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# OAR Box 1875 Prepped byOllie Stewart



### Document

Number: 

# 4DII-E-5 9 Docket Number: 

# A-90-1 9

Printed 12/1/200811:12:46

AM Sheet 41 of 86P. 2

AUG T199 1 

## A-90-1 9 ll-E-5 9

a ,r: < DE C : •0 /99 2 ' 

### MEMORANDU

M ^tk^lSkkll '"OX):' SUBJECT : Roundtabl e Discussio n o n Bubbling o f Sectio n 11 2 (MACT )

Standard s FROM : Doug Bell , Chie f

Standard s Developmen t Branch , ES D (MD-13 ) TO : Roundtabl e Participant s

Regiona l Ai r Divisio n Director s Thi s memorandu

msummarize s the mini-roundtabl e MAC T bubbl e discussio n hel d Jun e 19 , 199 1 i n Bil l Rosenberg' s offic e a t Watersid e Mall , Washington , D . C . Meeting material s an d a lis t o f participant s ar e attached . Bruc e Jordan , Directo r o f th e Emissio n Standard s Division , Offic e o f Ai r Qualit yPlanning an d Standard s (OAQPS) , opened th e meeting wit ha brie f introductio n regarding th e purpos e an d wha t he hoped the meetin g woul d accomplish . I n summary , he wante d t o elici t idea s and view s o n bubbling MAC T standard s fro mthe differen t perspective s an d experience s represente d a t the meeting , t o narro wth e rang e o f viabl e bubbl e options , an d t o sharpen an

d focu s o n th e rea l issue s associate d wit hthos e bubbl e options . Afte r describin g th e goal s o f th e meeting , Mr . Jordan the n asked the participant s t o introduc e themselves , whomthe y represented , and t o summariz e thei r philosoph yo n bubbling MAC T standards . Industryrepresentative s unanimousl yfavored the concep t o f bubble s an d wer e intereste d i n seeing th e concep t wor k in practice . I n contrast , th e nonindustryrepresentative s wer e generall yno t i n favo r o f bubble s citing enforcement , implementation , an

d administrativ e problems , an d th e possibility tha t a bubbl e coul d resul t i n significan t emissio n increase s ove r wha t the standard s woul d hav e otherwis e achieved . Followin

g th e introductions , NancyMaye r o f OAQP S summarize d EPA' s curren t polic yo n bubbling Nationa l Emissio n Standard s fo r Hazardou s Ai r Pollutant s (NESHAPs ) a s lai d ou t i n EPA' s Emissio n Tradin g PolicyStatemen t (ETPS ) (5 1 F R 43814 ; Decembe r 4 , 1986) .P. 3

Sh e describe d howcurren t policydoe s no t allo wbubblin g t o be use d t o mee t propose d o r promulgate d NESHAP . Th e participant s note d tha t th e curren t polic ywoul d hav e t o b e revise d i n orde r t o accommodat e bubbling i n MAC T standards . Severa l participant s wer e intereste d i n obtaining a copyo f th e policy . Acop yo f the policyi s attached . Th e firs t majo r issu e discusse d wa s whethe r standard s shoul d firs t be develope d an d the n bubbled , o r whethe r th e bubbl e shoul d b e considere d i n th e developmen t o f th e standard s themselves . I f th e bubbl e wer e par t o f th e standard s development , EPAcoul d conside r an

ycos t saving s a t tha t time , an d accoun t fo r bubbl e stringencyan

d implementatio n an d enforcemen t problem s withi n the framewor k o f th e standard . Th e standard itsel f woul d encompas s multipl e emissio n sources , bu t woul d no t specif yemissio n limit s fo r eac hsource . Instead , a singl e limi t woul d b e designated , an d th e regulatio n woul d describ e ho wemission s fromeac hpoin t woul d be determine d an d converte d t o compar e t o th e overal l limit , considering emissio n rate , capacit yutilization , an d hour s o f operation . Severa l possibl e type s o f bubble s wer e discussed . Amas s emissio n bubbl e woul d su mth e allowabl e emission s fromthe individua l source s a t a facilit yan d designat e tha t su ma s th e overal l bubbl e limi t fo r tha t facility , e.g. , 5 Mg/yr . Th e owne r o r operato r woul d the n adjus t th e emission s fromeac hsourc e t o hi s likin

g a s lon

g a s th e su

mo f thos e emission s di d no t exceed th e 5 Mg/yr . A n emissio n rat e bubbl e woul d explicitl yti e th e bubbl e limi t t o productio n rate , i.e. , a s productio n fluctuated , s o woul d the aggregat e bubbl e limi t th e owne r o r operato r woul d have t o meet . The bubbl e limi t woul d b e expresse d i n term s o f mas s o f emission s pe r mas s o f product . Bot hth e mas s emissio n an d emissio n rat e bubble s woul d be base d o n allowabl e emissions , i.e. , thos e allowe d b yth e standards . I f an owne r o r operato r achieve d greate r reduction s than allowed , h e woul d b e abl e t o tak e credi t fo r th e differenc e an d us e tha t differenc e t o offse t othe r emission s elsewher e i n th e bubble . I t wa s acknowledge d tha t even withou t a bubble , an owne r o r operato r woul d likel yd o bette r than th e standard , bu t tha t unde r a bubbl e h e woul d ge t a credi t tha t h e otherwis e woul d no t hav e had . Thi s concer n wa s raise d b

