s o f tota l cos t becaus e i t coul d b e applie d selectivel yi n non-attainmen t area s only . I t als o ha s th e potentia l for implementatio n in th e shortes t overal l leadtime (althoug htha t advantag e i s no t completel y clear) . However , onboard' s greate r tota l cos t arise s largel yfro

mit s nationwid e character , whic hbring s additiona l benefit s beyond thos e offere d b yStag e II . Give n a decisio n t o propos e onboard controls , ther e i s a s wel l an optio n t o propos e Stag e I I contro l for th e shor t term . Thi s approac hcoul d provid e emissio n reduction s i n th e shor t ter

mwhil e ne wcar s wit honboar d control s wer e being phase d int o th e fleet . However , th e realizatio n o f thes e shor t ter

m benefit s i s unclea r becaus e o f uncertaint y ove r th e timetabl e for implementing Stag e II . Theywoul d als o b e substantiall ymor e costl ythan th e benefit s o f eithe r onboar d or Stag e I I alon e sinc e theywoul d b e shor t

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-P.8 6 ter mbenefit s an

d incrementa l t o onboard . Thus , a s describe d earlie r i n Sectio n II , EPAbelieve s tha t decision s abou t th e us e o f Stag e I I i n th e shor t ter m shoul d b e include d in th e Stat e Implementatio n Plan developmen t process . I t maybe a s wel l tha t additiona l area s wil l adop t Stag e I I controls . An ysuchadoptio n o f Stag e I I b

yloca l government s mayalte r the cos t effectivenes s o f a Stag e I I progra mcompare d t o onboar d control .

Afina l optio n t o b e mentione d concern s possibl e Agenc yactio n subsequen t t o it s fina l rulemaking o n today' s proposal . I f th e onboard requiremen t wer e t o b e finalize d wit ha substantiall ylonge r leadtime requiremen t tha n proposed , EPAwoul d hav e the optio n o f reviewing th e basi s for it s actio n shortl ybefor e th e requiremen t wer e actuall y implemente d t o determin e i f onboard contro l wa s stil l appropriate . Thi s migh t b e reasonabl e give n th e sensitivit yo f EPA' s decisio n t o factor s whic hcoul d chang e in th e future . Th e lengt ho f time require d t o implemen t onbaor d contro l affect s it s benefi t an d cost-effectivenes s compare d t o Stag e II , a s doe s th e numbe r o f non-attainmen t area s exceeding th e ai r qualit ystandard . I n addition , i f a larg e numbe r o f non-attainmen t area s wer e t o adop t Stag e I I requirement s i t coul d alte r th e desireabilit yo f

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-P.8 7 implementing onboard controls . Suc ha reviewwoul d b e conducte d approximatel yon e yea r befor e th e firs t applicabl e mode l year .

B . Analytica l Issue s Th e propose d choic e betwee n onboard an d Stag e I I ha s relie d upo n a

n extensiv e bod

yo f analysi s whic hha s bee n conducte d ove r a severa l yea r period . Thes e analyse s are . quit e comple xan

d b ythei r natur e involve a grea t numbe r o f projections , judgment s an d assumptions . Some o f thes e area s ar e generall yagree d upon , whil e other s ar e not . I n addition , some matter s hav e mor e impac t o n th e outcome o f th e analyse s than others . Th e following section s revie w assumption s whic har e eithe r controversia l or know n b yEPA t o hav e a significan t impac t o n it s analyses . Theyar e being describe d her e for th e purpos e o f invitin g publi c scrutin yan d comment . Th e Agenc ywishe s t o cautio n commenter s however , tha t i t i s quit e possibl e tha t importan t analytica l issue s exis t whic har e no t identifie d below . Thus , th e Agenc y encourage s al l partie s t o carefull yrevie wal l o f it s analyse s an

d no t t o confin e comment s solel yt o issue s raise d below .

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-P.8 8 1 . Fue l Volatilit y

Th e impac t o f fue l volatilit yo n th e analysi s o f refueling control s wil l b e reviewe d furthe r i n Sectio n VI , therefor e i t wil l no t b e describe d in dept hhere . A s noted , the primaryanalyse s describe d in today' s proposa l hav e bee n conducte d unde r the assumptio n o f in-us e fuel s being at curren t ASTMlimit s (11. 5 RV P for summertime month s i n Clas s C areas) . Thes e condition s pos e the mos t difficul t technica l challeng e an d greates t cos t t o manufacturers . I f th e Agenc yfinalize s it s propose d reductio n o f fue l volatilit yt o 9. 0 RVP for Clas s C areas , the n manufacture r cost s woul d declin e whil e cos t effectivenes s value s woul d increase . A s describe d above , th e cos t effectivenes s o f onboard control s woul d increas e abou t 2 2 percen t whil e Stag e I I woul d increas e abou t 1 3 percent . Th e singl e bes t volatilit yassumptio n t o us e i s difficul t t o determin e a t thi s point , sinc e EPAha s no t ye t finalize d it s volatilit yregulation . Th e presentatio n i n today' s notic e indicate s tha t EPAwoul d expec t t o procee d wit honboar d control s regardles s o f whethe r o r no t volatilit yi s controlle d t o th e level s proposed . At th e same time , interaction s betwee n th e two proposal s indicat e tha t th e questio n o f fue l volatilit yb e resolve d befor e

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-P.8 9 fina l actio n on refueling . Thus , at th e time o f fina l rulemaking , EPAintend s t o presen t it s refueling analyse s unde r th e volatilit ycondition s being promulgate d at tha t time . In th e meanwhile , commenter s ar e requeste d t o conside r th e effec t o f varying fue l volatilit yin thei r comment s on thi s proposal . 2 . Numbe r o f Non-Attainmen t Area s

Base d upo n 198 2 through198 4 (the lates t dat a for whic hmodeling i s completed) , ther e ar e currentl y6 1 urba n non-attainmen t area s outsid e o f California . I n valuing ozon e reductions , EPAha s credite d reduction s i n al l 6 1 o f thes e area s a s contributing t o solutio n o f th e non-attainmen t problem . However , th e projection s o f futur e condition s use d i n analyzing th e effect s o f contro l show tha t th e numbe r o f non-attainmen t area s maydrop significantl yi n th e mid-1990 s unde r variou s possibl e circumstances . Fo r example , th e analysi s supporting th e volatilit yproposa l indicate s tha t ther e mayb e a s fewa s 2 9 non-attainmen t area s i n 199 5 wit hth e adoptio n o f bot h

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-P.9 0 volatilit ycontro l an d onboar d controls. * Thus , i t migh t b e argue d tha t ozon e reduction s shoul d b e counte d in a s fe w a s abou t 3 0 areas . Ther e ar e severa l importan t reason s wh yth e Agenc yha s no t followe d th e above approac hin it s analyses . First , th e sam e projection s whic hindicat e a declin e in th e numbe r on non-attainmen t area s t o 2 9 als o predic t a n increas e t o 3 9 agai n b

yth e yea r 2010 , th e perio d whe n onboard control s wil l b e full yphase d i n an d come t o thei r maximu mleve l o f control . Thus , 4 0 area s mayb e th e bette r estimate . Second , an

d mor e importantly , a close r look at th e modeling result s indicate s tha t almos t non e o f th e modele d area s eve r gai n a substantia l margi n o f complianc e agains t th e ozon e ai r qualit ystandard . Fo r example , eve n assuming volatilit ycontro l t o 9 RVP an d th e adoptio n o f onboard

* Th e volatilit yai r qualit yanalysi s i s base d upo n somewha t differen t assumption s concerning th e futur e o f stationarysourc e control s tha n th e onboar d analysis . Ther e i s considerabl e uncertaint yabou t ho w muc hne wVO C contro l i s availabl e fromstationary source s fo r th e future . Th e onboar d analysi s assume s n o additiona l stationarysourc e controls , whil e th e volatilit yanalysi s include s some moderat e gains . Fo r th e same conditions , thi s cause s th e onboar d analysi s t o predic t 4 t o 8 mor e non-attainmen t area s than th e volatilit yanalysis . EPAi s unsur e whic ho f thes e approache s i s th e mor e accurate . Fo r thi s discussion , th e lowe r number s fro mth e volatilit yanalysi s ar e being used .

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-P.9 1

controls , 5 8 o f th e 6 1 area s modele d remai n a t or above 0.1 1 pp mozon e throughou t th e perio d o f analysis . Thi s represent s onl yabou t a 1 2 percen t margi n belo wthe 0.1 2 pp mstandard . Suc hlevel s ar e wel l withi n th e uncertaint y o f EPA' s models , whic hhav e historicall ytende d t o overpredic t reductions. * Thus , EPAbelieve s tha t reduction s i n al l th e modele d area s hav e valu e i n controlling non-attainmen t conditions . Ther e i s anothe r reaso n arguing fo r considering a n eve n large r numbe r o f area s than th e 6 1 whic hEPAha s identified . Ozon e i s a broa d regiona l phenomena , no t confine d withi n th e specifi c geographi c boundarie s o f non-attainmen t areas . Th e transpor t o f ozon e forming precursor s int o non-attainmen t area s fro madjacen t attainmen t area s i s a significan t contributo r t o non-attainmen t problems . Thus , emission s i n area s adjacen t t o th e 6 1 non-attainmen t area s shoul d als o b e value d for

Th e Agenc yha s consistentl ystresse d th e nee d fo r cautio n i n interpreting modelin g result s o f thi s sort . Yea r t o yea r meteorologyvariation s can rapidl y chang e th e numbe r o f non-attainmen t area s whe n s o man y area s li e veryclos e t o th e standard . On e indicatio n o f thi s effec t i s foun d i n recen t dat a estimating th e numbe r o f non-attainmen t areas . Base d upo n 198 3 through198 5 data , the numbe r o f non-attainmen t area s appear s t o hav e increase d fro m6 1 t o 6 5 whil e modeling woul d predic t some decline .

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-P.9 2 attainmen t o f th e standard (the inheren t abilit yo f onboar d t o contro l suc hemission s i s on e o f th e advantage s o f thi s technology) . EPAi s no t i n a positio n a t thi s time t o identif yspecifi c area s wher e thi s overlap occurs , bu t believe s i t coul d b e substantial . Comment s on estimating thi s effec t woul d b e helpful . Examinatio n o f a fewdifferen t assumption s abou t the numbe r o f non-attainmen t area s t o us e indicate s tha t the . sensitivit yo f onboard cos t effectivenes s t o thi s paramete r i s smal l for mos t combination s (Tabl e 6) . Fo r example , Tabl e 6 indicate s tha t decreasing th e numbe r o f area s fro m 6 1 t o 5 0 increase s th e cos t effectivenes s o f onboar d control s b

y9 t o 1 3 percen t (depending upo n whic hset s o f benefit s ar e being valued , se e Tabl e 5) . Usin g 4 0 area s represent s a 1 9 t o 2 7 percen t increase . Tabl e 6 EFFEC T O F VARYIN

GTH E NUMBE R O F NON-ATTAINMENT AREA S ON ONBOARD COS T EFFECTIVENES S

N/ AAre a VO C Cos t Effectivenes s 4 0 Area s 5 0 Area s 6 1 Area s >6 1 Area s Benefit s Include d (28%) * (31%) * (35%) * (50%) * N/ AAre a VO C Onl y280 0 240 0 220 0 150 0 N/ AAre a VO C + B Z 100 0 92 4 85 0 67 0 an d C 6 G V Incidence s + A AVO C Reduction s Percen t o f nationa l gasolin e consumptio n -91

-P.9 3 A s noted , ther e ar e reason s for considering eve n mor e than 6 1 area s i n th e non-attainmen t are a analysis . Ozon e i s a broad scal e regiona l phenomenon , involving geographi c transpor t an

d ongoing photochemica l processes . A s th e technica l understanding o f ozon e formatio n grows , i t appear s mor e an

d mor e importan t t o conside r emissio n control s beyon

d the specifi c designate d non-attainmen t area s whic hhav e historicall ybee n analyzed . Here , becaus e th e exac t identificatio n o f adjacen t area s whic hmigh t b e directl yinvolve d i s difficult , EPAlack s a specifi c se t o f area s t o include . Sinc e non-attainmen t are a benefit s ar e a direc t functio n o f fue l consumptio n i n th e selecte d areas , th e Agenc yha s use d a n alternativ e base d upo n a n increas e i n the fractio n o f fue l assume d consume d i n non-attainmen t areas . Th e curren t 6 1 area s represen t 3 5 percen t o f nationwid e fue l consumption . Assuming an increas e in th e amoun t o f controlle d fue l t o 5 0 percen t woul d improve th e cos t effectivenes s o f onboar d b y2 0 t o 3 0 percent . 3 . Valu e o f Healt hBenefit s an d Attainmen t Are a Ozon e Reduction s Closel yrelate d t o th e questio n o f ho wman y non-attainmen t area s t o us e i s th e questio n o f th e valu e o f th e benefit s o f reducing cance r incidence s an d th e ozon e reduction s fro

m attainmen t areas . EPA' s analysi s examine d

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-P.9 4 the overal l cos t effectivenes s o f onboard assumin g value s o f $7.5M

Mpe r incidenc e avoide d (fo r variou s assume d incidenc e levels ) an d $25 0 pe r to n o f VO C reductio n i n attainmen t area s (whichEPAbelieve s i s conservative) . T o illustrat e th e effec t o f changing th e assume d values , some alternat e value s hav e bee n considered . Th e cos t pe r incidenc e avoide d (assumin g incidence s relate d onl yt o benzen e plu s C 6 an d above gasolin e vapo r components ) ha s bee n assume d t o rang e fro m$3.5M Mpe r incidenc e avoide d t o a s higha s $10MM . Fo r potentia l attainmen t are a benefits , a valu e o f $50 0 pe r ton ha s bee n use d i n additio n t o $25 0 pe r ton . Tabl e 7 present s th e result s o f thi s sensitivit y analysis . FromTabl e 7 , i t can b e see n tha t th e overal l attainmen t are a VO C cos t effectivenes s o f onboard range s fro ma lo wo f $15 0 pe r to n fo r th e maximu mvaluatio n o f al l benefit s up t o a s higha s $220 0 pe r to n i f n o valu e i s assigne d t o eithe r attainmen t are a VO C reduction s o r incidenc e reductions .

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-P.9 5 Tabl e 7 ONBOARD COS T EFFECTIVENES S ($/Mg )

VO C Valu e i n N/ AArea s Considering BZ+C 6 G V Benefi t Valu e Incidenc e an d A/ AVO C $MM/INCI D $/M

g o f A/ AVO C Reductio n Benefit s 0 3. 5 7. 5 1 0 3. 5 7. 5 1 0 0

25 0 25 0 25 0 50 0 50 0 50 0 220 0 130 0 85 0 54 0 95 0 46 0 15 0 Tabl e 7 doe s no t includ e th e cas e wher e al l incidence s attributabl e t o whol e gasolin e vapor s ar e valued . The y hav e bee n omitte d fro mth e tabl e t o indicat e th e cost-effectiv e natur e o f onboar d control s eve n i f thi s mor e controversia l sourc e o f incidence s i s excluded . I f al l ga s vapor s wer e included , th e cos t effectivenes s o f VO C contro l i n non-attainmen t area s woul d remai n negativ e fo r mos t o f th e case s give n in Tabl e 7 . 4 . In-Us e Efficienc yo f Onboar d Control s Ther e ar e thre e factor s affecting th e averag e in-us e efficienc yo f onboard systems : th e theoretica l efficiency , th e rat e o f tampering wit hin-us e system s an d th e rat e o f malmaintenanc e an

d defect s fo r in-us e systems . Fo r al l o f thes e areas , th e Agenc yha s had t o deriv e appropriat e value s t o us e base d upo n indirec t data , sinc e onboar d

-94

-P.9 6 system s ar e no t ye t i n routin e production . Sinc e th e overal l contro l efficienc ydirectl yaffect s emissio n reduction s t o b e gained , EPA' s approac ht o thes e area s i s important . Th e theoretica l efficienc yuse d for EPA' s analysi s correspond s t o a 9 7 percen t reductio n o f uncontrolle d emissions . B

ycomparison , th e reduction s require d t o attai n th e standard o f today' s proposa l ar e abou t 9 9 percent . Th e reaso n fo r th e differenc e in . value s come s fro mth e fac t tha t th e basi c analysi s o f onboar d impact s wa s conducte d base d upo n earlie r estimate s o f onboar d contro l efficienc ythan tha t eventuall yembodie d i n th e propose d standard . Th e impact s analyse s hav e no t bee n revise d t o reflec t thi s mor e recen t assessment , largel y becaus e th e impac t i s smal l an d becaus e an

yerro r ca n b e considere d conservativ e (i.e. , underestimating benefit s rathe r than overestimating them) . Arevise d analysi s woul d reflec t abou t a two percen t improvemen t i n cos t effectivenes s du e t o th e inclusio n o f thi s change . EPA' s analysi s fo r it s fina l rul e wil l reflec t th e efficienc yo f th e standard adopted . Tampering rate s for onboar d system s wer e derive d fro m EPA' s experienc e wit hevaporativ e controls . Thos e component s o f onboar d system s directl yaccessibl e t o th e operato r (vapo r lines , purg e lines , canisters , etc. ) ar e

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-P.9 7 essentiall yth e sam e a s component s o n curren t evaporativ e controls . Thus , EPAassume d tha t tampering wit hthes e component s woul d occur a t th e same rat e a s currentl yoccur s on evaporativ e systems . Thi s tampering rate , on a flee t weighte d averag e basis , amount s t o 2. 8 percent . Assuming tha t tampere d system s ar e completel ydisabled , ther e i s a corresponding 2. 8 percen t los s i n averag e contro l efficiency .

EPA' s analysi s ha s bee n conducte d base d upo n th e assumption s a s jus t described . However , ther e i s reaso n t o believ e tha t thes e assumption s ar e overl yconservative . Recen t indication s fro msome manufacturer s indicat e tha t onboard canisters , i n a t leas t some applications , wil l b e les s accessibl e than evaporativ e canisters . Tha t is , some manufacturer s hav e indicate d tha t theymaylocat e refueling canister s i n underbod ylocation s or towar d th e rea r o f th e vehicle . Th e degre e t o whic hthi s wil l occu r i s currentl y unclear . However , i f suc happroache s ar e used , theywil l likel yreduc e th e degre e o f tampering whic hoccurs . Thi s effec t ha s no t bee n estimated , an d comment s o n th e appropriat e approac ht o thi s questio n woul d b e valuable . Th e third facto r affecting in-us e efficienc y identifie d abov e i s th e effec t o f malmaintenanc e an d defect s (M&D ) on emissions . A s for tampering rates , EP A ha s relie d on experienc e wit hevaporativ e system s t o -96

-P.9 8

estimat e th e effec t o f M& D o n onboard systems . However , th e translatio n o f M& D effect s fro mevaporativ e system s t o onboard system s i s mor e problemati c than tampering , a s wil l b e describe d below .

I n it s approach , EPAexamine d M& D dat a for evaporativ e system s t o identif yproblem s whic har e commo n t o onboar d systems . Fo r example , problem s suc ha s missing ga s cap s or damage d ai r cleane r gasket s wil l caus e exces s evaporativ e emission s t o occur , bu t wil l no t alte r th e performanc e o f onboard systems . Thes e wer e therefor e exclude d fro mth e onboard analysis . Afte r thes e exclusions , 7. 9 percen t o f th e vehicle s wer e foun d t o hav e M& D problems . Next , using tes t dat a gathere d using commercia l (hig hRVP ) fuel , th e evaporativ e emission s o f thes e problemvehicle s wer e compare d t o th e emission s o f problemfre e vehicles . Whe n weighte d int o th e flee t average , thi s compariso n indicate d a 10. 9 percen t increas e i n evaporativ e emission s wa s occurring du e t o relevan t M& D problem s whe n teste d o n commercia l fuel . EPAthe n applie d thi s percen t increas e t o onboard emissions , an d relate d thi s amoun t t o an equivalen t los s i n contro l efficiency . Tha t is , th e M& D problem s woul d increas e emission s fro monboar d equippe d car s fro m approximatel y0.17 7 gram s pe r gallo n t o 0.19 6 gram s pe r gallo n (compare d t o uncontrolle d rate s o f abou t 5. 9 gram s

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-P.9 9

pe r gallon) . Thi s increas e i n emissio n corresponde d t o a chang e i n contro l efficienc yfro m9 7 percen t t o 96. 7 percent . Being s o small , th e M& D impac t wa s considere d negligibl e an

d no t considere d furthe r i n th e analyses .

