# OAR Box 1107 Prepped byOllie Stewart



## Document

Number: 

# 19)V-B- 1 Docket Number: 

# A-81-2 1

Printed 4/11/20083:03:45PM Sheet 19of 90 P. 1P. 2



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## - X Unite d State s Environmenta l Protectio n Agenc y Offic e o fAi rQualit y Plannin g an d Standard s Researc h Triangl e Par k N C ?' Ai r 

# Viny l Chlorid e Standards : Response s t o Comment s o n Januar y198 5 Propose d Revision s EPA-450/3-86-00 4 Septembe r198 6 

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# Viny i Chlorid e Standards : Response s t o Comment s o n Januar y198 5 Propose d Revision s

Emissio n Standard s an d Engineerin g Divisio n

U.S

. ENVIRONMENTA LPROTECTIO N AGENC Y

Offic e o fAi ran d Radiatio n Offic e o fAi rQualit yPlannin g an d Standard s Researc h Triangl e Park , N C 2771 1

Septembe r198 6P. 4

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Thi s repor tha s bee n reviewe d b yth e Emissio n Standard s an d Engineerin g Divisio n ofth e Offic e o fAi rQualit y Plannin g an d Standards , EPA

. an d approve d fo rpublication

. Mentio n o ftrad e name s o rcommercia l product s i s no tintende d t o constitut e endorsemen to rrecommendatio n fo ruse . Copie s o fthi s repor tar e availabl e throug h th e Librar yService s Offic e (MD-35) , U.S

. Environmenta l Protectio n Agency , Researc h Triangl e Park , Nort h Carolin a 27711 ; or , fo ra fee , fro m th e Nationa l Technica l Informatio n Services , 528 5 PortRoya l Road , Springfield , Virgini a 22161

.P. 5

VINY L CHLORID E STANDARD : RESPONSE S T O COMMENT S O N

JANUAR Y198 5 PROPOSE D REVISION S

EMISSIO N

STANDARD S ANDENGINEERIN GDIVISIO N

U.S . Environmenta l Protectio nAgenc y Offic e o f Ai r andRadiatio n Offic e o f Ai r Qualit y Plannin gandStandard s Researc hTriangl e Park , Nort hCarolin a 2771 1

SEPTEMBE R198 6



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TABL E O F CONTENT S

Sectio nPag e 1. 0 SUMMAR Y• 1- 1 1. 1 SUMMAR YO F CHANGE S SINC E PROPOSA L 1- 1 1. 2 SUMMAR YO F IMPACT S O F PROMULGATE D ACTIO N1- 3 2. 0 SUMMAR YO F PUBLI C COMMENT S AND RESPONSE S 2- 1 2. 1 GENERA L POLIC YAND LEGA L ISSUE S 2- 1 2. 2 REVISION S T O RELIE F VALV E DISCHARG E STANDAR D 2-1 0 2. 3 REVISION S T O LEA K DETECTIO NAN D REPAI R REQUIREMENT S 2-2 2 2. 4 DEFINITION S 2-4 1 2. 5 REVISION S T O OTHE RPART S O F TH E STANDAR D 2-5 8 2. 6 MISCELLANEOU S 2-6 5 3. 0 PETITIO NFORRECONSIDERATIO N3- 1P. 7

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1. 0 SUMMAR Y

O nJanuar y9 , 1985 , th e U . S . Environmenta l Protectio nAgenc y(EPA ) propose d revision s t o th e nationa l emissio nstandar d fo r viny l chlorid e (VC ) (5 0 FR1182 ) unde r authorit yo f Sectio n11 2 o f th e Clea nAi r Act . Th e standar d limit s atmospheri c emission s o f VC fro mplant s producin g ethylen e dichlorid e (EDC ) b

yth e reactio no f oxyge nan d hydroge nchlorid e wit hethylene , plant s producin g VC b yanyprocess , and plant s producin g on e o r mor e polymer s containin g anyfractio no f VC (e.g. , polyviny l chlorid e (PVC)) . Th e Januar y9 , 1985 , Federa l Registe r notic e propose d administrativ e and clarifyin g revision s t o th e VC standar d base d o na revie wo f th e standard . Publi c comment s wer e requeste d o nth e proposa l i nth e Federa l Registe r notice . Atota l o f 1 6 commen t letter s wer e received . Commenter s include d industr yrepresentatives , representative s o f industr ytrad e organizations , Stat e an d Federa l legislators , on e environmenta l grou p and on e Stat e regulator y agency . Th e publi c comment s ar e summarize d i nthi s documen t alon g wit h response s t o th e comments . Th e comment s an d response s serv e a s th e basi s fo r change s and clarification s t o th e revise d standar d mad e betwee nproposa l and promulgation . 1. 1 SUMMAR YO F CHANGE S SINC E PROPOSA L I nrespons e t o th e publi c comments , on e majo r chang e and a fe wmino r change s an d clarification s hav e bee nmad e i nth e propose d revision s t o th e VC standard . Th e majo r chang e involve s th e propose d reformattin g o f th e relie f valv e discharg e standard . Severa l comment s wer e receive d tha t resulte d i n withdrawa l o f th e propose d requirement s fo r relie f valv e discharges . Othe r comment s resulte d i nsevera l mino r clarification s t o definition s and othe r regulator ylanguage .



### 1- 1P. 8

H .

Th e revise ddefinitio no f "ED C purification " i nth e propose d standar dha s bee nfurthe r clarifie dbyspecificall yexemptin g intermediat e andfina l produc t storage . Th e definitio no f relie f valv e ha s bee nmodifie dt o exclud e tw o speci f i c pressur e contro l systems : polymerizatio nshortsto p system s andrefrigerate dwate r systems . Also , emission s fro m pressur e relie f device s tha t contro l exhaus t ga s flo wt o incinerator s ar e no t considere drelie f valv e discharges . Th e definitio no f lea k ha s bee nclarifie db yaddin g th e EP Ates t metho do nwhic hlea k measurement s ar e t o b e based . T h e provisio n specifyin g tha t leak s ar e emission s no t regulate dunde r exhaus t ga s provision s ha s bee ndropped . Three-hou r averagin g period s hav e bee nspecifie di nth e oxychlorinatio nven t standar dan di nthre e othe r provision s wher e exhaus t ga s limit s ar e prescribed . (Three-hou r average s wer e specifie di nal l othe r exhaus t ga s provision s i nth e propose d standard. ) Certai nopen-ende dline s hav e bee nmad e exemp t fro mSubpar t V requirements . Th e provisio nallowin g plant s t o demonstrat e effectivenes s o f existin g lea k detectio nandrepai r program s throug ha performanc e tes t o f a sampl e o f valve s ha s bee nrevise dt o mor e clearl yindicat e th e numbe r o f valve s require dt o b e tested . Metho d60 1 o f 4 0 CF R136. 3 wa s approve dandincorporate db yreferenc e fo r measuremen t o f VC i ninproces s wastewater . Th e America nSociet yo f Testin g an dMaterial s (ASTM ) metho dfo r determinin g b

yproces s sampl e whethe r equipmen t i s i nVC servic e ha s bee nincorporate db yreference . Th e definitio no f connecto r i nSubpar t V ha s bee nmodifie dt o allo w exemptio nfro mreportin g andrecordkeepin g requirement s fo r al l screwe dan dwelde dconnector s an dflange dconnector s tha t ar e covere dbyinsulatio no r othe r materials .



### 1-2P. 9

1. 2 SUMMAR YO F IMPACT S O F PROMULGATE D ACTIO N N o change s i nth e environmental , energ yan deconomi c impact s o f th e standar dhav e occurre dsinc e proposal . Further , sinc e n o majo r revision s t o th e standar dwer e proposed , th e impact s o f th e origina l standar dremai n nc.r, g';"21 "

j \i ijp.chaneed . T!"es e imDac^ s ar* 3 ^""•scribe di n^h^ nr 0 *^^ 1 - tp ---s. propose drevision s (5 0 FR1182) .



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Thi s documen t include s response s t o publi c comment s o nth e propose d revision s t o th e VC standard . Alist , o f th e commenters , thei r affiliations , an dth e EPAdocke t number s assigne dt o thei r correspondenc e i s give ni n Tabl e 2-1 . Th e comment s ar e organize daccordin g t c topi c in . th e fcllowir. c sections . 2. 1 Genera l Polic yan dLega l Issue s 2. 2 Revision s t c Relie f Valv e Discharg e Standar d 2. 3 Revision s t o Lea k Detectio nandRepai r Requirement s 2. 4 Definition s 2. 5 Revision s t o Othe r Part s o f th e Standar d 2. 6 Miscellaneou s 2. 1 GENERA L POLIC YAN D LEGA L ISSUE S

Commen t Leve l o f Standar d Si xcommenter s (IV-D-1 , IV-D-2 , IV-D-6 , IV-D-11 , IV-D-12 , IV-D-13 ) addresse dth e leve l o f contro l associate dwit hth e VC standard . Thre e commenter s (IV-D-1 , IV-D-2 , IV-D-6 ) agree dwit hth e EPA' s decisio nno t t o regulat e additiona l source s o r chang e th e quantitativ e emissio nlimit s o f th e standard . The yallege dn o basi s exist s fo r makin g th e standar dmor e stringen t base do nhealt heffects , an dtha t ther e i s n o ne wtechnolog ywhic hwoul d justif ya mor e stringen t standard . On e commente r (IV-D-6 ) furthe r state d tha t i nligh t o f th e EPA' s finding s tha t othe r regulation s hav e bee neffectiv e i nreducin g V C emissions , a mor e stringen t standar dunde r Sectio n11 2 canno t b e justified . I ncontrast , fou r othe r commenter s (IV-D-11 , IV-D-12 , IV-D-13 , IV-D-16 ) state dtha t th e leve l o f th e standar dwoul db e weakene db yth e



### 2-1P.1 1

I I

TABL E 2-1 . LIS T O F COMMENTER S ONPROPOSE D REVISION S

T O TH E VINY L CHLORID E STANDAR D

Docke t Ite mNumbe r Commente r and Affiliatio n IV-O- I w . C . Hoi-brook Th e Viny l Institut e 35 5 Lexingto nAvenu e Ne wYork , Ne wYor k 1001 7 Date : Marc h15 , 198 5 IV-D- 2 Davi d L . Lul l Occidenta l Chemica l Corporatio n P.O . Bo x69 9 Pottstown , Pennsylvani a 1946 4 Date : Marc h19 , 198 5 IV-D- 3 J . C . Ledvin a Vist a Chemica l Compan y P.O . Bo x1902 9 Houston , Texa s 7722 4 Date : Marc h21 , 198 5 IV-D- 4 R . R . Kienl e Shel l Oi l Compan y P.O . Bo x432 0 Houston , Texa s 7721 0 Date : Marc h19 , 198 5 IV-D- 5 Pau l M . Kin g PP GIndustries , Inc . On e PP GPlac e Pittsburgh , Pennsylvani a 1527 2 Date : Marc h22 , 198 5 IV-D- 6 Joh nT . Bar r Ai r Product s and Chemicals , Inc . P.O . Bo x53 8 Allentown , Pennsylvani a 1810 5 Date : Marc h20, " 198 5 IV-D- 7 Willia mT . Newma n Georgi a Gul f Corporatio n P.O . Bo x62 9 Plaquemine , Louisian a 70765-062 9 Date : Marc h20 , 198 5

a Th e docke t numbe r fo r thi s projec t i s A-81-21 . Docket s ar e o nfil e a t EPA' s Centra l Docke t Sectio ni nWashington , D.C . 2- 2P.1 2

TABL E 2- 1 (Continued) . LIS T O F COMMENTER S ONPROPOSE D REVISION S T O TH E VINY L CHLORID E STANDAR D

a Dccke t ItemNumber ' Commente r an d Affiliatio n IV-D- 3 T . E . Lingafelte r Do wChemica l U.S.A . 203 0 Willar d H . Do wCente r Midland , Michiga n4864 C Date : Marc h19 , 198 5 IV-D- 9 Geraldin e V . Co x Chemica l Manufacturer s Associatio n 250 1 MStreet , N.W . Washington , D.C . 2003 7 Date : Marc h25 , 198 5 IV-D-1 0 Charle s A . Johnso n Nationa l Soli d Waste s Managemen t Associatio n 173 0 Rhod e Islan d Avenue , N.W . Washington , D.C . 20C3 6 Date : Marc h21 , 198 5 IV-D-1 1 Jeffre yG . Mac k Delawar e Hous e o f Representative s Dover , Delawar e 1990 4 Date : Marc h21 , 198 5 IV-D-1 2 Davi d D . Donige r Nationa l Resource s Defense Counci l 135 0 Ne wYor k Avenue , N.W . Washington , D.C . 2000 5 Date : Marc h25 , 198 5 IV-D-1 3 To mCarpe r U.S . Hous e o f Representative s Washington , D.C . 2051 5 Date : Marc h25 , 198 5 IV-D-1 4 Jame s D . Fanni n Th e B F Goodric hCompan y 610 0 Oa k Tre e Boulevar d Cleveland , Ohi o 4413 1 Date : Marc h19 , 198 5

a Th e docke t numbe r fo r thi s projec t i s A-81-21 . Docket s ar e o nfil e a t EPA' s Centra l Docke t Sectio ni nWashington , D.C . 

### 2- 3P.1 3

TABL E 2- 1 (Concluded) . LIS' T O F COMMENTER S ONPROPOSE D REVISION S T O TH E VINY L CHLORID E STANDAR D

Docke t Ite m

Number - Commente r andAffiliatio n 17-0-1 5 W . Eaile yBarto n Borde nInc . 16 5 M . Washingto nAvenu e Columbus , Ohi o 4321 5 Date : Marc h25 , 198 5 IV-C-1 6 Patrici a L . Norto n Louisian a Departmen t o f Environmenta l Qualit y P.O . Bo x4406 6 Bato nRouge , Louisian a 7080 4 Date : Apri l 3 , 198 5 Th e docke t numbe r fo r thi s projec t i s A-81-21 . Docket s ar e o nfil e a t EPA' s Centra l Docke t Sectio ni nWashington , D.C .



### 2-4P.1 4

propose d change s and shoul d b e mad e mor e stringent . On e commente r (IV-D-11 ) state d tha t EP Ashoul d replac e th e standar d wit hon e whic hprovide s additiona l ris k reduction . Th e othe r commente r (IV-D-13 ) argue d tha t th e leve l o f th e standar d shoul d b e base d o nth e protectio no f publi c healt hand th e environ

ment , rathe r tha nth e abilit yo**" industr yt o compl yw't hth e steward . ~r e commente r state d th e leve l o f th e standar c shoul d provid e incentiv e f or tne developmen t o f improve d emissio ncontro l systems . Respons e Thes e comment s relat e t o ho wEPAselect s th e leve l o " contro l fo r standard s unde r Sectio n11 2 o f th e Clea nAi r Act . A s note d b ythes e commenters , standard s se t byEP Aunde r Sectio n11 2 reflect.th e leve l o f contro l necessar yt o provid e anampl e margi no f safet yt o protec t publi c health . However , i ncontras t t o som e o f th e commenters , EP Abelieve s tha t thi s leve l o f contro l mus t als o b e achievabl e t o b e meaningfu l and t o avoi d bein g arbitrar yan d capricious . Th e V C standard , establishe d i n197 6 a s an appropriat e leve l o f contro l unde r Sectio n112 , represente d th e mos t stringen t leve l o f contro l tha t ca nb e achieve d b yVC and PVC plant s base d o nbes t availabl e technologies , whil e avoidin g unreasonabl e cost . Becaus e th e revision s t o th e standar d propose d o nJanuar y9 , 1985 , di d no t substantivel y chang e th e leve l o f contro l associate d wit hth e standard , EP Aconsidere d thes e comment s i nth e contex t o f th e leve l o f contro l establishe d i n1976 . A s discusse d i nmer e detai l i nth e followin g response , EP Aconclude d tha t th e leve l o f contro l i nth e VC standar d i s appropriate . Commen t Zer o Discharg e Goa l and Consideratio no f Cost s Tw o commenter s (IV-D-1 , IV-D-6 ) concurre d wit hth e EPA' s conclusio ntha t Sectio n11 2 o f th e Clea nAi r Ac t doe s no t requir e emission s o f VC t o b e eliminated . On e o f th e commenter s (IV-D-1 ) adde d tha t th e 197 7 propose d amendment s wer e base d o nth e "erroneou s premise " tha t a zer o discharg e leve l shoul d b e achieved . I ncontrast , anothe r commente r (IV-D-12 ) pointe d ou t tha t EP Apreviousl yrecognize d a zer o emission s goal .



### 2-5P1 5

Thre e commenter s (IV-D-6 , IV-D-8 , IV-D-12 ) addresse dth e us e o f cost s an dcos t effectivenes s i nth e developmen t o f th e standard . On e commente r (IV-D-6 ) emphasize dth e importanc e o f a sound , cost-effectiv e regulation . Th e secon dcommente r (IV-D-8 ) state dtha t th e propose dmodification s t o th e standar dar e aime da t reducin g emission s i nth e mos t co s : >effeet* :w e c ?.**.r.e " . eve nthoug hsem e ne wrequirement s hav e bee nadded . Conversely , tw o co^me : - = r s (IV-D-11 , IV-D-12 ) objecte dt o th e EPA' s consideratio no f cost s indevelopin g th e VC standard .

P £ S 0 ° C> S ^ Inth e EPA' s judgment , th e VC standar dprotect s th e publi c healt hwithi n th e meanin g o f Sectio n112 , an dEP Ama yconside r cos t an dfeasibilit yi n settin g th e standard . Th e EP Aview s ar e explaine di nth e 1975-7 6 VC rule

making , andi nth e Agency' s brie f i nNRD C v . LPA , No . 85-115 0 (D.C . Cir) . Th e NRDC/ED F provide dn o ne winformatio no nthi s issue . Commen t Emissio nStandard s vs . Equipmen t ari d Wor k Practic e Standard s Th e commente r (IV-D-16 ) state dtha t uncertaintie s i nth e existin g standar dhav e require denforcemen t personne l t o develo p enforcemen t policie s outlinin g th e leve l o f effor t expecte do f plant s fo r compliance . Th e commente r recommende dtha t revision s t o th e standar dspecif yrequire dequipmen t an d operatin g practice s fo r meetin g th e existin g limits . Revisin g th e standar d i nthi s manne r woul densur e continue dstric t contro l o f V C emission s whil e providin g industr yan denforcemen t personne l wit hspecifi c guidanc e o n require dleve l o f effort . Th e resul t woul db e mor e effectiv e enforcemen t o f th e standard . Respons e Unde r th e requirement s o f th e Clea nAi r Act , a s amended , EP Ai s t o se t emissio n(i.e. , performance ) limit s whereve r possibl e an dt o allo wth e owner s an' doperator s o f affecte dfacilitie s t o achiev e tha t limi t i nan ywa y available . I nth e cas e o f V C emissions , i t i s bot hpossibl e an dappropriat e



### 1-6P.1 6

to " establis ha nemissio nlimi t fo r mos t sources . Thus , EP Aca nno t requir e th e us e o f specifi c type s o f equipmen t fo r mos t o f th e source s covere d b yth e standard . However , wher e i t i s no t practicabl e t o se t a nemissio nstandard , EP Aha s require d th e us e o f equipmen t and othe r wor k practices . Commen t Evidenc e o f Huma nHealt hRis k On e commente r (IV-D-1 ) questione d th e nee d fo r a standar d regulatin g VC emission s o nth e basi s o f healt hrisks , citin g th e absenc e o f huma ndeath s relate d t o V C exposur e i nth e vicinit yo f regulate d plants . Anothe r commente r (IV-D-14 ) state d tha t th e absenc e o f predicte d cance r case s cause d b yVC exposur e ar e proo f o f th e succes s o f th e VC standard . Respons e Generally , th e absenc e o f specifi c evidenc e linkin g huma ndeath s relate d t o V C emission s t o th e environmen t i s no t indicativ e o f th e absenc e o f ris k fro mthes e emissions . A t th e tim e th e origina l V C standar d wa s developed , uni t ris k factor s wer e develope d base d o nstudie s o f th e healt heffect s fro m exposur e t o V C emissions . Thes e healt hstudie s implicate d instance s o f live r angiosarcoma , othe r cancers , and noncarcinogeni c disorder s i nanimal s fro m inhalatio no f VC . Whil e ther e hav e bee nn o recen t epidemiologica l studie s relatin g t o exposur e t o V C emissions , instance s o f live r angiosarcom a i n individual s expose d t o VC hav e bee nreported . A s par t o f th e revie wo f th e VC standard , th e EP Acarcinoge nassessmen t grou p reviewe d th e origina l healt h studie s and subsequen t healt hinformatio nwhic hconfirme d th e lin k betwee nVC exposur e and brai nand live r cancer . Th e revie wconclude d tha t th e healt h effect s associate d wit hV C an d th e ris k estimate s develope d a t th e tim e o f th e origina l standar d remai nvalid . T o th e exten t tha t th e origina l VC standar d ha s bee neffectiv e i n reducin g o r eliminatin g incidences o f cance r du e t o exposur e t o VC , the nth e effort s o f EPA , industr yan d individual s i ncontrollin g V C emission s hav e bee nsuccessful . However , give nth e latenc yperio d fo r healt heffect s and th e existenc e o f confoundin g variable s i nexposur e and developmen t o f cancer , bot hth e Agenc yand industr yshoul d continu e t o mak e reasonabl e effort s t o continu e controllin g V C emissions . 