ynonindustr

yrepresentative s an d i s discusse d below . Athird typ e o f bubbl e wa s th e emissio n poin t bubble . Unde r thi s bubbl e n o credi t coul d b e take n fo r operatin g a give n contro l devic e bette r tha n th e efficiencyassigne d t o tha t devic e i n developing th e standard . Fo r example , an incinerato r rate d a t a 9 8 percen t emissio n reductio n efficiencycoul d no t tak e credi t fo r operatin

g a t 99.9 9 percent , eve n thoughi t migh t reall ybe doing so . Additiona l reduction s woul d hav e t o b e achieve dP. 4

throughproces s changes , a differen t bu t mor e efficien t kin d o f contro l device , o r productio n curtailments . Acentra l issu e wa s identifying wher e th e offsetting emission s fo r bubbling , o r "credits, " woul d come from . Th e grou p identifie d two potentia l source s o f credits , bu t came t o n o agreemen t on whethe r o r no t the yshoul d b e allowed : (1 ) additiona l reduction s achieve d b yth e installe d contro l devic e beyond wha t th e standard require s and.(2 ) additiona l reduction s achieve d b

ycontrolling a sourc e no t otherwis e require d t o b e controlled . Th e emissio n credi t generate d b y(1 ) wa s characterize d b

yon e participan t a s a "windfall " i n tha t thes e reduction s woul d have occurre d anyway . H e explaine d tha t standard s ar e se t a t a relativel yloos e leve l an d tha t control s installe d t o mee t th e standard s d o significantl ybetter . H e wa s concerne d tha t allowing thos e reduction s tha t woul d hav e occurre d anywa yt o be use d t o balanc e othe r emissio n point s wit hles s contro l woul d resul t i n greate r overal l emissions . H e describe d a n exampl e wher e a VO C standar d wa s se t fo r coating operation s a t a leve l tha t woul d have force d installatio n o f th e desire d technolog

ywhic hwa s designe d fo r greate r emissio n reductions . Some operators , i n respons e t o th e standards , however , completel y reformulate d thei r coating s fo r some line s an d acquire d larg e "credits " tha t wer e the n use d t o bubbl e wit huncontrolle d coating lines . I f th e bubbl e had no t bee n allowed , al l th e line s woul d hav e bee n controlle d t o th e leve l o f th e standard , resulting i n a greate r overal l emissio n reductio n tha n achieve d wit hth e bubble . H e fel t tha t thos e owner s an d operator s had "gamed " th e system , taking advantag e o f th e wayth e standard s wer e se t t o substantiall yunder-control , an d tha t suc hsituation s coul d hav e bee n bette r deal t wit hi f considere d directl yi n th e standards

setting process . I n response , industr yrepresentative s note d tha t th e resultan t ne t emission s wer e n o differen t tha n thos e allowe d b y th e standards , bu t tha t th e emissio n reduction s wer e achieve d i n a mor e cost-effectiv e way . However , th e nonindustryparticipan t contende d tha t suc h"pape r credits " shoul d no t b e availabl e becaus e theywer e a n artifac t o f wher e th e standard s wer e se t an d no t wha t th e actua l contro l leve l woul d hav e been . H e mad e th e poin t tha t credit s shoul d onl yaris e fro madditiona l contro l abov e an

d beyon d contro l tha t woul d hav e bee n achieve d i n practice , an

d no t tha t leve l beyond wha t wa s required . I t wa s als o note d tha t th e ETP S doe s no t allo wth e differenc e betwee n require d an

d actua l t o b e use d a s a credit . Industr yparticipant s disagree d wit hth e "windfall " descripto r an

d believe d tha t suc ha scheme woul d encourag e plan t operator s t o d o bette r tha n th e standar d an d fin d innovativ e way s t o increas e th e efficiencyo f thei r controls . Theyals o pointe d ou t tha t afte r applicatio n o f a MAC T standard , ther e wil l b e littl e "wiggl e room " t o gai n additiona l reductions . On e industr yP. 5