A n alternativ e approac ht o evaluating M& D impact s ha s bee n advance d whic hindicate s a greate r possibl e effect . Unde r thi s alternativ e approach , rathe r than computing a proportiona l increas e in emissions , M& D vehicle s ar e evaluate d for an indicate d los s i n overal l evaporativ e contro l efficiency , an d thi s los s i s applie d directl yt o the corresponding onboard contro l efficiency . Operating o n the mos t curren t M& D dat a for M& D problemrate s an d emissio n impact s o n commercia l fuel , thi s approac hha s bee n argue d t o produc e a los s in efficienc yo f thre e t o four percent . However , ther e ar e severa l consideration s whic h mus t b e addresse d befor e a reasonabl e estimat e can b e determine d using thi s approach . Th e viabilit yo f using a direc t transfe r o f efficienc y effect s depend s upo n establishing equivalen t condition s fo r evaluating impact s fo r th e two technologies . Firs t i s th e nee d t o evaluat e th e effec t o f M& D impact s o n evaporativ e system s unde r condition s thes e system s wer e designe d t o manage . Thi s mean s tha t th e M& D impact s mus t b e evaluate d wit h9 RVP fuel . Eve n problemfre e vehicle s hav e exces s

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-P. 1 emission s whe n teste d on commercia l fuel , becaus e th e evaporativ e control s ar e operating beyon d thei r design capacity . Thus , a smal l disablemen t migh t increas e emission s on commercia l fue l bu t hav e n o impac t wit h9 RVP fuel . Sinc e onboard control s wil l b e designe d t o properl y operat e on whateve r commercia l fue l i s eventuall y establishe d throughEPA' s volatilit yproposal , design fue l mus t b e use d t o evaluat e evaporativ e emissio n effects . Whe n result s o n 9 RVP fue l ar e considered , the impac t o f M& D problem s on evaporativ e emission s i s different . Th e numbe r o f vehicle s whic hcan b e considere d t o hav e M& D problem s i s reduce d becaus e some o f th e problemvehicle s mee t th e evaporativ e standard whe n teste d on 9 RVP fuel . Th e absolut e amoun t o f exces s emission s i s als o greatl y decreased . However , emission s fro m problem

fre e vehicle s declin e eve n furthe r and , expresse d a s a percentag e change , M& D problem s hav e a greate r effec t a t 9 RVP than a t 11.5 . Thus , wherea s M& D problem s wit h11. 5 RVP fue l wer e describe d abov e a s increasing averag e emission s b y10. 9 percent , a t 9 RVP th e increas e i s 3 0 percent . Using EPA' s origina l methodology , thi s woul d mea n a reductio n o f onboar d contro l efficienc yt o 96. 3 percent . T o appl ythi s dat a t o a n estimate d los s o f contro l efficiency , th e emissio n level s o f th e M&D - vehicle s on 9 RVP fue l wer e compare d t o expecte d uncontrolle d levels . O n -99

-P. 2 thi s basis , th e M& D vehicle s experience d a los s o f contro l o f abou t 3 5 percent . Average d ove r th e flee t thi s amount s t o abou t a 2. 5 percen t los s o f efficienc yan d change s th e onboard contro l efficienc yt o 94. 5 percent . Thi s valu e represent s a n estimat e o f th e maximu m impac t M& D problem s coul d hav e o n onboard systems . However , th e actua l impac t i s likel yt o b e muc hless . Fo r example , 4 5 percen t o f th e M& D problem s wer e th e resul t o f clogge d o r dirt yfilter s on th e evaporativ e canister . EP A expect s tha t most , i f no t all , onboard systems wil l us e close d bottomcanister s whic hdo no t hav e suchfilters . Furthermore , ther e i s an essentia l differenc e betwee n ho w manufacturer s wil l approac hth e design o f onboard system s compare d t o evaporativ e system s whic hi s impose d b yth e propose d tes t procedure . Th e evaporativ e procedur e test s system s unde r nea r averag e condition s whil e th e onboard procedur e use s a nea r "wors t case " se t o f conditions . Thi s differenc e wil l resul t i n onboard system s whic hhav e a substantia l degre e o f exces s capacit yfor averag e conditions . Thus , partia l disablement s a s represente d b y th e M& D problem s o n evaporativ e system s wil l hav e littl e o r n o impac t o n refueling emission s unde r mos t conditions . I n fact , EPAbelieve s i t quit e reasonabl e t o assume tha t currentl yknow

n M& D problem s wil l no t noticeabl yaffec t onboar d emissions , whic hwa s th e resul t o f EPA' s original

approac ht o estimating th e effec t o f thi s problem . -100

-P. 3 Ther e i s actuall ya potentia l benefi t o f onboar d control s relate d t o M& D problem s whic hha s ye t t o b e quantified . Thi s benefi t i s the likel yeliminatio n o f evaporativ e exces s emission s cause d b yM& D problems . Give n th e exces s capacit yt o b e designe d int o onboard systems , an d give n th e fac t tha t for mos t o f it s driving mile s the onboard caniste r wil l b e i n a highl ypurge d condition , onboar d system s wil l hav e th e abilit yt o absorbM& D effect s withou t an

ycorresponding los s o f evaporativ e emissions

control . Thi s mean s tha t onboard system s coul d captur e exces s evaporativ e emission s whic har e no t expecte d t o b e eliminate d b

yth e propose d control s o f fue l volatilit yor othe r change s t o th e evaporativ e emissio n tes t procedur e being considere d t o mak e i t mor e effective . Ther e ar e othe r condition s beside s M& D problem s whic h ar e currentl ybelieve d t o caus e exces s evaporativ e emission s whic hwil l als o b e affecte d b yonboar d controls . I n general , theyconsis t o f thos e condition s whic hresul t i n cumulativ e evaporativ e emission s whic hwil l excee d th e capacit yo f eve n a wel l designe d system . Thi s woul d includ e suc hthing s a s vehicle s whic har e no t drive n regularl yan

d underg o repeate d diurna l emissio n load s withou t adequat e opportunit yt o purg e th e canister . A n onboar d caniste r woul d b e abl e t o absorbsevera l diurnal s befor e emission s breakthroughwoul d occur . Asimila r

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-P. 4 situatio n woul d occur fo r vehicle s drive n on mostl yshor t trips , agai n allowing insufficien t opportunit yfo r th e evaporativ e systemt o purge . A n onboard syste

mwoul d be muc hmor e toleran t o f suc hdeviation s than woul d curren t evaporativ e systems . Th e Agenc yha s no quantitativ e estimat e o f thi s benefi t at present , bu t believe s i t coul d b e significant . Th e questio n o f th e appropriat e leve l o f in-us e efficienc yt o us e for analysi s o f onboard systems i s a n importan t matter . Th e Agenc ytherefor e request s commen t directe d a t thi s issue , especiall ydealing wit hth e point s discusse d above . An yassistanc e fro mcommenter s i n quantifying thes e impact s woul d b e mos t helpful . 5 . Fue l RecoveryCredit s for Onboar d

Th e ne t cos t fo r onboar d o r Stag e I I system s include s a credi t fo r th e fue l valu e o f recovere d vapors . Fo r onboar d thi s credi t i s partiall yoffse t b yth e impac t o f th e adde d weigh t o f th e onboard hardwar e o n th e fue l econom yo f affecte d vehicles . Some manufacturer s hav e argue d tha t whe n th e adde d weigh t o f th e onboar d hardwar e i s incorporate d int o ne wvehicl e design s ther e wil l b e a n adde d weigh t increas e throughth e effec t o f th e onboar d componen t weight s on th e design o f othe r vehicl e system s (e.g. , frame members , springs , engin e an d driv e trai n components , etc.) . -102

-P. 5 Fo r everypoun

d increas e in payload , thi s argumen t goes , ther e wil l b e a n additiona l 0. 7 pound s added t o th e res t o f th e vehicle . Thus , the impac t o f the onboar d weigh t mus t b e increase d b ya facto r o f 1. 7 befor e computing it s effec t o n fue l consumption . Manufacturer s hav e als o argue d tha t th e fue l econom ysensitivit yo f newl y designe d vehicle s t o change s i n weigh t wil l b e greate r than tha t assume d b

yEPAbecaus e the engin e displacemen t woul d b e adjuste d t o maintai n a constan t driving performanc e characteristic . I n addition , additiona l cos t mus t b e associate d wit hthi s adde d weigh t an d counte d a s par t o f th e onboard contro l cost .

EPA' s curren t analysi s assume s tha t th e onboard hardwar e on futur e vehicle s wil l no t impac t th e weigh t o f an yothe r part s o f ne wvehicles . I t i s appropriat e in some context s t o relat e overal l vehicl e weigh t t o "payload " weight , sinc e th e design o f frames , springs , etc. , i s clearl ydetermine d b yth e require d payload . However , in th e rang e o f four t o fiv e pound s o f ne t weigh t chang e a s involve d here , th e vehicl e platfor mdesign shoul d no t b e sensitiv e t o suc hsmal l changes . Thi s i s a chang e comparabl e t o th e weigh t o f a se t o f floo r mats . Ther e ar e undoubtedl ychange s o f greate r magnitud e than thi s mad e t o ne wvehicl e component s a s th e vehicl e desig n evolves , an d EPAdoe s no t believ e i t i s reasonabl e t o argu e tha t change s

-103

-P. 6

ar e mad e in , fo r example , howbi g the spring s wil l b e eac h time thi s happens . Indeed , thi s valu e undoubtedl yfall s wel l withi n th e rang e o f norma l design toleranc e an d eve n rando m vehicl e t o vehicl e weigh t variability . Th e allocatio n o f tota l vehicl e weigh t t o payload ite mweight s i n thi s rang e i s mor e a n accounting techniqu e than a reflectio n o f actua l effects . Whil e EPAdoe s no t necessaril yfee l tha t the weigh t multiplicatio n argumen t i s appropriat e in the onboard situatio n becaus e o f th e smal l weigh t change s involved , i t ha s don e a sensitivit yanalysi s t o asses s th e impac t o f sucha n assumption . Thi s analysi s ha s bee n don e using a weigh t multiplying facto r o f 1. 3 instead o f th e 1. 7 valu e advance d b

ysome manufacturer s an d NHTSA . Th e 1. 7 valu e ha s bee n develope d b yNHTS Ain connectio n wit hth e developmen t o f bumpe r standards , an d use d for weigh t change s generall ytwic e o r mor e thos e being considere d here . Th e rang e o f possibl e value s fo r thi s paramete r according t o th e NHTS Aanalysi s wa s fro m1. 3 t o 2.0 . I n addition , an

yeffec t fo r light-dut ytruck s o r heavy-dut y vehicle s woul d b e lowe r than fo r passenge r cars , becaus e truc k design i s mor e heavil ydetermine d b ycarg o weigh t requirements .

-104

-P. 7 EPAha s mad e no adjustmen t t o th e sensitivityfacto r for fue l econom

yversu s weigh t change . Th e change s involve d ar e simpl yto o smal l t o b e reasonabl yabl e t o impac t engin e design . Fo r example , th e chang e in 0 t o 6 0 mile s pe r hour acceleratio n time associate d wit hth e weigh t o f onboard control s woul d amoun t t o a n acceleratio n los s o f some 0.0 3 seconds . Suc ha smal l chang e woul d no t eve n b e detectable . EPAfind s littl e basi s t o assume tha t suc h smal l impact s woul d actuall yaffec t engin e design decisions .

I n determining a cos t valu e t o assign t o th e adde d weigh t th e Agenc ybegan wit hrepresentativ e cost s for stee l purchase d b

yth e automobil e industr y(20ci/lb) , assume d 10 0 percen t in valu e adde d an d 2 6 percen t fo r overhead an d profi t t o arriv e a t a valu e o f 50 0 pe r pound . Sinc e th e effec t i s being assume d t o onl yaffec t newl ydesigne d vehicles , a phase-i n schedul e wa s develope d assuming a two yea r lag following implementatio n o f th e ne wstandards , an d a flee t turn-ove r o f si xyear s following that .

Base d upo n th e above assumptions , EPAestimate s tha t th e overal l cos t o f onboar d control s o n newl ydesigne d vehicle s woul d increas e b yabou t 1 0 percen t ($1.40) . Th e flee t averag e impac t considering th e phase-i n schedul e woul d b e t o increas e th e overal l onboar d cos t effectivenes s b yabou t 5. 5 percent .

-105

-P. 8 Ther e i s anothe r facto r in the calculatio n o f fue l recover ycredit s whic hdirectl yaffect s thei r overal l value . Tha t i s th e assume d pric e for a gallo n o f gasoline . Th e valu e use d i n EPA' s curren t analysi s i s $1.20 , whic hrelate s approximatel yt o a crud e oi l pric e o f $3 0 pe r barrel . Some forecast s o f futur e crud e oi l price s indicat e cost s rising abov e th e $3 0 pe r barre l level . Base d upo n a

n increas e in the crud e oi l pric e t o $3 3 pe r barrel , ther e woul d b e a 6 0 pe r gallo n increas e i n th e cost o f gasoline . I f suc ha n increas e i s applie d t o the fue l recoverycredit s for onboard , ther e i s a ne t reductio n i n th e onboard cos t effectivenes s o f abou t thre e percent . I n a simila r fashion , a 6 0 pe r gallo n increas e i n fue l cos t woul d improve Stag e I I cos t effectivenes s b yabou t thre e percent . 6 . Contro l o f Spillag e Emission s

On e sourc e o f gasolin e vapo r emission s associate d wit h refueling operation s i s th e spillag e o f fuel . Wha t migh t generall yb e considere d spillag e can come fro msevera l causes . Spitbac k spillag e can occur whe n fue l i s discharge d fro

m th e fillpip e du e t o exces s pressur e buildu p i n th e fue l tan

k vapo r space . Thi s can happe n nea r th e en d o f a fillu

p a s th e tan

k i s nearl yfull . I t can als o occur earlie r whe n in-us e fue l dispensing rate s excee d th e rate s

-106

-P. 9 tha t th e fillpip e an d fue l tan

k ar e abl e t o accept . Overflo wspillag e can als o occur fro mth e operator' s attemp t t o "to

p off " th e fue l tan k following automati c nozzl e shutoff , or i f th e nozzl e malfunction s an d fail s t o shu t off . Take n a s a whol e spillag e emission s hav e bee n estimate d t o represen t abou t 5 percen t o f tota l refueling emission s an

d hav e bee n considere d unchange d b yeithe r onboard or Stag e I I controls . Althoughno t ye t considered , bot honboard an d Stag e I I equipmen t ar e likel yt o affec t spillage . Th e onboard tes t procedur e requirement s wil l requir e vehicle s t o b e abl e t o refue l a t th e maximu min-us e dispensing rate , thu s eliminating spitback . Finally , give n th e improve d fillabilit ythi s represents , i t i s likel ytha t reduce d topping of f operation s wil l occur . Stag e I I equipmen t wil l no t directl ybring abou t th e eliminatio n o f spillag e sources . However , sinc e th e fue l woul d b e containe d withi n th e vapo r collectio n boo t on th e Stag e I I nozzle , spillag e woul d b e containe d somewhat . However , sinc e some o f tha t fue l coul d subsequentl yb e spille d a s th e operato r replace d th e nozzl e on th e dispenser , th e degre e o f possibl e contro l i s difficul t t o estimate . I n addition , sinc e th e operato r canno t visuall y observ e th e refueling operation , attempt s t o top of f th e tan k maycaus e increase d spillage . -107

-P.1 0 Overall , i t appear s tha t onboard an d Stag e I I wil l hel p reduc e spillage . Onboar d appear s likel yt o contro l spillag e bette r than wil l Stag e II , bu t th e Agenc yha s no t incorporate d quantitativ e estimate s o f thes e benefit s int o it s cost-effectivenes s analysis . Base d upo n the estimate s o f spillag e note d above , however , withou t an yfue l recovery credi t for the recovere d fue l th e tota l contro l o f spillag e coul d improve cos t effectivenes s a s muc ha s 5 percent . 7 . Contro l o f Emptying Losse s Anothe r componen t o f overal l refueling emission s i s tha t categoryo f emission s know n a s emptying losses . Thes e emissions , whic hcontribut e abou t 5 percen t o f overal l refueling emissions , ar e considere d t o b e generate d a s par t o f th e proces s i n whic hambien t ai r i s draw n int o th e gasolin e underground storag e tan k t o replac e th e los t volum e o f fue l having bee n dispensed . Th e air , a s i t become s saturate d wit hth e gasolin e vapor s i n th e underground tank , expand s slightly . Thi s expansio n i s the n presume d t o giv e ris e t o emission s bac k ou t th e underground tank' s ven t pipe . Emptying losse s hav e no t bee n measured , bu t hav e bee n estimate d base d upo n th e theoretica l consideration s jus t outlined . EPAbelieve s tha t ther e i s reaso n t o believ e

-108

-P.1 1 tha t emptying losse s mayactuall yb e eithe r muc hsmalle r than estimate d or essentiall ynon-existent . Th e proces s o f drawing ou t fue l i s relativel yslowcompare d t o the whol e volume o f th e undergroun d tank , an

d i t appear s likel ytha t ai r draw

n int o th e tan

k during th e earl yportio n o f a refueling even t wil l come int o equilibriu mwhil e th e refueling operatio n i s continuing . In thi s event , rathe r than causing a

n actua l releas e o f vapo r saturate d air , the expansio n proces s woul d merel yreduc e th e amoun t o f replacemen t ai r neede d t o b e draw n i n during th e late r portion s o f th e refueling event . Thus , th e onl ylikel y emission s woul d come at the veryen d o f th e refueling event . Beyond this , sinc e refueling i s an ongoing proces s wherei n multipl e refueling event s ar e generall yoccurring i n overlapping fashion , eve n th e potentia l emptying los s emission s a t th e en d o f on e refueling even t woul d ten d t o b e eliminate d b

yentrainmen t demand s fro mother , continuing refuelings . Thus , i t appear s tha t emptying losse s may , i n fact , b e verysmall . I n EPA' s curren t analysis , thes e emission s ar e assume d t o b e controlle d b yStag e II , whic hrecirculate s vapo r bac k fro

mth e vehicl e fue l tan k t o th e undergroun d tank , eliminating ai r entrainment . Onboard , on th e othe r hand , i s assume d t o hav e n o effec t o n emptying losses .

-109

-P.1 2 Thus , eliminating th e 5 percen t o f emptying los s emission s fro m th e analysi s woul d no t chang e onboard cos t effectiveness , bu t woul d increas e th e Stag e I I valu e abou t 5 percent . 8 . Stag e I I Exemptio n Level s an d Inconvenienc e Cost s

Bot hexemptio n level s an d inconvenienc e cost s hav e bee n discusse d earlie r i n thi s preambl e an d thei r effect s upo n Stag e I I performanc e an d cos t effectivenes s described . Th e exemptio n leve l use d b yEPAcorrespond s t o approximatel yth e mos t cos t effectiv e leve l for Stag e II . Reducing exemption s woul d increas e th e fractio n o f vapor s capture d b

yStag e II , bu t woul d do s o a t highmargina l cos t effectiveness . Fo r example , VO C reduction s fro mincluding station s betwee n 2,00 0 an d 10,00 0 gal/mo woul d cos t mor e than nin e time s thos e include d in EPA' s primaryanalysi s an d woul d increas e th e averag e cos t effectivenes s o f Stag e I I abou t 5 5 percent . Inconvenienc e cost s hav e bee n show n t o hav e a dramati c impac t upo n Stag e I I cos t effectivenes s eve n at a verylo w valuation . A t onl y10 0 pe r refueling event , inconvenienc e cost s mor e than tripl e th e Stag e I I cos t effectiveness . Whil e th e Agenc ydoe s no t hav e an exac t estimat e fo r actua l inconvenienc e cost s fo r Stag e II , th e us e o f Stag e I I

-110

-P.1 3 system s require s th e involvemen t o f th e publi c an d wil l resul t i n some inconvenienc e t o them . 9 . Coordinatio n o f Stag e I I an d EPA' s Underground Storag e Tank Progra m Th e Agency' s recentl ypropose d Underground Storag e Tan k (UST ) progra

mcoul d potentiall yreduc e th e overal l cos t o f a Stag e I I vapo r recover yprogram . Th e US T progra m i s designe d t o detec t an d replac e o r repair , a s needed , leaking storag e tank s tha t caus e groundwate r contamination . I f th e installatio n o f Stag e I I control s wer e coordinate d wit hunderground tan k repai r or replacement , th e trenching an d paving cost s associate d wit h Stag e I I vapo r recoveryline s potentiall ycoul d b e reduced . Th e Agency' s sensitivit yanalysi s o f a coordinate d Stag e II/US T progra mi s containe d in Volume 1 o f the draf t RIA . I n essence , EPAassume d a five-yea r phase-i n perio d for th e coordinate d progra mt o correspond t o th e US T provision s requiring tha t al l underground storag e tan k system s mus t b e teste d fo r leak s withi n tha t time . Further , i t wa s assume d tha t 3 5 percen t o f th e tank s woul d b e foun

d leaking an

d tha t immediat e correctiv e actio n a t servic e station s woul d occur a t a relativel ylinear rat e ove r th e five-yea r period . Base d o n thes e principl e assumptions , combining th e Stag e I I progra mwit hth e US T

-111

-P. M

progra mwoul d improve th e cos t effectivenes s o f Stag e I I b y abou t si xpercent . Nonetheless , eve n thi s smal l improvemen t mayb e overl y optimistic . Th e assumptio n tha t 3 5 percen t o f th e underground storag e tank s wil l nee d repai r or replacemen t i s a worst-cas e estimate . Informatio n tha t i s onl y recentl ybecoming availabl e suggest s thi s valu e i s to o high , perhap s b

ya facto r o f three . I f th e fina l valu e i s close r t o 1 0 percent , the resulting improvemen t in Stag e I I cos t effectivenes s woul d b e onl ytwo percent . Thes e result s ar e als o predicate d on full ycoordinating th e two programs . I n reality , i t i s doubtfu l tha t Stag e I I installatio n an

d US T repair s woul d occur simultaneousl yin everyinstance . Finally , i t i s importan t t o not e tha t a coordinate d Stag e II/US T progra mcoul d delayth e environmenta l benefit s o f vapo r recoverycontrols . Th e Agency' s "optimum " phase-i n schedul e for Stag e I I in non-attainmen t area s i s thre e years , bu t a s discusse d abov e thi s coul d b e extende d t o fiv e year s i f coordinate d wit hth e US T requirements . The n again , eve n thi s latte r phase-i n schedul e assume s tha t lea k detectio n an

d correctiv e actio n occur a t a relativ e linea r rat e ove r th e five-yea r period . Thi s mayb e unrealistic , becaus e man ytan k owner s ar e - likel yt o wai t