### 2-7P.1 7

Commen t Technolog yDemonstratio nRequirement s On e commente r (IV-D-12 ) state d tha t ther e i s n o languag e i nSectio n11 2 whic hwoul d requir e a contro l technolog yo r emissio nleve l t o b e demonstrate d i norde r t o serv e a s th e basi s o f a NESHAP . Th e commente r pointe d t o th e statemen t i nth e preambl e tha t "1 0 ppm vrepresent s th e lowes t leve l o f contro l whic hha s bee nconsistentl yachieved " a s indicativ e tha t EP Awa s applyin g suc ha requiremen t i nevaluatin g alternativ e exhaus t ga s limits . Th e commente r state d tha t th e requirement s o f Sectio n11 2 ar e intende d t o be technolog yforcing , base d o nprojection s o f th e capabilitie s o f technolog y rathe r tha no npas t achievements . Respons e Th e VC standar d wa s establishe d a t a leve l whic hwa s determine d t o b e achievabl e usin g bes t availabl e contro l technologies . Th e dat a o nVC emission s contro l indicat e tha t a 5 pp m emissio nlimi t woul d no t b e consistentl y achievable , and EPAselecte d a 1 0 ppmemissionlimi t t o reflec t th e leve l o f contro l require d byth a standard . I ndoin g so , EP Aconsidere d bot hth e feasibilit yo f thi s leve l o f contro l and th e healt himpact s resultin g fro m thi s contro l leve l includin g tha t th e standar d provide s a nampl e margi no f safet yfo r publi c health . Comment Withdrawa l o f 197 7 Proposa l Thre e commenter s (IV-D-4 , IV-D-7 , IV-D-14 ) state d thei r support fo r th e EPA' s withdrawa l o f th e 197 7 propose d amendment s t o th e standard . Respons e A s discusse d i nth e preambl e (5 0 F R1183) , EP Adi d no t believ e i t wa s appropriat e t o leav e th e propose d amendment s t o th e VC standar d i neffec t o r t o promulgat e amendment s base d o nth e propose d amendments . Thi s decisio nwa s th e outcom e o f a revie wprocedur e tha t considere d th e 197 7 proposal , a s wel l a s a recen t reevaluatio no f existin g an d ne wcontro l technologies , o f VC source s no t regulate d b yth e standar d and o f enforcemen t and complianc e experienc e sinc e promulgatio no f th e standard .



### 2- 8P.1 8

Commen t Effectivenes s o f VC Standar d On e commente r (IV-D-14 ) state d tha t th e industr yha s effectivel y implemente d th e VC standar d a s evidence d b yth e fac t tha t actua l VC emissio n reduction s unde r th e standar d hav e exceede d th e origina l standar d estimates . Anothe r commente r ^IV-D-15 ) als o state d tha t th e VC standar d lia s bee n successfu l ingreatl yreducin g VC emissions , an e pointe d ci: t th e considerac1 ? expens e t o plant s i nLouisian a t o instal l contro l equipmen t and implemen t operatin qprocedure s t o mee t th e standard . Resoons e N o respons e necessary . Commen t Clarificatio no f Preambl e and Regulatio n Thre e commenter s (IV-D-1 , IV-D-6 , IV-D-9 ) state d tha t th e explanatio nc f th e standar d containe d i nth e preambl e and th e languag e o f th e standar d itsel f nee d t o b e clarifie d and mad e mor e consistent . On e commente r (IV-D-1 ) suggeste d tha t th e interpretativ e languag e o f th e preambl e b e incorporate d int o th e standard , wher e appropriate , t o hel p ensur e consisten t interpretation . Th e commente r stresse d th e importanc e o f resolvin g uncertaintie s associate d wit hth e standar d t o preven t unnecessar ycos t t o th e industr yand EPA . A secon d commente r (IV-D-6 ) als o emphasize d th e nee d t o remov e al l ambiguit y fro mth e standar d t o preven t th e cost s o f negotiatio nand litigatio ncause d b ydifferin g interpretation s o f th e standard . Respons e On e purpos e o f th e propose d revision s wa s t o enhanc e th e clarit yo f th e requirement s o f th e VC standard . Al l specifi c instance s o f confusio nove r provision s o f th e standar d and th e languag e o f th e preambl e cite d b yth e commenter s hav e bee naddresse d i nothe r response s directe d towar d th e relie f valv e definition , th e lea k detectio nrequirements , th e applicabilit yc f th e standar d t o storag e tanks , th e three-hou r averagin g period , and othe r issues . Th e EP Abelieve s tha t wit hthes e clarification s th e requirement s o f th e standar d ar e clea r and consisten t wit hth e inten t o f thi s action .



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Commen t Nee d t o Updat e Standar d Th e commente r (IV-D-14 ) emphasize d th e nee d t o updat e th e standar d base d o neigh t year s o f experienc e b yEPAand industr ysinc e promulgatio no f th e standard . H e note d tha t EPAha s effectivel vanalyze d experienc e unde r tri e

Resoons e cevelcoi r. n rev-' s i :n s

M o respons e necessary . Commen t .Author-'t*- ' fo r Wor k Prcctia Standard ; Th e commente r (IV-D-1 ) restate d industry' s positio ndurin g th e origina l rulemakin g tha t EP Aha d n o lega l authorit ya t tha t tim e t o promulgat e wor k practic e rules . Respons e Wha t th e Agency' s authorit ywa s i n197 6 i s no t a subject o f thi s rulemaking . 2. 2 REVISION S T O RELIE F VALV E DISCHARG E STANDAR D 2.2. 1 Numerica l Limi t Forma t Commen t Numerica l Limi t Forma t Seve ncommenter s (IV-D-2 , IV-D-7 , IV-D-9,.IV-D-12 , IV-D-13 , IV-D-14 , IV-D-16 ) addresse d th e numerica l limi t forma t selecte d fo r th e relie f valv e discharg e standard . Fou r commenter s (IV-D-11 , IV-D-12 , IV-D-13 , IV-D-16 ) objecte d t o th e proposa l t o gran t a nallowabl e relie f valv e discharg e rate . On e o f thes e commenter s (IV-D-=16 ) state d tha t althoug hth e propose d revise d relie f valv e discharg e requirement s mor e clearl yspecif ywhic hrelie f valv e discharge s ar e i nviolatio no f th e standard , the yd o no t penaliz e discharge s whic hma yb e cause d b

ygros s negligence . Th e secon d commente r (IV-D-12 ) urge d EPAt o retai nth e existin g standar d tha t relie f valv e discharge s ar e violation s o f th e standar d unles s unpreventable . Th e commente r state d tha t EPAha s presente d

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n o analysi s o f th e "significant " burde no nAgenc yresource s whic hwa s cite d a s on e reaso nfo r th e proposal . Further , th e commente r state dtha t preventabl e discharge s shoul db e avoide da s a matte r o f principle , and pointe dou t tha t relie f valv e discharge s ar e th e sincl e larges t remainin qsourc e o f V C emission s a t som e plants . Finally , th e commente r objecte dt o th e allowabl e discharg e provisio na s bein g a significan t weakenin g o f th e standar dsinc e curren t EPA enforcemen t polic yha s routinel yconclude dtha t th e vas t majorit yo f release s ar e preventable . Th e commente r expresse dconcer ntha t th e numerica l limit s woul dlegitimiz e th e curren t discharg e rate s b yindustry , regardles s o f th e abilit yt c lowe r the m further . T h e thir dcommente r (IV-D-13 ) state dtha t th e propose dnumerica l standard s ar e no t consisten t wit hth e Congressiona l inten t fo r th e regulatio no f hazardou s substances . Th e commente r pointe dou t tha t th e propose dstandard s woul db e les s stringen t tha nth e requirement s o f a consen t agreemen t reache di na recen t cas e agains t Formos a Plastic s i n Delaware . Th e commente r state dtha t th e recen t relie f valv e discharg e performanc e o f th e Formos a Plastic s facilit ywoul dno t hav e bee naffecte d b y th e propose dstandard , eve nthoug hi t wa s th e to p V C emitte r i nth e country . Bot hcommenter s IV-D-1 1 andIV-D-1 2 urge dEP At o dro p th e propose drevision s andt o develo p mor e stringen t requirement s fo r relie f valv e discharges . Fou r commenter s (IV-D-2 , IV-D-7 , IV-D-9 , IV-D-14 ) expresse dgenera l suppor t fo r th e EPA' s proposa l o f numerica l limits . On e o f thes e commenter s (IV-D-14 ) state dhi s belie f tha t th e propose dnumerica l limit s fo r relie f valv e discharge s ar e practica l bu t sufficientl ystringen t t o requir e furthe r progres s b

yindustr yi npreventin g discharges . Anothe r o f thes e commenter s (IV-D-2 ) furthe r urge dEPAt o adop t a nenforcemen t polic yo f reviewing al l relie f valv e discharg e incident s i nexces s o f th e limit s andsuspendin g enforcemen t i f thos e incident s wer e deeme dt o b e emergencies . Respons e A t th e tim e th e origina l VC standar dwa s developed , i t wa s recognize d tha t relie f valve s andothe r safet yrelie f device s ar e a potentia l sourc e o f VC emission s whic har e controllabl e throug ha combinatio no f equipmen t and wor k practices . However , informatio nwa s no t availabl e o nth e effectivenes s

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o f contro l measure s o nrelie f valv e discharg e performance . Th e origina l standar dregulate drelie f valv e discharg e emission s b yprohibitin g al l nonemergenc ydischarges . Emergenc ydischarge s ar e describe da s thos e whic h coul dno t hav e bee navoide db ytakin g measure s t o preven t th e discharge . Thi s standar di s anemissio no r performanc e standar dtha t limit s al l V C emission s excep t thos e resulting fro memergenc ydischarges . Durin g th e revie wo f th e VC standar dbegu ni n198 0 andcomplete di n 1982 , includin g enforcemen t andcomplianc e experienc e unde r th e VC standard . EP Aenforcemen t personne l reporte dsignifican t manpowe r andresourc e require

ment s wer e bein g use dt o monito r complianc e wit hth e relie f valv e discharg e standard . Ihi s wa s primaril ydu e t o th e effor t require dt o individuall y evaluat e eac hrelie f valv e discharg e fo r preventability . Th e revie wstudy als o foun dtha t man yproducer s wer e uncertai nabou t whethe r the ycomplie d wit hth e relie f valv e discharg e standard . Th e revie wstud yconclude dtha t th e forma t o f th e standar dshoul db e reviewed , primaril yt o reduc e th e enforcemen t burde no nEP Aandt o improv e industry' s understandin g o f com plianc e requirements . Base do nth e recommendation s o f th e revie wstudy , EP A se t ou t t o establis ha standar dfo r relie f valv e discharge s base do nnumerica l discharg e limit s reflectin g performanc e representativ e o f complianc e wit hth e origina l standard . Th e result s o f thi s effor t t o reforma t th e relie f valv e discharg e standar dwer e propose di nJanuar y198 5 (se e 5 0 FR1182) . I nrespons e t o comment s objectin g t o th e propose drevise drelie f valv e discharg e requirements , EP Aha s reconsidere dth e propose dactio nt o add ne w numerica l limit s fo r relie f valv e discharges . I nparticular , EP Aha s reviewe d th e basi s fo r th e revie wstud yrecommendation s tha t th e forma t o f th e standar d b e change d(i.e. , t o reduc e enforcemen t burde nandt o improv e understandin g o f complianc e requirements) . Durin g th e fiv e year s sinc e th e revie wstud y wa s conducted , efficienc yo f activitie s relatin g t o th e enforcemen t o f relie f valv e discharg e standar dha s improved . Thi s i s du e i nlarg e par t t o experienc e establishe dove r th e las t 5 year s i nenforcin g th e origina l standard . A s a result , EP Aenforcemen t personne l conside r thi s standar dt o b e muc hles s resourc e andmanpowe r intensive . Furthermore , enforcemen t action s take nb y EP Aagains t a numbe r o f plant s sinc e th e tim e o f th e revie wstud yhav e serve d

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tw o purposes . First , the yhav e resulte di nimprove dcontro l o f relie f valv e discharge s accompanie db ya reductio ni nrelie f valv e discharg e emissions . Second , som e o f thes e enforcemen t action s hav e resulte di nconsen t decree s whic houtlin e specifi c measure s require dt o b e take nb yth e individua l plan t f.t r como l i a ne e turoose s ~hes e consen t decree s ne t onl yserv e t o clari~ v complianc e requirement s fo r th e subjec t plan t bu t serv e a s guideline s fo r a! 1 plant s o f th e type s o f measure s deeme dappropriat e b yEP Afo r controllin g relie f valv e discharges . Inthi s way , understandin g o f complianc e requirement : ha s bee nappreciabl yimproved . Becaus e thes e recen t finding s tendt o invali

dat e th e maic r conclusion s c f th e revie wstud vEP Abe i ieve s i t i s r.c longe r appropriat e t o reforma t th e origina l standard . Consequently , th e propose d numerica l limit s fo r relie f valv e discharges , ar e no t bein g promulgated . 2.2. 2 Leve l o f Numerica l Limit s Commen t Ca p o nMas s Emissions , 100-Poun d D e Minimu s Exemptio n Th e commente r (IV-D-13 ) state dtha t th e revise drelie f valv e discharg e limit s shoul dals o includ e a ca p o nth e siz e o f discharge s s o tha t th e quantit yo f V C emitte di s regulate di nadditio nt o th e frequenc yo f discharg e events . Tw o commenter s (IV-D-2 , IV-D-7 ) recommende dtha t relie f valv e discharge s les s tha n10 0 pound s b e exempte dfro mth e revise drelie f valv e discharg e requirements . On e o f th e commenter s (IV-D-7 ) emphasize dth e smal l environ

menta l impac t o f brie f relie f valv e "chatter " incidents . The . secon dcommente r (IV-D-2 ) state dtha t th e administrativ e burde nandpersonne l requirement s fo r investigating , documenting , reporting , an dnegotiatin g mino r discharge s ar e disproportionat e t o th e correspondin g hazar dt o huma nhealth . Respons e A s discusse di nSectio n2.2.1 , EP Aha s decide dno t t o reforma t th e origina l standar dwit hnumerica l limits . Th e origina l relie f valv e discharg e standar dprovide s fo r revie wo f al l discharges , includin g bot hlarg e an d smal l discharges . An yrelie f valv e discharg e whic hi s preventabl e i s i n violatio no f th e standar dan dsubjec t t o enforcement .

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Commen t Numerica l Limi t Applie dt o EDC/VC Productio nUnit s Thre e commenter s (IV-D-1 , IV-D-5 , IV-D-14 ) provide drecommendation s o n applyin g th e relie f valv e discharg e limi t fo r EDC/VC plant s t o multi-uni t complexe s andexpande dplants . Commente r IV-D- 1 requeste dtha t th e limi t o f 4 discharge s ?e r yea r t e applie dt o eac hindividua l productio nuni t withi na plant . Commente r IV-D- 5 suggeste c tha t th e l^'mi t b e applie dseparatel yt o eac hdiscret e plan t unde r separat e managemen t i na multi-plan t complex . Commente r IV-D- 1 a"s o recommende dtha t th e relie f valv e discharg e limi t b e applie dt o eac hne wEDC/V C productio nuni t adde dt o a nexistin g facility . Alternat^'ely , Commente r IV-D- 1 agree dw't hth e suggestio no f anothe r commente s (IV-D-14 ) tha t th e limi t fo r expande dEDC/VC plant s b e increase di nproportio n t o th e increas e i nproductio ncapacity . Respons e A s discusse di nSectio n2.2.1 , EP Aha s decide dno t t o revis e th e relie f valv e discharg e requirement s b yaddin g numerica l limits . A s don e currently , EP Awil l continu e t o evaluat e th e preventabilit yo f eac hdischarge . 2.2. 3 Contro l Measure s Commen t Equipmen t Requirement s i nRelie f Valv e Discharg e Standar d Th e commente r (IV-D-16 ) requeste dtha t th e revise dstandar ddelineat e th e type s o f measure s considere dadequat e t o preven t unnecessar ydischarge s fro mrelie f valve s andfaile dequipment . I nparticular , th e commente r (IV-D-16 ) recommende dtha t a provisio nb e adde dt o th e standar drequirin g a leve l o f redundanc yfo r anyequipmen t an dcontro l instrumentatio nwhic h influenc e operatin g pressure s s o tha t failur e o f a singl e equipmen t piec e o r contro l instrumen t doe s no t caus e a relie f valv e discharg e fro m overpressurization . Respons e Ihe approac hrecommende dbyth e commente r i s inappropriat e i nthi s case . Th e Clea nAi r Act , a s amended , require s EP At o establis hemissio nstandard s

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(i.e. , performanc e standards ) unles s the yar e no t feasibl e t o prescrib e o r enforce . Thus , becaus e EP Aca nestablis ha nemission/performanc e standard , suc ha s a standar dprohibitin g al l relie f valv e discharge s excep t emergencies , EP Ai s reouire dt o d o so . Informatio no nth e effectivenes s o f variou s equipmen t andoperationa l procedure s fo r controllin g relie f valv e discharge s wa s no t availabl e a t th e tim e th e origina l standar dwa s written . It-wa s expecte dtha t differen t combination s o f contro l measure s woul db e equall y effectiv e i npreventin g relie f valv e discharges . On e findin g o f th e revie w stud ywa s tha t individua l "contro l techniques " (includin g equipmen t and operationa l measures ; associate dwit hpreventio no f relie f valv e discharge s ca nno t b e directl yrelate dt o emission s reduction . Furthermore , th e attitud e o f plan t owner s andoperator s appear s t o b e animportan t facto r i ncontrollin g relie f valv e discharg e occurrences . Durin g visit s t o fiv e PVC plant s wit h goo dperformanc e records , EP Alearne dtha t thes e plant s ha deffectivel y implemente ddifferen t combination s o f equipmen t andwor k practice s fo r preventin g relie f valv e discharge s (Docke t Ite mII-B-31) . Base do nthes e findings , EP Acontinue s t o believ e tha t i t i s mor e effectiv e t o allo wplant s t o develo p thei r owncombinatio no f preventiv e measure s tha t wil l enabl e the m t o eliminat e preventabl e discharge s limit s rathe r tha nt o prescrib e contro l measures . Th e EP Aagree s tha t redundan t instrumentatio nandcertai nothe r eauipmen t ar e a nimportan t facto r i npreventio no f relie f valv e discharge s a t som e plants . However , th e leve l o f redundanc yvarie s according t c plan t and th e typ e o f discharg e t o b e controlle dandcanno t b e uniforml yspecifie dfo r al l plants . Generally , a t leas t on e leve l o f redundanc yfo r ke yinstrumentatio n andequipmen t affectin g relie f valv e discharg e incidenc e i s considere db yEPA . t o b e necessar yfo r prope r operatio nandmaintenance . Commen t Gasholde r Containmen t Syste m Tw o commenter s (IV-D-11 , IV-D-12 ) urge dEP At o strengthe nth e standar d b yspecifyin g th e us e o f al l availabl e equipmen t andpractice s t o minimiz e emissions , particularl ygasholders . On e o f th e commenter s (IV-D-12 ) state d tha t gasholde r containmen t system s ar e feasibl e andshoul dno t b e rejecte d o n