participan t indicate d tha t hi s compan ymos t likel ywoul d conside r controlling source s tha t woul d no t b e controlle d b yth e regulatio n (becaus e o f smal l siz e o r throughput) , bu t whic hmay be les s costl yfo r hi mbecaus e o f plant-specifi c factors . Thi s prompte d th e suggestio n b ya nonindustryparticipan t tha t cutoff s in th e standard s may , therefore , b e drawn i n the wrong plac e an d tha t th e standard s shoul d hav e n o cutoff s i n return fo r a bubble ; tha t wayth e sourc e woul d decid e wher e th e appropriat e cutoff s woul d b e fo r it s specifi c configuration . Th e conversatio n then turne d t o ho wa bubbl e coul d b e developed , using a specifi c example . Th e exampl e wa s a mi xo f emissio n point s a t a plan t (proces s vents , storag e tanks , transfe r operations , an d wastewater) , eac hwit hdifferen t kind s o f standards , e.g. , percen t reduction , equipment , an d concentration . Anumbe r o f problem s wer e identified : (1 ) ho wt o translat e standard s wit hdifferen t format s int o a commo n emissio n basis , (2 ) ho wt o translat e source s wit hdiffering emissio n rate s int o a commo n basi s (i.e. , howt o bubbl e batc han d continuou s processes) , (3 ) wha t woul d b e th e averaging perio d fo r compliance , and (4 ) howwoul d emission s b e determine d fo r compliance ? I t wa s observe d tha t i f a bubbl e wer e no t considered , on e woul d no t hav e t o determin e th e mas s emission s fro ma percen t reduction , equipment , or.wor k practic e standard , bu t tha t unde r a bubbl e suc ha calculatio n woul d b e necessary . I t wa s als o noted tha t a bubbl e woul d increas e the administrativ e an

d enforcemen t burde n o n bot hindustr yan d th e reviewing authority , althoug hn o agreemen t wa s reache d o n th e degree . On e o f the nonindustr yrepresentative s expresse d th e opinio n tha t a bubbl e woul d mak e complianc e "a n orde r o f magnitude " mor e complicate d an d tha t complianc e determination s woul d b e significantl ymor e difficult . H e cite d th e resourc e burde n o f additiona l training o f permi t writers , additiona l tim e in negotiating permits , an d th e complexit yo f enforcing a permi t o n emissio n point s whic hhad differen t permitte d emissio n level s an d emissio n format s fro m thos e specifie d i n th e MAC T standards . Anothe r participan t expresse d concer n ove r howon e woul d kee p trac k o f emission s withi n th e bubbl e ove r time t o compar e i t wit h the tota l emission s allowe d unde r th e bubble , especiall ywhe n productio n wa s variable . Al l emissio n calculation s woul d hav e t o be mad e o n th e sam

e basis . Conversio n calculation s woul d hav e t o be well-documente d an d equivalen t emission s demonstrated . Additiona l resource s woul d b e necessaryt o evaluat e thes e conversion s an

d approve bubbles . Enforcemen t personne l wer e o f the opinio n tha t the averaging tim e t o determin e complianc e wit h a bubbl e shoul d be th e sam e a s fo r determining complianc e wit h the MAC T standard , an d tha t th e averagin g time s shoul d b e shor t enought o b e enforceable . Interes t wa s als o expresse d b yth e grou p i n learning mor e abou t Regio n II' s recordkeeping problem s wit hNe wJersey' s bubble , mentione d i n th e meeting materials . Thes e recordkeeping problem s wer e allude d t o during a visi t b yaP. 6

headquarter s EPArepresentativ e t o Regio n II , bu t n o detail s wer e provided . Informatio n o n thes e problem s wil l b e sough t an d provide d t o th e grou p whe n available . Industryparticipants , however , perceive d th e burde n o f implementing a bubbl e a s relativel ysmal l compare d wit hth e additiona l requirement s tha t woul d b e impose d b

yth e permitting proces s itself , an d agree d t o work o n approache s tha t woul d alla yconcern s o f th e nonindustr y participants . Anothe r issu e discusse d wa s th e possibl e creatio n o f a disincentive t o participat e i n th e Earl yReductio n Progra mi f bubbling MAC T standard s wer e allowed . On e o f th e advantage s o f the Earl yReductio n Progra mi s tha t a sourc e ca n bubbl e man y unrelate d emissio n points . I f a MAC T bubbl e wer e als o availabl e i t wa s believe d tha t som e source s ma

ypas s up Earl yReduction s an d institut e a MAC T bubbl e directly , i f i t coul d acquir e th e sam e bubbling advantage . However , th e participant s generall y agreed tha t th e Earl yReductio n progra mstil l provide d a significan t advantag e t o source s seeking t o delaycomplianc e wit h a MAC T standard , perceive d a s likel ybein g mor e stringent , an d tha t bubbling MAC T standard s woul d b e an optio n theycoul d stil l d o a t a late r time , e.g. , the program s wer e no t relate d an d participating i n on e woul d no t affec t participatio n in the other , an d bot hprogram s offere d benefits . Afte r a brie f discussion , i t appeare d tha t th e availabilit yo f a MAC T bubbl e woul d no t likel y have an impac t o n a source' s incentiv e t o participat e i n th e Earl yReductio n Program . Th e fina l issu e discusse d wa s tha t o f bubbling differen t pollutants . On e industr yparticipan t state d tha t he wa s thinking o f one-for-on e trades , bu t woul d no t oppos e including som e sor t o f indexin