-112

-P.1 5 unti l th e las t momen t t o conduc t lea k tests . I f thi s i s th e case , a shortag e o f contractor s t o performthe necessarywor k maydevelop , leading t o a dela yin correctiv e actio n an d a stretch-ou t o f Stag e I I implementation . Th e longe r Stag e I I implementatio n takes , th e mor e i t approache s th e onboard phase-i n schedule , erroding or eliminating th e potentia l short-ter memission s reductio n advantag e o f Stag e II . C . Summaryo f Sensitivit yIssue s Th e previou s sectio n ha s reviewe d a numbe r o f issue s affecting onboar d an d Stag e I I cos t effectivenes s values , an d attempte d t o identif yth e possibl e impact s associate d wit heach . Mos t o f th e impact s ar e small , excep t for Stag e I I inconvenienc e costs . Today' s proposa l i s base d upo n a RegulatoryImpac t Analysi s whic hassume s 6 1 principa l non-attainmen t areas , a fue l volatilit yo f 11. 5 RVP , an d value s fo r th e othe r keyparameter s a s jus t described . Th e appropriat e value s fo r thes e an d othe r parameter s t o b e include d i n EPA' s fina l RegulatoryImpac t Analysi s may significantl yaffec t th e result s o f th e fina l analyses . Therefore , th e Agenc yencourage s commen t o n al l o f thes e factors , along wit han yother s whic hcommenter s believ e t o b e o f importance . Specifi c area s for commen t a s identifie d abov e are : (1 ) th e prope r treatmen t o f fue l volatility ,

-113

-P.1 6 (2 ) th e appropriat e numbe r o f non-attainmen t area s t o use , (3 ) th e appropriat e value s for healt hbenefit s an d attainmen t are a ozon e reductions , (4 ) th e in-us e efficienc y o f onboard controls , (5 ) treatmen t o f fue l recoverycredit s for onboard , (6 ) contro l o f spillag e emissions , (7 ) the contro l o f emptying losses , (8 ) Stag e I I exemptio n level s an d inconvenienc e costs , an d (9 ) th e coordinatio n o f Stag e I I an d EPA' s undergroun d storag e tan

k program . Clearly , specifi c quantitativ e analysi s wit hsupporting dat a wil l b e o f mos t us e t o th e Agenc yin completing it s fina l study . IV . Respons e t o Challenge s Regarding EPA' s Lega l Authorit y

I t ha s bee n suggeste d t o EPAtha t th e Administrato r i s obligate d t o requir e Stag e I I control s b yregulatio n fo r al l ozon e non-attainmen t area s and , thus , a s a practica l matter , tha t th e Agenc yha s n o discretio n t o choos e onboar d control s ove r Stag e II . Thi s argumen t i s base d principall y on th e assumptio n tha t Sectio n 17 2 o f th e CA Arequire s th e SIP s for thes e area s t o includ e Stag e I I control s a s a "reasonabl yavailabl e contro l measure " (RACM). * EPAdoe s

* Sectio n 172(b)(2 ) o f th e CA Arequire s tha t al l non-attainmen t are a SIP s provid e fo r implementatio n o f al l "reasonabl yavailabl e contro l measure s a s expeditiousl ya s practicable " t o ensur e attainmen t o f eac hprimaryNAAQ S b yDecembe r 31 , 198 2 or , i n th e cas e o f ozon e an

d CO , b

yDecembe r 31 , 1987 . Neithe r th e statut e no r EPA' s implementing regulation s expressl ydefin e RACMan d th e Agenc yha s broad discretio n t o determin e whethe r an d unde r wha t circumstance s an

ycontro l measur e shoul d b e considere d "reasonabl yavailable. " -114

-P.1 7

no t agree . A s discusse d in mor e detai l i n a separat e memorandu

m i n th e publi c docket , th e Agenc ybelieve s tha t Congress ' intent , a s expresse d in Sectio n 202(a)(6 ) o f th e CAA , i s tha t EPAshoul d mak e a careful , reasone d choice , o n th e merits , betwee n onboard an d Stag e I I controls.[10 ] Thus , the argumen t tha t Stag e I I mus t b e considere d RACM an d tha t Congres s assume d Stag e I I control s wer e RACM , i s inconsisten t wit hth e purpos e o f Sectio n 202(a)(6 ) an d woul d effectivel yrende r tha t sectio n a nullity . Th e Agenc ydoe s no t believ e Congres s woul d hav e intende d suc ha result . Moreover , EPA' s interpretatio n i s consisten t wit h othe r provision s o f the CA A(an d it s legislativ e history) , whic hindicat e tha t Congres s anticipate d tha t th e Administrato r migh t no t requir e Stag e I I controls .

EPA' s conclusio n i s no t change d b yth e fac t tha t Sectio n 17 2 set s Decembe r 31 , 198 7 a s th e deadlin e fo r ozon e attainment . I t doe s no t followfro mth e existenc e o f th e deadlin e tha t EPAi s preclude d fro mthoroughl y considering Stag e I I an d onboar d unde r Sectio n 202(a)(6 ) an d the n choosing th e mor e "desirable " technology . Nothing i n Sectio n 202(a)(6) , o r an yothe r statutoryprovision , require s tha t th e Administrato r bas e hi s decisio n o n whethe r t o requir e Stag e I I or onboard solel yor primaril y o n whic htechnolog ycan mor e easil ymee t th e Decembe r 198 7 deadline , or tha t h e sacrific e the potentia l long-ter m benefit s fro

m onboard control s i n favo r o f th e greate r

-115

-P.1 8 short-ter

mozon e reduction s tha t Stag e I I migh t produce . I n an ycase , fo r an

ynon-attainmen t are a no t alread y implementing Stag e II , th e leadtime necessaryfo r installatio n o f thes e controls , althoughshorte r than th e time neede d for onboard t o become full yeffective , i s far to o lon g t o affec t attainmen t b yDecembe r 31 , 1987 . Finally , EPAdoe s no t agre e wit hth e additiona l argumen t tha t th e Agenc yitsel f ha s previousl ydeclared ' Stag e I I t o b e RACM . Althoughsome olde r EPAinformatio n an d SI P polic ydocument s showtha t Stag e I I wa s considere d technologicall yfeasible , EPAha s neve r require d tha t a Stat e includ e Stag e I I a s 5RAC Mi n it s ozon e non-attainmen t SI P a s a conditio n for SI P approval , o r otherwis e define d Stag e I I t o b e RACMi n an ySI P or othe r rulemaking .

In summary , EPAi s no t legall yrequire d t o declar e Stag e I I t o b e 5RAC Mi n al l ozon e non-attainmen t area s an d i s no t preclude d fro mproposing onboar d contro l a s a n alternativ e t o Stag e II . V . Interaction s Betwee n th e Contro l o f Vehicl e Refueling Emission s an

d th e Propose d Regulatio n o f Fue l Volatilit y Thi s sectio n explore s th e effec t o f controlling fue l volatilit yo n variou s aspect s o f today' s proposal , an d in larg e par t i s a summaryo f th e mor e detaile d analysi s

-116

-P.1 9 containe d i n th e draf t RIA . Suc ha consideratio n i s importan t becaus e EPAi s proposing t o contro l th e volatilit yo f commercia l fuel , a s describe d elsewher e in today' s Federa l Register . A s alread ydiscusse d i n Sectio n II.D.2 . o f thi s notice , th e volatilit yo f commerciall y availabl e fue l ha s risen steadil yi n th e las t severa l year s an d i s no wsignificantl yhighe r than tha t o f th e fue l use d in emission s certificatio n testing . Th e Agenc yha s determine d tha t thi s situatio n i s a primaryreaso n wh yman y vehicle s excee d th e applicabl e evaporativ e emissio n standard s in custome r service .

I n th e futur e EP

Aintend s t o hav e th e volatilit yo f certificatio n fue l reflec t tha t o f in-us e fuel . Ther e ar e two basi c approache s for ensuring thi s occurs . Th e firs t consist s o f increasing th e certificatio n fuel' s volatilit y unti l i t reflect s the summertime volatilit yo f commercia l fue l fo r "Clas s C " area s o f th e countrya s define d b yth e America n Societ yfo r Testing an d Materials . (Clas s C area s ar e importan t becaus e th e temperatur e condition s associate d wit hth e emissio n tes t procedure s mos t closel yresembl e th e summertime temperature s o f thes e locations. ) A s describe d earlier , thi s approac hwa s assume d i n th e previou s analyse s o f refueling controls . Specifically , th e analyse s use d a n assume d certificatio n fue l RVP o f 11. 5 psi , rathe r than th e curren t requiremen t o f 9. 0 ps i (whichrepresente d Clas s C are a summertime value s i n th e earl y1970's) . -117

-P.2 0 A s a n alternative , th e volatilit yo f commercia l an d certificatio n fuel s coul d b e regulate d t o some leve l belo w tha t currentl yfoun d i n th e marketplace . Thi s i s the approac htake n i n th e Agency' s paralle l proposa l t o establish , ultimately , th e volatilit yo f commercia l gasolin e i n Clas s C area s a t an RVP o f 9. 0 ps i during th e summe r month s (i.e. , MaythroughSeptember) , whe n th e majorit yo f ozon e NAAQ S violation s occur . Thi s leve l correspond s t o tha t o f curren t certificatio n fuel , whic h woul d b e maintaine d at 9. 0 psi . Th e RVP o f commercia l fuel s woul d b e uncontrolle d b yth e Federa l rule s fo r th e remainde r o f th e year . I n area s othe r than Clas s C , RV P woul d b e reduce d proportionally . I f EPAfollow s thi s approac han

d act s t o regulat e fue l volatilit yi n th e future , th e benefits , costs , an d cos t effectivenes s o f refueling control s woul d b e affected , i n additio n t o th e specifi c design o f onboar d systems . Th e implication s o f suc hcontro l o n thes e two genera l area s ar e discusse d below . Turning firs t t o th e sensitivit yo f th e refueling analysi s t o volatilit ycontrol , th e relativ e change s i n benefits , costs , an d cos t effectivenes s wil l b e illustrate d fo r th e cas e wher e th e in-us e summertime RVP i n Clas s C area s an

d th e RVP o f certificatio n fue l i s 9. 0 psi . Th e sensitivit yanalysi s wil l firs t focu s o n th e resulting change s i n emissio n reductions , costs , an d cos t effectivenes s o f the alternativ e refueling contro l technologies , an

d the n o n th e estimate d cance r incidences .

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-P.2 1 Th e principa l effec t o f changing th e volatilit yleve l i s on th e gasolin e vapo r emissio n facto r (i.e. , gram s o f vapo r pe r gallo n o f dispense d fuel) . Unde r th e 9. 0 RVP case , th e annua l averag e gasolin e refueling emissio n facto r i s abou t 1 1 percen t les s than for th e 11. 5 RV P case . Thi s chang e i n emissio n facto r ha s a simila r effec t o n the hydrocarbo n emissio n reduction s associate d wit hStag e I I an d onboard controls . I n eac hcase , th e benefit s ar e directl yproportiona l t o th e chang e i n emissio n factors , s o tha t th e overal l mas s o f emission s controlle d als o decrease s b

yabou t 1 1 percent . Unlik e th e emissio n reductions , however , th e cost s o f th e two contro l technologie s ar e affecte d differentl yb ychange s i n th e emissio n factor .

A s state d previously , th e cost s o f Stag e I I control s fal l int o thre e basi c categories : capita l costs , operating expenses , an

d a vapo r recoverycredit . O f these , onl yth e vapo r recoverycredi t i s affecte d b ychange s i n th e gasolin e emissio n factor . Lik e emissio n reductions , th e vapo r recoverycredi t i s abou t 1 1 percen t les s fo r 9. 0 RVP fue l tha n fo r 11. 5 RVP fuel . Using thi s lowe r vapo r recoverycredi t in th e analysi s raise s th e overal l cos t o f Stag e I I control s b yabou t 6 percent .

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Fo r onboard , a chang e i n th e gasolin e emissio n facto r affect s bot hth e cos t o f th e requisit e contro l hardwar e an d th e vapo r recoverycredit . Regarding th e hardware , i t mus t b e remembere d tha t EPA' s estimat e o f onboar d contro l cost s i s incrementa l t o tha t necessaryt o contro l exces s evaporativ e emissions . Wit hthi s i n mind , lowering th e certificatio n fuel' s volatilit yfro man RVP o f 11. 5 ps i t o 9. 0 ps i result s in bot ha smaller , les s costl yrefueling emission s storag e canister , an d a reductio n i n the cos t o f th e requisit e vehicle-base d evaporativ e emissio n controls . However , th e chang e associate d wit hth e caniste r i s significantl ysmalle r than the chang e in th e evaporativ e controls . Therefore , th e incrementa l cos t o f onboar d control s ove r evaporativ e emissio n control s wit h9. 0 RVP fue l i s abou t 5 percen t highe r than th e incrementa l cos t o f onboar d ove r evaporativ e control s wit h11. 5 RV P fuel . Th e exten t t o whic hth e onboar d vapo r recover ycredi t i s affecte d b

ya les s volatil e fue l depend s on change s i n th e amoun t o f fue l tha t i s recovere d (the gros s recovery credit ) an

d i n th e amoun t o f fue l tha t i s use d b yth e vehicl e t o overcome th e adde d weigh t o f th e onboard system . A s wa s th e cas e fo r Stag e II , th e gros s recovery credi t fo r onboar d unde r th e 9. 0 RVP cas e directl yrelate s t o th e chang e i n th e emissio n factors . However , regardles s o f th e fuel' s volatility , ther e i s no significan t chang e i n

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th e weigh t penalt yassociate d wit hth e onboard system . Therefore , th e ne t chang e i n th e onboar d vapo r recovery credi t i s large r than indicate d b yth e rati o o f th e emissio n factor s alone . Tha t is , i n respons e t o th e 1 1 percen t reductio n in th e emissio n factor , the fue l recovery credi t decrease s b y1 7 percent . Using th e highe r system cos t an

d th e lowe r vapo r recoverycredi t i n th e analysi s raise s th e overal l incrementa l cos t o f onboard control s b y abou t 8 percent . No wtha t th e relativ e change s i n emissio n reduction s an d cost s fo r th e two RVP scenario s hav e bee n identified , th e accompanying change s in th e respectiv e cost-effectivenes s value s can b e discussed . Fo r Stag e II , th e lowe r emissio n reduction s an d highe r cost s resul t i n increasing th e cos t pe r megagra mo f VO C reduce d b yabou t 1 3 percen t fo r 9. 0 RVP fue l compare d t o 11. 5 RVP fuel . Fo r onboard , th e cost-effectivenes s valu e increase s abou t 2 2 percent . Thes e relativel ysmal l change s i n cos t effectiveness , however , d o no t affec t th e overal l conclusio n (a s discusse d previously ) tha t refueling control s ar e a reasonabl e an d reasonabl ycost-effectiv e metho d fo r reducing ozon e precursor s i n non-attainmen t areas . Neithe r doe s th e smal l potentia l increas e in onboard' s cos t effectivenes s relativ e t o Stag e I I control s significantl yaffec t EPA' s preferenc e fo r onboard a s th e

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-P.2 4 required contro l technique , becaus e th e overal l benefit s o f onboard stil l mak e i t mor e desirable .

I n considering th e benefit s o f mitigating th e cance r ris k associate d wit hexposure s t o refueling emissions , th e effec t o f volatilit ycontro l depend s o n th e typ e o f emission s being evaluated : whol e gasolin e vapor s (GV) , th e heavie r molecula r weigh t fractio n (>C S ) , o r benzene . In eac hcas e the difference s i n cance r incidenc e reduction s shoul d b e approximatel yproportiona l t o th e chang e in th e emissio n factors , bu t th e relativ e chang e for eac h pollutan t typ e wil l b e different . Fo r th e G V category , moving fro

m 11. 5 RV

P fue l t o 9. 0 RVP fue l reduce s th e emissio n facto r b

yabou t 9 percen t a s alread ymentioned . Thi s shoul d caus e th e estimate d incidenc e reduction s associate d wit hG V exposure s t o declin e b ya simila r percentage . Th e chang e in emissio n factor s fo r th e ^C 6 fractio n an d benzen e depend s on th e method s gasolin e refiner s us e t o reduc e volatility . Generally , EPAbelieve s producer s wil l reduc e th e amoun t o f lighte r hydrocarbo n compound s i n th e fuel . Thi s wil l caus e th e relativ e percentag e o f heavie r compound s t o increas e somewhat , making th e emissio n facto r an d associate d chang e i n incidenc e reduction s associate d wit hth e _>C 6 vapo r fractio n slightl ygreate r fo r 9. 0 RVP

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-P.2 5 fue l than 11. 5 RVP fuel . Th e effec t o f RVP contro l o n the estimate d incidence s fo r benzen e i s difficul t t o assess . I f volatilit yi s indeed reduce d b ydecreasing th e fractio n o f lighte r hydrocarbons, ' ther e als o wil l b e a concommiten t reductio n i n octan e rating . Thi s maynecessitat e th e us e o f octan e boosting compound s t o maintai n desire d driveabilit yan

d performance . On e metho d o f accomplishing octan e enhancemen t i s t o increas e th e amoun t o f benzen e in th e fuel . Th e Agenc yestimate s that , i f in-us e fue l RVP i s reduce d fro

m11. 5 ps i t o 9. 0 psi , th e benzen e emissio n facto r mayincreas e slightly , causing th e relativ e incidenc e reduction s t o als o increas e somewhat . Considering al l source s o f refueling relate d incidences , a s wel l a s wha t i s know n abou t likel ychange s i n fue l composition , controlling fue l volatilit ymayeithe r slightl yincreas e or decreas e th e cance r incidenc e reduction s associate d wit hrefueling controls . Neithe r o f thes e change s woul d appreciabl yaffec t th e overal l result s o f EPA' s cance r ris k assessment . Turning t o th e interactio n betwee n certificatio n fue l volatilit yan

d onboar d designs , some manufacturer s hav e suggeste d tha t i t i s impossibl e t o identif yth e specifi c characteristic s o f thei r contro l system s unti l a fina l decisio n i s mad e on th e volatilit yissue . The yclai mtha t

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-thi s prevent s themfro madequatel ycommenting on a n onboar d proposal . Th e Agenc ydisagree s wit hthi s claim . Th e for m an d functio n o f onboard system s ar e wel l understoo d a s a resul t o f th e significan t prototyp e developmen t tha t ha s alread yoccurred . Fue l volatilit yaffect s suc hparameter s a s the exac t caniste r siz e or purg e rat e required , bu t no t th e basi c systemdesign . Furthermore , th e 11. 5 RVP certificatio n tes t fue l assume d i n EPA' s bas e analyse s represent s a worst-cas e situatio n wit hrespec t t o th e cos t an d feasibilit yo f onboard controls , because , les s volatil e fuel s reduc e hardwar e cost s an d eas e th e tas k o f accommodating highe r caniste r purg e rates . Thus , th e proposa l in th e volatilit yrulemaking t o retai n a lowe r volatilit yfue l doe s no t significantl yaffec t th e decisio n t o promulgat e refueling control s i n genera l or onboar d control s i n particular . Nevertheless , becaus e o f th e interactio n betwee n onboard design s an d volatility , EPAi s publishing bot hth e onboard an

d volatilit yproposal s simultaneousl yt o hel p manufacturer s focu s thei r comments . Therefore , although comment s o n bot hproposal s shoul d principall yb e mad e i n th e contex t o f 9. 0 RVP certificatio n fuel , theyshoul d reflec t th e fac t tha t th e fina l RVP o f certificatio n fue l coul d b e anywher e fro m8. 0 t o 11. 5 psi .

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-P.2 7 Th e Agenc yagree s wit hth e comment s mad e b ysome manufacturer s regarding th e nee d t o kno wth e exac t certificatio n fue l volatilit ybefor e finalizing th e design o f a n onboard syste

mfor specifi c applications . Therefore , EP Aintend s t o complet e actio n o n th e propose d volatilit y rulemaking issue before , or i n conjunctio n with , a fina l rulemaking o n th e onboard refueling contro l reguirements .

I n summary , th e Agenc ybelieve s tha t whil e th e ultimat e leve l o f fue l volatilit yi s relevant , i t i s no t a n impedimen t t o th e proposa l t o implemen t onboar d refueling controls . Nonetheless , t o ensur e tha t thi s issu e i s full y considere d in the onboar d rulemaking , comment s ar e specificall yrequeste d o n th e interactio n betwee n volatilit yan

d al l aspect s o f refueling control . Th e Agenc ybelieve s adequat e informatio n i s availabl e t o enabl e intereste d partie s t o full yconside r th e effec t o f variou s volatilit ylevel s (i.e. , fro m8. 0 t o 11. 5 psi ) o n th e refueling proposal , an d t o provid e substantial , detaile d comments .