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th e basi s o f cos t o r th e smal l quantit yo f emission s tha t woul d b e controlle d throug ha gasholde r system . Th e commente r asserte d tha t cos t i s a ninappro

priat e facto r fo r consideratio nunde r Sectio n11 2 an d tha t gasholde r containmen t system s hav e bee ninstalle d pursuan t t o enforcemen t actions . Further , th e commente r state d tha t VC emission s contro l throug hth e us e o~ gasholde r containmen t system s shoul d b e pursued , eve ni f the yar e onl y effectiv e i ncontrollin g emergenc yrelease s o f VC . Th e secon d commente r (IV-D-11 ) state d tha t EP Ashoul d examin e th e us e c f gasholde r containmen t system s o nPVC plant s t o contai nrelease s o f VC . Thi s commente r pointe d ou t tha t suc ha syste mi s bein g require d f or a PVC p i ?..'*. ' - > Delawar e pursuan t t o a consen t decree . Respons e Gasholder s ar e on e o f man ycontro l measure s tha t ar e availabl e t o plant s t o contro l relie f valv e discharg e emissions . I nfact , som e plant s currentl y hav e gasholder s availabl e a s par t o f th e VC recover ysyste mo r a s a surg e vesse l feedin g th e incinerato r o r othe r primar ycontro l devic e (Docke t Ite m II-A-19) . A t leas t on e PV C plan t vent s relie f valve s o ncertai nequipmen t (i.e. , equipmen t othe r tha nreactor s and storag e spheres ) t o a gasholde r (Docke t Ite mII-B-31) . Th e EP Ai s unawar e o f anyplan t tha t currentl yvent s relie f valve s o nPVC reactor s directl yt o a gasholder . Althoug hgasholder s ma yb e appropriat e technolog yfo r certai nplant s t o reduc e relie f valv e discharg e emissions , the yar e no t essentia l contro l technolog yfo r al l plants , a s evidence d b yth e fac t tha t som e plant s wit hth e lowes t relie f valv e discharg e rate s d o no t hav e gasholders . Consequently , EP Abelieve s i t i s inappropriat e t o requir e gasholder s fo r al l plants . However , EP Adoe s no t discourag e th e us e o f gasholde r containmen t system s a s a contro l technolog yfo r relie f valv e discharge s whe nappropriate . 2.2. 4 Applicabilit yo f Numerica l Limit s Commen t Multipl e Discharge s Durin g Singl e Overpressur e Even t Thre e commenter s (IV-D-1 , IV-D-3 , IV-D-6 ) requeste d tha t multipl e relie f valv e discharge s tha t occu r fro m th e sam e piec e o f equipmen t becaus e o f a

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singl e overpressur e even t b e considere d a singl e discharg e regardles s o f whethe r the yoccu r simultaneously . Respons e Thi s commen t refer s t o th e metho d fo r countin g discharge s unde r th e propose d revise d requirement s fo r reiie f valv e discharge s whic hEPAha s decide d no t t o promulgat e (se e Sectio n2.2.1) . Th e numbe r o f relie f valve s tha t discharg e durin g a noverpressur e even t i s no t critica l t o complianc e determination s unde r th e curren t standard . Commen t Discharge s Vente d t o a Contro l Devic e Iw o commenter s (IV-D-1 , IV-D-14 ) requeste d additiona l clarificatio no n th e applicabilit yo f th e relie f valv e discharg e limit s t o discharge s tha t ar e vente d t o a contro l device . On e commente r (IV-D-1 ) suggeste d th e limit s specif ytha t onl ydischarge s direc t t o th e atmospher e ar e t o b e considere d whendeterminin g complianc e wit hth e limits . Th e secon d commente r (IV-D-14 ) questione d whethe r a relie f valv e discharg e vente d t o a contro l devic e no t meetin g th e 1 0 ppmlimi t woul d b e counte d a s a relie f valv e discharg e fo r complianc e purposes . H e expresse d concer ntha t bot ha 1 0 ppmviolatio nand a relie f valv e discharg e violatio ncoul d b e cite d i f th e standar d doe s no t clearl yindicat e tha t relie f valv e discharge s conveye d t o a contro l devic e ar e n o longe r considere d t o b e relie f valv e discharge s regardles s o f whethe r 1 0 ppmi s achieved . Respons e A s wit hth e previou s comment , thi s commen t refer s t o th e metho d o f determinin g whic hrelie f valv e discharge s ar e subjec t t o th e numerica l discharg e limits . Althoug hEP Aha s decide d no t t o revis e th e relie f valv e discharg e standar d (se e Section2.2.1) , th e discussio no nwhic hdischarge s ar e subjec t t o th e standar d remain s valid . Specifyin g tha t onl yrelie f valv e discharge s direc t t o th e atmospher e ar e t o b e considere d relie f valv e dis

charge s fo r complianc e purpose s i s inconsisten t wit hth e tPA' s intent . Relie f valve s tha t discharg e t o header s tha t ultimatel ydischarg e t o th e

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atmospher e withou t contro l ar e clearl y intende db

y EPA t o be relie f valv e discharge s subjec t t o th e standard . A s explaine dinth e preambl e t o th e propose drevision s (5 0 F R1189) , relie f valv e discharge s tha t ar e vente dt o a contro l devic e meetin g 1 0 pp m ar- exemp t fro mth e relie r \alv e discharg e standard . Analyse s incicat e thr..*

- a 99. 9 percen t reductio ni nV C conten t i s achievabl e whe na relie f valv e discharg e i s vente dthroug ha contro l devic e designe dt o reduc e emission s t o 1 0 ppm . Consequently , althcug hi t i s no t feasibl e t o ven t al l relie f valv e discharge s t o a contro l device , benefit s i nemissio nreduction s ar e attainabl e i nman ycases . Therefore , th e EP Asupport s an dencourage s th e ventin g c f relie f valv e discharge s t o a contro l devic e a s lon g a s suc hventin g doe s no t interfer e wit hth e abilit y o f th e contro l devic e t o reduc e exhaus t ga s emission s t o 1 0 ppm . Inth e even t tha t a relie f valv e discharg e i s vente dt c a contro l devic e whil e i t i s no t meetin g1 0 ppm , bot hth e standard s fo r exhaus t ga s andrelie f valv e discharge s ar e applicable . 2.2. 5 Complianc e Metho d Commen t Batc hProductio nRat e a t Bul kPlant s Tw o commenter s (IV-D-1 , IV-D-2 ) requeste dtha t th e relie f valv e discharg e complianc e metho dfo r bul kPVC plant s be change dt o allo w separat e countin g o f prepolymerizatio nandpostpolymerizatio nbatches . Respons e Thi s commen t i s no t relevan t becaus e i t refer s t o countin go f batche s fo r demonstratin gcomplianc e wit hpropose dlimit s onth e numbe r o f discharge s pe r 10 0 batches . A s discusse di nSectio n2.2.1 , EPA ha s decide dno t t o revis e th e relie f valv e discharg e standard . Commen t . Effec t o f Batc hProductio nRate s On e commente r (IV-D-1 ) state dtha t th e metho dfo r determinin gcomplianc e wit hth e relie f valv e discharg e limit s fo r PVC plant s undul y penalize s plant s whos e batc hproductio nrate s ar e slightl y les s tha nth e exac t numbe r o f batche s neede dt o qualif y fo r th e nex t intege r o f permitte ddischarges . Th e

2-1 8P.2 8

commente r allege d tha t th e metho d i s unfai r becaus e busines s condition s alon e determin e ho wman ybatche s a plan t makes . A. secon d commente r (IV-D-15 ) als o pointe d ou t th e penalt yt o plant s operatin g a t lo wcapacit y(les s tha n2,85 8 batche s pe r year ) suc htha t a singl e discharg e woul d violat e th e limit . Respons e A s wit hth e previou s comment , thi s commen t i s no t relevan t becaus e EPA i s n o longe r plannin g t o measur e complianc e wit hth e relie f valv e discharg e standar d a t PVC plant s base d o na numbe r o f allowabl e discharge s pe r batc h productio nrate . Commen t Roundin g o f Calculate d Discharg e Frequenc y On e commente r (IV-D-2 ) objecte d t o th e "preciseness " o f th e propose d relie f valv e discharg e limit s and requeste d clarificatio no nho wroundin g woul d b e use d t o compar e calculate d discharg e frequencie s t o th e limits . Respons e A s wit hpreviou s comments , thi s commen t i s n o longe r relevant . Comment Lo wBatc hRat e Provisio n Thre e commenter s (IV-D-1 , IV-D-9 , IV-D-14 ) recommende d alternativ e languag e fo r th e propose d provisio ni n4 0 CF R61.65(a)(l)(iii ) pertainin g t o allowabl e discharge s a t lo wbatc hproductio nPVC plants . Respons e A s wit hpreviou s comments , thi s commen t i s n o longe r relevant . Commen t 2-Yea r vs . 12-Mont hComplianc e Perio d Thre e commenter s (IV-D-1 , IV-D-2 , IV-D-6) , pointe d ou t tha t th e relie f valv e discharg e limit s ar e base d o ntw o year s o f performanc e dat a bu t ar e applie d o na nannua l basis . Accordingly , tw o o f th e commenter s (IV-D-2 , IV-D-6 ) state d tha t a 2-yea r complianc e perio d woul d b e mor e appropriate .

2-1 9P.2 9

Respons e A s wit hpreviou s comments , thi s commen t i s n o longe r relevant . Commen t Fixe d 12-Mont hComplianc e Perio d Tw o commenter s 'IV-D-8 , IV-D-9 ) recommende d tha t th e complianc e perio d fo r relie f valv e discharge s b e change d from a 12-mcnt hperio d rollin g ever y 6 month s t o a fixe d 12-mont hperio d t o ensur e tha t th e sam e discharg e o r grou p o f discharge s ar e ne t counte d toward s mor e tha non e exceedence . Respons e A s wit hpreviou s comments , thi s commen t i s n o longe r relevant . Commen t Alternativ e Regulatio nForma t Th e commente r (IV-D-2 ) suggeste d tha t th e basi s o f prescribin g th e relie f valv e discharg e limit s fo r PVC plant s b e revise d b yadoptin g " a syste m o f permitte d discharges , expresse d a s whol e integers , fo r increasin g incre

ment s o f range s o f numbe r o f batche s polymerized : 2,85 8 t o 5,716 ; 5,71 6 t o 8,754 ; etc. " Respons e A s wit hpreviou s comments , thi s commen t i s n o longe r relevant . 2.2. 6 Reportin g Requirement s Commen t 10-Da yvs . Quarterl yRepor t Thre e commenter s (IV-D-12 , IV-D-13 , IV-D-16 ) objecte d t o th e chang e in relie f valv e discharg e reportin g requirement s fro m10-da yt o quarterl y reporting . Tw o o f th e commenter s (IV-D-12 , IV-D-13 ) state d tha t a shorte r reportin g perio d woul d aler t State , Federa l an d loca l official s a s wel l a s th e publi c o f VC release s sooner . Commente r IV-D-1 2 urge d adoptio no f a 24-hou r reportin g requiremen t a s consisten t wit hrequirement s o f th e Comprehensiv e Environmenta l Response , Compensatio nan d Liabilit yAc t (CERCLA) , Th e thir d commente r (IV-D-16 ) explaine d tha t th e curren t practic e fo r enforce

men t personne l t o complet e investigation s o f discharge s withi n4 5 day s o f th e inciden t ha s bee nmutuall yadvantageou s t o industr yand enforcemen t personnel .

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Respons e Th e EP Aha s reviewe denforcemen t dat a andagree s wit hth e commenter s tha t retentio no f th e 10-da yreportin g requiremen t i s desirable . Federal , Stat e andloca l official s promptl yrevie wthes e report s an dus e th e informatio i containe dtherei ni nenforcemen t activit yt o ai di nth e preventio no** ' repeat ; incidents . Allowin g a longe r reportin g perio dwoul dne t onl ymak e i t mor e difficul t t o investigat e a releas e becaus e o f th e passag e o f time , bu t woul d unnecessaril ydela yappropriat e actio nb yth e enforcemen t agenc yandpossibl y als o th e source . Further , 1 0 day s i s a sufficien t tim e fo r source s t o gathe r th e neede dinformatio nt o prepar e a report . A24-hou r reportin g requiremen t wa s no t selected . Th e EPA . believe s tha t th e benefit s o f th e 10-da yreport s woul dno t b e significantl yincrease db y 24-hou r reporting . Also , a t leas t on e Stat e alread yrequire s it s sourc e t o repor t discharge s b ytelephon e withi nthre e hours . Th e EP Afeel s tha t othe r State s ma yals o includ e th e requiremen t i f th e nee dandenforcemen t resource s exist . Owner s andoperator s shoul drevie wandconside r th e nee dt o repor t emission s o f VC a s the yrelat e t o th e Comprehensiv e Environmenta l Response , Compensatio nandLiabilit yAc t (CERCLA) . I nparticular , emission s o f VC no t allowe db

yth e V C standar dandgreate r tha nth e CERCL A"reportable quantity " ma ynee dt o b e reporte dt o th e Nationa l Respons e Center . 2. 3 REVISION S T O LEA K DETECTIO NAN D REPAI RREQUIREMENT S 2.3. 1 Nee dfo r Subpar t V i nVC Standar d Commen t Reaues t t o Dro p Subpar t V Severa l commenter s urge ddroppin g th e additio no f Subpar t V i nth e VC standard . Fiv e commenter s (IV-D-4 , IV-D-3 , IV-D-5 , IV-D-14 , IV-D-15 ) state dtha t existin g lea k detectio nandeliminatio nprogram s ar e a t leas t a s effectiv e a s Subpar t V

i ncontrollin g equipmen t leaks . Accordin g t o thes e commenters , applyin g Subpar t V

t o th e V C industr yi s no t justifie dbecaus e emissio n reductio nwoul db e insignifican t andn o healt hbenefi t woul dresult . Further

more , Subpar t V

woul dcreat e additiona l administrativ e burde ntha t woul d necessitat e a nincreas e i nresourc e an dmanpowe r requirements . 2-2 1P.3 1

Tw o commenter s (IV-D-3 , IV-D-12 ) state d tha t incorporatio no f Subpar t V i nth e VC standar d coul d potentiall yresul t i nles s stringen t contro l o f equipmen t leak s becaus e som e plant s hav e existin g lea k detectio nand elimi

natio nprogram s wit hmor e stringen t lea k definition s tha nSubpar t V . Commente r IV-D-1 2 urge d EP At o prepar e and mak e publi c a pcint-by-poin t analysi s comparin g existin g lea k detectio nand eliminatio nprogram s t o requirement s i r Subpar t V . Respons e Th e origina l VC stancar d require d implementatio no f a formalize d pro g ran ; fo r detectio no f leak s fro mequipmen t i nVC servic e and eliminatio no f thes e leaks . Thi s progra m wa s base d o na narea-wid e monitorin g syste mand routin e us e o f a portabl e monito r t o detec t leaks . Detaile d requirement s fo r thes e lea k detectio nand repai r program s wer e no t specified ; rather , plant s wer e require d t o develo p thei r ownplan s subjec t t o approval . Durin g th e revie w o f th e origina l standard , EP Afoun d tha t existin g lea k detectio nand repai r program s implemente d b yplant s var ysignificantl yfro m plan t t o plan t (Docke t Ite mII-A-19) . Whil e som e o f th e difference s i nthes e program s resulte d fro m site-specifi c difference s i nplant s (e.g. , layou t o f plant , backgroun d concentration , etc.) , other s resulte d fro mineffectiv e approache s t o routin e lea k detectio nand repair . Fo r example , difference s i nplan t program s includ e variation s i nlea k definition s and monitorin g practices . Lea k definition s use d i nconjunctio nwit hportabl e monitor s ar e yery stringen t (1 0 t o 2 5 ppm ) a t som e plants , whil e som e plant s hav e n o specifi c lea k leve l define d fo r portabl e monitors . Som e lea k definitio nconcentratio nlevel s wer e comparabl e t o th e 10,00 0 ppmuse d i nth e routin e progra mo f Subpar t V bu t wer e base d o nmeasurin g th e lea k a t a distanc e fro m th e equipmen t rathe r tha na t th e surfac e (lea k interface ) o f th e equipmen t a s require d b ySubpar t V . Similarly , som e plant s routinel ymonito r equipmen t component s fo r leak s wit h a portabl e monito r o na forma l schedule , whil e other s monito r fo r leak s onl y whe nindicate d b

ya nare a monito r detection . Thes e difference s ca nsignifi

cantl yaffec t th e effectivenes s o f lea k detectio nand repai r programs . Base d o nthes e findings , EP Aconclude d tha t mor e specifi c lea k detectio nand repai r

2-2 2P.3 2

requirement s shoul d b e establishe d fo r certai nequipmen t i nVC service . Th e EP Adi d no t propos e t o chang e th e leve l o f contro l (emissio no r ris k reduction s o r cos t implications ) wit hthi s par t o f th e V C standar d a s som e commenter s indicated , bu t instea d propose d t o provid e a bette r wa yt o evaluat e complianc e wit hth e origina l decisio nt o requir e effectiv e lea k detectio nand elimination . A s note d i nth e preambl e t o th e propose d revision s (5 0 F?. 1190) , studie s conducte d b

yEP Aand industr yi nconjunctio nwit hdevelopmen t o f equipmen t lea k standard s fo r othe r industrie s hav e provide d informatio no nwha t consti

tute s a neffectiv e progra mfo r detectin g and repairin g equipmen t leak s sinc e th e VC standar d wa s firs t develope d i n197 5 and 1976 . Base d o nthes e studies , EP Aselecte d equipmen t and wor k practic e requirement s tha t represen t a n effectiv e lea k detectio nand repai r progra mand include d the mi n4 0 CF RPar t 6 1 Subpar t V . Thi s subpart , promulgate d o nJun e 6 , 1984 , establishe d lea k detectio nand repai r requirement s fo r equipmen t i nvolatil e hazardou s ai r pollutan t (VHAP ) service . Thes e requirement s wer e specificall ydevelope d t o regulat e emission s o f hazardou s pollutant s suc ha s benzen e and ar e equall y applicabl e t o VC . Accordingly , EP Apropose d t o designat e VC a s a VHA P i nth e contex t o f Subpar t V . Additio no f Subpar t V t o th e VC standar d woul d ensur e effectiv e contro l o f equipmen t leak s o na consisten t basi s throughou t th e VC and PVC industries . (I t shoul d b e note d tha t new , modified , o r reconstructe d VC productio nand recover yplant s ar e covere d b yth e ne wsourc e performanc e standar d fo r th e organi c chemica l industry . Thi s standar d fo r VO C emissio n i s essentiall yidentica l t o Subpar t V. ) Th e basi s fo r addin g Subpar t V t o th e VC standar d wa s explaine d i ndetai l i nth e preambl e t o th e propose d revision s (5 0 FR1190-92) . Prio r t o th e Januar y9 , 1985 , proposal , EP Arequeste d and the nresponde d t o industr ycomment s b yadjustin g ho wSubpar t V i s t o b e applie d unde r th e VC standard . A t tha t time , industr ycomment s emphasize d th e effectivenes s o f existin g lea k detectio nan d repai r program s resultin g fro mcomplianc e wit h requirement s o f th e VC standar d and OSH Aregulations . Th e industr ycommenter s suggeste d tha t Subpar t V b e require d onl yfo r thos e plant s wit hinferio r programs . Whil e Subpar t V alread yprovide s alternativ e standard s fo r reducin g th e burde no nplant s wit heffectiv e lea k detectio nan d repai r program s (se e