g t o allo wfo r pollutan t toxicity . Conversely , the nonindustr

yparticipant s wante d t o limi t bubblin g onl yt o th e sam e pollutant . Theywer e concerne d wit htrading pollutant s wit h differen t toxicities , even i f a weightin g scheme wer e instituted , an d becaus e differen t pollutant s ar e no t controlle d t o the same degree , even wit hth e sam e contro l device . Amajo r concern wit h bubbling acros s pollutant s wa s tha t speciatio n o f emission s an d quantificatio n o f individua l pollutant s woul d b e necessar yt o , determin e relativ e weighting fo r toxicit yan d t o accoun t fo r differen t contro l efficiencie s fo r differen t pollutants . Anothe r concern wit hbubblin g acros s pollutant s wa s th e environmenta l impac t o f emission s fro mdifferen t kind s o f emissio n points . Whil e thi s i s als o a concern i n bubbling th e same pollutant , the effec t coul d b e greatl ymagnifie d i f a lowe r toxi c pollutan t fro m a heated , elevate d sourc e wer e bubble d wit ha highe r toxi c pollutan t fro

ma cooler , ground-leve l sourc e tha t woul d resul t i n muc hhighe r ambien t concentrations . Nea r th e en

d o f th e meeting , nex t step s wer e discussed . Mr . Jordan expresse d hi s desir e t o narrowthing s dow n t o bette r focu s on th e issues , an

d observe d tha t th e group seeme d t o prefe r th eP. 7 ~ P "

"emission point " bubbl e ove r th e othe r possibl e bubbl e option s outline d in th e meeting material s (se e attached) . Th e emission poin t bubbl e woul d reduc e nonindustryconcern s ove r taking credi t fo r th e differenc e betwee n actua l emission s an d wha t ar e allowed b ythe standard s b

yassigning a nomina l efficienc y(e.g. , 9 8 percen t fo r a

n incinerator ) t o a particula r contro l devic e regardles s o f wha t i t achieve d i n practice . Thi s optio n woul d thu s spur credit s throughth e us e o f mor e stringen t control s o r proces s changes , o r promp t a sourc e t o contro l emissio n point s tha t i t woul d hav e no t otherwis e bee n require d t o control . The participant s favore d a followu p meeting t o discus s i n mor e detai l th e emission poin t bubbl e i n ligh t o f th e issue s an d wit hrespec t t o EPA' s ETPS . I t wa s note d tha t th e "emissio n point " bubbl e need s a mor e appropriat e descriptor . Mr . Jordan closee i th e meeting b yagai n asking th e participant s thei r vie wo f bubbling an d whethe r o r no t thos e view s ha

d change d ove r th e cours e o f th e meeting . Th e industr y participant s wer e please d tha t th e discussion s had bee n initiated an d tha t the

ywer e bette r abl e t o understan d th e issue s an

d concern s associate d wit ha bubble . A s a resul t the ybelieve d theywer e bette r abl e t o addres s th e problem s an d t o hel p devis e a workabl e bubbl e tha t woul d no t b e environmentall ydetrimental . Th e nonindustr

yparticipant s reiterate d tha t thei r concern s mus t b e satisfactoril yaddresse d befor e theywoul d accep t a bubble . Theyfel t i t necessarytha t th e Offic e o f Genera l Counse l addres s a s soon a s possibl e th e lega l issue s o f whethe r o r no t the Clean Ai r Ac t allow s MAC T bubbling an d i f bubbling acros s pollutant s i s permitted . Th e nonindustryparticipant s indicate d tha t som e for m o f bubbl e ma

yb e acceptabl e i f i t adhere d t o restriction s in the ETPS , di d no t exten d t o ne wsources , an d wa s environmentall y neutra l o r resulte d i n a ne t benefi t t o th e environmen t ove r no t having a bubble . The OA R staf f think s tha t a reasonabl e an d workabl e bubbl e wil l be advantageou s t o th e environmen t an d woul d allo wmor e cost-effective complianc e wit hMAC T standards . W e ar e working wit hothe r office s withi n th e Agenc yt o develo p a positio n o n MAC T bubbles . W e ar e planning anothe r discussio n i n Septembe r t o presen t thi s position . Thi s roundtabl e ma yinclud e additiona l participant s an

d b e expande d t o includ e discussio n o f othe r issue s related t o th e Hazardou s Organi c NESHAP . Yo u wil l receive detail s concerning thi s roundtabl e i n th e nea r future . I f yo u hav e questions , pleas e contac t Bruc e Jorda n a t (919 ) 541-5572 3 o r me a t (919 ) 541-5568 . Attachment s bcc : Ron Campbel l To m Helm s OAQPS:ESD:SDB:RColyer:JStevens:FT S 629-5262:MD-13(Mutual):8-7-9 1•1

MAC T Bubbl e Jun e 19 , 199 1 Nam e Larr yWeinstoc k Bo bStriete r Re g Modii n Bria n Tarant o Nanc yCookso n Davi d Donige r Chery l Sutterfiel d Chuc k Grigsby Ric k Colye r Dou g Bel l Bruc e Jorda n Andre wOti s Jan e Enger t Danie l For t Car l Mazz a Patrici a Embre y Michae l Wine r Kath yKaufma n Barr yElma n Do n Theile r Nanc yMaye r Ji mWeigol d Joh n Silvas i Davi d Spragu e Lind a Chapu t Lydi a Wegma n Roundtabl e Participant s Roo m939 , EP AWes t Towe r Oraanizatio n OAR-1 0 AP I MVM A Exxo n Che m CM A NRD C PMA SOCMA EPA/OAQP S EPA/OAQP S EPA/OAQP S EPA/OPP E EPA/OAQP S EPA/OT S EPA/OA R EPA/OG C EPA/OG C EPA/OA R EPA/OPP E Wisconsi n EPA/OAQP S EPA/OAQP S EPA/OAQP S EPA/OAQP S EPA/OAQP S EPA/OAQP S (CMA )