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VI . Descriptio n o f th e Proposa l

A . Introductio n

A s describe d earlier , today' s notic e propose s tha t th e emission s o f gasolin e vapor s t o th e atmospher e resulting fro mth e refueling o f light-dut yvehicles , light-dut y truck s an

d gasoline-fuele d heavy-dut yvehicle s b e limite d t o 0.1 0 gram s o f vapo r pe r gallo n o f fue l dispense d (g/gal ) (0.02 6 gram s o f vapo r pe r lite r o f fue l dispensed). * Th e exac t effectiv e dat e o f th e regulation s wil l b e determine d a s par t o f th e rulemaking process . However , a s discusse d mor e full ylate r i n thi s portio n o f th e Preamble , i t woul d no t b e feasibl e t o begi n th e requirement s earlie r than tw o mode l year s afte r promulgation . Associate d wit hth e ne wstandard s ar e propose d change s t o th e existing certificatio n protocol s t o incorporat e suc h thing s a s th e definitio n o f refueling familie s an d allowabl e maintenanc e provisions . Tes t procedure s fo r

Th e curren t emissio n regulation s requir e that , unles s exempted , light-dut ytruck s sol d i n designate d high-altitud e location s mus t mee t separat e high-altitud e standards . Further , emissio n standard s fo r light-dut yvehicle s appl ya t al l altitudes , a s require d b

ySectio n 20 2 o f th e CAA . Therefore , a s discusse d mor e full ylate r i n thi s section , a refueling standard o f 0.1 0 g/ga l i s bein g propose d fo r light-dut ytruck s at bot hlowan d highaltitud e an d fo r light-dut yvehicle s regardles s o f elevation . -126

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determining th e level s o f refueling emission s ar e als o being propose d an

d ar e containe d i n a ne wsubpar t o f th e regulations , Subpar t C (applicabl e t o bot hlight

- an d heavy-dut yvehicles) . Also , relate d change s t o evaporativ e an d exhaus t emission s tes t procedure s ar e proposed , including tha t caniste r system s b e loade d a t leas t t o th e "breakthrough " poin t prio r t o beginning th e evaporativ e tes t sequence , an

d tha t heavy-dut ygasoline-fuele d engin e exhaus t test s b e performe d wit hevaporativ e an d refueling canister s connecte d t o th e engine . Als o include d i n th e propose d regulatorylanguag e i s a clarifie d definitio n o f evaporativ e emissions , a s wel l a s revise d specification s for certificatio n fuel . Thes e evaporativ e emissio n an d certificatio n fue l relate d change s ar e als o being propose d i n a separat e actio n o n th e regulatio n o f fue l volatility , whic happear s elsewher e i n today' s Federa l Register . Fo r additiona l informatio n o n thes e revisions , th e intereste d reade r shoul d consul t th e volatilit yproposal . Th e remainde r o f thi s sectio n provide s a furthe r descriptio n o f today' s proposal . Presente d firs t i s a discussio n o f th e propose d standard an d it s technologica l feasibility . Nex t th e propose d tes t procedure s ar e summarized . Thi s wil l b e followe d b ya discussio n o f severa l matter s relate d t o th e proposa l including suc h

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thing s a s in-us e vehicl e testing , vehicl e safety , Selectiv e Enforcemen t Audi t testing an d Nonconformanc e Penalties . Finally , leadtime requirement s an d projecte d economi c impact s o f th e propose d regulatio n ar e discussed . Mor e detaile d informatio n i s availabl e o n th e topic s addresse d i n thi s section . Background informatio n o n th e developmen t o f th e propose d tes t procedur e can b e foun d in th e "Summar

yan d Analysi s o f Comment s on th e Recommende d Practic e fo r th e Measuremen t o f Refueling Emissions."[11 ] Fo r informatio n o n th e technologica l feasibilit yo f onboar d control s an

d th e othe r impact s o f th e proposal , th e reade r i s referre d t o Volume s 1 an d 2 o f th e draf t Regulatory Impac t Analysi s (RIA)[3 ] an d th e "Evaluatio n o f Ai r Pollutio n RegulatoryStrategie s fo r Gasolin e Marketin g Industry—Respons e t o Publi c Comments."[12 ] Al l o f thes e document s ar e availabl e i n th e publi c docke t (A-87-11) .

B . Selectio n o f th e Standar d

Th e technologyexpecte d t o b e use d t o contro l refueling emission s i s simila r t o tha t currentl yuse d t o contro l evaporativ e emissions . Vapor s generate d during refueling ar e directe d t o a caniste r o f activate d . carbo n wher e theyar e absorbe d o n th e surfac e o f th e carbo n particles . Thes e vapor s ar e subsequentl yremove d b ya purging proces s whic hdraw s fres hai r ove r th e carbo n an d

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the n feed s th e purge d vapor s t o th e engin e wher e the yar e burne d a s fuel . Give n th e similarit yi n contro l technology , EPAha s followe d th e same basi c philosoph yi n selecting a propose d refueling emission s standard a s wa s use d t o deriv e th e evaporativ e emissio n standard . Th e curren t evaporativ e hydrocarbo n standar d fo r light-dut yvehicle s an d light-dut ytruck s unde r low altitud e tes t condition s ( 2 grams/test ) (4 0 CFR 86.087- 8 an d 86.087-9 ) i s essentiall ya "zer o emissions " standard . Tha t is , evaporativ e contro l system s can b e designe d t o effectivel ycontro l essentiall yal l o f th e evaporativ e hydrocarbo n emission s fro mth e vehicle . Th e standar d wa s se t a t 2 grams/tes t t o provid e an adequat e margi n fo r suc h thing s a s in-us e background emission s an d testing variability. * EPAbelieve s tha t refueling emissio n contro l system s ca n b e designe d t o conformt o a similarl ystringen t standard . Some automobil e manufacturer s hav e commente d tha t curren t evaporativ e emissio n contro l system s ar e

EPAi s proposing t o us e th e ter m"evaporativ e emissions " t o replac e "fue l evaporativ e emissions " i n th e evaporativ e emissio n standards , 4 0 CF R Par t 86 , s o a s t o clearl yidentif ytha t th e existing evaporativ e regulation s encompas s background emission s an d accoun t fo r testing variabilit yrathe r than jus t evaporativ e emission s emanating fro mfue l sources . Th e wordin g "fuel " wa s no t in th e origina l standards , bu t wa s erroneousl yintroduce d a t a late r date . -129

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functioning poorl yi n us e an d ar e no t reall ycapabl e o f th e highdegre e o f contro l EPArequires . However , EPA' s investigatio n o f evaporativ e emission s ha s show n tha t exces s emission s i n th e fiel d fro mwell-maintaine d vehicle s ar e due , i n part , t o th e highvolatilit yo f in-us e fuel s or t o systemunderdesign , or both.[8 ] Ther e i s n o evidenc e tha t th e problem

i s du e t o an

yinheren t inadequacie s i n th e basi c contro l technology . Properl ydesigne d evaporativ e emissio n contro l system s hav e demonstrate d th e abilit yt o contro l hydrocarbo n emission s t o extremel ylo wlevels , an

d EPAwoul d expec t refueling system s t o performin a simila r fashion . Severa l tes t program s hav e bee n performe d whic hhav e show n tha t refueling emissio n contro l system s ca n effectivel ycontro l th e emission s o f refueling vapor s i n practice . EPAtest s hav e demonstrate d tha t mor e tha n 9 8 percen t o f th e hydrocarbon s emitte d during th e refueling o f a n uncontrolle d vehicl e can b e controlle d whe n th e vehicl e i s equippe d wit han onboar d contro l system.[13 ] Th e American Petroleu mInstitut e report , "Vehicl e Onboar d Refueling Control " show s th e result s o f refueling test s o n thre e vehicle s i n whic hrefueling emission s wer e limite d t o les s tha n 0. 1 gra

mpe r gallo n (g/gal)[14] . Genera l Motor s als o recentl yperforme d a serie s o f refueling s o n a passenge r car equippe d wit han onboar d systeman d observe d emission s ranging fro m0.0 5 t o 0.0 6 g/gal . EPAnote s tha t thes e tests , showing result s alread ycapabl e o f meeting th e -130

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propose d standard , wer e conducte d o n "firs t generation " onboard systems . Systemrefinement s woul d b e expecte d t o produc e eve n lowe r emissio n level s fro mfutur e vehicles . Currentl yEPAknow s o f n o tes t dat a for refueling contro l system s installe d on heavy-dut ygasolin e vehicles . However , sinc e th e same contro l technolog ywoul d b e use d an d sinc e th e standard i s expresse d on a per-gallo n basis , EPAbelieve s tha t th e require d leve l o f contro l shoul d b e n o mor e difficul t for heavy-dut yvehicle s than for light-dut ymoto r vehicles . Therefore , EPAi s proposing th e sam e standar d fo r heavy-dut ygasolin e vehicle s a s for light-dut yvehicle s an d light-dut ytrucks . Sinc e bot hlight-dut yvehicle s an d light-dut ytruck s wil l hav e t o mee t th e propose d refueling standard a t highe r elevations , i t i s als o importan t t o conside r th e effect s o f altitud e o n refueling emissions . I n thi s regard , th e Agenc yi s unawar e o f an ytes t dat a tha t characterize s refueling emission s a t highe r elevations . However , ther e doe s no t appea r t o b e an yreaso n tha t th e lowe r atmospheri c pressur e a t highaltitud e woul d hav e a significan t advers e effec t o n refueling emissions . Actually , i n th e contex t o f today' s onboar d an d volatilit yproposals , complying wit hth e same numerica l standard shoul d b e les s difficul t a t highaltitud e tha n a t

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lowaltitude . Thi s occur s because , i n th e proposal , th e RVP o f high-altitud e certificatio n tes t fue l mayb e lowe r tha n tha t o f th e low-altitud e tes t fuel , an d a les s volatil e fue l wil l produc e fewe r refueling emissions . Therefore , EPAbelieve s th e propose d refueling standard s ar e feasibl e a t bot hlo wan d highaltitudes . Base d upo n it s evaluatio n o f th e factor s describe d above , EPAha s selecte d th e propose d 0.1 0 g/ga l standard . Thi s leve l represent s a highdegre e o f contro l ( a reductio n o f 9 8 t o 9 9 percen t ove r baselin e levels) , bu t base d o n dat a availabl e fro mcurren t generatio n systems , thi s leve l appear s reasonabl yattainable . Th e standard se t a t thi s level , moreover , allow s sufficien t leewa yt o accoun t for an ymeasuremen t variability . C . Descriptio n o f Tes t Procedure s

I n Jul yo f 1985 , EPArelease d a draf t recommende d practic e fo r th e measuremen t o f refueling emission s fro m moto r vehicles.[15 ] Th e recommende d practic e di d no t represen t a fina l EPAdeterminatio n o f a refueling tes t procedure , an

d wa s no t a rulemaking action , bu t outline d th e procedure s that , a t tha t time , EPAexpecte d woul d b e use d a s th e basi s fo r a refueling tes t procedure . EPA recognize d tha t ther e wer e certai n deficiencie s i n th e tes t procedur e a s proposed , an d undertoo k two keystep s t o -132

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generat e improvements . Th e firs t wa s t o solici t publi c commen t o n th e draf t procedure . Th e secon d wa s t o undertak e a tes t progra mt o gai n a bette r understanding o f th e performanc e o f activate d carbo n canister s i n th e contro l o f refueling emissions . Th e respons e t o th e reques t for publi c commen t wa s extensiv e an

d th e comment s suggeste d severa l area s in th e procedure s wher e improvement s wer e needed . EPAconcurre d wit hth e comment s i n severa l areas , th e mos t significan t o f whic hwere : 1 ) vehicl e preconditioning fo r th e refueling test , 2 ) specification s fo r fue l an d vapo r temperature s require d i n th e refueling test , 3 ) fue l tank heating methods , an

d 4 ) th e valu e o f a clea r lin e o f demarcatio n betwee n th e refueling segmen t o f th e procedur e an d othe r segments .

I n respons e t o thes e comments , an d a s a resul t o f EPA' s ow

n testing program , th e recommende d procedur e wa s modifie d s o tha t th e onboar d systemcoul d b e evaluate d i n a singl e tes t following an initia l preconditioning sequence . Thi s revise d recommende d procedur e wa s presente d a t a publi c worksho p o n Apri l 10 , 198 6 an d wa s generall y receive d a s a significan t improvemen t whic hovercame th e majo r limitation s o f th e origina l draf t procedure . Th e serie s o f specifi c change s tha t mad e up th e describe d modification s resulte d i n a recommende d procedur e whic h

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wa s greatl yshortene d fro mit s origina l for man d whic hwa s no t affecte d b

yth e historyo f th e vehicl e prio r t o testing . Numerou s othe r change s o f lesse r magnitud e wer e als o mad e t o simplif yth e recommende d procedur e and/o r reduc e th e possibl e cost s associate d wit han ysuc hvehicl e testing . Thes e change s generall yinvolve d fue l temperatur e specification s an

d th e procedure s tha t woul d hav e t o b e followe d t o achiev e th e prescribe d temperatures . Th e procedur e propose d toda yi s essentiall ytha t whic h wa s describe d a t th e Apri l 10 , 198 6 workshop . Ther e hav e bee n some mino r change s an d refinement s base d upo n comment s receive d sinc e th e workshop , bu t th e basi c concept s an d functioning o f th e procedur e ar e unchanged . Th e propose d procedur e ha s als o bee n broadene d i n scop e t o includ e heavy-dut ygasoline-fuele d vehicles . ( Amor e complet e understanding o f th e propose d procedur e can b e gaine d fro m a revie wo f th e draf t regulation s themselve s a s wel l a s fro mReferenc e 11. )

1 . Overvie wo f Tes t Procedur e Th e purpos e o f a

n onboar d systemfo r th e contro l o f refueling emission s i s t o preven t th e escap e t o th e atmospher e o f thos e hydrocarbo n vapor s generate d during th e refueling o f th e moto r vehicl e throughou t th e usefu l lif e o f th e vehicle . I n orde r t o serve thi s purpose , th e system

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mus t hav e hydrocarbo n storag e capacit ysufficien t t o accommodat e th e vapor s generate d during a ful l refueling performe d a t an

ycondition , including nea r wors t cas e conditions . I n addition , th e systemmus t hav e a mean s o f regeneratio n capabl e o f purging th e collecte d vapor s an d restoring ampl e storag e capacit ybetwee n successiv e refuelings . I f i t i s t o b e effective , an yprocedur e designe d t o tes t th e functioning o f a n onboard refueling emissio n contro l systemmus t tes t bot hth e storag e capacit y an d restorativ e capabilit yo f th e system . Conceptually , th e propose d tes t procedur e can b e broke n int o thre e segment s (Figur e 5) . Th e firs t two segment s take n togethe r constitut e a preconditioning sequenc e designe d t o exercis e th e purging par t o f th e system tha t serve s t o restor e hydrocarbo n storag e capacity . Thes e segment s involve firs t loading th e hydrocarbo n storag e mediu mt o an approximatio n o f saturation * an

d the n operating th e vehicl e o n a driving

I n th e propose d tes t procedures , EPAha s actuall y specifie d a caniste r loading procedur e whic hwil l resul t i n canister s being loade d a t leas t t o th e "breakthrough " point . Thi s i s a minimu m conditio n an

d system s wil l b e require d t o pas s th e tes t eve n i f loade d beyond thi s poin t prio r t o entering th e tes t sequence , a s migh t occur , fo r example , o n some in-us e vehicles .

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-

## £

Integrate d System Caniste r Purge , Cycli c Drive a . Disconnec t Vapo r Lin e t o Caniste r b . Drai n Fue l Tan

k c . 40 % Fueling d . Reconnec t Vapo r Line t o Caniste r e . Drive On e LA- 4 f . On e Hou r Ho t Soak g . Repea t (e ) an

d (f ) Twic e h . Disconnec t Vapo r Lin e t o Caniste r 1 . Drai n Fue l Tank j . 40 % Fueling k . Reconnec t Vapo r Lin e t o Caniste r 1 . Mea t Buil d (60 ° + 2° F Initial , 2 4 + 1° F Rise ) m . Repea t (e ) Through(1 ) Twic e n . Drive On e LA- 4 Caniste r Loading t o Breakthrough ° Drai n Fue l Tank ° Soak Vehicl e fo r 6 Hour s ° Fue l in SHE D t o Breakthrough Integrate d System Caniste r Purge , Continuou s Drive a . Disconnec t Vapo r Line t o Caniste r b . Drai n Fue l Tank c . 40 % Fueling d . Reconnec t Vapo r Lin e t o Caniste r e . Drive Repeate d LA-4 s Unti l Mileag e Accumulate d = Mileag e Reguire d fo r Purg e Equivalen t t o Cycli c Drive . Mileag e Accumulatio n Stop s a t the Firs t Idl e Pas t the Mileag e Requiremen t 

# 1 Non-integrate d System Caniste r Purge , Continuou s Driv e a . Disconnec t Vapo r Lin e t o Caniste r b . Drai n Fue l Tank c . 95 % Fueling d . Reconnec t Vapo r Lin e t o Caniste r e . Drive Repeate d LA-4 s Unti l 85 % o f Tank Volume I s Consume d

Vehicl e Coo l Dow

n Disconnec t Lin e t o Caniste r Drai n Fue l Tank 10 % Fueling Soa k Vehicl e 6 t o 2 4 Hour s 

# I Refueling Emission s Measuremen t Reconnec t Vapo r Lin e t o Caniste r Fue l t o Automati c Nozzl e Shut-of f (85 % Mimimun Fueling) . Restar t Fueling Following An

yPrematur e Shut-off s Withi n 1 5 Seconds )

OIinOAUL ) TL-:U T1'UCiCKDIIR E l'I.O WCI1AK T Figur e5P.3 9

schedul e whic hwoul d provid e sufficien t opportunit yfo r a properl yfunctioning contro l systemt o restor e hydrocarbo n storag e capacit ycorresponding t o tha t normall yavailabl e b yth e time th e fue l tank i s essentiall yempty . Th e third par t o f th e procedur e i s designe d t o tes t th e overal l systemstorag e capacity . I t involve s refueling th e vehicl e i n a SHED * unde r fue l temperatur e specification s whic h represen t fairl ysever e condition s for refueling vapo r generation.* *

I n a relate d matter , EPAi s concerne d tha t presen t mixing blowe r flowrat e specification s fo r SHE D testing ar e inappropriat e fo r refueling tests , becaus e o f th e shor t time interval s associate d wit hth e mixin g o f bot h breakthroughan

d refueling vapor s i n th e SHE D relativ e t o time interval s availabl e fo r mixing o f evaporativ e emissions . Th e Agenc yi s proposing , therefore , tha t th e lowe r flowrate s i n th e curren t SHE D tes t specification s (4 0 CF R 86.207 ) n o longe r b e allowed . Th e increas e i n

* SHE D i s a

n acrony

m fo r Seale d Housing fo r Evaporativ e Determination , whic hi s an airtigh t enclosur e use d t o measur e emission s fro mth e entir e vehicl e during refueling emissio n tests . Thi s i s th e same enclosur e whic hi s currentl yuse d fo r evaporativ e testing . * * Activate d carbo n i s no t a proportiona l contro l device . Rather , onc e it' s storag e capacit yi s exceeded , furthe r emission s ar e essentiall y uncontrolled . Therefore , i t i s necessaryt o tes t vehicle s i n a waywhic hwil l insur e th e us e o f design s having th e capacit yt o handl e nearl yal l situations .

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** Figur e 6

Propose d Tes t Procedur e Flo wDiaqra m

- - LOAD CANISTE R

DRIV E PRECONDITIONIN G SEQUENC E

REFUE L IN SHE DP.4 1

flo wrat e i s propose d t o b e achieve d b yraising th e lowe r limit s (ligh t an

d heavy-duty ) o f th e mixing blowe r flow rat e specification .

Amor e detaile d outlin e o f th e step s require d t o conduc t th e refueling tes t i s give n i n Figur e 6 . Caniste r Loading . Th e initia l step in th e test , a s identifie d above , involve s loading th e vehicle' s refueling canister(s ) wit hrefueling vapors . EPAbelieve s tha t unde r in-us e conditions , i t i s entirel ypossibl e tha t a vehicle' s refueling emissio n contro l caniste r coul d become saturate d wit hhydrocarbons . Thi s coul d occur , for example , i f th e vehicl e wer e no t drive n regularl yan d therefor e accumulate d a serie s o f repeate d diurnal s (fue l tan k emission s produce d b ytypica l diurna l temperatur e changes) , or unde r drivin g pattern s consisting mainl yo f veryshor t trip s wit h inadequat e opportunit yt o purg e th e canister . I t coul d als o occur du e t o highvolatilit ycommercia l fuels , th e us e o f alcoho l blend fuels , o r abnormall yhighambien t temperature s experience d b yth e vehicle . EPAwoul d expec t tha t unde r condition s suc ha s represente d b yth e propose d preconditioning sequence , suc ha vehicle' s purg e system woul d hav e th e abilit yt o quickl yrestor e th e hydrocarbo n storag e capacit yo f th e canister . I f th e vehicl e wer e incapabl e o f doing this , additiona l hydrocarbo n load s (whethe r refueling or evaporative ) woul d resul t i n

•139

-uncontrolle d emissions . Therefore , t o insur e tha t purg e

system s ar e sufficient , th e propose d tes t procedur e call s fo r a heavy , near-saturation , loadin g a t th e star t o f th e refueling test . Th e caniste r loading step , a s proposed , consist s o f repeate d refueling s i n a SHE D until , a t a minimum , caniste r "breakthrough " occurs , a s define d i n th e procedur e (basically , th e poin t a t whic hth e SHE D hydrocarbo n analyze r detect s a sudde n ris e i n hydrocarbo n vapors) . During testing o f in-us e vehicle s thi s mayb e performe d wit hvapor s escaping fro mth e fue l fille r neck , or some othe r possibl e sources , being allowe d t o ven t outsid e th e SHED . EPAha s receive d considerabl e commen t on th e suggeste d procedur e fo r defining breakthrough , requiring a s i t doe s th e us e o f a SHED . Th e possibilit yha s bee n raise d tha t a metho d fo r determining breakthroughwithou t th e SHE D mayb e possible . EPAi s sensitiv e t o th e issu e o f resourc e impacts , an

d agree s tha t a non-SHE D procedur e coul d b e desirable , bu t ha s no t ye t successfull ydevelope d an alternativ e approach . However , recen t testing b yth e Agenc yha s indicate d tha t a non-SHE D procedur e using a hydrocarbo n prob e place d a t th e caniste r outle t mayb e viable . I f thi s prove s t o b e th e case , the n EPAwoul d expec t t o includ e suc ha n approac hi n th e fina l rule . Commen t i s therefor e requeste d on thi s possibilit yan d ho w th e procedur e migh t dea l wit hsuc hthing s a s varying

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-P.4 3

caniste r outle t configuration s o r th e contro l o f roo mai r current s outsid e o f a SHED . Driving Cycles . Following caniste r loading , th e vehicl e i s drive n ove r on e o f thre e preconditioning driving cycle s whic har e designe d t o exercis e th e vehicle' s purg e system . Th e purpos e o f al l o f th e driving schedule s i s th e same : t o allowth e vehicle' s purg e contro l systemt o restor e th e storag e capacit yo f th e refueling caniste r t o a leve l approximating tha t whic hwoul d b e availabl e (unde r in-us e driving conditions ) wer e th e fue l tan k t o b e essentiall yempt yan d read yt o b e refueled . Selectio n o f th e prope r cycl e t o us e i n an yparticula r cas e i s primaril y a functio n o f th e contro l systemtype , a s describe d below . I n orde r t o understand th e functioning o f th e driving cycles , i t i s firs t necessaryt o describ e some keyaspect s o f th e purg e operatio n o f a refueling system . Wit hrespec t t o purging , ther e ar e two broad type s o f refueling systems : integrate d an d non-integrated . A n integrate d systemrefer s t o a system whic huse s th e refueling emissio n contro l caniste r t o stor e bot hth e refueling vapor s an d som e o r al l o f th e evaporativ e emissio n load . A non-integrate d systemi s on e i n whic hth e refueling caniste r store s onl yrefueling vapors , an d al l evaporativ e emission s ar e handle d b ya separat e canister .