### •2 3P.3 3

4 0 CF R61.243) , industr yrepresentative s pointe d ou t tha t eve nth e alterna

tiv e Subpar t V

requirement s woul d requir e plant s t o inventor yequipmen t component s i nV C service , a nunreasonabl e administrativ e burde naccordin g t o th e industr ycommenters . Eve nthoug hEP Afind s i t difficul t t o understan d ho wa neffectiv e progra mca nexis t withou t anequipmen t inventory , EPA responde d t o th e industr yconcern s i nth e Januar y9 , 1985 , proposa l b y allowin g plan t owner s and operator s t o determin e complianc e wit hth e alterna

tiv e standard s i nSubpar t V b ytestin g a prescribe d sampl e o f al l valves , thereb yreducin g significantl yth e administrativ e burde nassociate d wit h inventoryin g VC servic e equipment . Th e EP Adisagree s wit hth e commen t tha t Subpar t V coul d resul t i nles s stringen t contro l o f equipmen t leak s tha nexistin g programs . I ngeneral , Subpar t V

represent s a bette r wa yt o determin e complianc e wit hrequirement s fo r lea k detectio nand repair . I ncontras t t o th e provision s fo r lea k detectio nand repai r program s i nth e origina l V C standard , Subpar t V contain s a detaile d lis t o f requirement s that , onc e implemented , wil l resul t i n effectiv e contro l o f equipmen t leak s a t reasonabl e cost . An yplant s wit h effectiv e existin g program s base d o nmor e stringen t lea k definition s o r monitorin g practice s tha nSubpar t V wil l continu e t o effectivel ycontro l equipmen t leak s eithe r b yimplementin g Subpar t V o r continuin g wit hthei r existin g program . Anyincreas e i nequipmen t lea k emission s cause d b yplant s switchin g t o Subpar t V woul d b e mor e tha noffse t b yadditiona l reduction s achieve d a t plant s wit hprogram s les s effectiv e tha nSubpar t V . I nthi s way , th e overal l leve l o f contro l o f equipmen t lea k emission s woul d no t b e change d b yincorporatio no f Subpar t V i nth e VC standard . 2.3. 2 Applicabilit yo f Subpar t V Unde r VC Standar d Commen t Optio nt o Implemen t Subpar t V Tw o commenter s (IV-D-2 , IV-D-14 ) recommende d tha t th e regulatio nclearl y specif ytha t plant s ma yelec t t o implemen t Subpar t V o r continu e thei r existin g lea k detectio nan d eliminatio nprogra msupplemente d t o demonstrat e tha t les s tha n2 percen t o f valve s i nV C servic e ar e leaking . Similarly , anothe r commente r (IV-D-6 ) requeste d tha t th e regulatio nclearl yindicat e

2-2 4P.3 4

tha t plant s demonstratin g tha t les s tha n2 percen t o f valve s ar e leakin g ar e no t subjec t t o Subpar t V . Athir dcommente r (IV-D-14 ) als o recommende dtha t plant s b e give nth e optio no f continuin g existin g program s o r complyin g wit h Subpar t V , explainin g tha t suc hanoptio ni s appropriat e i nth e absenc e o f justificatio ntha t Subpar t V i s mor e effectiv e tha nexistin g programs . Respons e Th e EPA . wil l us e Subpar t V , a s reeded , t o supplemen t determination s c f complianc e wit hth e requirement s o f §61.65(b) . Becaus e Subpar t V dee s no t addres s som e source s covere dunde r 561.65(b) , Subpar t F wil l serv e a s th e •mai nbasi s fo r determination s o f complianc e fo r thes e sources . Fo r example , Subpar t V

doe s no t addres s loadin g o r unloadin g line s (excep t t o th e exten t suc hline s ar e open-ende dline s o r valves ) and , therefore , th e requirement s o f §61.65(b)(1 ) wil l b e use dt o evaluat e compliance . Othe r source s covere d b y§61.65(b ) (e.g. , pumps ) ar e als o covere db ySubpar t V . Fo r thes e sources , Subpar t V

wil l b e use dt o supplemen t Subpar t F whe nEP Amake s complianc e determinations . Th e EP Adecide dt o propos e andpromulgat e thi s approac h because , while

- th e wor k practice s an dequipmen t requirement s o f Subpar t F specif yth e goa l o f th e origina l standard , i t di dno t alway s clearl yspecif y ho wt o achiev e acceptabl e compliance . Fo r example , th e requirement s fo r pump s [§61.65(a)(3)(i) l requir e doubl e mechanica l seal s o r equivalent . Subpar t V

goe s o ht o defin e complianc e fo r al l th e knownequivalen t system s fo r pumps : othe r dua l sea l system s andleakles s pumps . Th e onl yaspec t o f Subpar t F wher e complianc e determination s woul db e substantiall ychange d concern s th e routin e lea k detectio nan drepai r requirement s o f §61.65(a)(8)(ii) . Th e basi s fo r thi s decisio ni s discusse di nth e previou s . respons e andi s neede dt o spel l ou t clearl yho wcomplianc e i s determined . I n makin g thi s chang e EP Aconsidere doptions , a s requeste db yindustr ycommenters , befor e th e standar dwa s propose dan dselecte da napproac ha s discusse dbelow . Th e optio nrecommende db yth e commente r o f continuin g th e existin g lea k detectio nan deliminatio nprogra mo r complyin g wit hth e Subpar t V monitorin g andrepai r requirement s fo r valve s i s alread yoffere di nth e revise dstandard , bu t onl yfo r plant s wh o initially , annually , anda t th e reques t o f EP A

2-2 5P.3 5

demonstrat e tha t les s tha n2 percen t o f th e prescribe d sampl e o f valve s ar e leaking . Plant s failin g th e performanc e tes t a t anytim e ma yn c longe r elec t th e optio no f onl ycontinuin g thei r existin g progra mand performin g a nannua l test . Remova l o f thi s optio ni s ne t unreasonabl e becaus e failur e o f th e performanc e tes t i s indicativ e tha t improvemen t i nlea k detectio nand rep?.'; ' technique s i s neede d and warranted . Suc himprovemen t i s provide d b yth e requirement s o f Subpar t V . However , plant s require d t o compl ywit hal l requirement s o f Subpar t V ma yb e abl e t o perfor mannua l lea k check s instea d o f mor e frequen t monitoring . Thi s i s possibl e becaus e Subpar t V contain s alternativ e provision s exemptin g valve s fro mroutin e monitorin g requirement s i f a nannua l tes t demonstrate s tha t les s tha n2 percen t o f valve s ar e leaking . Commen t Additiona l Equipmen t Requirement s Unde r Subpar t V Thre e commenter s (IV-D-1 , IV-D-8 , IV-D-9 ) note d tha t th e EPA' s conclusio n tha t al l equipmen t excep t valve s an d flange s ar e alread ycontrolle d t o a leve l consisten t wit hSubpar t V i s no t adequatel yreflecte d i nth e propose d regulation . Th e commenter s recommende d tha t th e inconsistencie s i nrequire

ment s o f Subpar t V

and th e V C standar d b e clarifie d b ylistin g whic h requirement s appl yt o specifi c equipment . I nparticular , severa l commenter s (IV-D-1 , IV-D-2 , IV-D-3 , IV-D-4 ) pointe d ou t tha t Subpar t V contain s requirement s fo r sensor s o npum p seal s no t foun d i nth e V C standar d and tha t unde r th e revise d standard , plant s woul d b e require d t o retrofi t pump s wit hsea l senso r device s a t significan t cost . On e o f th e commenter s (IV-D-3 ) als o state d tha t complianc e wit hth e open-ende d valv e requirement s o f Subpar t V woul d requir e retrofi t expenditure . Anothe r commente r (IV-D-2 ) expresse d concer nabou t th e cos t c f performin g annua l lea k check s o nvalves , man yo f whic har e reportedl ydifficul t t o access . Thre e commenter s (IV-D-1 , IV-D-2 , IV-D-4 ) state d tha t th e are a monitor s operate d unde r th e VC standar d provid e adequat e lea k detectio nfo r sea l failures .

2-2 6P.3 6

Respons e A s state di nth e preambl e t o th e propose drevision s (5 0 F R1191) , additio no f Subpar t V t o th e VC standar dsubstantivel yaffect s onl yvalve s an dflange s i nVC service . Mor e specifically , eve nthoug hSubpar t V wil l t e use dt c suDplemen t complianc e determination s wit honl yth e equipmen t lea k requirement s inSubpar t F , plant s complyin g wit hth e eouipmen t andwor k practic e requirement s o f Subpar t F fo r equipmen t component s othe r tha nvalve s andflange s .shoul d automaticall ycompl ywit hth e Subpar t V provisions . Requirement s i n4 0 CF R61.65(b ) o f Subpar t F fo r valves , pumps , compressors , andleakag e fro mrelie f valve s ar e consisten t wit hrequirement s i nSubpar t 7 . Despit e th e concern s raise db yth e commenters , thi s conclusio ni s stil l judge db

yEP At o b e essentiall ycorrec t wit hth e followin g exception . Fo r thos e plant s tha t hav e no t alread yadopte dth e usua l industr y practic e o f cappin g open-ende dlines , Subpar t V -wil l requir e thes e line s t o b e capped . Cappin g o f open-ende dline s i s require dbot hi nSubpar t V fo r controllin g equipmen t leak s o f volatil e hazardou s ai r pollutant s an di nth e SOCM I equipmen t lea k standard s (4 0 CF RPar t 6 0 Subpar t VV) . I nbot hcases , cappin g open-ende dline s wa s judge dt o b e a cost-effectiv e metho dfo r elimi

natin g leak s fro m

open-ende dlines . Th e cos t effectivenes s o f cappin g open-ende dline s i s abou t $400/M g VOC . Th e EP Abelieve s thi s findin g als o applie s t o mos t open-ende dline s i nVC service . However , EP Ainvestigate d th e retrofi t expenditur e fo r cappin g open-ende dline s a t th e plant s operate d b yCommente r IV-D- 3 an dfoun dtha t certai nopen-ende dline s resultin g whe n multi-purpos e line s use dt o charg e material s t o polymerizatio nreactor s i n PVC plant s ar e i nVC servic e (i.e. , chargin g VC ) ma yb e unreasonabl e t o cap , becaus e o f th e hig hcos t associate dwit hadditiona l pipin g an dothe r retrofi t requirement s (Docke t Item s IV-C-9 , IV-B-10) . Fo r thi s reason , EP Aha s decide dt o exemp t certai nopen-ende dline s i nbatc hoperation s fro mth e requirement s o f Subpar t V . Th e basi s fo r th e commen t tha t complianc e wit hSubpar t V woul drequir e plant s t o retrofi t thei r V C servic e pump s wit hsea l sensor s i s unclear . Th e VC standar drequire s plant s t o minimiz e emission s fro mseal s o npump s i nVC servic e b

yinstallin g sealles s pumps , pump s wit hdoubl e mechanica l seals , o r

2-2 7P.3 7

equivalent . Plant s choosin g t o mee t th e requiremen t b yinstallin g pump s wit h doubl e mechanica l seal s ar e require dt o maintai nth e pressur e betwee nth e tw o seal s s o tha t an ylea k tha t occur s i s int o th e pum p c r b yductin g anyVC betwee nth e tw o seal s t o th e primar ycontro l device . Inorde r t o ascertai n prope r operatio no f thes e sea l systems , som e metho do f monitorin g th e barrie r flui di s essential . T o tn e EPA' s knowledge , area-wid e monitorin g i s onl y effectiv e fo r detectin g larg e leak s an dcanno t b e relie dupo nt o indicat e th e nee dfo r repai r o f sea l system s prio r t o catastrophi c failure . Informatio n fro msevera l PVC plant s abou t thei r sea l system s indicate s a rang e o f monitorin g method s fro ma sigh t glas s markin g th e leve l o f flui di nth e barrie r flui dpo t t o a pressur e gaug e measurin g th e nitroge npa duse dt c maintai nth e barrie r flui da t a positiv e pressur e t o th e pumpe dmaterial . Th e EP Aconsider s thes e type s o f method s o f monitorin g th e sea l syste mt o b e adequat e fo r meetin g th e Subpar t V requirement s fo r sea l sensor s o npump s wit hdoubl e mechanica l seals . Commen t Approva l o f Existin g Plan s Thre e commenter s (IV-D-1 , IV-D-3 , IV-D-4 ) questione dth e requirement s fo r obtainin g approva l fo r lea k detectio nan deliminatio nprograms . On e commente r (IV-D-4 ) recommende dtha t resubmissio no f plan s b e require donl y i f plant s modif ythei r plans . Th e secon dcommente r (IV-D-1 ) recommende d tha t alread yapprove dplan s b e exemp t fro mresubmitta l requirements . Th e commente r (IV-D-1 ) suggeste dtha t th e standar dspecif ytha t plan s submitte dfo r approva l tha t ar e no t acte dupo nwithi n6 0 day s wil l b e considere dapproved . Th e thir dcommente r (IV-D-3 ) questione dwhethe r effectiv e existin g lea k detectio nandeliminatio nprogram s woul db e deeme dequivalen t t o Subpar t V i f the ydi dno t contai nth e extensiv e administrativ e requirement s o f Subpar t V . Th e commente r adde dtha t pas t experienc e i nsubmittin g equivalenc yrequest s ha s indicate dtha t significan t man-hour s ar e require dt o prepar e a nacceptabl e equivalenc yrequest .

2-2 8P.3 8

Respons e Th e commenter s misinterprete d th e meanin g o f th e provisio ni npropose d 4 0 CF R61.65(b)(8 ) whic hintroduce s criteri a fo r approva l o f lea k detectio n and eliminatio nplans . Th e EPAdoe s no t intend fo r plant s t o resubmi t plan s alread yapprove d under th e origina l standard . Onl yne wo r modifie d plan s ar e require d t o be submitte d fo r approva l unde r th e revise d standard . EPAwil l us e Subpar t V , a s a naid , whe nevaluatin g complianc e wit hrequirement s fo r pumps , compressor s and othe r equipmen t components . However , complianc e wit h th e VC standar d requirement s (i n4 0 CF R61.65(b)(8)(3) ) fo r thes e equipmen t component s represent s complianc e wit hSubpar t V . "Equivalency " o f existin g lea k detectio nand eliminatio nprogram s wit hth e Subpar t V requirement s ma y b e demonstrate d throug ha performanc e tes t o f valve s a s prescribe d i npropose d 4 0 CF R61.61(b)(8)(ii) . Thi s doe s no t appl yt o equipmen t requirement s fo r pump s an d othe r equipmen t o r th e performanc e standar d fo r leak s fro mpressur e relie f devices . Commen t Basi s o f Subpar t V Requirement s Th e commente r (IV-D-3 ) state d tha t th e emissio nreduction s projecte d fo r Subpar t V

ar e base d o nrefiner yfugitiv e dat a and ar e no t accurat e fo r th e VC industr ywhic hi s a low-lea k industry . Respons e Subpar t V

wa s develope d base d o nlea k studie s fo r VOC , i ngeneral , and benzene , specifically . A s note d b yth e commenter , thes e studie s wer e performe d a t petroleu mrefineries . However , EP Ainvestigate d othe r lea k studie s per forme d i nth e syntheti c organi c chemica l manufacturin g industr y(SCCMI ) i n developin g equipmen t lea k standard s fo r SOCMI . (Viny l chlorid e productio ni s par t o f SOCMI. ) Th e SOCM I equipmen t lea k standar d (4 0 CF RPar t 6 0 Subpar t VV ) contain s th e sam e equipmen t an d wor k practic e requirement s a s Subpar t V . Th e difference s betwee npetroleum refiner yand SOCM I lea k dat a wer e foun d t o b e unimportan t i ndevelopin g standard s fo r thes e industries . I naddition , Subpar t V contain s a provisio nfo r low-lea k plant s suc ha s som e o f th e plant s i nth e VC industr y(se e 4 0 CF R61.243) . Thi s provisio n

2-2 9P.3 9

allow s plant s tha t hav e demonstrate d thei r low-lea k statu s t o monito r fo r leak s o na les s frequen t basi s and therefor e significantl yreduc e th e cos t o f controllin g equipmen t leak s t o th e require d level . Commen t ' Subpar t V 2 . Metho d 2 1 - Notic e fo r Revie w Th e commente r (R-D-9 ) state d tha t EPA . shoul d issu e a notic e allowin g fo r publi c revie wand commen t o nSubpar t V and EPATes t Metho d 2 1 a s the y aopl vt o VC .

Respons e Comment s o nSubpar t V and EP ATes t Metho d 2 1 a s the yappl yt o th e VC standar d hav e bee nconsidere d indevelopin g th e promulgate d standar d fo r VC . A. separat e notic e i s no t needed . Response s t o specifi c comment s o nSubpar t V and Metho d 2 1 a s the yappl yt o VC ar e include d i nSection s 2.3. 7 and 2.3.8 . 2.3. 3 Alternativ e Complianc e Demonstratio nOptio n Commen t VO C Servic e vs . VC Servic e Component s Fou r commenter s (IV-D-1 , IV-D-4 , IV-D-8 , IV-D-9 ) requeste d tha t th e provisio nallowin g plant s t o demonstrat e equivalenc yo f lea k detectio nan d eliminatio nprogram s wit hSubpar t V throug ha performanc e tes t specif ya sampl e o f VC servic e valve s t o b e teste d instea d o f VO C servic e valves . Tw o o f th e commenter s (IV-D-8 , IV-D-9 ) state d tha t testin g o f VO C servic e valve s i s inappropriat e unde r a standar d regulatin g VC . Respons e Th e EP Aagree s tha t specifyin g a performanc e tes t o f valve s i nVC servic e woul d b e mor e appropriat e fo r demonstratin g th e effectivenes s o f a plant' s lea k detectio nand repai r progra m fo r controllin g V C leaks . Subpar t V alread yinclude s a noptio nfo r plant s t o demonstrat e thei r program' s effec

tivenes s throug ha nannua l performanc e tes t o f VC servic e valve s (se e 4 0 CF R61.243) . However , i nrespons e t o concern s raise d b yindustr yrepresen tatives , EP Arecognize d i f a performanc e tes t o f VC servic e valve s i s

2-3 0P.4 0

prescribed , som e plant s woul dhav e t o identify , ta gan dkee pa recor do f al l VC servic e valve s fo r th e firs t time . A t th e Augus t 30 , 1984 , meetin go f th e Nationa l Ai r Pollutio nContro l Technique s Advisor y Committe e (NAPCTAC) , industr yrepresentative s voice doppositio nt o inventoryin g equipmen t component s fo r purpose s c ' lea k testin g becaus e o f th e additiona l administrativ e burde n associate dwit htaggin g equipmen t an dmaintainin g records . Th e EF Abelieve s thi s administrativ e burde nca nb e reduce dwithou t affectin gth e leve l o f contro l expecte dt o b e demonstrate ddurin g th e performanc e tes t byallowin g plant s t o tes t a sampl e o f valve s inVO C servic e whic har e mor e readil y icentifiab'e . Th e EPA' s decisio nt c specif ya performanc e tes t o f VO C servic e valve s i s base donth e assumptio ntha t i f 2 percen t o r les s o f th e teste dVO C servic e valve s ar e leaking , i t is , reasonabl e t o expec t tha t 2 percen t o r les s o f th e VC servic e subse t o f thes e valve s ar e leaking . Base donthes e considerations , EPA . see s no reaso nt o revis e thi s provision . Commen t Lea kCriteri a Two commenter s (IV-D-8 , IV-D-9 ) recommende dtha t th e provisio nallowin g plant s t o demonstrat e equivalenc y o f existin glea kdetectio nan deliminatio n program s wit hSubpar t V throug ha performanc e tes t specif y tha t instrumen t reading s exceedin gth e plant' s approve dlea kdefinitio nbe use da s th e lea k criteri a rathe r tha ninstrumen t reading s greate r tha n10,00 0 pp m a s specifie d i nSubpar t V . Th e commente r state dtha t us e o f th e plant-specifi c lea k definitio nwoul db e mor e consisten t wit hth e provisio nrequirin gplant s t o develo plea kdefinition s a s par t o f thei r lea kdetectio nandeliminatio n programs . Respons e Th e commente r apparentl y believe s tha t i f a performanc e tes t i s t o demonstrat e th e effectivenes s o f existin glea kdetectio nandrepai r .programs practice db

y plant s relativ e t o th e Subpar t V requirements , i t shoul db e base donth e lea kdefinitio nimplemente da s par t o f th e existin gprogram . In contrast , EP A

believe s tha t demonstratio no f effectivenes s o f existin g program s [relativ e t o Subpar t V ] ca nb e achieve donl y wit ha performanc e tes t