(Phon e (Phon e (Phon e (Phon e (Phon e (Phon e (Phon e Phon e

202-382-217 4 202-682-833 7 313-956-550 2 713-870-611 7 202-887-124 1 202-624-933 4 202-835-354 8 201-397-280 8 919-541-526 2 919-541-556 8 919-541-557 2 202-245-374 9 703-308-868 4 202-382-369 4 202-382-740 3 202-382-762 5 202-382-760 6 202-475-895 0 202-382-272 7 hookup ) hookup ) hookup ) hookup ) hookup ) hookup ) hookup ) P. 8P. 9



### MAC TBUBBLE S MINI-ROUNDTABL E DISCUSSIO N

JUN E 19 , 199 1 10:00-4:0 0 BIL L ROSENBERG' S OFFIC EP.1 0



## MAC TBUBBLE S AMACTbubbl e woul d allowsom e o ral l source s subjec t t o MACT standard s at a contiguou s facilit yto fin d th e bes t "fit " i n term s o femissio n reduction s an d cos t withou t exceedin g wha t tota l emission s woul d have bee n at th e facilityha d eac h source subject t o a MAC Tstandard bee n require d t o compl ywit h eac h individua l standard
. To determin e a bubble , on e woul d su m th e emission s allowe d unde rMAC Tfo reac h emissio n ooin t an d require th e owne ro roperato ro fth e facilityt o meet th e su m emissio n numbe ran ywa yh e chooses
. Suc h a n approac h woul d -.heoreticall yresul t i n over-contro l o fsom e source s an d under-contro l o f others , providin g th e owne ro roperato rmaximu m flexibilityt o achiev e hi s emissio n reductio n i n th e mos t cost-effectiv e manne rpossible
. Regulation s unde rdevelopmen t i n respons e t o th e 199 0 Clea n Ai r Ac t Amendment s d o no

t explicitl ypreclud e th e us e o fbubbles
. However , there ar e man ylegal , technical , an d policyissue s that must b e resolve d before EP

Aca n se t a bubbl e polic yfo rMACT
. Thes e issues , identifie d at a Ma y29
. Workgrou p meeting , are outline d below
. Th e scope , options , an d issue s are not intende d to b e exhaustive , an d other s ma yb e developed
.P.1 1


## BUBBL E SCOP E OPTION S

•» Al l source s covere d b ya MACTstandar a within_contiguou s facility
. A n industria l sit e wit h a numbe rofdifferen t emission-causin g operation s woul d b e subject t o multipl e MAC Tstandards
. -£c_Lgxam^le
. reacto rproces s vents , storag e tanks , etc.
. coul d b e coyejg^at^a_giyf> n poin t i n tim e b yseparat e MACTstandards : wherea s othe roperation s suc h as degreasin g o rsurfac e coatin g ma ynotjge
. Onl ythos e source s covere d b ya MAC Tstandar d woul d b e include d i n th e bubble
. As MAC T standard s wer e se t fo rth e othe rsources , th e bubbl e woul d grow .
•Bubbl e define d i n eac h MAC Tstandar d (case-by-case)
.

Assumin g a genera l bubbl e policyi s adopted , th e specific s o n wha t an a howeac h sourc e covere d bya MAC Tstandar d coul d b e bubble d wit h othe rsource s withi n a contiguou s facilit ywoul d b e spelle d ou t i n eac h standard
. Thi s woul d b e a case-by-cas e approach , an d woul d addres s an yspecia l situation s peculia rt o eac h source .
•Bubbl e source s withi n sam e MAC Tstandard
.

Thi s optio n woul d limi t bubblin g t o al l source s t o whic h th e sam e MAC Tstandar d applie s withi n th e facility , e.g. , al l storag e tanks wit h th e sam e MAC Tstandar d coui d b e bubbled , bu t storag e tank s an d proces s vent s coul d not
.
•Al l emissio n point s withi n sam e proces s uni t o rsubcategory
.

Thi s optio n woul d limi t bubblin g acros s a collectio n o fintegrate d X equipmen t tha t result s i n a product o racros s a define d subcategory
. I n th e HON
. fo rexample , on e woul d bubbl e acros s al l emissio n source s i n a butadien e productio n unit , i.e.
. storag e tanks , proces s vents , wastewater
. transfer , an d equipmen t leaks
.
•Bubbl e acros s Earl yReductio n o rothe rnon-MAC Tsources .