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-P.4 4 Th e functioning o f th e tw o systemtype s wil l b e quit e differen t unde r typica l driving conditions . Fo r a n integrate d system(whichEPAbelieve s wil l b e th e preferre d design) , a s th e vehicl e goe s throughth e norma l pattern s o f driving , ther e wil l b e a n ongoing proces s o f unloading an d loading a s driving (unloading vi a purge ) alternate s wit h parking (loadin

g vi a ho t soak s an d diurna l emissions) . Unde r repetitiv e conditions , a n equilibriu

mi s quickl y establishe d betwee n th e ho t soak and/o r diurna l loading s t o th e caniste r an

d th e amoun t o f vapo r purged . Onc e thi s equilibriu

m i s reached , additiona l period s o f simila r driving n o longe r resul t in a n increas e i n refueling storag e capacity . (The equilibriu mpoin t would , o f course , chang e i f a differen t driving patter n wer e followed . Les s driving pe r da

ywoul d generall yproduc e a lowe r equilibriu m capacit ypoint. )

I n contrast , a non-integrate d systemexperience s n o added loading t o th e refueling caniste r betwee n vehicl e trips . Therefor e i t wil l continu e t o purg e th e caniste r t o lowe r level s a s th e vehicl e i s driven . I n thi s case , availabl e refueling capacit ycontinue s t o increas e righ t up unti l th e time th e vehicl e i s refuele d an d a lowe r averag e rat e o f purg e tha n require d fo r integrate d system s can b e used . However , th e purg e proces s i s highl ynon-linear , wit hveryrapi d purg e initially , followe d b yincreasingl y les s an d les s purg e a s th e caniste r approache s "empty. "

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So , eve n i n thi s cas e mos t o f th e availabl e capacit yfo r refueling vapor s i s generate d earl yi n th e driving proces s (often referre d t o a s fue l tank "drivedown" ) following fue l tan k fillup . Fo r vehicle s wit hintegrate d onboar d systems , ther e ar e two propose d optiona l driving schedules . Th e firs t schedul e involve s operatio n o f th e vehicl e ove r a cycli c driv e sequenc e whic hsimulate s severa l day s o f in-us e driving . Fo r eac hsimulate d "day, " th e vehicl e woul d b e subjecte d t o thre e Urba n Dynamomete r Driving Schedule s (UDDS's), * eac hfollowe d b ya n hour lon

g hot-soak , an

d a singl e diurna l hea t build . A s outline d above , operatio n o f th e vehicl e fo r onl ya limite d numbe r o f day s restore s th e ful l capacit yfo r th e storag e o f a refueling load . Base d upo n it s modeling analysis , EPAbelieve s tha t a perio d o f thre e "days " shoul d b e sufficien t t o establis hequilibriu m for nearl yal l cases . Fo r thos e case s requiring mor e driving t o come t o ful l equilibrium , th e impac t o f restricting th e conditioning perio d t o thre e day s i s marginal , involving onl ya fewgram s o f store d

Th e UDD S fo r light-dut yvehicle s an d trucks , als o calle d th e LA-4 , i s a 7. 5 mil e tri p whic hwa s designe d t o represen t th e typica l tri p an urba n commute r makes . Fo r heavy-dut yvehicles , th e UDD S represent s approximatel y5. 6 mile s o f operatio n a t an averag e speed o f 18. 9 mph . Thes e cycle s ar e foun d i n 4 0 CF R Par t 86 , Appendi xI .

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hydrocarbons . O n th e othe r hand , every"day " o f simulate d driving represent s increase d testing time an d cost , whic h EPAdesire s t o minimize . Therefore , th e Agenc yi s proposing thre e simulate d day s for th e lengt ho f thi s preconditioning drive . Th e optiona l secon

d driving schedul e fo r vehicle s wit h integrate d system s woul d involve muc hles s driving time than woul d b e neede d fo r th e cycli c drive . Thi s proposed , schedul e i s a shor t continuou s driv e designe d t o purg e th e caniste r t o th e sam e leve l a s attaine d b yth e cycli c driv e withou t going throughth e actua l load/purg e cycli c process . I t i s an abbreviate d schedul e designe d primaril y t o reduc e testing time compare d t o th e ful l cycli c drive . Th e actua l lengt ho f th e driv e woul d b e determine d b y testing t o establis hequivalenc e t o th e cycli c drive , an d woul d b e establishe d uniquel yfo r eac hrefueling famil y during th e certificatio n process . EPA' s analysi s indicate s tha t mos t system s shoul d b e properl ypurge d wit honl yfiv e t o twenty-fiv e mile s o f continuou s UDD S driving . Th e shor t continuou s driv e provide s a mean s o f testin g th e restorativ e capacit yo f th e refueling system wit ha greatl yabbreviate d procedure . Becaus e o f this , EPA expect s t o us e th e continuou s driv e fo r mos t o f it s testing work . EPAals o expect s tha t manufacturer s woul d us e th e abbreviate d procedur e whereve r possibl e t o minimiz e testin g

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-P.4 7

resources . Th e Agenc yrecognize s tha t ther e i s some adde d burde n for manufacturer s i n having t o conduc t th e cycli c procedur e initiall yi n orde r t o develo p th e appropriat e continuou s driv e mileage , bu t onc e thi s i s don e fo r a particula r configuration , th e abbreviate d cycl e coul d b e use d fo r subsequen t repetitiv e test s (e.g. , o n durabilit y vehicles) .

I n spit e o f it s usefulnes s a s an abbreviate d preconditioning cycle , th e continuou s driv e ha s some limitations . Th e abbreviate d procedur e doe s no t physicall y demonstrat e tha t th e systemha s th e abilit yt o sufficientl y purg e th e caniste r whe n ho t soak an d diurna l load s ar e included . Rather , thi s procedur e assume s th e contro l systemha s bee n designe d suc htha t thi s woul d b e th e cas e wer e th e cycli c driv e t o b e used . Therefore , althoughth e continuou s driv e woul d b e th e procedur e o f choic e fo r mos t routin e testing , th e cycli c driv e coul d b e use d shoul d EPA desir e t o performconfirmatorytesting an d t o mor e full y exercis e th e onboar d system . Thus , al l vehicle s woul d hav e t o b e designe d t o b e abl e t o mee t refueling emission s standard s afte r following eithe r driving schedul e an d EPA coul d choos e t o confirmatorytes t an yvehicl e usin g th e cycli c driv e or th e shor t continuou s drive .

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Bot hth e cycli c an d th e shor t continuou s drive s jus t describe d ar e intende d fo r vehicle s using integrate d refueling contro l systems . Th e thir d driving sequenc e i s intende d for vehicle s wit hnon-integrate d refueling an d evaporativ e contro l systems . Becaus e non-integrate d system s continu e t o gai n purg e capacit ywhil e bein g driven , i t i s difficul t t o completel ytes t th e restorativ e capabilit yo f th e systemusing a n abbreviate d driving schedule . Therefore , in today' s notice , EPApropose s a continuou s driv e whic hinvolve s a repetitiv e serie s o f UDDS' s whic hwoul d us e fue l equivalen t t o approximatel y8 5 percen t o f th e vehicle' s nomina l tan k capacity . B

y actuall ydriving ou t th e tan k o f fuel , a non-integrate d systemwil l clearl yb e prepare d fo r a ful l refueling . Sinc e non-integrate d system s ar e no t affecte d b ydiurna l or ho t soak loadings , th e driving schedul e i s a continuou s process .

Aful l drive-dow n requiremen t suc ha s thi s i s obviousl yquit e resource-intensiv e an d EPAwoul d lik e t o develop a suitabl e alternative . On e alternativ e whic h appear s promising i s base d upo n th e non-linea r natur e o f th e purging process . Becaus e o f thi s non-linearity , i t appear s tha t a partia l drive-dow n o f perhap s 3 0 t o 4 0 percen t o f tan

k volum e woul d generat e mos t o f th e refueling contro l capacit ywhic hth e vehicl e wa s capabl e o f producing . I n suc ha case , i t woul d b e possibl e t o perform •146

-P.4 9

a refueling tes t whic hwoul d measur e nearl yal l th e expecte d emission s afte r onl ya partia l drive-down . Whil e sucha tes t woul d no t directl yverif yful l refueling capacity , tes t point s coul d b e derive d fro m an engineering analysi s whic hwoul d clearl yindicat e tha t satisfactory performanc e a t tha t intermediat e leve l woul d b e expecte d t o resul t i n ful l performanc e o n an essentiall yempt ytank . Based , a s i t woul d be , on a les s than ful l verificatio n o f systemperformance , EPAwoul d trea t suc han approac h similarl yt o th e shor t continuou s driv e for integrate d systems . Tha t is , th e partia l drive-dow n woul d b e a

n optiona l abbreviate d test , wit hal l vehicle s being require d t o b e abl e t o pas s th e ful l drive-dow n i f s o require d b y EPA . EPAspecificall yrequest s commen t o n thi s concep t a s a n alternativ e driving sequenc e fo r vehicle s wit h non-integrate d systems . I f afte r furthe r analysis , suc ha concep t i s foun

d t o b e valid , EPAcoul d choos e t o includ e suc ha provisio n i n th e fina l rulemaking . Fina l SHE D Refueling Procedure . A s state d earlier , following th e performanc e o f th e appropriat e drivin g schedule , th e vehicl e woul d b e fuele d i n a SHE D unde r specifi c condition s o f fue l temperatur e an d volatility . Th e refueling woul d b e accomplishe d wit ha typica l nozzl e inserte d througha boo t i n th e wal l o f th e SHED . Th e tes t woul d begi n wit hresidua l fue l i n th e tank corresponding t o 1 0 percen t o f tan

k capacity ; refueling woul d procee d unti l

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automati c nozzl e shutoff . Fo r a vali d test , th e tank woul d hav e b e fuele d t o a t leas t 9 5 percen t o f capacity . Th e fueling operatio n woul d b e re-starte d i f automati c shutof f occurre d befor e thi s point . Base d on a variet yo f governmen t an d industrytes t programs , i t ha s bee n show n tha t th e temperatur e an d volatilit yo f th e dispense d an d residua l tan

k fuel s during th e refueling largel ydetermin e th e uncontrolle d refueling emissio n rate . In orde r t o insur e th e maximu m degre e o f control , thes e temperature s hav e bee n selecte d suc htha t refueling a t th e propose d condition s result s i n refueling emission s o f greate r magnitud e than ar e generate d i n mos t actua l in-us e refuelings . AlthoughEPAi s reasonabl yconfiden t tha t th e propose d condition s woul d adequatel yensur e tha t a system i s capabl e o f meeting th e propose d refueling standar d unde r mos t conditions , i t i s difficul t t o determin e exactl ywha t percentag e o f al l refueling situation s wil l b e full y controlled . Dat a describing th e distributio n o f tank an d dispense d fue l temperature s during summertime condition s forme d th e origina l basi s fo r EPA' s paramete r selection.[15 ] Base d upo n consideratio n o f tha t dat a alone , th e tes t condition s mayappea r somewha t severe . However , ther e ar e othe r variable s affecting th e contro l syste mperformanc e tha t ar e no t s o easil yquantified . On e

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-P.5 1

o f thes e i s vehicl e driving patterns . Th e propose d preconditioning cycle s fo r integrate d system s describe d earlie r ar e base d upo n a driving patter n o f thre e trip s pe r day . Fo r thos e vehicle s driving fewe r trips , caniste r purging can b e significantl yreduced , thereb yreducing effectiv e refueling capacity . Anothe r importan t variabl e i s th e degre e t o whic hho t soak an d diurna l evaporativ e loading s during ozon e non-attainmen t day s mayexcee d th e nomina l value s use d i n th e preconditioning sequence . Increase d loading s o f thes e sort s woul d . als o reduc e availabl e refueling capacity , an d d o i t precisel ya t thos e time s whe n i t i s mos t needed . Tha t i s wh yEPApropose s t o requir e system s t o b e designe d t o functio n effectivel y regardles s o f thes e an d othe r variables . Overall , EPAbelieve s tha t th e preconditioning an d refueling tes t conditio n requirement s a s propose d wil l ensur e contro l systemdesign s capabl e o f adequat e contro l ove r nearl yal l expecte d refueling events . Ther e mayb e some combination s o f in-us e condition s wher e refueling emission s mayno t b e full ycontrolled . Th e Agenc ybelieve s tha t thos e condition s wil l b e sufficientl yinfrequen t a s t o hav e n o significan t impac t o n overal l complianc e wit hth e propose d standard , or o n th e leve l o f vapo r emissio n reductio n projecte d unde r th e propose d standard .

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-P.5 2 2 . Fue l Nozzl e Desig n During th e developmen t o f th e recommende d refueling tes t procedures , th e topi c o f difference s betwee n fue l nozzle s produce d b ydifferen t manufacturer s ha s occasionall ybee n raised . Fo r example , For d ha s performe d a limite d numbe r o f uncontrolle d refueling test s using nozzle s o f variou s design s an d ha s suggeste d tha t nozzl e geometrycan strongl yinfluenc e refueling emissions . I n fact . Ford claim s tha t nozzl e dimension s can affec t bot h th e uncontrolle d emissio n rat e an d th e rat e a t whic ha particula r fillnec k design wil l permi t refueling . Becaus e o f thes e effect s For d ha s strongl yurge d EPAt o specif ya standard nozzl e fo r us e i n th e refueling test . [16 ]

EPAi s als o concerne d abou t th e impac t tha t nozzl e geometrymayhav e o n refueling emissions , bu t ha s littl e dat a a t presen t wit hwhic ht o evaluat e thes e claims . I f i t wer e tru e tha t nozzl e geometrycan substantiall yaffec t th e performanc e o f refueling systems , the n a standardize d design woul d b e indicated . I n EPA' s view , i f thi s wer e th e case , suc hstandardizatio n woul d hav e t o b e applie d bot ht o tes t equipmen t an

d t o in-us e nozzles . Otherwise , refueling system performanc e woul d suffe r i n practice .

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-P.5 3 EPArequest s comment s o n th e nee d fo r standardize d nozzl e geometry . Particularly , EPArequest s th e submissio n o f tes t dat a demonstrating th e degre e o f sensitivit y refueling control s mayshowt o nozzl e variants , a s wel l a s specificatio n o f whic hnozzl e design parameter s woul d nee d t o b e standardized . Th e Agenc ybelieve s tha t i f suc h geometrystandard s ar e needed , th e mos t likel ydesign parameter s involve d woul d includ e tota l length , spou t bending angle , lengt ho f spou t straigh t section , an d automati c shut-of f por t location . Commenter s shoul d addres s th e standardizatio n o f thes e an d an yothe r parameter s o f principa l concern . Thi s shoul d als o b e accompanie d b

ya n analysi s clearl ydemonstrating wh yi t woul d b e bette r t o standardiz e nozzl e geometrythan t o requir e refueling design s whic har e les s sensitiv e t o thes e factors . I f th e comment s substantiat e th e nee d fo r nozzl e standards , EPAma yinclud e themi n th e fina l rulemaking o n today' s proposal . 3 . Relate d Change s t o Existing Tes t Procedure s

I n additio n t o th e regulation s governing th e measuremen t o f refueling emissions , EPAi s proposing severa l change s i n th e curren t Federa l Tes t Procedur e a s par t o f today' s notice . Th e mos t significan t change s wil l b e discusse d late r i n thi s sectio n an d involve th e preconditioning o f emissio n contro l canister s prio r t o

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evaporativ e emissio n complianc e testing , th e inclusio n o f canister s i n heavy-dut ygasoline-fuele d engin e emission s testing an

d th e manne r i n whic hcanister s ar e preconditione d fo r fue l econom ytesting . Othe r revision s includ e change s t o th e researc hoctan e number , aromati c content , sulfur content , an d distillatio n characteristic s o f certificatio n fuel . In addition , th e oxyge n conten t o f certificatio n fue l i s being specifie d fo r th e firs t time . Thes e changes , a s wel l a s thos e jus t described , ar e als o being propose d in EPA' s actio n t o contro l th e volatilit yo f commercia l moto r vehicl e fuel . Tha t notic e appear s elsewher e i n today' s Federa l Registe r an d shoul d b e consulte d b

yth e reade r for mor e detai l on th e evaporativ e an d certificatio n fue l relate d revisions . Ther e ar e als o othe r minor , technica l change s t o th e tes t procedur e being propose d a s par t o f today' s notice , i n orde r t o updat e th e procedur e an d mak e i t mor e consisten t wit hactua l practice . Th e reade r wh o wishe s a ful l understanding o f th e detail s o f thes e technica l change s shoul d consul t th e appendi xan d draf t regulation s accompanying today' s notice .

I t ha s bee n EPA' s positio n tha t evaporativ e emissio n contro l system s shoul d b e designe d t o wor k effectivel yan d maintai n thei r leve l o f contro l unde r in-us e operating conditions . I t als o ha s bee n EPA' s positio n tha t evaporativ e emissio n contro l system s shoul d b e abl e t o -152

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quickl yrecove r thei r hydrocarbo n storag e capacit yafte r experiencing an

yo f th e variou s condition s tha t migh t occur in-use . I n particular , th e Agenc ydescribe d it s inten t tha t evaporativ e emissio n contro l system s hav e th e capabilit yt o restor e hydrocarbo n storag e capacit ywit ha singl e UDD S (even i f th e caniste r i s saturate d a t th e star t o f th e tes t sequence ) i n EPAAdvisoryCircula r 50A . Nonetheless , some vehicl e manufacturer s continu e t o expres s confusio n on thi s issue .

I n orde r t o clarif ythi s matter , an d avoi d a simila r problemregarding th e capabilit yo f refueling emissio n contro l systems , th e Agenc yi s proposing a requiremen t t o loa d evaporativ e an

d refueling contro l canister s at leas t t o th e breakthroughpoin t prio r t o th e FT P preconditioning UDDS . Fo r evaporativ e emission s testing , breakthrough woul d b e define d b yth e same procedur e a s develope d for th e refueling test . Thi s chang e woul d appl yt o bot hlight

- an d heavy-dut yvehicles .

Aclosel yrelate d chang e i s being propose d fo r th e testing o f heavy-dut ygasolin e engines . I n th e curren t Federa l Tes t Procedur e fo r heavy-dut yengines , ther e i s n o requiremen t fo r evaporativ e emissio n contro l system s t o b e i n operatio n during th e performanc e o f th e exhaus t emissio n tes t sequence . Thi s mean s tha t an yevaporativ e hydrocarbo n load s tha t woul d b e sen t t o th e engin e during norma l operation s ar e no t sen t t o th e engin e during th e exhaus t -153

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test . Therefore , an yimpact s tha t th e evaporativ e hydrocarbon s migh t hav e on exhaus t emission s ar e overlooke d i n th e curren t tes t procedure . EPAdoe s no t believ e tha t thi s situatio n i s appropriat e for eithe r evaporativ e o r refueling contro l systems . Therefore , EPAi s proposing tha t prio r t o th e heavy-dut yengin e test , th e vehicle' s evaporativ e an

d refueling contro l canister(s ) b e attache d t o th e engine . Loading o f th e canister(s ) wil l correspond t o a poin t equivalen t t o th e loadin g whic hwoul d exis t a t th e en d o f th e diurna l breathing los s test . Thi s chang e wil l insur e tha t manufacturer s focu s appropriat e attentio n on eliminating an

yexhaus t impact s o f th e contro l systems , a s i s alread

yrequire d b

yth e light-dut yprocedure s afte r th e 199 0 mode l year . Othe r propose d change(s ) woul d affec t th e tes t procedure s use d fo r determining light-dut yfue l econom y values , whic har e ultimatel yuse d i n calculating a manufacturer' s corporat e averag e fue l econom y(CAFE) . Becaus e i t ha s bee n argue d tha t th e additio n o f onboar d contro l system s coul d affec t vehicl e fue l econom y measurements , EPAi s proposing t o giv e th e manufacture r th e choic e o f performing th e fue l econom ytes t wit ho r withou t th e step o f loading th e caniste r beforehand . Th e manufacture r woul d b e allowe d t o pic k th e procedur e whic h i t desires , wit hth e conditio n tha t al l fue l econom ytest s wit hunloade d canister s woul d b e subjec t t o prio r approva l b yth e Administrator . -154

-P.5 7 Th e Agenc yi s considering othe r CAFE-relate d changes . First , rathe r than th e manufacture r performing a duplicat e tes t wit han unloade d caniste r for fue l econom ypurpose s only , whic hcoul d increas e testing costs , EPAmigh t includ e a CAF E adjustmen t t o accoun t for th e fue l econom yeffec t o f testing wit ha loaded canister . Second , EPAi s contemplating whethe r o r no t a CAF E credi t shoul d b e develope d representing th e expecte d recoveryan d us e o f refueling vapors . Comment s ar e specificall ysolicite d on th e appropriatenes s o f suc ha CAF E adjustmen t an d credit , a s wel l a s th e methodologie s fo r thei r determination . I n addition , EPAinvite s comment s on othe r alternative s tha t woul d avoi d doubl e testing fo r fue l econom ypurposes . Th e Agenc ywoul d als o lik e t o acknowledg e tha t i f th e volatilit yo f tes t fue l i s change d fro m th e currentl y specifie d RVP o f 9. 0 psi , a n optio n whic hha s bee n evaluate d a s par t o f th e volatilit yproposal , the n appropriat e revision s t o th e CAF E determinatio n procedure s woul d b e mad e a s par t o f th e fina l rulemaking o n volatility . 4 . Testing In-Us e Vehicle s

EPAha s alway s intende d for moto r vehicl e emissio n standard s t o b e me t in-use . Tha t is , EPAexpect s tha t properl ymaintaine d an d use d vehicle s wil l compl ywit h applicabl e emissio n standard s in-us e i f teste d a t an y

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mileag e poin t up t o thei r ful l usefu l life . Vehicle s would , o f course , als o b e expecte d t o compl ywit hrefueling emission s standard s in-us e an d the procedure s describe d in today' s proposa l wer e designe d fo r us e i n bot h certificatio n an

d in-us e testing . During th e developmen t o f th e propose d procedures , carefu l consideratio n ha s bee n give n t o th e implication s o f testing in-us e vehicles . EPA ha s als o consulte d extensivel ywit hindustr yon thi s topi c an d believe s tha t th e procedure s propose d todaywil l tes t in-us e vehicle s appropriately . On e importan t concern raise d b ymanufacturer s abou t testing in-us e vehicle s i s tha t th e conditio n o f th e vehicl e (especiall yth e activate d carbo n canisters ) i s unknow n befor e th e vehicl e begin s th e tes t sequence . I t i s importan t tha t th e procedur e b e abl e t o accuratel yasses s th e performanc e o f th e contro l systemregardles s o f it s stat e prio r t o testing . Th e propose d refueling tes t procedur e ha s bee n designe d s o tha t thi s i s th e case .