2-3 1P.4 1

o nvalve s usin g th e lea k criterio ni nSubpar t V (i.e. , instrumen t reading s o f greate r tha n10,00 0 ppma t th e interfac e base do ncalibratio nwit hmethane) . I nfact , usin g th e Subpar t V lea k criterio ndurin g th e performanc e tes t i s mor e appropriat e the nusin g th e plant-specifi c definition s becaus e o f differ

ence s i nplant-specifi c lea k definition s whic hcontribut e t o ineffectiv e programs . Us e o f a standar d""ea k criterio nensure s tha t th e performanc e tes t i s applie dwit hequa l stringenc ya t al l plant s throughou t th e industry . Plant s ma yreques t tha t existin g lea k definition s establishe da s par t c f thei r plant-specifi c program s b e allowe dfo r us e durin g performanc e tests . Us e o f th e plant-specifi c lea k definition s wil l b e allowe di f the yar e demonstrate dt o b e mor e stringen t tha nth e lea k criterio nfoun di nSubpar t V . Commen t Numbe r o f Valve s Require dt o b e Teste d Thre e commenter s (IV-D-4 , IV-D-8 , IV-D-9 ) requeste dclarificatio n regardin g th e numbe r o f valve s require dt o b e teste da s par t o f th e perform

anc e tes t t o demonstrat e equivalenc yo f lea k detectio nan deliminatio n program s wit hSubpar t V . Respons e Th e provisio ni npropose d4 0 CF R61.65(b)(8)(ii)(B ) prescribin g th e performanc e tes t state s tha t " a minimu mo f 20 0 o r 9 0 percen t o f th e tota l valve s i nVO C service " withi neac hproces s uni t ar e t o b e tested . Specifi

cally , proces s unit s wit hmor e tha n20 0 valve s i nVO C servic e ar e require d t o tes t a t leas t 20 0 valve s whil e proces s unit s wit hles s tha n20 0 valve s i nVO C servic e mus t tes t 9 0 percen t o r mor e o f valves . Accordingly , th e provisio n ha s bee nclarified : §61.65(b)(8)(ii)(B ) "Fo r eac hperformanc e test , a minimu mo f 20 0 o r 9 0 percent , whicheve r i s less , o f th e tota l valve s . . . . "

Commen t 3 0 Da yRetes t & Annua l Optio n Fou r commenter s (IV-D-1 , IV-D-3 , IV-D-4 , IV-D-5 ) suggeste dtha t plant s failin g t o demonstrat e equivalenc yo f existin g lea k detectio nan deliminatio n

2-3 2program s wit hSubpar t V throug ha performanc e tes t b e allowe dt o retes t withi n3 0 day s rathe r tha nbecom e automaticall ysubjec t t o al l Subpar t V requirements . Commente r IV-D- 3 adde dtha t a retes t woul dprovid e incentiv e fo r plant s t o evaluat e andcorrec t problem s prio r t o th e retes t t o avoi d becomin g subjec t t o Subpar t V . Commente r IV-D- 4 explaine dtha t e. retes t i s appropriat e considerin g th e tim e require dt o implemen t Subpar t V . Tw o commenter s (IV-D-1 , IV-D-3 ) als o recommende dtha t plant s b e allowe dth e optio no f revertin g bac k t o th e existin g lea k detectio nandeliminatio n program s afte r a yea r unde r Subpar t V . On e commente r (IV-D-3 ) recommende ddroppin g inclusio no f Subpar t V requirement s i nth e VC standard , bu t maintainin g th e propose dprovisio n requirin g plant s t o demonstrat e th e effectivenes s o f thei r existin g lea k detectio nandeliminatio nprogra mthroug hanannua l performanc e test . Respons e Th e change s recommende db yth e commenter s ar e no t consisten t wit hth e purpos e fo r addin g Subpar t V t o th e V C standard . Th e V C standard , a s revised , require s plant s t o implemen t a neffectiv e lea k detectio nandeliminatio n progra mfo r valve s eithe r b ycomplyin g wit hSubpar t V o r b yfollowin g thei r existin g progra m

i f i t result s i nfewe r tha n2 percen t leakin g valves . A s discusse dabove , othe r requirement s o f Subpar t V wil l b e use dt o supplemen t complianc e determination s wit h§61.65(b)(8) . I nth e EPA' s judgement , a performanc e tes t measurin g greate r tha n2 percen t leakin g valve s i s indicativ e o f a ninadequat e existin g program . Consisten t wit hth e purpos e o f addin g Subpar t V , i t i s appropriat e t o requir e thes e program s t o b e upgrade dt o compl ywit hSubpar t V requirement s becaus e the yrepresen t a neffectiv e progra mfo r detectio nan drepai r o f leak s fro mvalves . Th e performanc e tes t o nvalve s i s a convenien t andefficien t wa yfo r plant s t o demonstrat e th e effectivenes s o f thei r existin g lea k detectio nan d eliminatio nprogram s withou t th e additiona l burde no f inventoryin g equipmen t component s an dmaintainin g records . However , onc e failur e o f a performanc e tes t trigger s Subpar t V andth e associate dinventor yan drecordkeepin g requirements , th e benefi t o f th e convenien t an defficien t performanc e tes t

2-3 3P.4 3

optio nn o longe r exists . However , unde r Subpar t V , monitorin g o f valve s ma y als o b e limite d t o a nannua l performanc e tes t a s lon g a s 2 percent c r fewe r valve s ar e foun d t o leak . Commen t Impac t o f Performanc e Tes t Failur e Tw o commenter s (IV-D-3 , IV-D-4 ) recommende d tha t failur e b yplant s t o demonstrat e throug ha performanc e tes t tha t fewe r tha n2 percen t o f valve s lea k shoul d trigge r Subpart V requirement s fo r valve s onl yand no t c f he r equipmen t components . Respons e Th e commenters ' concer ni s no t relevan t becaus e plant s complyin g wit h th e equipmen t lea k provision s o f th e VC standar d alread ymee t th e Subpar t V requirement s fo r equipmen t component s othe r tha nvalve s and flanges , wit hth e possibl e exceptio no f open-ende d lines . (A s discusse d i nSectio n2.3.2 , plant s no t currentl ycomplyin g wit hth e open-ende d lin e requirement s i n Subpar t V

wil l hav e t o ca p thes e lines . Cappin g o f ope nende d line s i s considere d byEP At o b e a cost-effectiv e metho d fo r controllin g leak s fro m open-ende d lines. ) I naddition , th e requirement s o f Subpar t V wil l onl yb e use d t o supplemen t determination s o f complianc e wit h§61.65(b) . I f complianc e wit hSubpar t V

i s no t demonstrate d b ya plant , th e plan t doe s no t compl ywit h Subpar t F . 2.3. 4 Lea k Definitio n Commen t Clarificatio no f Lea k Definitio n Thre e commenter s (IV-D-4 , IV-D-8 , IV-D-9 ) requeste d clarificatio n regardin g th e requiremen t tha t plant s establis ha lea k definitio na s par t o f thei r lea k detectio nan d eliminatio nprogram . Tw o o f th e commenter s (IV-D-8 , IV-D-9 ) recommende d tha t th e provisio nrequirin g plant s t o establis ha lea k definitio na s par t o f thei r lea k detectio nan d eliminatio nprogra m indicat e whethe r th e lea k definitio napplie s t o bot hare a monitor s and t o portabl e monitors , o r jus t t o are a monitors . Th e thir d commente r (IV-D-4 ) recommende d modifyin g th e provisio nrequirin g establishmen t o f a lea k definitio nt o

2-3 4requir e plant s instea dt o defin e a lea k leve l i nconjunctio nwit hare a

monitor s suc htha t are a monito r reading s i nexces s o f th e define dleve l ar e no t considere dleak s i nthemselve s bu t rathe r a nindicatio nt o searc hfo r a "leak " a s no wdefine db yth e criteri a o f Subpar t V . Respons e Unde r th e origina l VC standard , plant s ar e require dt o defin e a lea k a s par t o f thei r progra m fo r detectin g an deliminatin g equipmen t leaks . Althoug h differen t approache s wer e take nb yplants , th e inten t wa s fo r plant s t c establis ha definitio no f lea k a s measure db ya nare a monito r compare dt o •backgroundconcentrations . Then , whe nportabl e monitor s wer e use dt o pin

poin t lea k sources , a differen t lea k definitio nwa s t o b e applied . Becaus e o f difference s amon g plant s i nth e numbe r an dlocatio no f are a monitor s and backgroun dconcentrations , lea k definition s pertainin g t o are a monito r detection s necessaril yvar yan dshoul dremai na plant-specifi c measurement . However , bot hth e industr yandEPAma ywan t t o revie wandalte r th e are a monito r lea k definition s t o improv e thei r usefulness . Unlik e th e lea k definitio nfo r are a monitors , th e definitio nuse dt o measur e leak s fro m

specifi c equipmen t component s ca nandshoul db e standard

ized . Additio no f Subpar t V t o th e V C standar dprovide s thi s standardiza

tion . A s a result , plant s n o longe r ar e require dt o develo p thei r ow nlea k definitio nfo r detectin g leak s wit ha portabl e monitor . I nrespons e t o th e commen t tha t leak s define di nconjunctio nwit hare a monito r detectio no f leak s shoul db e considere danactio nleve l indicatin g th e nee dt o searc hfo r a leak , i t shoul db e pointe dou t tha t a readin g i n exces s o f th e are a monito r lea k definitio ni s a nindicatio no f a leak . Eve n i f th e actua l sourc e o f th e lea k i s no t found , th e even t i s recorde da s a lea k fo r complianc e purposes . 2.3. 5 Relie f Valv e Monitorin g Requirement s Commen t Ruptur e Dis c Exemptio n Thre e commenter s (IV-D-3 , IV-D-8 , IV-D-9 ) requeste dtha t relie f valve s equippe dwit hruptur e disc s b e exemp t fro mth e propose dmonitorin g requirement s

?-?CP.4 5

fo r relie f valves . Commente r IV-D- 9 furthe r recommende d tha t relie f valve s connecte d t o a proces s line , recover ysyste mo r equivalen t b e exemp t fro m relie f valv e monitorin g requirements . Th e commenter s recommende d tha t Subpar t V

b e revise d accordingly . Respons e Section11 2 o f th e Clea nAi r Ac t require s EP At o se t performanc e standards , wheneve r feasible . I nth e cas e o f relie f valv e leaks , i t i s possibl e and appropriat e fo r a performanc e standar d t o b e applied . Further

more , th e EP Adoe s ne t agre e tha t onl yequippin g relie f valve s wit hruptur e .disc s i s adequat e basi s fo r exemptin g relie f valve s fro m monitorin g require

ment s fo r leaks . A s par t o f goo d operatio nand maintenanc e practices , ruptur e disc s shoul d b e checke d a t leas t annuall yand afte r eac hdischarg e t o maintai nthei r integrity . Th e bes t wa yt o ensur e tha t integrit yo f th e ruptur e dis c i s constantl ymaintaine d i s throug hth e performanc e tes t i n Subpar t V . Th e EP Aagree s tha t ventin g a relie f valv e throug ha close d ven t syste m t o a contro l devic e warrant s exemptio nfro m monitorin g requirements . Th e Subpar t V

requirement s reference d i nth e V C standar d fo r controllin g equip

men t leak s fro mrelie f valve s alread yexempt , relie f valve s connecte d throug h a close d ven t syste m t o a contro l devic e fro mmonitorin g requirements . I n thi s situation , proces s line s o r recover ysystem s ma yqualif ya s contro l device s fo r th e purpos e o f complyin g wit hSubpar t V . 2.3. 6 Calibratio nRequirement s Commen t Calibratio nGa s fo r Monitor s Tw o commenter s (IV-D-8 , IV-D-9 ) requeste d clarificatio no ncalibratio n ga s requirement s fo r monitor s unde r th e revise d standard . Commente r IV-D- 9 recommende d that.th e standar d specif ycontinue d us e o f VC a s calibratio nga s instea d o f methan e o r hexan e a s prescribe d i nSubpar t V .

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Respons e Ther e ar e tw o differen t definition s o f a leak , an dthu s tw o differen t calibratio nga s requirements . Leak s ar e detecte di ntw o differen t ways : b y a nare a monito r specifi c t o VC measurin g th e genera l conditio no r possibl e presenc e o f VC leak s i nanarea ; andb yroutin e lea k detectio nmonitorin g 'o f particula r valv e o r pum p seals , etc. ) t o determin e i f specifi c piece s o f equipmen t ar e leaking . Th e are a monito r mus t b e specifi c t o andcalibrate dwit hVC becaus e othe r organic s ma yb e presen t i nth e ai r t o suc ha nexten t tha t th e VC concentratio nwoul db e masked . Whethe r th e routin e lea k detectio nmonito r i s calibrate dwit hV C o r som e othe r organi c i s no t a s critica l t o EP Aa s lon g a s tha t monito r i s les s responsiv e t o VC tha nth e alternativ e calibratio ngas . I f suc ha monito r i s calibrate dwit hVC , the nth e definitio no f a lea k i s i n effec t lowered , an dEP Awoul dconside r tha t acceptabl e i na nalternativ e metho drequest . Commen t Monito r Spa nCheck s Tw o commenter s (IV-D-8 , IV-D-9 ) suggeste dtha t becaus e th e sam e instrument s ar e ofte nuse dfo r bot hare a monitorin g an dexhaus t ga s moni

toring , a singl e spa nchec k usin g a 1 0 ppmV C standar dshoul db e allowe d instea do f tw o separat e spa nchecks . Respons e Are a monitorin g an dexhaus t ga s monitorin g serv e tw o differen t regulator y purpose s withi nth e standard . Whil e a 1 0 pp mspa ni s appropriat e fo r emissio n monitorin g fo r th e exhaus t ga s standard , i t ma yo r ma yno t b e appropriat e fo r are a monitoring , dependin g o nth e backgroun dconcentratio no f V C i nth e area s o f th e plan t t o b e monitored . Therefore , whil e th e sam e instrumen t ma yb e use dt o serv e bot hmonitorin g requirements , ther e i s n o regulator yjustifica

tio nfo r requirin g tha t th e require dspa ngase s b e th e sam e concentration .

2-3 7P.4 7

2.3. 7 Subpar t V Commen t Exemptio nfro mAdministrativ e Requirement s Tw o commenter s (IV-D-8 , IV-D-9 ) requeste dtha t a provisio nb e adde dt o Subpar t V

allowin g exemptio nfro mcertai ninventor yan drecordkeepin g require

ment s fo r valve s i f a performanc e tes t indicate s tha t 2 percen t c r -ewe r valve s i nVHA P servic e ar e leaking . Commente r IV-D- 8 als o recommende dtha t a simila r provisio nb e adde dt o Subpar t VV . Respons e Subpar t V

o f Par t 6 1 andSubpar t V V o f Par t 6 0 alread ycontai na prcvis" : oi ' whic hallow s plant s tha t establis ha lo wvalv e lea k rat e (i.e. , les s tha n 2 percent ) t o ski p monthl ymonitorin g an dt o perfor mmonitorin g o na nannua l basis . Thi s differ s fro mth e provisio ni nth e VC standar dtha t exempt s plant s tha t initially , annually , an da t th e reques t o f EPA , demonstrat e a 2 percen t o r bette r lea k rat e fro mcertai ninventor yan drecordkeepin g requirements . Exemptin g VC plant s tha t consistentl ydemonstrat e a lo wlea k rat e fro mthes e inventor yan drecordkeepin g requirement s i s reasonabl e becaus e thes e plant s hav e ove r eigh t year s o f operatin g experienc e unde r forma l lea k detectio nan drepai r plan s require db yth e origina l V C standard . Specia l consideratio nshoul db e give nt o thos e plant s fo r thei r successfu l effort s i nrespons e t o th e origina l V C standar drequirements . Becaus e othe r plant s subjec t t o 4 0 CF RPar t 6 1 Subpar t V an d4 0 CF RPar t 6 0 Subpar t V V d o no t hav e thi s leve l o f experienc e no r hav e the ybee nsubjec t t o a prio r NSP S o r NESHA P fo r equipmen t leaks , i t i s reasonabl e t o requir e thes e plant s t o compl ywit hal l th e requirement s unde r Subpar t V . Commen t Equipmen t Identificatio n Th e commente r (IV-D-8 ) recommende dtha t Subpar t V b e revise dt o als o allo widentificatio no f equipmen t b ylabelin g o nengineerin g drawing s rathe r tha nonl ytaggin g i nth e field .



### •38P.4 8

Respons e Method s othe r tha ntaggin g i nth e fiel d ar e currentl yallowe d fo r identificationo f equipmen t component s fo r testin g purposes . However , mor e detai l tha ni s typicall yavailabl e o nengineerin g drawing s i s ofte nrequired . Fo r example , photograph s o f equipmen t components o r othe r identificatio naid s ma yb e necessar yt o ensur e tha t inspector s and plan t personne l ar e abl e t o fin d th e locatio no f al l equipmen t component s subjec t t o Subpar t V requirements . Commen t Flang e Identificatio n Th e commente r (IV-D-8 ) state d tha t Subpar t V should , clearl yspecif ytha t onl yflange s whic hhav e bee nfoun d t o b e leakin g ar e require d t o b e identified . H e note d th e difficult yand expens e i nidentifyin g every flang e becaus e man y ar e covere d wit hinsulation . Respons e Flange s nee d t o b e identifie d t o ensur e effectivenes s o f th e lea k detectio nand repai r requirement s o f Subpar t V . However , EP Arecognize s tha t identificatio no f covere d flange s and othe r connector s accordin g t o th e inventor yrequirement s i nSubpar t V coul d b e to o costly . Thus , i nrespons e t o thi s comment , EP Aha s decide d t o ad d a provisio nt o Subpar t V allowin g plant s t o foreg o identificationo f covere d flanges . I naddition , Subpar t V i s bein g revise d t o exemp t al l othe r connector s fro midentificatio nan d taggin g requirements . However , thes e connector s ar e stil l subjec t t c lea k detectio nand repai r requirements . Commen t Valv e Repai r Th e commente r (IV-D-8 ) state d tha t valve s whic hhav e undergon e repai r durin g a shutdow nand whic har e foun d t o stil l b e leakin g afte r startu p shoul d b e considere d a ne wlea k and no t a nextensio no f th e firs t leak , providin g prope r repai r technique s wer e applied . Th e commente r explaine d tha t th e succes s o f th e repai r ofte nca nb e teste d onl yunde r operatin g conditions .