Thi s optio n woul d greatl yincreas e flexibilit yt o a n owne ro roperato r b yallowin g hi m t o bubbl e source s subjec t t o MAC Tagains t source s wit h a n Eari yReductio n extensio n o reve n source s no t ye t regulated
.P.1 2



## ^ ISSUES/CONSIDERATION S LEGA L

•Ca n source s withi n a bubbl e b e allowe d t o contro l t o les s tha n thei r applicabl e MAC Tstandard s and/o rtloors ? AMAC Tbubbl e woul d allo wa n owne ro roperato rt o over-contro l som e source s an d under-contro l others a t th e facility
. Thjs_wgul d resul ti n a[lowin q th e under-coctrolle d source s t o mee tsomethin g les s tha n th p MACTstandar^jQ£4hosaja0urces , somethin g les s than-the-MAST-Uooj ^ o rn o contro l a t all
. Ca n we allo wtoxicity-weighte d tradin g amon g hazardou s pollutants ? Shoui d w e giv e specia l consideratio n t o hig h ris k pollutants ? Th e Ac t doe s mentio n toxicitya s a facto ri n bot h earl yreduction s an d modifications , bu t doe s no t fo rsettin g MAC Tstandards
. I fi t i s determine d tha t bubblin g base d o n weighte d toxicit yi s acceptabl e an d desirable , w e mus t the n develo p a schem e tha t ma yo rma ynot resembl e that fo rmodification s o rearl yreduction
. Suc h a schem e woul d generall y reguire greate rtha n 1 -for- 1 reduction s o fmor e toxi cpollutant s ove rles s toxi cpollutants
.
POLIC Y Allowin g bubble s coul d creat e a disincentiv e t o participat e i n Earl y Reductio n Program
. Th e Earl yReductio n Progra m i s designe d t o offe rsource s a more cost-effectiv e emissio n contro l solutio n tha n wha t the yotherwis e ma y have t o compl ywit h unde rMACT
. Unde rth e Earl yReductio n Program , source s tha t achiev e a 90_p_ircen t reductio n befor e proposa l o fa n applicabl e MAC Tstandard_ca n ge t a 6-vea rcomplianc e extejpsi__iJo. r meetinjthejy]^1^andard
. Th e Earl yReductio n Progra m result s i nP.1 3 —r — significan t additiona l emissio n reductio n tha n woul d hav e otherwis e occurrea . Asourc e mayperceiv e tha t th e abilit yt o bubbl e MAC T standara s i s a n attractiv e alternativ e t o th e Earl yReductio n Progra m an d woui d cnoos e no t t o participate , resultin g i n a los s ofth e emissio n reduction s tha t woui d otherwis e hav e occurred
. TECHNICAUADMINISTRAT1VE/ENFORCEMEN T Howt o bubbl e differen t kind s o fstandards , i.e. , performance , wor k practice , equipment ? /y c A Standard s base d o n performanc e o remission s standard s ar e statutoril ypreferred , bu t wor k practic e o requipmen t standard s ar e a "las t < reson " whe n emission s canno t b e reasonabl ycapture d an d measured , an d consequently , th e actua l contro l efficiencyan d emission s ar e difficultL
. t o determine
. Estimate s ar e mad e fo rth e purpose s o fassessin g impacts/ " o fth e standard , bu t thes e ar e generall ycompose d o findustry-wid e r" averag e number s tha t d o no t easil ytranslat e int o individua l facilit yX numbers
. Determinin g emissions-associate d wit h equipmen t orworkr ' practic e stanoard s afTspecificJacilit vi s difficult , anrLdetemwttntr" " ^- ^ omission s fo rth e purpos e ofa bubbl e woul d b e eve n mo-redifficult,jC" - _ becaus e th e o__ne ro roperatQLwgu|d i ^antl o appl ya differenrgquipmeet^ ojiwonc-practir p othe rtha n MAC Tfo rwhjchjeiiT^sslonsjiiay^^ \ bee n calculated
. -*•— ^ Shoui d Droductio n curtailment s o rshutdown s b e allowe d i n bubbl e calculations ? Shutdown s o rcurtailment s i n productio n ca n creat e problem s i ffull y credite a i n al l situations
. Fo rexample , assum e tha tMAC Ti s base d o n 9 8 percen t reductio n an d 2 proces s unit s runnin g a tth e sam e productio n rat e were bubbled , on e achievin g 9 7 percen t an d th e othe r9 9 percent
. I f th e 9 9 percen t uni t shu t dow n an d th e productio n transferre d t o a differen t facility , th e bubbl e woul d the n b e achievin g onl y9 7 percen t reduction , an d th e facilitywit h th e ne w9 9 percen t uni t woul d b e allowe d t o bubbl e i t agains t anothe runi t achievin g les s tha n MACT
. However , on e coul d arou e that a curtailmen t o rshutdow n i s a rea l emissio n reductio n an dP.1 4