A s describe d above , th e firs t step i n th e refueling tes t i s tha t o f loading th e refueling caniste r a t leas t t o th e breakthroughpoint . Thus , fo r al l thos e vehicle s presente d fo r testing wit hcaniste r loading a t some poin t belo wth e breakthroughlevel , th e procedur e result s i n a standardize d conditio n a t th e beginning of . testing . Fo r thos e vehicle s beginning th e sequenc e wit hthei r canister s -156

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alread yloade d pas t th e breakthroughpoint , th e situatio n woul d b e somewha t different . Two observation s appl yt o thi s situation . First , i t i s EPA' s positio n tha t th e vehicl e purg e system shoul d b e abl e t o full yrecove r fro m sucha conditio n withou t adde d preconditioning . Th e breakthroughloading sequenc e i s intende d onl ya s a minimu m loading requirement . I f a significan t numbe r o f vehicle s wer e actuall yoperating wit hsaturate d canister s i t woul d b e a s a consequenc e o f th e manufacturer' s systemdesign . I n sucha case , EP Awoul d requir e tha t thes e vehicle s pas s th e tes t a s received . Th e secon

d observatio n on thi s poin t i s tha t al l th e informatio n availabl e t o EPAindicate s tha t a saturate d refueling caniste r wil l presen t n o significan t liabilit y fo r a properl ydesigne d systembecaus e suc hheavil yloade d canister s purg e extremel yrapidl yo n th e propose d preconditioning cycles . Following th e preconditioning driv e sequences , i t woul d b e difficul t t o distinguis h betwee n a caniste r whic hbega n th e tes t saturate d an d on e whic hwa s onl yloade d t o breakthrough . I t shoul d als o b e note d tha t EPAbelieve s tha t th e preconditioning sequenc e effectivel yeliminate s an yunanticipate d effect s o n th e refueling system

du e t o suc hcause s a s th e us e o f non-standar d fuels .

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-P.6 0 Anothe r face t o f in-us e testing involve s thos e vehicle s fo r whic hoptiona l preconditioning cycle s exist . Th e Agenc ywishe s t o mak e i t clea r tha t whe n optiona l preconditioning cycle s ar e available , th e optio n selecte d b yEPAfor certificatio n testing doe s no t dictat e th e optio n t o b e use d t o tes t for in-us e compliance ; moreover , th e vehicl e mus t b e abl e t o pas s using an yapplicabl e optiona l cycle s bot hduring certificatio n an d in-use . Similarly , failur e o f a vehicl e using on e preconditioning cycl e woul d no t entitl e th e manufacture r t o as k fo r testing using anothe r cycle .

D . Selectiv e Enforcemen t Audit s During th e developmen t o f th e recommende d tes t procedur e for refueling emissions , two mino r issue s wer e raise d whic hmaynee d t o b e addresse d i n Selectiv e Enforcemen t Audi t (SEA ) tes t procedures * fo r refueling emissions . Thes e potentia l issue s ar e relate d t o th e fac t tha t SEAinvolve s th e testing o f newly-buil t moto r vehicles , an

d for tha t reaso n theyar e uniqu e t o th e SE A program .

SE Atesting refer s t o testing unde r Sectio n 206(b ) o f th e CA Aan d 4 0 CF R Par t 8 6 o f a statistica l sampl e o f assembly-lin e vehicle s t o ensur e tha t vehicle s bein g produce d do i n fac t confor mwit hemissio n standard s an d th e term s o f th e applicabl e certificate .

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-P.6 1 Th e firs t issu e regard s a possibl e influenc e o f ne w vehicl e background evaporativ e emission s (i.e. , hydrocarbo n emission s fro

msuc hthing s a s th e fres hpain t on a ne w vehicl e whic hha s no t ye t full ycured ) o n th e refueling emission s measurement . EPAunderstand s wh ynon-fue l backgroun

d emission s ar e significan t i n evaporativ e emission s testing fo r SE Apurpose s an d consequentl yEPA doe s no t normall yconduc t SEAtesting fo r evaporativ e emissions . However , EPAdoe s no t believ e tha t background emission s wil l improperl yaffec t refueling los s measurement s during SEAtesting. * Refueling emissio n measurement s hav e a duratio n o f les s than five minutes , s o th e actua l time for backgroun d evaporativ e losse s t o occu r i s veryshort . Also , refueling measurement s ar e take n a t a n ambien t temperatur e o f approximatel y80°F , s o fue l an d non-fue l evaporativ e emission s wil l no t b e increase d b y heating o f th e vehicl e fue l tank , engin e o r othe r subsystems , a s occur s during th e usua l evaporativ e emission s testing . Becaus e o f thos e factors , i t i s reasonabl e t o expec t tha t background emission s wil l hav e littl e o r n o impac t on th e measuremen t o f refueling emissions , an

d EPAdoe s no t believ e tha t provision s t o

I n addition , unde r th e propose d refueling standard n o attemp t wil l b e mad e t o distinguis hothe r evaporativ e emission s fro

mthos e generate d b yrefueling . A s alread y noted , th e standard i s intende d t o includ e background emissions .

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addres s th e effect s o f background emission s during SE A refueling testing ar e necessary .

However , EPAi s ope n t o commen t o n thi s issu e an d specificall yrequest s an yavailabl e dat a suggesting tha t non-fue l background emission s fro mnewl ybuil t vehicle s woul d b e significan t in th e refueling tes t procedur e propose d b

yEPA . Sinc e th e propose d refueling standar d i s intende d t o includ e whateve r norma l background emission s occur fo r in-us e vehicles , dat a supporting th e impac t o f background emission s during SE Atesting mus t demonstrat e tha t ne wvehicl e backgroun d emission s significantl yexcee d in-us e vehicl e backgroun d emissions . I f evidenc e exist s tha t background emission s ar e significant , EPApropose s t o incorporat e an additiona l procedur e int o th e SEArefueling emission s tes t procedures . Thi s procedur e woul d provid e fo r th e measuremen t o f ne wvehicl e background emission s an d subtrac t themfro

mth e refueling emission s measurement . I n general , th e propose d procedur e i s a s follows :

1 . Plac e th e vehicl e i n th e SHE D immediatel yprio r t o th e refueling emission s measuremen t sequenc e o f th e refueling test .

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-P.6 3 2 . Sea l th e SHE D an d measur e th e ambien t concentratio n o f hydrocarbon s i n th e SHED . 3 . Afte r a 1 0 minut e perio d tak e anothe r measuremen t o f th e SHE D ambien t hydrocarbo n concentration , calculat e th e tota l gram s o f hydrocarbo n emitte d (fina l minu s initia l measurement ) an d divid e b

y1 0 t o calculat e a per-minut e emissio n rate . 4 . Perfor

mth e refueling emission s measuremen t a s describe d i n th e refueling tes t procedure, , recording th e duratio n o f th e refueling measuremen t process , rounde d t o th e neares t minute . 5 . Multipl yth e background emissio n rat e (determine d i n step 3 ) b yth e numbe r o f minute s obtaine d i n step 4 , an

d subtrac t thi s numbe r fro mth e tota l gram s o f emission s calculate d fro mth e refueling emission s measuremen t t o obtai n a correcte d valu e fo r tota l refueling emissions . Th e secon

d issu e pertain s t o th e conditio n o f th e refueling/evaporativ e emissio n canister(s ) prio r t o SE A testing . I t i s generall yaccepte d tha t activate d carbo n canister s requir e a numbe r o f hydrocarbo n load an d purg e cycle s (aging ) t o attai n a stabilize d condition . During thi s cycling , th e canister' s capacit yt o retai n

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hydrocarbon s i s reduce d fro mit s virgi n (newcanister ) leve l t o some lowe r stabilize d leve l generall yreferre d t o a s th e working capacity . Thi s los s i n capacit yi s commonl y know n a s th e "heel" . T o hel p accoun t fo r an ylarg e differenc e tha t mayexis t betwee n an unuse d caniste r an d a somewha t use d canister , EPApropose s tha t refueling/evaporativ e emissio n canister(s ) o f SE Avehicle s b e aged througha benc hprocedure , prio r t o being teste d fo r refueling emissions . Th e propose d procedur e fo r aging th e caniste r i s detaile d i n th e accompanying draf t regulations . Th e Agenc ywant s t o mak e i t clear , however , tha t thi s procedur e i s mean t onl yt o approximat e some degre e o f caniste r aging . I t i s no t know n t o wha t exten t i t simulate s actua l real-worl d caniste r stabilizatio n o r deterioratio n wit hage . Therefore , whil e propose d fo r SE A testing , th e benc haging proces s i s inappropriat e fo r th e purpos e o f certificatio n testing or th e developmen t o f deterioratio n factors . Th e Agenc yi s intereste d i n obtaining comment s addressing th e appropriatenes s o f performin g SE Arefueling emissio n test s withou t stabilizing refueling canister s o n th e vehicles , othe r possibl e procedure s o r requirement s fo r cycling (aging ) canisters , an d th e leve l t o whic hcanister s shoul d b e aged .

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-P.6 5 E . Nonconformanc e Penaltie s (NCPs )

I n th e regulation s governing NCP s (4 0 CF R 86.1103-87) , EPAspecifie s th e criteri a whic hmus t b e me t befor e an NC P wil l b e mad e availabl e fo r a ne wemissio n standar d applicabl e t o an

ysubclas s o f heavy-dut yvehicle s (i.e. , vehicle s wit ha GVW R in exces s o f 600 0 lbs) . A s describe d in thos e regulations , a n NC P mayb e establishe d fo r a ne w emissio n standard i f substantia l wor k wil l b e require d t o mee t th e ne wstandard an d a technologica l laggard i s likel y t o exist . Substantia l wor k mean s th e applicatio n o f technolog

yno t previousl yuse d i n a vehicl e clas s or subclas s or th e significan t modificatio n o f existing technolog

yo r design parameters . Whil e onboar d system s hav e no t bee n use d t o contro l refueling emission s o n heavy-dut yvehicles , EPAdoe s no t believ e tha t a

n onboar d requiremen t constitute s substantia l wor k a s define d i n th e NC P regulation s no r doe s EPAbeliev e tha t a technologica l laggard wil l exist . Th e fundamenta l design o f a

n onboard contro l systemi s basicall yan extensio n o f existing evaporativ e emissio n contro l technolog

yrathe r than th e applicatio n o f ne wtechnology . EP Aexpect s manufacturer s t o us e activate d carbo n fo r storag e o f refueling vapor s an d ai r stripping fo r regeneration , jus t a s i s no wuse d i n evaporativ e emissio n contro l system s o n heavy-dut ygasolin e vehicles . Purg e

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system s woul d hav e t o b e refine d t o handl e increase d hydrocarbo n loads , bu t thes e improvement s woul d no t involv e th e applicatio n o f ne wtechnology , especiall ygive n th e manufacturers ' plan s t o incorporat e fue l injectio n an d feedbac k contro l system s t o upgrad e th e performanc e o f thes e vehicles . Whil e ther e mayb e some subjectiv e disagreemen t o n whethe r or no t "substantia l work " wil l b e involve d i n meeting th e standard , EPAbelieve s al l th e manufacturer s o f thes e vehicle s wil l b e abl e t o compl ywit hth e standard an d tha t n o technologica l laggard wil l exist . EPArecognize s tha t effor t wil l b e require d t o equi p heavy-dut yvehicle s wit honboar d contro l systems , bu t th e contro l technology require d i s wel l define d an d availabl e t o al l affecte d manufacturers .

I n addition , th e NC P regulation s als o permi t consideratio n o f NCP s for othe r emissio n standards , fo r whic hNCP s ar e no t alread yprovided , i f th e standard s become mor e difficul t t o mee t a s a resul t o f a ne w standard . However , a s i s discusse d i n th e technologica l feasibilit yportion s o f th e suppor t documents , EPAdoe s no t believ e tha t manufacturer s wil l encounte r significan t additiona l difficult yi n maintainin g complianc e wit h curren t standard s a s a resul t o f th e propose d onboar d standard . "Substantia l work " wil l no t b e reguire d an d n o

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technologica l laggard s ar e expected . Therefore , EPA propose s no t t o mak e additiona l NCP' s availabl e for exhaus t or evaporativ e emissio n standard s a s a resul t o f an yne w onboard standard . Give n th e informatio n currentl yavailabl e regarding onboard contro l technology , EPApropose s no t t o mak e NCP s availabl e for th e refueling emission s standard . However , EPAmaychang e thi s positio n base d o n informatio n presente d in th e comments . I f NCP s fo r refueling ar e ultimatel y proposed , theywil l b e addresse d i n a rulemaking actio n separat e fro

m th e refueling emissio n standard . However , th e paramete r value s neede d t o calculat e an ypropose d penalt yrate s an

d th e uppe r limi t analyse s mayb e base d o n informatio n use d i n th e fina l rulemaking analysi s fo r refueling controls .

F . Change s t o Certificatio n Protocol s

I n additio n t o ne wemissio n standard s an d tes t procedure s fo r refueling , thi s notic e propose s a numbe r o f revision s t o th e certificatio n protocol s i n Subpar t A . Thes e revision s ar e necessaryt o integrat e th e propose d refueling contro l progra mint o th e existing protocol s fo r exhaus t an

d evaporativ e emissio n certification . I n general , th e certificatio n requirement s fo r refueling emission s ar e quit e simila r t o th e existing evaporativ e

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emission s requirements . However , som e ne wprovision s an d change s t o existing provision s wer e require d b yth e additio n o f th e refueling standards . Th e mos t significan t revision s t o Subpar t Aar e a s follows : Sectio n 86.090-2 1 (Applicatio n fo r certification ) require s manufacturer s t o describ e th e metho d use d t o determin e refueling emissio n deterioratio n factor s fo r thei r refueling emissio n families . Thes e requirement s ar e simila r t o thos e currentl ygoverning evaporativ e emission s deterioratio n facto r determination . Additionally , however , manufacturer s ar e require d t o stat e i n thei r applicatio n th e lengt ho f th e continuou s drivedow n necessaryt o purg e th e refueling canister(s ) t o th e appropriat e leve l require d b yth e tes t procedure . Sectio n 86.090-2 3 (Require d data ) dat a reguirement s for refueling certificatio n fo r light-dut yvehicle s an d truck s ar e simila r t o curren t exhaus t an d evaporativ e emission s dat a requirements . Similarly , th e requirement s for heavy-dut ymanufacturer s ar e simila r t o th e curren t heavy-dut yevaporativ e emission s requirements . (Not e tha t Subpar t C no wrequire s tha t a loade d evaporative/refuelin g caniste r b e attache d t o th e engin e during exhaus t emissio n testing. )

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-P.6 9 Sectio n 86.090-2 4 (Tes t vehicle s an d engines ) contain s criteri a fo r determining refueling familie s an d refueling contro l systems . Man yo f thes e criteri a ar e th e same a s thos e fo r evaporativ e famil yan d contro l system determination , du e t o basi c systemdesign similarities . However , othe r criteri a suc ha s degre e o f integratio n wit h th e evaporativ e contro l system , typ e o f fillpip e sea l an d fil l limite r ar e uniqu e t o refueling systems . Therefore , a refueling famil ymayno t necessaril ycove r th e same portio n o f a manufacturer' s produc t lin e a s a n evaporativ e family . Th e same refueling family/systemcriteri a ar e applicabl e t o bot hlight-dut yan d heavy-dut yvehicles . Suggeste d criteri a fo r identifying worst-cas e emitter s withi n a give n family/systemcombinatio n fo r certificatio n purpose s can b e foun d i n a memorandu mentitle d "Refueling Configuratio n Criteria " i n th e publi c docket . Sectio n 86.090-2 5 (Maintenance ) define s refueling emissio n component s a s critica l emission-relate d component s an d prescribe s full-lif e maintenanc e interval s fo r suc h items a s fillpip e seals , vapo r storag e canisters , an d purg e syste m hardware . Sectio n 86.090-2 8 (Complianc e wit hstandards ) provide s tha t refueling emissio n deterioratio n factor s shal l b e additive .

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-P.7 0 Sectio n 86.090-3 5 (Labeling ) require s tha t refueling familie s b e labele d a s suc han d tha t secondary manufacturer s mus t ad d vapo r storag e capacit yi n proportio n t o an yadded fue l tan

k volume . Furthermore , i t require s themt o certif ytha t an yadditiona l fue l tank capacit y beyon d th e maximu

mspecifie d fo r a refueling famil ywil l no t caus e tha t famil yt o excee d th e applicabl e exhaust , evaporativ e or refueling standards . Althoughth e majo r change s i n th e regulation s hav e bee n summarize d above , th e intereste d reade r i s urge d t o consul t th e appendi xt o thi s notic e an d th e propose d amendment s t o Subpar t Ai n thei r entiret yfo r a complet e understanding o f th e technica l effect s o f th e propose d ne w refueling standard s o n th e tes t procedures . Th e Agenc y invite s comment s o n al l aspect s o f th e propose d revisions . I n particular , EPArequest s tha t eac hmanufacture r submi t a projectio n o f th e likel ynumbe r o f refueling familie s an d refueling contro l system s tha t woul d exis t unde r th e propose d criteria . G . In-Us e Dispensing Rate/Nozzl e GeometryStandard s

A s par t o f thi s action , beginning i n Septembe r 1989 , EPAi s proposing t o limi t th e in-us e dispensing rat e o f gasolin e t o 1 0 gallon s pe r minut e (gpm) . Furthermore , a s discusse d earlie r i n Sectio n VI.C.2 . o f thi s notice , EPAi s

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-P.7 1 seeking commen t on th e nee d t o standardiz e fue l nozzl e spou t design geometries . A s describe d below , EPAi s considering thes e action s t o insur e compatibilit ybetwee n in-us e operating condition s fo r onboar d system s an d thos e unde r whic hth e system s wil l b e certified . Th e fue l dispensing rat e during refueling operation s affect s th e design o f onboard control s throughsuc h parameter s a s fillpip e capacity , fillnec k sea l performance , exces s ai r entrainment , vapo r line sizing , caniste r siz e an d geometry , th e generatio n o f nuisanc e shutoff s an d fue l spitback . Thi s topi c ha s bee n raise d t o EPAb y manufacturer s i n comment s o n th e developmen t o f th e suggeste d refueling tes t procedur e discusse d earlier.[14 ] Therefore , i n developing it s propose d certificatio n tes t procedures , EPAconducte d an analysi s o f prevailing in-us e dispensing rates . Th e propose d dispensing rat e fo r tes t condition s (1 0 gpm ) i s base d upo n th e highes t dispensing rate s presentl yfoun d a t mos t gasolin e dispensers . However , a s vehicle s capabl e o f accepting fue l a t th e curren t maximu

mflowrate s become mor e prevalen t i n use , gasolin e marketin g pressure s fo r increase d throughpu t (i.e. , t o increas e sale s volume ) woul d b e expecte d t o lead t o increase d in-us e dispensing rate s up t o th e poin t wher e custome r complaint s begi n t o aris e du e t o spitbac k an d

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othe r spillage. * (The likelihoo d o f thi s occurring ha s bee n acknowledge d b

ygasolin e marketer s i n discussion s wit h EPA) . Thus , i n orde r t o maintai n th e ful l effectivenes s o f onboard system s i n th e future , EPAbelieve s i t i s importan t t o als o insur e tha t in-us e dispensing rate s ar e limite d s o a s t o b e compatibl e wit hth e certificatio n procedure . ' I f th e in-us e an

d certificatio n rate s ar e compatible , onboar d system s woul d perfor ma s designed . Thi s woul d als o hav e th e effec t o f reducing spillag e in-us e du e t o th e fue l spitbac k whic hofte n accompanie s nozzl e shut-off . Th e Agenc yha s pursue d th e developmen t o f a voluntary in-us e dispensing rat e standard wit hth e America n Petroleu m Institut e (API) , whic hrepresent s petroleu mindustry interests . A s summarize d i n thei r statemen t o f Augus t 6 , 198 6 [17] , AP I ha s conclude d tha t i t i s no t feasibl e t o develop a voluntarystandard . AP I als o conclude d tha t i t shoul d b e th e moto r vehicl e manufacturers ' responsibilit y t o develo p refueling contro l system s whic hcaus e nozzl e shutof f withou t spitbac k i f design flowlimit s ar e exceeded . "Spillage " i s an

ylos s o f gasolin e during a refueling even t du e to : dripping fro mth e nozzl e spout , spitback , o r overflow . "Spitback " i s th e los s o f gasolin e fro

mth e fillpip e whic hsometime s occur s i n a refueling even t whe n pressur e build s up i n th e fue l tank an

d th e automati c shut-of f mechanis mo f th e fue l nozzl e i s activated .