2-3 9P.4 9

Respons e Th e commenter' s recommende d approac hi s alread yallowed . I nthes e cases , a revie wo f th e repai r effort s i s mad e b yEPA . I f the yar e judge d t o b e proper , the nth e subsequen t lea k woul d b e a ne wleak . Commen t Proces s Accumulator s Th e commente r (IV-D-3 ) requeste d tha t th e Subpar t V provisio nregulatin g proces s accumulator s b e modifie d f o specif ytha t vent s and no t al l fugitiv e source s o nproces s accumulator s i nVHA P servic e ar e require d t o b e controlled . Respons e Th e proces s accumulato r ven t standar d i nSubpar t V i s no t applicabl e t o PVC an d EDC/V C plant s becaus e thes e vent s are . alread yregulate d unde r th e VC standar d b

yth e mor e restrictiv e requirement s o f th e exhaus t ga s limits . However , valve s and othe r equipmen t component s associate d wit hproces s accumulator s i nVHA P servic e ar e intende d t o b e controlle d lik e other-VHA P servic e equipmen t component s unde r Subpar t V , an d consequently , unde r th e VC standard . Commen t Connecto r Definitio n Tw o commenter s (IV-D-8 , IV-D-9 ) state d tha t th e definitio no f connecto r i nSubpar t V

a s i t applie s t o VC shoul d clearl yexemp t welde d joint s whic h ar e permanent . Respons e Subpar t V

alread ycontain s th e recommende d exemption . 2.3. 8 Metho d 2 1 Commen t Sampl e Flowrat e Tw o commenter s (IV-D-8 , IV-D-9 ) pointe d ou t tha t th e nomina l sampl e flowrat e requiremen t o f one-hal f t o 3 liter s pe r minut e i nEP ATes t Metho d 2 1 shoul d b e delete d becaus e a respons e tim e equa l t o o r les s tha n3 0 second s i s specifie d i na separat e provision . Th e commenter s explaine d tha t certai n. reliabl e instrument s ar e preclude d b yth e flowrat e requirements . 2-4 0P.5 0

Respons e Metho d2 1 include s a flowrat e specificatio nspecificall yt o exclud e fro m th e metho dthos e type s o f monitor s tha t hav e a larg e o r unccnfine d sampl e inle t area , becaus e EP Afoun dtha t thos e instruments wer e no t sufficientl y responsiv e t o leak s o f a magnitud e tha t EPAexpect s t o b e identifie dan o corrected . Commen t Prob e Placemen t Tw o commenter s (IV-D-8 , IV-D-9 ) requeste dtha t EP ATes t Metho d2 1 b e revise dt o specif ytha t equipmen t component s ar e t o b e monitore db yplacin g th e prob e inle t withi n1 cmo f th e componen t interfac e rathe r tha ndirectl y o nth e surfac e o f th e interface . Respons e Metho d2 1 fo r measurin g VO C leak s fro mfugitiv e emissio nsource s specifie s tha t th e portabl e monito r i s t o b e place do nth e surfac e o f th e interfac e t o b e tested . I nth e cas e o f rotatin g equipmen t suc ha s pumps , a distanc e o f 1 c mbetwee nth e prob e inle t andequipmen t interfac e i s specified . Th e lea k definitio nspecifie di nconjunctio nwit hMetho d2 1 i s base do ndat a collecte d b yplacin g th e sampl e prob e directl yo nth e surfac e o f th e interfac e (excep t fo r rotatin g shaft s o npump s andcompressors) . Inth e EPA' s judgment , changin g th e samplin g distanc e t o 1 c mfo r al l equipmen t component s i s inappropriate . 2. 4 DEFINI T I0N S 2.4. 1 I nV C Servic e Commen t Reaso nfo r Revisin g "I nVC Service " Definitio n Thre e commenter s (IV-D-1 , IV-D-4 , IV-D-14 ) recommende dmodificatio nt o th e revise ddefinitio no f "i nV C service " andt o th e relate dprovisio ni n propose d4 0 CF R61.67(h ) whic hdescribe s ho wt o determin e whethe r equipmen t i s i nV C service . On e o f th e commenter s (IV-D-14 ) state dtha t th e rational e fo r changin g th e definitio no f "i nVC service " andaddin g requirement s fo r determinin g whethe r equipmen t i s i nVC servic e ha s no t bee nadequatel y

2-4 1P.5 1

explaine d and tha t th e existin g definitio nshoul d b e retaine d becaus e i t i s clea r an d workable . Th e commente r (IV-D-14 ) als o pointe d ou t tha t certai n piece s o f equipmen t alternat e i nand ou t o f V C service , dependin g o nth e operatio nbein g conducted . Resoons e Durin g th e revie wo f enforcemen t and complianc e experienc e unde r th e VC standard , EP Afoun d tha t th e classificatio no f "i nVC service " i s a poin t o f contentio nbetwee nregiona l complianc e and industr ypersonne l (Docke t Item II-A-19) . Th e EP Aconclude d tha t th e definitio no f "i nVC service " neede d clarificatio nt c ensur e tha t al l equipmen t capabl e o f emittin g VC i s identi

fie d and tha t th e burde no f identificatio nfall s o nplan t personne l and no t Regiona l complianc e personne" 1

. T o achiev e th e desire d clarification , EP A adopte d th e approac hfo r identifyin g equipmen t i nVHA P servic e develope d fo r th e Subpar t V

regulatio nfo r equipmen t leaks . I nSubpar t V , a definitio nfo r "i nVHA P service " i s give nalon g wit ha metho d fo r determinin g whethe r equipmen t i s i nVHA P service . Th e VHA P provision s effectivel yplac e th e burde no nplan t personne l t o identif yal l equipmen t capabl e o f emittin g VHAP . Th e EP Abelieve s tha t adoptio no f th e "i nVHA P service " provision s o f Subpar t V i nth e V C standar d i s reasonabl e and appropriat e and tha t change s t o thes e provisions i ncontex t o f th e VC standar d ar e no t warranted . Th e concer nraise d b yth e commente r regardin g equipmen t tha t alternate s i nand ou t c f VC servic e i s apparentl ydirecte d towar d polymerizatio nreactor s an d othe r vessel s and equipmen t tha t normall ycontai nVC bu t ar e occasionall y purge d prio r t o openin g fo r routin e o r emergenc ymaintenance . Th e V C standar d contain s specifi c requirement s fo r minimizin g emission s durin g reacto r and equipmen t opening . Discharge s fro m equipmen t no t i nVC servic e d o no t contai nV C and therefor e ar e no t intende d t o b e regulate d b yth e standard . Th e provisio nregulatin g relie f valv e discharge s ha s bee nclarifie d t o appl y t o discharge s containin g VC t o th e atmospher e fro mrelie f valve s o nequipmen t i nV C service . Th e provisio nha s als o bee nclarifie d t o mor e adequatel y addres s equipmen t use d i nbatc hprocesse s b yreferrin g t o containe d volume s i nadditio nt o proces s flui d streams .

2-4 2P.5 2

2.4. 2 ED C an dVC Purificatio n Commen t Clarificatio no f Covere dEquipmen t Fiv e commenter s (IV-D-1 , IV-D-3 , IV-D-4 , IV-D-5 , IV-D-14 ) requeste d clarificatio no f equipmen t covere db yth e revise ddefinitio no f ED C purifica

tion,

- particularl ystorag e tanks . Commente r IV-D-1 4 requeste dconfirmatio n tha t equipmen t liste di na previou s draf t o f th e definitio nbu t delete d in th e propose ddefinitio nar e no t intende dt o b e covered . Thes e equipmen t include dstorag e tank s fo r crud e EDC ; ligh t end s separation , condensatio nand storage ; heavyend s separation , condensatio nan dstorage ; inproces s ED C storage ; anddryers. Commente r IV-D- 5 questione dth e clai minth e preambl e tha t al l equipmen t followin g ED C formatio nwa s intende dt o b e covere db yth e standard , notin g tha t thi s inten t i s no t expresse di nth e preambl e t o th e origina l standard . Tw o o f th e commenter s (IV-D-1 , IV-D-14 ) requeste dtha t EPAprovid e justificatio nfo r an yadditiona l equipmen t include di nth e revise ddefinition . Commente r IV-D- 4 als o requeste dclarificatio no f whethe r storag e vessel s ar e include dunde r th e revise ddefinitio no f "V C purification. " Thre e commenter s (IV-D-1 , IV-D-5 , IV-D-14 ) state dtha t regulatio no f storag e tank s i s no t justifie dbecaus e o f hig hcos t an dlo wemissio nreduction . Commenter s IV-D- 1 andIV-D- 5 referre dt o informatio nsubmitte dpreviousl yt o EP Aprovidin g cos t an demissio nreductio nestimate s fo r regulating storag e tank s (Docke t Ite mII-E-73) . Commente r IV-D- 5 state dtha t ED C storag e tank s ar e alread ywel l controlled , hav e lo wVC emission s andthu s hav e lo whealt h risk s i ncompariso nwit hothe r source s covere db yth e standard . H e pointe d ou t tha t th e sam e basi s wa s use dt o conclud e tha t regulatio no f othe r VC source s no t previousl ycovere db yth e standar di s no t warranted . On e additiona l commente r (IV-D-7 ) recommende dalternativ e languag e fo r th e definition s o f ED C purificatio nan dVC purificatio nt o bette r clarif y specifi c equipmen t component s subjec t t o th e standard . Respons e Th e origina l V C standar ddi dno t clearl ydelineat e whic hpurificatio n proces s equipmen t wer e subjec t t o regulatio na s ED C an dVC purificatio n equipment . However , i t i s clea r fro mth e backgroun dinformatio ndevelope d

2-4 3P.5 3

fo r th e origina l standar dtha t purificatio nequipmen t containin g V C wer e intende dt o b e covere db yth e standard . Durin g th e revie wo f th e standard , EP Alearne dtha t differen t interpretation s o f th e definition s o f ED C and VC purificatio nha dbee napplie db yindustr ypersonne l wit hth e resul t tha t som e plant s wer e controllin g emission s fro mal l equipmen t i nth e purificatio n processes , includin g storag e tank s whil e other s wer e controllin g onl yth e majo r emissio nsource s (i.e. , finishin g columns) . Interpretatio nc f thes e definition s als o varie damon g complianc e personnel . Inparticular , complianc e personne l wer e concerne dtha t som e plant s interprete dth e definitio no f VC purificatio nsuc htha t ccntro l o f emission s fro mVC storag e followin g V C .purificatio nwa s no t required . A s a resul t o f thes e findings , EP Abelieve d i t wa s appropriat e t o clarif yth e definition s o f ED C an dV C purificatio ni n th e propose drevision s t o th e standard , primaril yt o ensur e eliminatio no f overl yrestrictiv e interpretation s o f th e definition s resultin g i nfailur e t o contro l potentiall ysignifican t source s o f V C emission s suc ha s V C storag e tanks . Comment s receive do nth e propose ddefinition s addresse dth e appropriatenes s o f includin g ED C storag e tank s unde r th e revise ddefinitio n o f ED C purificatio nequipment . Becaus e thes e tank s represen t a muc hsmalle r potentia l sourc e o f VC emission s tha nV C storag e tank s an dbecaus e th e inten t o f th e origina l standar di s unclear , EP Adecide dt o evaluat e th e reasonablenes s o f regulatin g ED C storag e tank s unde r th e V C standard . Fo r thi s evaluation , EP Aestimate dth e cost s an dVC emission s reduction s tha t woul dresul t fro m regulatio no f ED C intermediat e an dfina l storag e tank s whic hfollo wth e fina l finishin g column . Base do nemission s dat a submitte db yth e commenters , uncontrolle dVC emission s fro mintermediat e an dfina l ED C storag e tank s a t a typica l EDC/V C plan t wer e estimate dt o b e 0. 1 t o 2 Mg/y r VC . Contro l cost s wer e base do nventin g existin g ED C storag e tank s t o a nexistin g primar y contro l devic e (i.e. , incinerator ) a s require db yth e standar dfo r purificatio n equipment . Th e EP Aestimate dth e cos t t o contro l thes e tank s woul dexcee d $8,500/M g VC (198 4 dollars ) an dachiev e a nemissio nreductio no f 0.6 7 t o 1 4 Mg/y r (Docke t Ite m IV-E-8) . Th e EP Aconclude dfro mthei r evaluatio ntha t contro l o f V C emission s fro mED C storag e tank s whic hstor e ED C afte r th e

2-4 4P.5 4

fina l finishin g colum ni s no t cos t effectiv e an dtha t regulatio no f thes e tank s unde r th e V C standar di s no t warranted . Althoug hth e standar dunde r revie wregulate s VC emissions , EP Aconsidere d th e benefi t o f controllin g othe r VOC , primaril yEDC , i nit s decisio nregardin g whethe r t o regulat e thes e tank s uncer th e V C standard . Man yo~ ~ thes e tankj , •are alread ycontrolle dfo r VO C (andthu s VC ) accordin g t o stat e SI P provision; . Th e remainde r o f thes e tank s ar e locate dprimarilyi nattainmen t area s wher e les s stringen t VO C regulation s apply . Moreover , EP Ai s currentl yinvestigatin g ED C emission s fo r possibl e regulator ydevelopmen t a s a hazardou s ai r pollutan t unde r Sectio n112 . The'potentia l emissio nreductio nassociate dwit hccntro " .o f ED C storag e tank s woul damoun t t o abou t 60 0 Mg/y r andth e resultin g cos t effectivenes s woul db e abou t $330/M g ED C (Docke t Ite mIV-B-8) . Intermediat e andfina l ED C storag e tank s whic hfollo wth e fina l finishin g colum nwoul d likel yb e regulate dunde r a nED C regulation . Th e EP Aconclude dtha t regulatio n o f thes e storag e tank s woul db e mor e appropriatel ycarrie dou t b ythes e othe r regulator ymechanisms . 2.4. 3 Relie f Valv e Commen t Exemptio no f Nonventin g Pressur e Contro l System s Fou r commenter s (IV-D-1 , IV-D-4 , IV-D-9 , IV-D-14 ) requeste dadditiona l clarificatio nt o th e definitio no f relie f valve . Tw o o f th e commenter s (IV-D-1 , IV-D-9 ) requeste dtha t relie f valv e b e define da s anypressur e relie f syste muse dt o protec t proces s component s fro moverpressur e condition s b yventin g directl yt o th e atmosphere . Th e commenter s furthe r recommende d tha t th e definitio no f relie f valv e explicitl yexemp t pressur e contro l system s suc ha s reactio nshortsto p systems , refrigerate dwate r system s and othe r system s whic hac t t o reduc e pressur e b ymean s othe r tha nventin g t o th e atmosphere . Th e thir dcommente r (IV-D-4 ) state dhi s understandin g fro mpas t discussion s wit hEP Atha t th e nonventin g pressur e contro l system s ar e no t intende dt o b e covere db yth e definition . Th e commente r (IV-D-4 ) als o recommende dtha t th e definitio nb e modifie dt o exclud e al l device s controllin g flo waroun da nincinerator , no t jus t contro l valves . Th e fourt hcommente r



### •4 5(IV-D-14 ) state dtha t althoug hth e revise drelie f valv e discharg e standar d

eliminate s th e mos t significan t proble mi nth e origina l regulation , additiona l clarificatio nt o th e definitio nc f relie f valv e i npropose d4 0 CF R61.61(v ) i s neede dt o adequatel yreflec t th e expresse dinten t i nth e preambl e •'5 0 FP . 1192) . Th e commente r recommende dtha t th e definitio nspecificall y identif yal l type s o f relie f device s tha t ar e subjec t t o regulatio na s i i'Xxr valves . Thi s clarificatio nwoul deliminat e vaguenes s andachiev e consistenc y wit hth e preamble . Respons e On e purpos e o f definin g relie f valv e i s t o ai di nidentificatio no f emission s o f VC t o th e atmospher e whic har e subjec t t o th e relie f valv e discharg e standard . Th e commenters ' concer ntha t th e definitio no f relie f valv e coul db e interprete dt o includ e shortsto p system s an drefrigerate d wate r system s i s irrelevan t becaus e i t i s difficul t t o conceiv e tha t VC coul d b e emitte dfro m

thes e pressur e contro l system s t o th e atmosphere . Nonetheless , EP Aha s revise dth e definitio no f relie f valv e t o explicitl yexclud e shortsto p system s an drefrigerate dwate r systems . However , th e promulgate ddefinitio n ha s no t bee nrevise dt o exemp t al l pressur e contro l system s tha t protec t proces s component s fro moverpressur e condition s b ymethod s othe r tha nventin g directl yt o th e atmosphere . Th e EP Abelieve s tha t exemptio no f al l nonventin g pressur e contro l system s woul db e inconsisten t wit hth e inten t tha t discharge s fro mgasholder s o r othe r containmen t system s t o whic hrelie f valv e discharge s ma yb e vente dar e subjec t t o th e relie f valv e discharg e standard . Th e definitio no f relie f valv e ha s als o bee nrevise da s recommende dt o exclud e al l device s controllin g flo waroun da nincinerator , an dno t jus t contro l valves . Thes e pressur e contro l device s ac t t o bypas s exhaus t ga s aroun dth e incinerato r i nth e even t o f overpressur e condition s o r incinerato r malfunction . Bypasse dexhaus t ga s i s subjec t t o th e 1 0 pp mexhaus t ga s standar dan dno t t o th e limit s fo r relie f valv e discharge s unles s th e bypas s i s cause db

ya relie f valv e discharge . Finally , th e definitio nidentifie s severa l type s o f pressur e relie f device s whic har e t o b e considere d"relie f valves " whe nevaluatin g complianc e

2-4 6P.5 6

wit hth e relie f valv e discharg e standard . A s explaine di nth e preambl e t o th e propose drevision s (5 0 F R1187) , thi s definitio ni s necessar yt o clarif y tha t th e relie f valv e discharg e standar dapplie s no t onl yt o emission s fro m pressur e relie f valve s bu t t o othe r type s o f pressur e relie f device s a s well . Inadditio nt o th e liste d equipment , th e definitio nals o state s tha t any othe r pressur e relie f system s tha t functio ni nth e sam e wa y(i.e. , t o protec t proces s component s fro moverpressur e conditions ) ar e t o b e considere drelie f valves . I nthi s way , th e inten t tha t al l pressur e re n ie f devices , andno t jus t certai ntypes , ar e subjec t t o th e relie f valv e discharg e standar di s emphasized . Commen t "Relie f Valve " vs . "Relie f Device " Tw o commenter s (IV-D-8 , IV-D-9 ) suggeste dtha t th e ter m"relie f valve " b e change dt o "relie f device " t o b e consisten t wit hth e America nSociet yo f Mechanica l Engineer s (ASME ) designatio nan dcommo nusag e andt o avoi dth e confusio no f referrin g t o a ruptur e dis c a s a valve . Respons e Th e commente r i s correc t i nnotin g tha t "relie f valve " i s a mor e narro w ter mtha n"relie f device " an dtha t "relie f device " bette r connote s th e variet yo f pressur e relie f equipmen t subjec t t o th e VC standard . However , mos t pressur e relie f discharge s fro mequipmen t i nPVC an dEDC/V C plant s occu r throug hrelie f valves . A s a result , th e origina l standar dwa s writte ni n term s o f "relie f valve " fo r convenienc e eve nthoug hothe r relie f device s wer e intende dt o b e included . I norde r t o clarif ytha t al l pressur e relie f device s ar e subjec t t o th e relie f valv e discharg e standard , a definitio no f relie f valv e ha s bee nadded . Th e EP Abelieve s tha t th e adde ddefinitio n provide s a les s cumbersom e solutio nfo r clarifyin g equipmen t subjec t t o th e standar dtha nth e commenter' s suggestion . Nonetheless , EP Aappreciate s th e confirmatio nb

yth e industr ycommente r indicatin g understandin g o f th e broa d us e o f th e ter m

"relie f valve" .



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2.4. 4 Lea k Commen t "Leak " Definitio n On e commente r (IV-D-14 ) recommende dtha t th e definitio no f lea k b e revise dt o distinguis hwha t a lea k i s fro mevent s tha t sugges t th e presenc e o f a leak . Respons e A s discusse di nth e preambl e t o th e propose drevision s (5 0 FR1192) , on e purpos e o f addin g a definitio no f lea k t o th e V C standar di s t o hel p dis

tinguish . VC emission s resultin g fro m"leaks " fro mVC emission s occurrin g a s .relie f valv e discharge s an dexhaus t gas . T o achiev e thi s purpose , th e definitio no f lea k list s event s regulate db yth e VC standar dan dSubpar t V (incorporate di nth e V C standar db yreference ) whic hindicat e a nee dfo r repai r o r furthe r actio no nth e par t o f plan t owner s o r operators . A s explaine di nresponse s t o othe r comments , EP Abelieve s tha t eac ho f th e regulate devent s liste di nth e definitio nrepresen t adequate " criteri a fo r requirin g repai r o r furthe r actio nan dar e appropriatel yinclude di nth e definition . Commen t Indication s o f Liqui dDrippin g Si xcommenter s (IV-D-1 , IV-D-2 , IV-D-3 , IV-D-4 , IV-D-8 , IV-D-9 ) recommende dmodification s t o th e portio no f th e lea k definitio npertainin g t c indication s o f liqui ddripping . Fou r o f th e commenter s (IV-D-1 , IV-D-3 , IV-D-8 , IV-D-9 ) state dtha t indication s o f liqui ddrippin g shoul db e considere d leak s onl yi f confirme db ya nobjectiv e measurement . Commente r IV-D- 3 suggeste dtha t a ninstrumen t readin g greate r tha n10,00 0 pp mb e th e criterio n fo r establishin g tha t drippin g liquid s ar e V C leaks . Commenter s IV-D- 8 an d IV-D- 9 recommende dtha t barrie r flui dlevel s and/o r pressure s b e relie d upo n instea da s indicator s o f V C leak s fro mdoubl e mechanica l sea l pumps . Commente r IV-D- 4 suggeste dtha t leak s define da s indication s o f liqui ddrippin g shoul d b e limite dt o liqui ddrippin g fro mpump seal s i nV C service . Commente r IV-D- 2 recommende ddeletio no f indication s o f liqui ddrippin g fro mth e lea k definitio no nth e basi s tha t drip s fro mpump s ar e likel yno t VC .