shoui d b e alloweo
. eve n thoug h i t doe s no t appea rt o reflect wha t MAC " i s intende d t o represent
. Shoul d w e allo wfugitiv e equipmen t leak s i n th e bubble ? Th e standar d fo requipmen t leak s ha s alread ybee n negotiate d amon g EPA , industry , environmenta l groups , an d Stat e an d loca l agencies
. Th e rul e ha s bee n formall yagree d t o b yal l partie s wit h th e understandin g tha t EPAwil l propos e an d promulgat e th e rul e agree d t o b yth e committee
. Th e negotiate d rul e represent s a delicat e balanc e of competin g interests , providin g bot h th e environmenta l protectio n demande d b yth e State s an d environmentalists , an d protectio n t o th e industryfro m enforcemen t action s i fthe yfaile d t o mee t specifie d performanc e levels
. I fEPAwer e t o allo wa plan t t o d o somethin g les s tha n require d b yth e rule, i t coul d b e interprete d byth e negotiatin g partie s tha t EPAha s renege d o n th e agreement , openin g th e rul e u p fo r litigation , an d throwin g EPA' s Re g Ne g progra m int o disarray
. I n addition , an yofth e negotiatin g partie s woul d b e abl e t o su e th e Agenc yo n th e basi s tha t i t di d no t liv e u p t o it s en d o fth e agreement
. Woul d bubblin g resul t i n overal l emissio n increases ? Bubblin g coul d resul t i n overal l emissio n increase s fo r2 reasons " First, wher e a n over-controlle d sourc e (99. 5 percent ) withi n a 98-percen t bubbl e shu t down , leavin g a n under-controlle d sourc e (96. 5 percent) , an d rebuil t a t 9 8 percen t contro l byitsel fo rwithi n anothe rbubble , a net v— - incEeaseJ n emission s woul d resultj ftota l emission s wer e no ttie d t o ^ -production
. Second , becaus e source s require d t o mee t a 98-percen t MAC Twoul d probabl ycontro l t o a greate rdegre e anywa y( a 98-percen t efficien t incinerato ri s a leas t commo n denominato rfo rmos t organi c pollutant s an d mos t actuall yachiev e greate refficiencie s wit h a properl y operatin g contro l device) , w e woul d b e allowin g th e sourc e t o us e th e _differenc e a s a n offse t fo rgreate renrnssjgns__alsewher 8 a t theiacjjjty
. On e wayt o correc t fo rthi s woul d b e t o charg e a "premium " t cbubble
. Suc h a schem e woul d disallo wone-for-on e bubbling , i.e. , 1 0 lbs
. fo r1 0 lbs. , an d woul d requir e som e additiona l percentage , e.g. , 2 0 percent
. Therefore , shoul d a n owne ro roperato rwan t t o bubble , h e mus t achiev e 1 2 lbs
. instea d of1 0 lbs
. reduction
..i t shoul d als o b e note d tha t EPA' s curren t Emissio n Tradin g Polic y Statemen t (ETPS ) doe s not allo wth e differenc e betwee n require d an d actua l t o D

e use d a s a credit ; an d als o suggest s chargin g a "premium " t o bubble
. Th e ETP S funhe rstate s tha t bubble s shoul d no t increas e emission s o

fhazardou s o rtoxi cai rpollutants
. (5 1 F R 43814 : Decembe r 4
. 1986 ) Wha t i s additiona l enforcement/administrativ e burde n associate d wit h bubbling ? Th e basi ctenan t underlyin g bubblin g i s tha t a n owne ro roperato r woul d over- an d under-contro l th e variou s MAC Tsource s withi n th e bubbl e t o achiev e th e sam e ne t emissio n rat e ha d h e controlle d eac h sourc e t o th e MAC Tstandard
. Consequently , additiona l informatio n i s necessar yt o determin e th e exten t o fover - an d under-contro l o feac h sourc e t o ensur e tha t the ybalance
. Fo rexample , assum e tha t a facilityhas bubble d a numbe rofsimila r proces s vent s t o determin e a singl e overal l emissio n limi t o rrate
. Althoug n th e bubbl e ha s a singl e emissio n limit , determinatio n o f complianc e woul d hav e t o b e mad e o n a point-by-poin tbasis , an d the n summe d t o compar e wit h th e bubbl e limit
. Testin g o rothe rshort-ter m complianc e determination s woul d no t translat e easil yint o a n longer-ter m bubbl e limit , especiall ywhe n productio n fluctuates
. Furthermore , th e owne ro roperato rmus t kee p trac k o fdifferen tlimit s fo reac h vent , eac h perhap s wit h it s ow n monitoring , recordkeeping , an d reportin g scheme , especiall ywhe n differen t contro l device s ar e used
. i n addition , t o th e exten t tha t change s i n productio n rate s du e t o marke t demand s (closur e o rcurtailment) , malfunctions , o rmaintenanc e occur , it ma

yb e necessaryt o adjus t th e bubbl e limi t an d thu s redefin e th e limi t fo reac h vent
. Furthermore , th e owne ro roperato rmus treadjus t th e bubbl e eac h tim e h e add s a ne wvent
. Ever yadjustmen tt o th e bubbl e tha t result s i n newlimit s fo reac h ven t woui d requir e a n additiona l complianc e determinatio n t o ensur e tha t th e newlimit s wer e bein g met
. i fbubblin g acros s pollutant s i s limited , o rtoxicit yindexin g i s used
. th e weighte d averagin g necessaryt o defin e an d readjus t th e bubbl e woul d ad d anothe rdimensio n ofcomplexit yi n keepin g trac k ofth e differen t limit s fo reac h vent
.P.1 6 