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-P.7 3 Whil e recognizing th e positio n take n b yAPI , EPA believe s tha t i t i s mor e appropriat e t o limi t in-us e dispensing rate s t o a leve l equivalen t t o tha t whic h manufacturer s mus t us e i n certifying th e performanc e o f thei r onboard systems . Sinc e th e 1 0 gp m limi t ha s bee n selecte d t o encompas s mos t curren t industrypractice , i t wil l impos e littl e o r n o burde n o n statio n owners . O n th e othe r hand , i t wil l provid e manufacturer s a fixed targe t fo r syste

mdesign s b

ymaking maximu

mcertificatio n an d in-us e dispensing rate s th e same . EPAdoe s no t believ e i t i s reasonabl e or practica l t o requir e manufacturer s t o certif yonboard systemperformanc e fo r undefined , eve r increasing flowrates . Therefore , EPAha s decide d t o propos e th e limit s containe d in today' s proposal . Mor e specifically , th e propose d metho d fo r controlling th e in-us e dispensing rat e i s t o requir e tha t every gasolin e retaile r o r wholesal e purchaser-consume r (a s define d i n 4 0 CF R 80.2(k ) an d (o) , respectively ) equi p eac h pum p fro mwhic hgasolin e i s introduce d int o moto r vehicles , wit ha nozzl e tha t shal l dispens e gasolin e a t a maximu m flowrat e no t t o excee d 1 0 gpm . Thi s approach , patterne d afte r curren t nozzl e spou t diamete r regulation s fo r leade d an d unleade d fuels , place s responsibilit ydirectl yo n th e retaile r o r wholesal e purchaser-consume r [nozzl e owner] . Enforcemen t o f thi s alternativ e woul d b e b ydirec t flo w

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measurement s a t th e station. * Sinc e al l aspect s o f complianc e woul d b e th e owner s responsibility , assignmen t o f liabilit yfo r violation s woul d b e straightforward , althoug hth e testing requiremen t woul d represen t some increase d enforcemen t burde n fo r EPA . Th e Agenc ybelieve s tha t littl e o r n o cos t t o statio n owner s wil l b e associate d wit hthi s aspec t o f th e proposal . Pump s a t mos t station s alread ymee t th e 1 0 gp

m limi t an

d wil l therefor e b e abl e t o retai n existing nozzles . Fo r thos e station s whic hrequir e some reductio n in flowrate , actua l cos t fo r a simpl e flowlimiting device , suc ha s a limiting-floworifice , shoul d b e minimal . Therefore , th e propose d limit s d o no t affec t th e cos t o f today' s proposa l give n elsewher e i n thi s document .

EPAi s proposin g th e in-us e flo wrat e restrictio n unde r Sectio n 211(c ) o f th e CAA . Thi s provisio n allow s EPA t o regulat e o r prohibi t th e offering fo r sal e o f an yfue l i f th e emissio n product s o f suc hfue l (i n thi s case , th e refueling vapor s o r evaporate d spille d fue l associate d wit h hig hdispensing rates ) wil l impair , t o a significan t degree , th e performanc e o f th e emissio n contro l devic e o r

Th e Agenc yintend s t o develo p a n in-us e complianc e tes t procedur e fo r measuring dispensing rate s i n a separat e action . Th e tes t procedur e wil l utiliz e eithe r an in-lin e flowmete r or a volume/tim e measuremen t technique . -172

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system . Th e flowrat e restrictio n propose d todayi s intende d t o enhanc e th e performanc e o f refueling contro l system s i n actua l use , b ylimiting th e in-us e rat e t o th e certificatio n tes t flowrate . I n addition , eve n moderat e amount s o f gasolin e spillag e can offse t th e emissio n reduction s t o b e achieve d throughonboard system s an d coul d caus e th e refueling standard t o b e exceeded . Adispensing rat e limi t wil l reduc e gasolin e spillag e an d hel p ensur e th e effectivenes s o f onboard controls . Sectio n 211(c ) furthe r require s th e Administrato r t o conside r availabl e scientifi c an d economi c dat a o n possibl e alternativ e emissio n controls , whic hwoul d no t requir e suc h a limitatio n on fue l sales . I n thi s case , th e onl y alternativ e tha t migh t b e advance d woul d b e t o requir e Stag e I I instead o f onboard . Tha t alternativ e ha s bee n exhaustivel yanalyze d byEPA , a s describe d earlie r i n today' s notice , an d ha s bee n rejected . Moreover , Stag e I I system s woul d als o likel yinclud e flowrat e limit s o f thei r own . Therefore , th e Agenc ybelieve s th e propose d in-us e flowrat e restrictio n i s consisten t wit hSectio n 211(c ) . EPArequest s commen t o n al l aspect s o f it s proposa l t o regulat e nozzl e flowrates , including suc harea s a s th e nee d fo r control , liabilit yaspects , hardwar e cost s o f flow regulating control s an d alternativ e regulatoryschemes . Fo r furthe r informatio n o n th e effect s o f in-us e dispensing -173

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rate s an

d nozzl e geometries , an EPAtechnica l repor t entitle d "Investigatio n o f th e Nee d fo r In-Us e Dispensing Rat e Limit s an

d Fue l Nozzl e GeometryStandardization " i s availabl e i n th e publi c docket.[18 ]

EPAi s als o seeking commen t o n th e nee d t o standardiz e nozzl e geometries . A s note d in th e discussio n o f th e refueling tes t procedure , EPAha s receive d commen t indicating tha t differen t nozzl e spou t design s mayaffec t onboard efficienc yan d contribut e t o refueling spillage . I f thi s wer e th e case , EPAwoul d conside r i t a n in-us e issu e a s wel l a s a testing issue . Tha t is , i f i t becam e necessaryt o standardiz e tes t nozzles , the n EPAwoul d als o expec t t o standardiz e commercia l nozzles . Thi s woul d b e absolutel ynecessaryt o insur e compatibilit ybetwee n commercia l nozzle s an d onboar d system s designe d aroun d th e certificatio n tes t procedure . Sinc e al l curren t nozzl e geometrie s ar e relativel ysimilar , however , suc h standardizatio n mayno t b e absolutel ynecessary . Th e Agenc ysolicit s comment s fro mconcerne d partie s o n thi s issue . Comment s ar e especiall ysolicite d whic hidentif y th e principl e parameter s o f concer n an d quantif yth e claime d impac t o f nozzl e designs . I f significan t impact s ar e identifie d whic hcanno t b e accommodate d i n onboar d system designs , EPA' s preferre d cours e o f actio n woul d b e t o establis hvoluntarynozzl e design standard s through combine d effort s wit hprofessiona l an d trad e organizations . -174

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However , suc hstandard s coul d als o b e include d in EPA' s fina l rulemaking o n today' s proposal .

H . Safet yIssue s Relate d t o Onboar d Control s Sectio n 202(a)(6 ) o f th e CA Adirect s th e Agenc yt o consul t wit hth e Departmen t o f Transportatio n (DOT ) concerning moto r vehicl e safetybefor e requiring th e us e o f onboar d contro l technology . During th e developmen t o f today' s proposal, . consultation s wer e hel d wit h representative s o f DOT' S Nationa l HighwayTraffi c Safet y Administratio n (NHTSA ) t o discus s th e potentia l safet y hazard s associate d wit honboard controls . During thes e discussions , EPA' s analysi s [19 ] wa s reviewe d an d th e Agenc ysough t NHTSA' s reviewan d commen t o n eac ho f th e safet yissue s identified . I t i s EPA' s finding tha t ther e appear s t o b e n o obstacl e whic hwoul d preven t th e desig n an d productio n o f saf e onboar d systems , althoughadditiona l stud ymayb e necessarybefor e fina l rulemaking actio n t o ensur e adequat e leadtime i s availabl e fo r vehicl e desig n an d testing . Th e Agency , o f course , wil l continu e t o b e responsiv e t o th e Congressiona l mandat e b yconsulting furthe r wit hDO T on potentia l safet yconcern s a s ne w informatio n o n probabl e systemdesign s become s available . Afina l safet yevaluatio n wil l b e mad e a s par t o f th e fina l rulemaking .

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-P.7 8 Th e Agenc yha s als o me t wit hth e Insuranc e Institut e fo r HighwaySafet y(IIHS) . Thi s trad e association , whic h i s supporte d b

yth e nation' s propert yan d casualt y insurers , ha s expresse d genera l concern s t o EPAregarding th e safet yo f onboard vapo r recoverysystem s i n vehicl e accidents . Th e view s expresse d b yIIH S hav e bee n full y considere d i n EPA' s safet yanalysi s an d wil l b e include d i n th e evaluatio n supporting th e fina l rulemaking .

I t i s EPA' s belie f tha t n o increas e i n overal l safet y ris k shoul d b e accepte d becaus e o f th e presenc e o f onboar d contro l systems . O f course , th e fina l choice s abou t exac t systemdesign s wil l b e wit hth e manufacturers , bu t EPA woul d no t adop t a n onboard progra

m unles s i t wer e clea r tha t saf e fue l systemdesign s wer e availabl e an d th e requisit e hardwar e coul d b e incorporate d i n th e moto r vehicl e flee t withi n th e leadtime provide d b yth e regulation . A t thi s time EPAbelieve s tha t thi s i s th e case . I n fact , th e Agency' s analysi s indicate s tha t i t woul d b e quit e possibl e fo r fue l systemsafet yt o improv e along wit hth e adoptio n o f onboard controls . On e exampl e o f ho wthi s migh t occur woul d b e throughth e us e o f flexibl e bladder s insid e th e fue l tank t o contai n th e liqui d fue l an

d eliminat e th e presenc e o f an yfue l vapors . Suc hcontainmen t woul d improve fue l systemsafet yan d als o eliminat e th e nee d fo r muc ho f th e evaporativ e contro l hardwar e alread

yon curren t vehicle s (e.g. , reduc e or eliminat e th e nee d fo r th e vapo r storag e canister) . -176

-P.7 9 Ther e ar e othe r aspect s o f overal l fue l systemdesign whic hmigh t b e modifie d a t th e time o f introducing onboard controls . Suc hthing s a s th e placemen t an d configuratio n o f th e fue l tank , th e us e o f sid e fil l versu s rear fil l fueling designs , an d externa l versu s interna l fueling vapo r ven t lines , ar e al l area s o f design determine d a s a resul t o f tradeoff s betwee n competing design goals . EPAbelieve s tha t curren t fue l systemdesign s can b e improve d i n suc h area s a s thes e an d tha t th e safet yo f onboar d equippe d vehicle s nee d no t b e compromised . Severa l specifi c design-relate d safet yissue s hav e bee n raise d a s being o f greates t concern i n th e design o f onboard systems . Th e potentia l problem area s involv e fue l spillage , fue l tan k pressurization , an d vapo r storag e caniste r location . Eac ho f thes e area s i s discusse d separatel ybelow . Th e concer n wit hfue l spillag e center s on preventing th e escap e o f liqui d gasolin e fro ma vehicle' s fue l tank a s a resul t o f th e vehicl e rolling ove r i n an accident . Th e highvapo r flowrate s associate d wit hrefueling requir e th e us e o f relativel ylarg e diamete r vapo r lin e (i.e. , approximatel y1/ 2 t o 3/ 4 inche s i n inne r diameter ) t o minimiz e systembac k pressur e a s vapor s ar e force d fro mth e fue l tank t o th e carbo n canister . Withou t a rollove r protectio n system , suc ha larg e vapo r lin e coul d lea d t o a

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substantia l fue l spil l unde r certai n circumstances , wit ha n attendan t ris k o f fire . Fue l spill s resulting fro mmoto r vehicl e accident s ar e regulate d b

yDO T i n Federa l Moto r Vehicl e Safet yStandar d (FMVSS ) 301. * Fo r onboar d system s t o compl ywit hth e reguirement s o f thi s standard , a rollove r valv e woul d hav e t o b e include d i n th e ven t line t o automaticall yclos e i f th e vehicl e rolle d over . Fo r variou s reasons , manufacturer s woul d mos t likel ydesign thi s valv e t o remai n close d i n mos t norma l operating modes , an d ope n onl yduring th e refueling process . Severa l specifi c design s hav e bee n suggeste d fo r jus t suc ha valv e b yth e developer s o f prototyp e onboar d contro l systems . Generally , th e valv e i s locate d a t th e fillnec k mout han d i s mechanicall yactivate d b yth e insertio n o f th e nozzl e int o th e fillnec k mouth . Althoughi t i s unclea r whic ho f th e valve s currentl yi n developmen t woul d b e bes t fo r ultimat e use , th e valv e i s conceptuall ysimpl e an d woul d requir e n o ne wtechnology . Th e concer n abou t fue l tank pressurizatio n during th e refueling operatio n i s relate d t o th e us e o f a mechanica l fillnec k sea l t o preven t th e escap e o f fue l vapor s t o th e atmosphere . Thi s devic e i s installe d i n th e mout ho f th e

Federa l Moto r Vehicl e Safet yStandar d 30 1 regulate s th e rat e a t whic hfue l i s allowe d t o flo wfroma vehicl e following a collisio n an d vehicl e rollover . -178

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fillnec k an

d create s a physica l sea l betwee n th e nozzl e spou t an

d th e fillnec k whe n th e nozzl e i s inserted . Unde r som e failur e scenarios , i f th e fue l tank become s overfilled , th e resulting exces s pressur e i n th e tan k coul d caus e fue l t o squir t ou t betwee n th e nozzl e an d seal , o r ou t o f th e fillnec k whe n th e nozzl e wa s removed . Thi s problemcan b e avoide d b yincluding a relie f valv e i n th e syste mt o ensur e tha t pressur e i s release d fro mth e fue l tan k befor e i t coul d reac ha dangerou s level . Suc hdevice s ar e no t comple xor difficul t t o design . Furthermore , othe r method s o f sealing th e fillnec k ar e availabl e (i.e. , th e liqui d seal ) tha t completel yavoi d thi s potentia l problem . Th e las t potentia l safet yproblem concern s th e locatio n o f th e onboard canister . I f a refueling caniste r wer e alread

yfull , o r th e system wer e tampere d wit hs o tha t th e ven t lin e t o th e caniste r wa s disconnected , refueling vapor s coul d b e vente d int o th e spac e nea r th e caniste r whe n th e vehicl e wa s refueled . Ther e i s some concer n tha t i f th e caniste r wer e locate d i n th e engin e compartmen t an d thi s situatio n occurred , a spark , or some othe r ignitio n source , coul d caus e an explosio n or fire . Th e exten t t o whic hthi s coul d actuall ybecom e a problemi s no t completel yclea r a t thi s time . Evaporativ e emission s contro l canisters , whic har e simila r t o onboar d canisters , ar e ofte n locate d i n th e engin e compartmen t an d ar e no t know n t o presen t a safet yhazard . I n an ycase , i t appear s

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tha t thi s potentia l problem coul d b e resolve d b ylocating th e caniste r outsid e o f th e engin e compartment , possibl yi n a fende r wel l o r nea r th e fue l tank . However , EPAwil l continu e t o stud

ythi s safet yquestion , i n consultatio n wit hDOT , t o ensur e tha t i t i s full yresolve d befor e a fina l refueling regulatio n i s issued . Overall , th e Agenc yfind s tha t th e design experienc e wit hexisting , evaporativ e emissio n contro l system s shoul d b e usefu l in designing onboard system s an d tha t ther e i s nothing extraordinaryabou t th e equipmen t neede d t o assur e saf e operation . Furthermore , eac ho f th e potentia l safet y hazard s discusse d above i s wel l know n t o th e variou s moto r vehicl e manufacturers , an d can b e accommodate d i n designing onboard systems . Fo r thes e reasons , EPAbelieve s tha t practica l an

d effectiv e onboar d system s ca n b e designe d an d built , a t a reasonabl e cost , tha t wil l no t adversel yaffec t vehicl e safety . Finally , th e interactio n betwee n safet yan d leadtime shoul d b e mentioned . EPAacknowledge s th e nee d t o provid e adequat e time fo r developmen t an d cras htesting i n orde r t o full yintegrat e onboard-relate d hardwar e int o existing vehicles . Th e Agenc ybelieve s tha t a minimu mo f two year s o f leadtime betwee n promulgatio n o f th e fina l rul e an d it s effectiv e dat e wil l b e necessaryt o complet e thes e an d othe r relate d activities , an d full yaddres s safet y -180

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concerns . However , th e Agenc yacknowledge s tha t some uncertaint yexist s regarding th e lengt ho f time whic hmay b e necessaryt o complet e developmen t an d cras htesting for al l vehicles . T o ensur e adequat e leadtime i s provide d i n th e fina l rulemaking , EPAsolicit s comment s o n th e leadtime issue , wit hemphasi s o n specifi c safety-relate d areas . Th e Agenc yi s als o considering a gradua l phase-i n o f refueling control s ove r a multi-yea r perio d i n orde r t o eas e th e burde n associate d wit hsimultaneou s emission s an d safet ycertification . Suc ha phase-i n coul d als o b e advantageou s i f some individua l vehicl e configuration s wer e t o requir e adde d leadtime t o addres s safety-relate d issues . Regardles s o f whethe r al l vehicle s ar e ultimatel y reguire d t o mee t an onboar d standar d beginning i n th e same mode l year , o r a phase-i n o f control s i s allowed , EPAi s committe d t o ensuring tha t manufacturer s hav e adequat e leadtime t o addres s potentia l safet yconcerns . I n fact , th e Agenc ywoul d b e especiall yope n t o allowing mor e leadtime i f i t woul d resul t i n enhancing overal l vehicl e safety . Amor e detaile d discussio n o f EPA' s leadtime analysi s i s containe d i n th e nex t section .

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I . Leadtime Sectio n 202(a)(6 ) o f th e CA Arequire s EPAt o provid e adequat e leadtime befor e th e implementatio n o f a fina l onboard rule , s o tha t th e regulate d industryha s sufficien t opportunit yt o prepar e fo r complianc e wit hth e standard s se t fort hi n th e rule . A s i n th e cas e o f othe r moto r vehicl e emissio n standards , thi s involve s componen t an d system design , vehicl e developmen t an d proveout , tooling , an d certification . EPAha s carefull yconsidere d th e impac t tha t a refueling emissio n regulatio n wil l hav e an d believe s that , althoughsome uncertaint yexist s (especiall ya s relate d t o safety) , a miniumu mo f 2 4 month s afte r promulgatio n wil l b e necessaryt o provid e manufacturer s wit hsufficien t leadtime t o compl ywit hth e refueling emissio n standard . Th e 2 4 mont hminimu m perio d allow s 1 2 month s fo r component/systemdesign an d vehicl e developmen t an d proveout . An additiona l 1 2 month s i s provide d fo r certificatio n (emissions , fue l economy , an d safety) . Vehicl e an

d componen t tooling action s ca n occur simultaneousl ywit hdevelopmen t o r certification . Thus , EPAi s proposing a minimu mtwo yea r leadtime fo r manufacturer s t o implemen t th e onboard standard .

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-P.8 5 Th e Agency' s rational e fo r th e adequac yo f a minimu m two yea r leadtime i s detaile d i n th e respons e t o publi c comment s document.[12 ] I n general , EPA' s on e yea r allowanc e fo r onboar d systemdevelopmen t an d design mayb e adequat e base d o n th e following considerations . Onboar d technolog

yi s verysimila r t o tha t use d i n curren t evaporativ e emissio n contro l systems . Wit hth e exceptio n o f two onboard systemcomponent s (the fillpip e sea l an d fue l tank valve) , al l hardwar e items resembl e those , presentl yuse d i n evaporativ e emissio n contro l systems . EPAexpect s onboar d system s wil l utiliz e activate d carbo n fo r hydrocarbo n storag e an d ai r stripping fo r regeneration . Whil e improvement s i n th e ai r stripping o r "purge " systemprobabl ywil l b e necessary , thes e improvement s shoul d involv e th e extensio n o f existing ai r managemen t technique s an d equipment . Eve n th e ne w component s neede d fo r onboar d system s pos e n o seriou s developmen t problem s becaus e severa l partie s hav e alread y propose d an

d demonstrate d fillpip e sea l an d fue l tank valv e designs . I n fact , mos t manufacturer s hav e alread ybegu n activ e onboar d systemdevelopment , an d EPAbelieve s al l syste m design parameter s ar e wel l define d wit hn o majo r uncertainties .

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-P.8 6 O n th e othe r hand , EPArecognize s ther e mayb e some uncertaint yregarding th e adequac yo f th e 1 2 mont hperiod , i f developing onboard system s fo r certai n vehicl e configuration s wer e t o tak e longe r tha n i s nowexpected . T o addres s thi s uncertainty , specific , detaile d comment s ar e requeste d o n th e lengt ho f time necessaryt o complet e th e design an

d developmen t o f onboard system s fo r al l vehicles .