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Respons e Th e EP Abelieve s tha t indication s o f liqui ddrippin g i s appropriat e criterio nfo r requirin g repai r action s o ndoubl e mechanica l sea l pump s i nVC servic e an dshoul dtherefor e b e include di nth e definitio no f leak . Visibl e leakag e fro m

al l type s o f pum

p sea's , includin g doubl e mechanica l seal s require db

yth e VC standard , i s generall yindicativ e o f sea l wea r eve ni f nc VC i s presen t i nth e leakin g fluid . T o preven t furthe r sea l wea r resultin g i ncatastrophi c sea l failur e accompanie db yVC emission s t o th e atmosphere , th e seal s shoul db e repaire dsoo nafte r leakag e i s initiall ydetected . Th e sam e lea k criterio nfo r doubl e mechanica l sea l pump s i s prescribe di necuiomer. ' lea k standard s fo r SOCM I an dbenzene . I nth e VC standard , th e portio no f th e lea k definitio nreferrin g t o indication s o f liqui ddrippin g applie s onl yt o pump s i nVC service . Barrie r flui dleve l an dpressur e sensor s als o provid e indicatio no f certai ntype s o f sea l wea r an dar e thu s include di nth e Subpar t V require

ment s fo r detectin g leak s fro mdoubl e mechanica l sea l pumps . I nth e EPA' s judgment , monitorin g o f barrie r flui da s wel l a s drippin g liquid s i s necessar y t o ensur e contro l o f equipmen t leak s fro mpump s wit hdoubl e mechanica l seals . Commen t Senso r Detectio no f Sea l Failur e Thre e commenter s (IV-D-1 , IV-D-2 , IV-D-4 ) disagree dwit hinclusio no f "senso r detectio no f failur e o f a sea l system " i nth e definitio no f leak . Tw o o f th e commenter s (IV-D-1 , IV-D-2 ) explaine dtha t sea l syste mfailure s ar e no t necessaril yindicativ e o f VC leak s t o th e atmosphere . Th e thir d commente r (IV-D-4 ) state dtha t senso r detectio no f sea l failure s shoul db e delete dfro mth e definitio no f lea k i nconjunctio nwit hth e recommende d remova l o f propose dsea l monito r requirement s fo r pump seals . Respons e A s i nth e cas e o f indication s o f liqui ddripping , EP Abelieve s tha t senso r detection s o f sea l failur e (i.e. , detectio no f a rapi dchang e i n barrie r flui dleve l o r pressure ) i s appropriat e criterio nfo r requirin g repai r action s fo r doubl e mechanica l sea l pump s i nV C servic e an dshoul db e

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include di nth e definitio no f leak . Althoug hfailur e o f a ninne r sea l o na doubl e mechanica l sea l pum p i nVC servic e ma yno t resul t i ndirec t emissio n o f VC t o th e atmosphere , continue doperatio nwoul dresul t i ntota l sea l failur e accompanie db ydirec t emissio no f VC t o th e atmosphere . Th e equipmen t "lea k standard s fo r 3CCM I andbenzen e als o lis t senso r detectio no f sea l failur e a s a criterio nrequirin g repai r action s fo r doubl e mechanica l sea l pumps . Th e EP Ai s ne t exemptin g doubl e mechanica l sea l pump s i nVC servic e fro m sea l monitorin g requirement s i nSubpar t V . Th e basi s fo r thi s decisio ni s describe di nSectio n2.3.2 . Commen t Lea k Definition s Unde r Existin g Standar d Fiv e commenter s (IV-D-1 , IV-D-3 , IV-D-4 , IV-D-8 , IV-D-9 ) requeste d clarificatio no f th e statu s o f lea k definition s establishe dunde r existin g lea k detectio nan deliminatio nprograms . Commente r IV-D- 1 recommende dtha t leak s define dunde r existin g approve dlea k detectio nan deliminatio nprogram s b e include di nth e definitio no f leak . Commente r IV-D- 3 disagree dtha t existin g lea k definition s shoul db e retaine dunde r th e revise dlea k definitio n o nth e basi s tha t som e plant' s existin g lea k definition s ar e muc hlowe r tha n th e propose dlea k definitio nan dtha t impositio no f Subpar t V repai r an d recordkeepin g requirement s fo r leak s foun dunde r thes e existing , mor e stringen t definition s woul dno t b e justified . Anothe r commente r (IV-D-4 ) state dtha t th e definitio no f lea k shoul dno t includ e event s regulate di nth e origina l VC standar do f detectio no f ambien t concentration s i nexces s o f backgroun d concentration . Instead , thes e event s shoul db e considere da nactio nleve l triggerin g a searc ht o detec t leak s o nth e basi s o f othe r define dlea k criteria . Tw o additiona l commenter s (IV-D-8 , IV-D-9 ) recommende dtha t th e portio no f th e definitio no f lea k referrin g t o event s regulate dunde r existin g plan t program s shoul dspecificall yreferenc e th e provisio ni nth e existin g standar dwher e thes e lea k event s ar e defined .

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Respons e Unde r 4 0 CF R61.65(b)(8)(vi ) o f th e VC standard , plant s ar e require dt o establis ha lea k definitio na t anacceptabl e leve l whe ncompare dt o th e backgroun dconcentration . Th e provisio nallow s fo r differen t lea k definition s t o b e establishe di ndifferen t part s o f th e plan t becaus e o f variation s in backgroun dconcentrations . Th e provisio nals o allow s fo r adjustment s i nlea k definition s ove r tim e a s backgroun dconcentration s ar e reduced . Durin g th e revie wo f th e standard , EP Afoun dtha t lea k definition s establishe dunde r thi s provisio nvarie dwidel yfro mplan t t o plan t (Docke t Ite mII-A-19) . Difference s inlea k definition s use dfo r detectin g leak s wit hare a monitor s ar e i npar t du e t o th e variabilit yamon g plant s i nth e numbe r an dlocatio no f are a monitor s an ddifference s i nbackgroun dconcentrations . Becaus e o f thes e factors , i t i s impossibl e t o establis ha standar dlea k definitio napplicabl e t o are a monitors . I nth e cas e o f detectio no f leak s usin g portabl e monitors , however , i t i s possibl e an dappropriat e t o establis ha standar dlea k definitio nan d metho dfo r detectio no f leaks . Consequently , th e definitio no f lea k i nth e V C standar dinclude s specifi c criteri a t o b e use db yplant s i nplac e o f existin g definition s fo r identifyin g leak s wit hportabl e monitors . Th e prescribe dlea k criteri a i s consisten t wit hth e criteri a develope dfo r detectio no f leak s wit ha portabl e monito r unde r equipmen t lea k standard s fo r benzen e an dSOCM I andma yb e mor e o r les s stringen t tha nth e definition s establishe dunde r th e origina l VC standard . Th e EP Abelieve s tha t th e lea k criteri a develope dfo r thes e othe r standard s represen t aneffectiv e progra m fo r detectio no f leak s wit hportabl e monitor s an dtha t mor e stringen t definition s ar e no t needed . Becaus e o f th e difficult yi nestablishin g standar dcriteri a fo r identifyin g leak s wit hare a monitors , th e definitio no f lea k incorporate s th e plant' s existin g definitio ndevelope dfo r us e wit hth e plant' s are a monitors . I nreviewin g th e standar dEP Adi dno t identif yspecifi c problem s wit hth e definition s o f lea k pertainin g t o area-wid e monitorin g system s i nus e b yth e plants . Th e EP Aconclude dtha t th e area-wid e lea k definition s ca nappro priatel yserv e thei r purpose . Further , EP Adoe s no t inten dfo r change s i n

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th e standar d t o interfer e wit hthi s metho d o f controllin g leaks . However , a s discusse d i nth e preambl e t o th e propose d revision s (5 0 F R1190) , plant s hav e th e optio no f alterin g th e numbe r o f point s tha t ar e monitore d an d th e distributio no f monitorin g location s associated wit hexistin g fixed-poin t monitorin g plan s t o bette r complemen t th e newl yprescribe d portabl e monitorin g requirements . Th e revise d portabl e monitorin g lea k detectio nrequirement s in conjunctio nwit hth e fixed-poin t monitorin g requirement s wil l ensur e contro l o f VC emission s fro mequipmen t leak s t o th e leve l intende d b yth e origina l regulation . Commen t Referenc e t o Event s an d Emission s Regulate d Elsewher e On e commente r (IV-D-14 ) state d tha t referenc e t o event s regulate d unde r Subpar t V

and unde r th e origina l lea k detectio nand eliminatio nrequirement s i n4 0 CF R61.65(b)(8)(i ) o f th e V C standar d i s no t appropriat e i nth e propose d lea k definitio nbecaus e th e reference d regulation s d o no t contai nlea k definitions . Th e commente r (IV-D-14 ) furthe r state d tha t th e provisio ni n th e propose d lea k definitio ntha t define s leak s a s emission s no t specificall y regulate d elsewher e i nth e standar d shoul d b e omitte d becaus e i t ha s n o apparen t basi s and woul d b e confusing . Respons e Fo r purpose s o f th e VC standard , a lea k i s define d a s thos e event s regulate d unde r th e V C standar d and Subpar t V (include d i nth e VC standar d b y reference ) whic hindicat e th e nee d fo r repai r o r furthe r actio nb yth e plant . Th e definitio no f lea k appropriatel yreference s wher e thes e event s ar e regulate d (i.e. , eithe r Subpar t V o r th e VC standard) . Th e provisio ni nth e definitio ntha t leak s includ e emission s no t regulate d unde r certai nprescribed part s o f th e V C standar d wa s include d primaril yt o hel p ensur e regulatio no f V C emission s fro msource s no t addresse d elsewher e i nth e standard . Fo r example , althoug huncommon , emission s o f V C occasionall yoccu r fro msource s suc ha s broke npipe s o r headers . I nth e past , i t wa s unclea r t o som e plan t owner s and operator s whethe r thes e type s o f emission s wer e subjec t t o

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regulatio na s exhaus t gas , a s a leak , a s both , o r a s neither . Th e propose d definition s o f lea k andexhaus t ga s include dprovision s intende dt o clearl y distinguis hbetwee nth e tw o type s o f emissions . However , thes e provision s wer e no t intende dt c impl ytha t complianc e wit hrequirement s fo r leak s and exhaus t ga s woul db e mutuall yexclusive . Afte r reviewin g th e propose d definitions , i t i s th e EPA' s opinio ntha t automatic classificatio no f emission s fro munconventiona l source s suc ha s broke npipe s a s eithe r a lea k o r exhaus t ga s i s neithe r practica l no r appropriate . Accordingly , th e provisio ni nth e . definitio no f lea k whic hspecifie s tha t emission s no t regulate dunde r th e prescribe dpart s o f th e standar dare t o b e considere dleak s ha s bee ndeleted . Commen t Instrumen t Reading s o f 50 0 ppmAbov e Backgroun d Fiv e commenter s (IV-D-1 , IV-D-2 , IV-D-3 , IV-D-4 , IV-D-9 ) suggeste dtha t th e distinctio nbetwee nleak s define da s instrumen t reading s greate r tha n 10,00 0 ppmandleak s define da s instrumen t reading s o f 50 0 ppmabov e backgroun d b e clarifie db

yspecifyin g tha t instrumen t reading s o f 50 0 ppmabov e backgroun d appl yonl yt o certai nequipment . Thre e o f th e commenter s (IV-D-1 , IV-D-2 , IV-D-9 ) recommende dtha t instrumen t reading s o f 50 0 ppmabov e backgroun db e applie dt o relie f valve s whe nno t relieving an dsealles s pumps . Afourt h commente r (IV-D-3 ) recommende dapplyin g th e 50 0 ppm ' abov e backgroun ddefinitio n t o leak s fro msealles s valve s i nadditio nt o pump s andrelie f valve s and th e fift hcommente r (IV-D-4 ) recommende dapplyin g th e 50 0 ppmabov e backgroun d definitio nt o non-relievin g relie f valve s only . Respons e Th e commenter s correctl ypointe dou t tha t leak s define da s instrumen t reading s o f 50 0 pp m abov e backgroun dar e intende dt o appl yt o equipmen t designate dt o compl ywit hn o detectabl e emissions . Accordin g t o th e revise d V C standard , relie f valve s ar e t o b e operate dwit hn o detectabl e emissions . I naddition , valves , sealles s pump s andcompressor s ca nb e designate dfo r n o detectabl e emission s unde r Subpar t V unde r certai nconditions . T o clarif y

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th e lea k definition , i t ha s bee nrevise d t o clearl ydistinguis hbetwee nleak s define d a s instrumen t reading s c f 10,00 0 ppmand leak s define d a s instrumen t reading s o f 50 0 ppmabov e backgroun d a s follows : r 3 61.61(w ) "Leak " mean s ar. yo f severa l event s .. . (4 ) detectabl e emission s a s indicate d b

yaninstrumen t readin g o f greate r tha nSC O comabov e backgroun d fo r equipmen t designate d fo r n o detectabl e emissions . Commen t Referenc e t o EP ATes t Metho d 2 1 Tw o commenters (IV-D-1 , IV-D-4 ) pointe d ou t tha t leak s define d a s instrumen t reading s o f greate r tha t 10,00 0 ppmshoul d be reference d t o EP A Tes t Metho d 21 . On e o f th e commenter s (IV-D-4 ) als o suggeste d tha t leak s define d a s instrumen t reading s greate r th e 50 0 ppmabov e backgroun d b e reference d t o Metho d 21 . Respons e A s recommended , th e lea k definitio nha s bee nrevise d t o appropriatel y referenc e EP ATes t Metho d 2 1 a s follows : §61.65(w ) "Leak " mean s anyo f severa l event s .. . (1 ) a ninstrumen t readin g o f 10,00 0 ppmmeasure d accordin g t o Tes t Metho d 2 1 (se e Appendi xAo f 4 0 CF R Par t 60 ) .. . (4 ) detectabl e emission s a s indicate d b ya ninstrumen t readin g o f greater tha n50 0 ppmabov e backgroun d fo r equipmen t designate d fo r n o detectabl e emission s measure d accordin g t o Tes t Metho d 2 1 (se e Appendi xA. c f 4 0 CF RPar t 60 ) . . . 2.4. 5 Exhaus t Ga s Commen t Reconsideratio no f "Leak " and "Exhaus t Gas " Definition s Th e commente r (IV-D-7 ) state d tha t unintentiona l emission s fro mequipmen t components fo r whic hemissio nlimit s ar e prescribe d shoul d no t b e considere d exhaus t gas , a s proposed , bu t rathe r b e considere d a s a leak , an d requeste d tha t th e propose d definition s fo r lea k and exhaus t ga s b e change d accordingly .

2-5 4Respons e Th e EP Aagree s wit hth e commente r tha t i ncertai nsituations , "unintentional " emission s fro m equipmen t component s fo r whic hemissio nlimit s ar e prescribe d ma yb e mor e appropriatel yregulate d unde r standard s applyin g t o equipmen t leak s tha nstandard s fo r exhaus t gas . Fo r example , a brea k in anexhaus t ga s heade r t o a contro l devic e resultin g i nemission s o f VC t o "th e atmospher e i nexces s o f 1 0 ppmwoul d apparentl yb e subjec t t o th e 1 0 ppm standar d fc r exhaus t ga s unde r th e propose d definitio no f exhaus t gas . ?u t emission s fro ma broke nheade r ar e likel yt o b e detecte d b yth e are a monito r and repaire d i na simila r fashio nt o leak s fro mspecifi c equipmen t component s suc ha s valve s and pumps . Th e fact s o f th e situation , suc ha s th e reaso nfo r th e emission , it s magnitude , and th e action s take nt o alleviat e it s impacts , woul d b e take nint o accoun t whe ndeterminin g th e applicabilit yo f th e standar d t o a specifi c incident . Commen t Referenc e t o Limit s fo r Equipmen t Th e commente r (IV-D-14 ) state d tha t referenc e i nth e exhaus t ga s definitio nt o ".. . equipmen t fo r whic h1 0 ppmemissio nlimit s ar e pre scribed " i s misleadin g an d shoul d b e delete d becaus e th e cite d section s appl y limit s t o exhaus t ga s and no t equipment . Respons e A s pointe d ou t b

yth e commenter , th e definitio no f exhaus t ga s refer s t o severa l section s i nth e VC standar d whic hprescrib e emissio nlimit s fo r exhaus t ga s fro mvariou s equipmen t i nPV C and EDC/V C plants . I norde r t o clarif yanymisunderstandin g regardin g whic hemission s ar e subjec t t o regula

tio na s exhaus t gas , th e definitio nha s bee nrevise d a s follows : §61.61(x ) "Exhaus t gas " mean s anyoffga s .. . i ndirec t contac t with.th e equipment , fo r whic hemissio nlimit s ar e prescribe d i n. . . Commen t Referenc e t o Dispositio no f Exhaus t Ga s Th e commente r (IV-D-14 ) recommende d tha t th e definitio no f exhaus t ga s b e revise d t o omi t th e word s "directl yo r ultimately " becaus e the yd o n o contribut e t o th e meanin g o f th e definition .Respons e Th e definitio nc f exhaus t ga s intentionall yspecifie s offga s discharge d "directl yo r ultimately " t o th e atmospher e t o clearl yindicat e tha t th e dispositio no f th e offga s doe s no t affec t th e applicabilit yo f th e "exhaus t gas " standards . Whethe r th e offga s i s vente d t o th e atmosphere , vente d t o a contro l devic e o r combine d wit hothe r offga s stream s i t i s subjec t t o th e "exhaus t gas " standards . Th e EP Abelieve s th e word s "directl yo r ultimately " contribut e meanin g and shoul d b e retained . Commen t Alternativ e Languag e Deoomir,ende c Th e commente r (IV-D-14 ) recommende d tha t th e definitio no f exhaus t ga s recogniz e tha t al l emission s whic hhav e bee ntreate d i na contro l devic e becom e exhaus t gas , regardles s o f thei r origin . H e recommende d alternativ e languag e t o identif yexhaus t ga s a s th e objec t o f contro l t o 1 0 ppm . Respons e On e purpos e o f addin g a definitio no f exhaus t ga s t o th e VC standar d i s t o hel p distinguis hV C emission s occurrin g wit hexhaus t ga s fro mVC emission s resultin g fro mleak s and relie f valv e discharges . Th e EP Abelieve s tha t th e propose d definitio nbette r achieve s tha t purpose . Thus , th e commenter' s suggestio ni s rejected . 2.4. 6 Relie f Valv e Discharg e Commen t "Relie f Valv e Discharge " Definitio n Th e commente r (IV-D-7 ) recommende d a nalternativ e definitio nfo r relie f valv e discharg e t o replac e th e propose d definition . Respons e Th e commenter' s recommendatio ntha t th e definitio no f relie f valv e discharg e b e expande d t o an y"non-lea k discharge " throug ha pressur e relie f devic e designate d t o protec t proces s component s fro moverpressur e condition s i s unnecessary . Th e definitio no f relie f valv e discharg e adequatel yserve s th e purpos e o f distinguishin g relie f valv e discharg e emission s fro m VC

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emission s occurrin g wit hexhaus t ga s and leaks . Moreover , th e definitio no f relie f valv e specifie s tha t relie f valve s ar e pressur e relie f device s designe d t o protec t proces s component s fro m overpressur e conditions . Inclusio no f thi s descriptio no f relie f valv e i nth e definitio no f relie f valv e discharg e i s redundan t and unnecessary . 2.4. 7 3-Hou r Perio d Commen t Potentia l fo r Thre e 3-Hou r Exceedence s o f 1 0 pp m

Limi t Fiv e commenter s (IV-D-1 , IV-D-2 , IV-D-4 , IV-D-6 , IV-D-14 ) note d tha t th e definitio nQ f 3-hou r perio d create s 2 4 3-hou r period s pe r da ywit hth e resul t tha t a singl e hourl yaverag e i nexces s o f 1 0 ppmcoul d caus e thre e 3-hou r exceedence s o f th e 1 0 ppmlimit . Tw o o f th e commenter s (IV-D-1 , IV-D-4 ) explaine d tha t establishmen t o f rollin g 3-hou r averagin g period s effectivel y negate s th e intende d clarificatio ntha t 1-hou r average s ar e no t th e intende d complianc e criteria . Anothe r commente r (IV-D-14 ) pointe d ou t tha t onl yeigh t performanc e test s prescribe d unde r 4 0 CF R61.6 7 coul d b e performe d durin g a 24-hou r period . Th e commenter s recommende d tha t th e 1 0 ppmregulation s specif ytha t a singl e hourl yaverag e i nexces s o f 1 0 ppmca nno t caus e mor e tha non e 3-hou r perio d t o b e considere d i nexces s o f 1 0 ppm . Respons e Th e commenter s correctl yinterprete d tha t th e definitio no f 3-hou r perio d create s 2 4 3-hou r average s pe r day . I naddition , th e commenter s correctl yconclude d tha t i ncase s whe nth e contro l devic e fail s significantl y causin g a 1-hou r exceedanc e o f th e 1 0 ppmexhaus t ga s limit , th e resul t ca n b e thre e 3-hou r exceedance s o f 1 0 ppm . Nonetheless , EP Abelieve s th e definitio no f 3-hou r perio d i s correc t and shoul d b e retained . Th e purpos e o f specifyin g a 3-hou r averag e fo r complianc e wit hth e 1 0 ppmlimit s fo r exhaus t ga s wa s t o improv e consistenc yo f th e exhaus t ga s standard s wit hth e performanc e tes t requirement s whic hspecif ya naverag e o f thre e run s o f 1 hou r each . Th e performanc e tes t metho d doe s not , however , preclud e takin g 2 4 1-hou r sample s durin g a 24-hou r period .