## BUBBL E OPTION S
N O BUBBLE . Bubblin g woul d not b e allowed , an d source s woul d hav e t o mee t th e emissio n limit s establishe d i n th e MAC Tstandar d fo rtha t source . PRO : I n practic e bubble s are no t easil yimplemented
. Th e majo r problem s hav e bee n outline d above
. Thes e problem s an d issue s wer e identifie d b ythos e o n th e Workgrou p wit h experienc e i n tryin g t o administe ran d enforc e variou s kind s o fbubbles , specificall yth e STAPP A representative , Offic e ofEnforcement , an d th e StationarySourc e Complianc e Division
. Concer n wa s expresse d abou t gamesmanshi p an d no t knowin g whethe ro rno t a facilit ywa s i n compliance
. Regio n I I officials, i n a subsequen t discussion , describe d Ne wJersey' s attemp t a t implementin g a bubbl e a s a recordkeepin g nightmare
. CON : Bubblin g ca n provid e a cost-effectiv e wa yt o mee t MAC T standards
. TOTA L MAS S EMISSIO N BUBBLE . Atota l mas s emissio n bubbl e woul d b e base d o n actua l emission s fo ral l source s covere d bya MAC Tstandar d withi n a contiguou s facility , e.g. , 1 ton/year
. Thi s woul d b e a bubbl e i n it s puris t form
. Unde rthi s option , th e emission s fro m eac h sourc e covere d b ya MAC Tstandar d woul d b e summe d an d th e aggregat e mas s emissio n numbe rwoul d becom e th e bubbl e limi t tha t th e facilit ywoul d hav e t o achieve
. PRO : A n owne ro roperato rwoul d hav e flexibilit yt o over-contro l o r under-contro l an ysourc e withi n th e bubbl e a s lon g a s th e overal l mas s limit(s ) wa s met
. CON : Recordkeepin g an d complianc e determinatio n wit h singl e bubbl e limi t mor e difficul t du e t o differen t control s o n simila rsource s (i.e.
. over-contro l an d under-contro l o fidentica l vents ) an d t o emissio n change s becaus e ofproductio n fluctuations
. 8P.1 7

EMISSIO N RAT E BUBBLE . A n emissio n rat e bubbl e base d o n production , e.g. , 1 ton/1.00 0 ton s product
. A n overal l facilityemissio n rat e limi t woul d b e established unde rthi s option , also , bu t woul d b e directl yrelate d t o production
. PRO : Woul d accoun t fo rchange s i n production
. A s productio n increase d o rdecrease d throug h shutdown s o rcurtailments , s o woul d th e bubbl e limit
. CON : I n additio n t o emissio n data , thi s optio n woul d als o requir e productio n data
. Woul d becom e mor e difficul t t o determin e complianc e at facilitie s wit h man yproduct s (e.g. , DuPont' s Chamberswork s Plan t make s 75 0 differen t products)
. AMISSIO N POIN TBUBBLE . Unde ra n emissio n poin t bubbl e contro l equipmen ti s assigne d a nomina l efficiency , regardles s ofth e actua l efficiencyi n th e specifi c application
. A n owne ro roperato rwoul d hav e t o over-contro l byusin g a mor e stringen t contro l device , o rb ycontollin g a sourc e tha t woul d no t hav e otherwis e bee n require d t o contro l (e.g. , a ven t abov e a Tota l Resourc e Effectivenes s cutoffo ra tan k belo wa siz e cutoff)
. I n return , h e coul d choos e t o under-contro l o rno t contro l certai n sources . However , becaus e a nomina l efficiencywoul d b e assigned , additiona l bubbl e credit s coul d not b e gaine d b

yusin g th e sam e contro l devic e mor e efficiently
. PRO : Becaus e eac h contro l devic e woui d hav e it s ow n assigne d efficiency , a sourc e tes t woul d no t b e necessarya s lon g a s th e devic e wer e operatin g properly
. CON : However , becaus e th e sam e contro l devic e mayno t resul t i n th e sam e efficiencyi n differen t applications , th e EPAwoul d hav e t o mak e som e determinatio n as t o th e appropriat e efficiencyfo reac h application , o rrequir e testing
.

# Theoretica l MACTBubbl e

5 9 (MAC TBubbl e limit )

/ 5/8 f T O 

### 5/

2 T O

TO = Transfe roperatio n S T= Storag e tan k P V= Proces s ven t 

### Emission s / Emission s Befor e bubble /

Afte rbubbl e
10/1 2 S T 

### 10/5

ST

MACTStandard 95 % Equipmen t 98 % 

### 10/8

ST 

### 3/ 1 P V 

## J 10/1 5

ST / 

### Chemica l plan t 3/6 PV 

### 3/2

PV

• /

0 0