I n additio n t o systemdesign an d development , EPA believe s manufacturer s mayb e abl e t o mak e an ynecessary componen t o r vehicl e tooling change s withi n th e 2 4 month s o f leadtime . I t i s no t necessaryfor al l pre-productio n complianc e preparatio n action s t o occur sequentially ; muc h o f i t can b e complete d i n parallel . I n thi s particula r rulemaking , th e onl ycritica l pat hitem s tha t shoul d procee d i n sequenc e ar e component/systemdesign , vehicl e development/proveou t an d certification . An ynecessary tooling change s ca n b e performe d i n paralle l wit hthes e critica l pat hitems . Onc e onboar d systemvehicl e developmen t an d proveou t wor k i s completed , th e certificatio n proces s can begin . Whil e 1 2 month s i s normall yadequat e leadtime fo r manufacturer s t o certify , EPAals o recognize s tha t th e implementatio n o f refueling control s maypresen t a uniqu e situation . Some uncertaint yexist s i n th e 1 2 mont h

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-P.8 7

estimat e becaus e manufacturer s wil l b e facing recertificatio n o f thei r entir e produc t line s an d th e Federa l Tes t Procedur e wil l b e expande d t o includ e a refueling emission s test . Manufacturer s als o nee d t o conduc t vehicl e safet ycras htesting t o assur e complianc e wit hFMVS S 301 . Simultaneou s emission s an d safet y certificatio n hav e occurre d previously , bu t no t fo r al l thre e vehicl e classe s (light-dut yvehicles , light-dut y trucks , an

d heavy-dut yvehicles ) i n th e same mode l year . Comment s specificall yaddressing thi s aspec t o f EPA' s leadtime analysi s ar e invited . On e wayt o reduc e th e certificatio n burde n woul d b e t o us e a gradua l phase-i n approac ht o refueling control s rathe r than requiring al l vehicle s t o compl yi n th e same year . Suc han approac hcoul d involv e th e phase-i n o f onboard control s ove r a two - o r three-yea r period , wit hth e majorit yo f vehicle s bein g requir e t o compl yi n th e firs t yea r (e.g. , 7 0 percen t o f productio n certifie d i n th e firs t year , 9 0 percen t i n th e secon d an d th e remainde r certifie d i n th e thir d year) . Suc ha "front-loaded " phase-i n perio d woul d als o provid e mor e time t o dea l wit han yuniqu e onboard systempackaging problems , o r safety-relate d concerns . I n addition , i t coul d actuall yimprov e th e cos t efficienc yo f control s b ypermitting manufacturer s t o foreg o developmen t o f onboar d system s fo r vehicl e model s schedule d fo r eliminatio n b yth e en

d o f th e phase-i n period . -185

-P.8 8 Agradua l phase-i n migh t als o b e an especiall y appropriat e mean s o f dealing wit honboar d control s fo r heavy-dut ygasolin e vehicles . Historically , heavy-dut y emissio n contro l technologyha s bee n base d o n system s develope d successfull yfo r light-dut yapplications . Althoughrefueling emissio n contro l technolog yi s basicall y identica l fo r eithe r vehicl e type , heavy-dut yonboar d contro l present s some additiona l concern s becaus e o f th e significantl ylarge r caniste r capacit yrequirement s an d th e inheren t complexit yo f th e two par t heavy-dut ytes t procedure . Afront-loade d onboard phase-i n perio d woul d allowmanufacturer s t o certif ymos t light-dut yvehicle s an d truck s i n th e firs t yea r whil e allowing additiona l time fo r heavy-dut yvehicle s and/o r an yisolate d light-dut yproblem cases . A s alread

ynoted , EPAi s ope n t o commen t o n th e adequac yo f 1 2 month s fo r certification , bu t ask s tha t an y reques t fo r additiona l leadtime o r a phase-i n perio d shoul d b e supporte d b yspecific , concret e informatio n demonstrating th e nee d fo r additiona l leadtime an d justifying an

ysuggeste d phase-i n period . Anothe r wayt o reduc e th e certificatio n burde n woul d b e t o allo wcarryove r o f exhaus t durabilit ydat a fo r previously-certifie d LD V family/systemcombination s fo r th e initia l yea r o f th e ne wstandards . Sinc e LD V engin e familie s constitut e abou t two-third s o f al l engin e familie s subjec t t o certificatio n requirements , providing LD V

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exhaus t emissio n durabilit ycarryove r woul d als o represen t a significan t decreas e i n th e initia l recertificatio n burde n associate d wit hth e propose d refueling regulations . However , on e potentia l problemwit hthi s approac hconcern s ho wwel l pre-refueling contro l deterioratio n dat a woul d represen t emission s fro mne wvehicle s wit hdifferen t purg e system s operating o n potentiall ydifferen t certificatio n fuel . EPAinvite s comment s regarding howthes e concern s migh t b e addresse d an d th e appropriatenes s o f th e us e o f durabilit ydat a carryove r fo r LDV s t o reduc e th e burde n o f th e initia l recertificatio n effort . Overall , then , EPAbelieve s a leadtime perio d o f a t leas t two year s mayb e adequat e fo r th e vas t majority , i f no t all , vehicl e families . Al l previou s evaporativ e emissio n standard s hav e bee n implemente d wit htwo year s o f leadtime . Du e t o th e importanc e o f ensuring adequat e leadtime , especiall ya s i t relate s t o addressing an y potentia l safet yconcerns , EPAremain s ope n t o commen t o n leadtime an

d o n th e nee d fo r a phase-i n period . J . Economi c Impac t

Th e complet e economi c analysi s o f thi s rul e i s containe d i n th e draf t RegulatoryImpac t Analysi s (RIA) , whic hi s availabl e i n th e docket . Th e highlight s o f th e

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-P.9 0

analysi s ar e summarize d here . Al l figure s ar e i n 198 6 dollars , an

d a te n percen t discoun t rat e i s assumed . 1 . Light-Dut yVehicle s Th e aggregat e cos t t o th e natio n resulting fro mth e firs t fiv e year s o f a refueling emissio n contro l requiremen t fo r light-dut yvehicle s i s estimate d t o b e $60 2 million , discounte d t o 1990 . Thi s estimat e include s fixe d cost s o f $4 6 millio n fo r developmen t an d design , $2 9 millio n fo r recertification , an d al l necessaryhardwar e costs . Becaus e th e additio n o f onboar d refueling emissio n contro l system s i s expecte d t o hav e a n impac t o n vehicl e fue l consumption , th e aggregat e cos t als o include s an allowanc e fo r th e expecte d ne t chang e i n operating costs . Manufacturer s ar e projecte d t o recove r thei r cost s throughan estimate d increas e o f approximatel y$1 7 i n th e purchas e pric e o f an averag e light-dut yvehicl e produce d during th e firs t fiv e years . Vehicl e owner s ar e projecte d t o recove r an averag e o f approximatel y$ 4 o f thi s cos t ove r th e lif e o f th e vehicl e throughimprove d fue l consumption . 2 . Light-Dut yTruck s Th e tota l five yea r aggregat e cos t t o th e natio n resulting froma refueling emissio n contro l requiremen t fo r -188

-P.9 1

light-dut ytruck s i s estimate d t o b e $26 6 million , discounte d t o 1990 . Thi s estimat e include s fixe d cost s o f $2 1 millio n for developmen t an d design , $1 2 millio n fo r recertification , an d al l necessaryhardwar e costs . A s wit h light-dut yvehicles , th e aggregat e cos t als o include s an allowanc e fo r th e expecte d decreas e in operating costs . Manufacturer s ar e projecte d t o recove r thei r cost s throughan estimate d increas e o f approximatel y$2 3 i n th e purchas e pric e o f a n averag e light-dut ytruc k produce d during th e firs t five year s o f th e standard . Singl e fue l tan k light-dut ytruc k price s woul d increas e b y$18 ; dua l tan k truc k price s woul d increas e b y$42 . Truc k owner s ar e expecte d t o recove r a n averag e o f approximatel y$ 6 o f thi s cos t ove r th e lif e o f th e vehicl e du e t o improve d fue l consumption . 3 . Heavy-Dut yGasolin e Vehicle s Th e tota l fiv e yea r aggregat e cos t t o th e natio n fo r heavy-dut ygasolin e vehicle s i s estimate d t o b e $2 5 million , discounte d t o 1990 . Thi s estimat e include s fixe d cost s o f $2. 5 millio n fo r developmen t an d design , $ 3 millio n fo r recertification , an d al l necessaryhardwar e costs , a s wel l a s a n allowanc e fo r th e expecte d ne t chang e i n operating costs .

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-P.9 2 Manufacturer s ar e projecte d t o recove r thei r cost s throughan estimate d increas e o f approximatel y$3 1 i n th e pric e o f a

n averag e ne wheavy-dut yvehicl e produce d during th e firs t fiv e year s o f th e standard . Fo r smalle r heavy-dut ygasolin e vehicle s thi s pric e increas e i s expecte d t o averag e $26 ; fo r large r one s a n averag e pric e increas e o f $4 4 i s expected . Vehicl e owner s ar e projecte d t o recove r a

n averag e o f approximatel y$1 5 o f thi s cos t ove r th e lif e o f th e vehicl e throughimprove d fue l consumption . 4 . Aggregat e Impact s Th e tota l fiv e yea r aggregat e cos t t o th e natio n resulting fro

m refueling emissio n contro l standard s for.al l gasolin e fuele d vehicle s i s estimate d t o b e $89 2 millio n discounte d t o 1990 . Thi s estimat e include s fixe d cost s o f $7 0 millio n fo r developmen t an d design , $4 4 millio n fo r recertification , an d al l necessaryhardwar e costs . Th e aggregat e cos t als o include s an allowanc e fo r th e expecte d ne t decreas e i n operating cost s for vehicle s produce d i n thos e fiv e years . Th e averag e firs t pric e increas e fo r al l gasolin e vehicl e classe s wil l b e approximatel y$19 . Likewise , th e averag e fue l recoverycredi t i s expecte d t o b e approximatel y$5 . -190

-P.9 3 Th e overal l socioeconomi c impac t o f thes e regulation s i s expecte d t o b e minimal . Aut o an d truc k manufacturer s ar e expecte d t o hav e n o troubl e underwriting th e capita l investmen t require d an d vehicl e sale s wil l no t b e impacte d b yth e verysmal l firs t pric e increas e cause d b yonboar d controls . Employmen t i n th e automotiv e an d relate d supplie s industrie s mayincreas e slightl ya s th e resul t o f th e nee d t o manufactur e an d instal l onboar d contro l systems . Thes e regulation s ar e no t expecte d t o hav e an y ne t effec t on th e balanc e o f trade . An yincreas e i n th e manufacturer' s invoic e pric e o f importe d vehicle s shoul d b e offse t b

yth e reductio n i n oi l import s permitte d b yth e ne t fue l consumptio n improvement . VII . Publi c Participatio n

Comment s an

d th e Publi c Docket . A s i n pas t rulemaking actions , EPAdesire s ful l publi c participatio n i n arriving a t fina l decisions . I n additio n t o thos e area s wher e specifi c commen t ha s bee n requeste d earlie r i n thi s preamble , EPAsolicit s comment s o n al l aspect s o f today' s proposa l fromal l intereste d parties . Whereve r applicable , ful l supporting dat a an d detaile d analyse s shoul d als o b e submitte d t o allowEPAt o mak e maximu mus e o f th e comments . Commenter s ar e especiall yencourage d t o provid e specifi c suggestion s fo r change s t o an yaspect s o f th e

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-P.9 4

proposa l tha t the ybeliev e nee d t o b e modifie d o r improved . Al l comment s shoul d b e directe d t o th e EPA Centra l Docke t Section , Docke t No . A-87-1 1 (se e "Addresses") . Person s intending t o participat e i n th e hearing s may submit t writte n question s on an ymatter s relevan t t o thi s proposa l t o th e presiding office r at an ytime . T o th e exten t tha t time permit s th e presiding officer , a t hi s discretion , maydirec t thes e question s t o witnesse s testifying a t th e hearing or a s appropriat e t o EPA personne l presen t a t th e hearing fo r answers . I f time doe s no t permi t al l suc hwritte n question s t o b e addresse d a t th e hearing , EPAwil l provid e th e remaining question s t o th e appropriat e witnesse s o r EPApersonne l fo r writte n respons e t o b e place d i n th e rulemaking docket . Publi c Hearing . An yperso n desiring t o presen t testimon

ya t th e publi c hearing (se e "Dates" ) shoul d notif y th e contac t perso n liste d abov e o f suc hinten t a t leas t seve n day s prio r t o th e dayo f th e hearing . Th e contac t perso n shoul d als o b e provide d an estimat e o f th e time require d fo r th e presentatio n o f th e testimon yan d notificatio n o f an ynee d fo r audio/visua l equipment . A sign-u p shee t wil l b e availabl e a t th e registratio n tabl e th e morning o f th e hearing fo r scheduling o f th e orde r o f testimony . -192

-P.9 5 I t i s suggeste d tha t sufficien t copie s o f th e statemen t o r materia l t o b e presente d b e brough t t o th e hearing fo r distributio n t o b e audience . I n addition , i t wil l b e helpfu l fo r EPAt o receiv e an advanc e cop yo f an

y statemen t o r materia l t o b e presente d a t th e hearing a t leas t on e wee k befor e th e schedule d hearing date , i n orde r fo r EPAstaf f t o hav e adequat e time t o giv e suc hmateria l ful l consideration . Suc hadvanc e copie s shoul d b e submitte d t o th e contac t perso n liste d above . Th e officia l record o f th e hearing wil l b e kep t ope n for 3 0 day s following th e hearing t o allowsubmissio n o f rebutta l an

d supplementarytestimony . Al l suc hsubmittal s shoul d b e directe d t o -th e EPACentra l Docke t Section , Docke t No . A-87-1 1 (se e "Addresses") . Th e hearin g wil l b e conducte d informally , an d technica l rule s o f evidenc e wil l no t apply . Writte n transcript s o f th e hearing wil l b e made . Anyon e desiring t o purchas e a copyo f th e transcrip t shoul d mak e individua l arrangement s wit hth e cour t reporte r recording th e proceedings .

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-VIII . ADMINISTRATIVE DESIGNATIONAN D REGULATORY ANALYSI S

Th e Administrato r ha s determine d tha t thi s proposa l constitute s a majo r propose d regulation , an d accordingl ya Draf t RegulatoryImpac t Analysi s ha s bee n prepare d a s require d unde r Executiv e Orde r 12291 . Thi s analysi s include s detaile d assessment s o f th e estimate d economi c an d environmenta l impact s o f th e regulation s propose d here , a s wel l a s mor e thoroughanalyse s o f th e technologica l feasibilit yo f th e emissio n standard s an d othe r regulatory provision s propose d here , an d th e alternative s tha t wer e considere d i n th e developmen t o f thi s proposal . Th e Draf t RegulatoryImpac t Analysi s ha s bee n place d i n th e publi c docke t reference d a t th e beginning o f today' s notice . I n addition , intereste d partie s mayobtai n singl e copie s througha writte n reques t t o th e publi c contac t liste d previously . Thi s propose d regulatio n als o wa s submitte d t o th e Offic e o f Managemen t an d Budge t (OMB ) fo r revie wa s require d b

yExecutiv e Orde r 12291 . Anywritte n comment s fro mOM B an

d EPArespons e t o thos e comment s hav e bee n place d i n th e publi c docke t fo r thi s rulemaking .

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IX . IMPAC T ONSMAL L ENTITIE S Sectio n 60 5 o f th e RegulatoryFlexibilit yAc t require s tha t th e Administrato r certif yregulation s tha t do no t hav e a significan t impac t o n a substantia l numbe r o f smal l entities . I certif ytha t thi s propose d regulatio n wil l no t hav e suc han effec t becaus e i t primaril yaffect s onl y manufacturer s o f moto r vehicle s an d moto r vehicl e engines , a grou p whic hdoe s no t contai n a substantia l numbe r o f smal l entities . I n addition , th e propose d nozzl e flowrat e limitatio n applicabl e t o nozzl e owner s wil l no t hav e significan t impac t becaus e i t woul d requir e little , i f any , investment . X . REPORTIN

GAN D RECORDKEEPIN

GREQUIREMENT S

Th e informatio n collectio n provision s relating t o th e propose d refueling emission s standard hav e bee n submitte d t o th e Offic e o f Managemen t an d Budge t (OMB ) unde r th e Paperwor k Reductio n Act , 4 4 U.S.C . 350 1 e t seq . An Informatio n Collectio n Reques t documen t ha s bee n prepare d b yEPA(IC

R No . 738 ) an

d a copymayb e obtaine d fro mBrya n C . Wood-Thomas , Informatio n Polic yBranch ; EPA40 1 M Street , S.W . (PM-223 ) Washington , D.C . 2046 0 or b ycalling (202 ) 475-8791 . Comment s mayb e submitte d t o EPAa t th e above address , bu t shoul d als o b e sen t t o th e Offic e o f

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Informatio n an

d RegulatoryAffairs ; Offic e o f Managemen t an d Budget ; 72 6 Jackso n Place , N.W. ; Washington , D.C . 2050 3 marke d "Attention : Des k Office r fo r EPA. " Th e fina l rul e wil l respon

d t o an

yOMB o r publi c comment s o n th e informatio n collectio n requirements .

XI . LIS T O F SUBJECT S IN4 0 CF R PART 8 6 Administrativ e practic e an d procedures , Ai r Pollutio n Control , Gasoline , Moto r vehicles , Labeling , Moto r vehicl e pollution . Reporting an d recordkeeping requirements . Authorit yfo r th e action s propose d i n thi s notic e i s grante d EPAb

ysection s 202 , 206 , 207 , 208 , 211 , an d 30 1 o f th e Clea n Ai r Ac t [4 2 U.S.C . 7521 , 7525 , 7541 , 7542 , an d 7601 ] . Dated : , 1986 . Le e M . Thomas , Administrato r

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-P.9 9 Reference s 1 . "Recommendatio n on Feasibilit yfo r Onboar d Refueling Los s Control, " U.S . EPA , OANR , OMSAPC , February 1980 . 2 . "Evaluatio n o f Ai r Pollutio n Regulatory Strategie s fo r Gasolin e Marketing Industry, " U.S . EPA , OAR , OAQP S an

d OMS , EPA-450/3-84-012a , Jul y1984 . 3 . "Draf t RegulatoryImpac t Analysis—Propose d Refueling Emissio n Regulatio n fo r 199 0 an d Late r Mode l Yea r Gasoline-Fuele d Moto r Vehicles , Volume s 1 an d 2, " U.S . EPA , OAR , OAQP S an

d OMS , EPA-450/3-87-001 a an d b , Jul y1987 . 4 . "Refueling Emission s fro mUncontrolle d Vehicles, " Rothman , D . an d R . Johnson , U.S . EPA , OAR , OMS , ECTD , EPA-AA-SDSB-85-6 , 1985 . 5 . "Factor s Influencing Benzen e Emission s From Passenge r Ca r Refueling, " Laing , P. , SAE Pape r no . 861559 , Octobe r 1986 . 6 . "Ai r Qualit yCriteri a fo r Ozon e an d Othe r Photochemica l Oxidants, " U.S . EPA , ORD , EPA-600/8-84-020aF , Augus t 1986 . 7 . "Interi m

Quantitativ e Cance r Uni t Ris k Estimate s Du e t o Inhalatio n o f Benzene, " EPA-600/X-85-022 , February 15 , 1985 . 8 . "Stud

yo f Gasolin e Volatilit yan d Hydrocarbo n Emission s fromMoto r Vehicles, " U.S . EPA , OAR , OMS , ECTD , EPA-AA-SDSB-85-5 , Novembe r 1985 . 9 . "Publi c Hearing o n th e EPAStud yo f Gasolin e Volatilit yan

d Hydrocarbo n Emission s fro mMoto r Vehicles, " Ann Arbor , MI , February4-5 , 1986 . (Publi c Docke t No . A-85-21 , EntryII-F-1. ) 10 . "Respons e t o Clai mtha t EPAi s Legall yRequire d t o Impos e Stag e I I Gasolin e Control s i n al l Ozon e Nonattainmen t Areas, " RalphCollel i an d Richar d Ossias , U.S . EPA , OGC , t o Docke t No . A-87-11 , Jun e 1987 . 11 . "Summaryan d Analysi s o f Comment s o n th e Recommende d Practic e fo r th e Measuremen t o f Refueling Emissions, " U.S . EPA , OAR , OMS , ECTD , Marc h1987 .

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-P. 1 Reference s (cont'd ) 12 . "Evaluatio n o f Ai r Pollutio n Regulatory Strategie s fo r Gasolin e Marketin g Industry—Respons e t o Publi c Comments, " U.S . EPA , OAR , Jul y1987 . 13 . "Evaluatio n o f th e Feasibilit yo f Liqui d Fillnec k Seals, " U.S . EPA , OAR , OMS , ECTD , EPA-AA-SDSB-86-3 , Decembe r 1986 . 14 . "Vehicl e Onboar d Refueling Control, " America n Petroleu

m Institute , Marc h1986 , AP I publicatio n no . 4424 . 15 . "Draf t Recommende d Tes t Procedur e fo r th e Measuremen t o f Refueling Emissions, " U.S . EPA , OAR , OMS , ECTD , EPA-AA-SDSB-85-5a , Jul y1985 . 16 . Memorandu

mt o R . Fre d Holbert , U.S . EPA , fro mW . M . Kreucher , Ford Moto r Company , Jun e 17 , 1986 . 17 . "AP I Respons e t o EPAReques t fo r Comment s o n Petroleu

mMarketing IndustryRefueling Rat e Voluntary Standard" , America n Petroleu m Institute , Augus t 6 , 1986 . 18 . "Investigatio n o f th e Nee d fo r In-Us e Dispensing Rat e Limit s an

d Fue l Nozzl e GeometryStandardization, " U.S . EPA , OAR , OMS , ECTD , EPA-AA-SDS-B-87-07 , May1987 . 19 . "Safet yImplication s o f Onboar d Refuelin g Vapo r RecoverySystems, " U.S . EPA , OAR , OMS , ECTD , EPA-AA-SDSB-87-05 , Jun e 1987 .

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