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I . * -» v

Rolling 3-hou r period s ar e necessar yt o ensur e tha t al l 3-hou r average s exceedin g 1 0 ppmar e reported . Otherwise , 1 0 ppmexceedance s durin g tw o consecutiv e hour s woul d onl yb e average d togethe r i f the yhappene d t o fal l i n th e sam e 3-hou r reportin g period . Rollin g 3-hou r period s als o hel p ensur e timel yrespons e i ncorrectin g period s o f exces s emissions . I nth e absenc e o f rollin g averages , hig hreading s durin g th e firs t hou r o f a 3-hou r perio d coul d b e lef t unattended fo r up t o tw o mor e hour s withou t influencin g reporte d result s o r th e action s o f operatin g personnel . 2. 5 REVISION S T O OTHE RPART S O F TH E STANDAR D 2.5. 1 Exhaus t Ga s Standard s Commen t Lowe r Exhaus t Ga s Limi t Achievabilit y On e commente r (IV-D-12 ) state d tha t th e EPA' s conclusio ntha t th e previousl ypropose d 5 ppmexhaus t ga s limi t shoul d b e withdraw ni s no t supporte d b

yth e suppor t documen t i nthi s rulemaking . Th e commente r asserte d tha t th e recor d support s th e achievabilit yo f th e 5 ppmlimi t b yne wsource s and b yexistin g source s withi n3 year s o f promulgation . Th e commente r pointe d t o th e statemen t i nth e 197 7 proposa l tha t th e 5 ppm limi t coul d b e achieve d throug hth e mor e efficien t operatio no f existin g equipmen t applie d t o eithe r ne wo r existin g sources . Th e commente r als o state d tha t th e additiona l emission s reductio ntha t woul d b e achieve d throug hth e us e o f a 5 ppmstandar d instea d o f a 1 0 ppm standar d shoul d no t b e foregone , give nth e carcinogeni c natur e o f VC . Finally , th e statemen t i nth e preambl e tha t industr ycommenter s objecte d t o th e "zer o emissio ngoal " whic hwa s th e objectiv e o f th e 197 7 proposa l would , th e commente r stated , b e counte r t o th e requiremen t o f Sectio n11 2 tha t a nampl e margi no f safet yb e required . Respons e A s state d i nth e preambl e (5 0 FR1184) , EP Aconclude d durin g th e revie w o f th e standar d tha t 1 0 ppmreflect s th e leve l o f performanc e tha t ca nb e consistentl yachieve d b yprimar ycontro l device s o na continuou s basis . Fo r thi s reason , th e 1 0 pp mexhaus t ga s limi t ha s bee nretaine d i nth e revise d VC

2-5 8P.6 8

standard . I nfact , however , emission s fro mprimar ycontro l device s o na short-ter mbasi s ar e ofte nmuc hles s tha n1 0 ppm . Thes e lowe r short-ter m emissio nlevel s woul d occu r regardles s o f th e leve l o f th e exhaus t ga s standards . Thus , tightenin g o f th e exhaus t ga s standard s t o 5 ppmwa s judge d t o b e unwarrante d becaus e i t woul d no t significantl yimpac t emission s o f VC . Th e commente r presente d n o evidenc e whic hwoul d warran t a revisio no f th e EPA' s decision . Commen t Equipmen t and Wor k Practic e R.ecuirement s On e commente r (IV-D-15 ) requeste d tha t th e revise d standar d delineat e •wha t degre e o f contro l equipmen t "backup " i s acceptabl e fo r complyin g wit h th e 1 0 ppmexhaus t ga s limit s whe nth e primar ycontro l equipmen t i s down . Th e commente r (IV-D-16 ) recommende d tha t a provisio nb e adde d t o th e standar d requirin g a doubl e leve l o f redundanc yfo r backu p emissio ncontro l equipmen t use d t o mee t th e exhaus t ga s limits . Th e commente r furthe r recommende d tha t backu p incinerator s b e require d t o b e maintaine d o n"warm " standb yan d tha t flare s b e approve d a s th e secon d leve l o f redundancy . Respons e Revie wo f enforcemen t and complianc e experienc e unde r th e VC standar d foun d tha t mos t plant s hav e installe d som e leve l o f backu p contro l equipmen t t o mee t exhaus t ga s limits . Fo r example , discussion s wit hfou r EDC/V C producer s indicate d a rang e o f 1 5 t o 10 0 percen t exces s incineratio ncapacit y availabilit yunde r norma l operatin g conditions . Th e fiv e EDC/V C plant s operate d bythes e producer s varie d i nth e numbe r o f productio nunit s and i n thei r associatio nwit hlarger , multi-comple xchemica l plants . A s wa s expected , th e numbe r an d configuratio no f backu p incinerator s v/a s differen t fo r eac h plant . I nsimila r discussion s wit htw o PVC producer s representin g seve n plants , i t wa s learne d tha t i nadditio nt o incineration , solven t absorptio n i s bein g use d fo r bot hprimar yand backu p contro l o f exhaus t gases . Agai n th e number , typ e an d configuratio no f backu p contro l device s varie d amon g th e differen t PVC plant s (Docke t Ite m IV-B-1) .

2-5 9P.6 9

" ^

Becaus e o f th e inheren t difference s i nth e plant s and processe s t o whic h exhaus t ga s contro l device s ar e applied , couple d wit hth e variatio ni n effectivenes s o f operatin g thes e devices , i t i s impractica l t o specif yth e exac t amoun t o f backu p needed . Nonetheless , EP Aagrees , i ngeneral , wit hth e commenter' s suggestion s o nth e nee d fo r and operatio no f backu p contro l devices . Fo r example , backu p contro l device s ar e necessar yt o hel p ensur e contro l o f VC emission s i nexhaus t ga s durin g period s whe nth e primar y contro l devic e i s down . I nth e absenc e o f a backu p contro l device , plant s migh t hav e t o underg o costl yshutdow no f proces s equipmen t eac htim e th e primar ycontro l devic e i s dow nfo r schedule d o r unschedule d maintenanc e t o avoi d violatin g th e 1 0 ppmexhaus t ga s limits . Eve nwhe nbacku p contro l device s ar e available , exceedence s o f th e 1 0 ppmexhaus t ga s limi t ar e possible . However , plant s mus t analyz e an d identif yway s o f operatin g thei r primar yand backu p contro l system s t o improv e th e abilit yo f th e combine d system s t o continuousl ycontro l exhaus t ga s emissions . Thus , becaus e i t i s impractica l t o specif yth e degre e o f backu p neede d i nth e standard . Commen t Specificatio no f 3-Hou r Averagin g Perio d i n Exhaus t Ga s Standard s Tw o commenter s (IV-D-1 , IV-D-4 ) recommende d tha t th e 3-hou r averagin g perio d b e specifie d i nthre e section s o f th e regulatio nwher e 1 0 ppmlimit s wer e no t clarifie d b yindicatin g a 3-hou r averagin g period . Respons e A s explaine d i nth e preambl e t o th e propose d revision s (5 0 FP . 1192) , th e exhaus t ga s standard s shoul d appropriatel yspecif ya 3-hou r averag e t o b e consisten t wit hth e performanc e tes t specification s fo r thes e emissio n sources . Th e thre e section s o f th e regulatio npointe d ou t b yth e commenter s hav e bee nrevise d a s recommended .

2-6 0P.7 0

v, *

2.5. 2 Oxychlorinatio nVen t Standar d Comment Withdrawa l o f Lowe r Oxychlorinatio n

Ven t Standar d Th e commente r (IV-D-12 ) pointe d ou t tha t th e 197 7 proposa l woul d hav e require d ne woxychlorinatio nvent s t o mee t anemissio nlimi t o f 5 ppmbase d o nth e us e o f oxygen , a s a fee d materia l instea d o f air . Th e commente r state d tha t EPAha s faile d t o presen t anydiscussio nwhic hwoul d justif yth e withdrawa l o f thi s proposal . Respons e I nth e preambl e (5 0 F R1185) , EP Apresente d evidenc e supportin g it s decisionno t t o requir e mor e stringen t contro l o f ne wand existin g oxychlori

natio nvents . First , th e revie wo f th e standar d identifie d n o ne wcontro l technolog yapplicabl e t o oxychlorinatio nvent s tha t ha d bee ndevelope d sinc e th e origina l standar d wa s established . Second , th e cos t t o incinerat e existin g oxychlorinatio nvent s wa s reevaluated , and th e conclusio no f th e origina l standar d suppor t study(Docke t Ite mII-A-2 ) tha t incineratio no f existin g oxychlorinatio nvent s i s no t cost-effectiv e wa s sustaine d i nth e ne w analysis . Finally , wit hth e possibl e exceptio no f on e plant , ne wEDC/V C plant s wit hoxychlorinatio nreactor s ar e no t expecte d t o b e constructed . However , i f constructed , a ne wplan t woul d b e subject t o th e Ne wSourc e Performanc e Standard s fo r ai r oxidatio nprocesse s o r t o BAC T o r LAE Rrequire

ment s o f ne wsourc e revie wregulations . A s a resul t o f thes e regulations , ne woxychlorinatio nvent s woul d b e controlle d t o a leve l consisten t wit hth e 1 0 ppmexhaus t ga s limit s i nth e V C standard . N o informatio nwa s provide d b yth e commente r t o chang e th e EPA' s decisio n t o retai nth e existin g oxychlorinatio nven t standard . Commen t Specificatio no f 3-Hou r Averagin g Perio d i nOxychlorinatio nReacto r Standar d Tw o commenter s (IV-D-1 , IV-D-4 ) recommende d tha t th e 3-hou r averagin g perio d b e specifie d i nth e emissio nlimi t fo r oxychlorinatio nreactors .

2-6 1P.7 1

l , . p• » •

Respons e A s explaine di nth e preambl e t o th e propose drevision s (5 0 F R1192) , th e exhaus t ga s limit s shoul dappropriatel yspecif ya 3-hou r averag e t o b e con sisten t wit hth e performanc e tes t specification s fo r thes e emissio nsources . Thi s i s als o tru e fo r th e oxychlorinatio nven t limit . Th e oxychlorinatio n reacto r standar dha s bee nrevise da s recommended . 2.5. 3 Residua l Viny l Chlorid e Standard s fo r PVC P.esins Commen t Withdrawa l o f Lowe r Strippin g Requirement s On e commente r 'IV-D-12 ) state dtha t EP Awithdre wth e propose dreductio n i nth e residua l VC limit s fo r ne wPVC resin s becaus e i t wa s determine dtha t onl ysom e resin s ca nno wb e strippe dt o thes e levels . Th e commente r asserte d tha t thi s conclusio ni s base do nth e assumptio nb yEP Atha t a nemissio nleve l mus t b e currentl ydemonstrate dt o for mth e basi s o f th e standard , bu t accordin g t o th e commenter , tha t demonstratio ni s no t require db ySectio n112 . Further , th e commente r state dtha t th e lowe r limit s ar e currentl ybein g achieve dby man yPV C productio nfacilitie s an dtha t man yo f th e remainin g facilitie s ar e clos e t o th e limits . Th e commente r state dtha t th e mor e stringen t limit s coul db e achieve db yne wfacilities , a s wel l a s b yexistin g facilitie s i f give na thre e yea r lea dtime , b ycopyin g th e equipmen t andprocedure s currentl y use db yth e leadin g facilities . Respons e A s discusse di nth e preambl e (5 0 FR1185) , EP Arejecte dmor e stringen t strippin g leve l requirement s fo r ne wresin s primaril ybecaus e o f th e difficult y i ndefinin g a "new " resin . Althoug hresi ncomposition s ar e adjuste droutinely , completel y"new " resin s ar e seldo mi f eve r made . Th e EP Afurthe r conclude dtha t ther e i s insufficien t technolog ybasi s fo r mor e stringen t strippin g requirement s fo r al l resins . I nparticular , improve dstrippin g technolog yi s capabl e o f lowerin g residua l VC level s i n onl ysom e o f th e resin s currentl yproduced . Th e abilit yo f improve dstrippin g technolog yt o achiev e lowe r residua l V C level s depend s o nth e resi ntyp e an d mi xa t a particula r plant . Th e equipmen t an dprocedure s tha t ar e effectivel y

2-6 2P.7 2

. <•«." . '

bein g use d t o stri p a specifi c resi nma yb e ineffectiv e o nanothe r resin . Man yplant s alread yus e improve d technolog ywher e applicabl e t o averag e ou t th e strippin g level s achieve d fo r hard-to-stri p resins . Thi s techniqu e o f averagin g th e strippin g result s o f hard-to-stri p resin s wit hresin s tha t ar e mor e readil ystrippe d allow s thes e plant s t o compl ywit hth e curren t residua l VC standar d whil e continuin g t o produc e th e hard-to-stri p resins . Increasin g th e stringenc yo f th e residua l VC standar d fo r al l resin s would , i nth e opinio no f EPA , forc e som e plant s t o discontinu e productio no f som e resin s unreasonably . Th e commente r submitte d n o ne winformatio no ntha t point . .2.5. 4 Reacto r Openin g Los s Standar d fo r In-Reactor-Stripper s Commen t Complianc e Waive r Reques t Th e commente r (IV-D-3 ) state d tha t th e propose d calculatio nprocedur e fo r determinin g reacto r openin g los s fo r reactor s use d a s stripper s ma y necessitat e installatio no f mor e accurat e instrumentation . H e requeste d tha t th e regulatio nprovid e fo r waiver s o f complianc e t o allo wtim e t o select , orde r and instal l additiona l instruments . Respons e Th e calculatio nprocedur e fo r determinin g reacto r openin g los s emission s fo r reactor s use d a s stripper s provide s plant s tha t perfor min-reacto r strippin g a noptiona l metho d fo r demonstratin g complianc e wit hth e emissio n limi t fo r reacto r openings . Plant s usin g th e calculatio nprocedur e wil l b e require d t o continu e thei r curren t practic e fo r demonstratin g complianc e whil e selecting , ordering , and installin g th e instrument s used't o measur e th e reacto r condition s necessar yfo r calculatin g reacto r openin g loss . Commen t Statu s o f Previousl yApprove d Method s Th e commente r (IV-D-1 ) note d tha t th e propose d emissio ntestin g requirement s fo r reactor s use d a s stripper s appea r t o requir e al l strippin g operation s wit happrove d calculatio nmethod s t o resubmi t thei r calculatio n method s fo r approva l and questione d whethe r resubmitta l o f alread yapprove d method s wa s intended .

2-6 3P.7 3

Respons e Th e EP Adevelope d a calculatio nprocedur e fo r determinin g reacto r openin g los s emission s fro mreactor s use d a s stripper s t o provid e a unifor m metho d fo r us e b

yal l plant s tha t perfor m in-reactor-stripping . However , plant s ma ycontinu e t o determin e reacto r openin g los s emission s fro mreactor s use d a s stripper s b ypreviousl yapprove d methods . Resubmitta l o f already approve d method s i s no t required . However , Regiona l personne l ma yrevie w thes e previousl yapprove d method s i nligh t o f th e newl yprescribe d calculatio n procedur e and require change s i nexistin g procedure s wher e appropriate . .2.5. 5 Inproces s Wastewate r Standar d Commen t Reques t fo r Approva l o f Metho d 60 1 Tw o commenter s (IV-D-8 , IV-D-9 ) suggeste d tha t th e VC standar d allo w eithe r Metho d 60 1 o r th e currentl yrequire d Metho d 10 7 fo r measurin g th e VC concentratio ni ninproces s wastewater . Th e commenter s explaine d tha t Metho d 60 1 ha s a detectio nlimi t o f 0.0 1 g/ 1 (0.0 1 ppb ) an d should , thus , b e acceptabl e fo r inproces s wastewate r measurement . Respons e Metho d 60 1 o f 4 0 CF R136.3(a ) i s acceptabl e fo r measuremen t o f V C i n inproces s wastewater , an d 4 0 CF R61.67(g)(2 ) ha s bee namende d t o allo wit s use . 2.5. 6 Equivalen t Equipmen t an d Procedure s Commen t Statu s o f Previousl yGrante d Equivalencie s Tw o commenter s (IV-D-8 , IV-D-9 ) recommende d tha t th e provisio no n obtainin g approva l fo r equivalen t equipmen t and procedure s indicat e tha t previousl ygrante d equivalencie s wil l remai ni neffec t fo r existin g facilities , Respons e AnyAgenc yapprova l previousl ygive nt o equivalen t equipmen t an d procedure s pursuan t t o Sectio n61.6 6 wil l remai nvali d and effectiv e unles s the yar e specificall ymodifie d o r withdraw nb yEPA . Alternativ e numerica l

2-6 4P.7 4

emissio nlimit s canno t b e grante di nplac e o f a nestablishe demissio nlimit , bu t onl yalternativ e mean s o f emissio nlimitation . 2. 6 MISCELLANEOU S COMMENT S

Commen t Regulator yFlexibilit yAc t - Smal l Busines s Definitio n Th e commente r (IV-D-3 ) state dtha t EP Aincorrectl yconclude dtha t n c smal l busines s (i.e. , les s tha n50 0 employees ) i s affecte db yth e proposal . Th e commenter' s subsidiar yPVC compan yha s 30 0 employees . Respons e I nrespons e t o th e commen t ther e ar e thre e point s tha t ar e important . Th e firs t poin t i s tha t a t th e tim e th e economi c analysi s (Docke t Ite mIV-B-11 ) wa s performe dth e commenter' s compan ydi dno t exist . Th e secon dpoin t i s tha t th e Regulator yFlexibilit yAc t (RFA ) define s a smal l busines s base dupo nth e siz e o f th e tota l compan yincludin g th e paren t compan yplu s al l subsidiaries , rathe r tha nth e siz e o f individua l subsidiarie s o r individua l plants . Th e commenter' s assertio ntha t i t i s a smal l busines s referre donl yt o th e siz e o f a subsidiar yan dno t t o th e tota l company . Late r informatio nprovide di nrespons e t o question s fro mEP Ashow s tha t th e tota l compan yi s no t a smal l busines s becaus e i t ha s mor e tha n50 0 employees . Th e thir dpoin t i s tha t siz e alon e i s no t th e onl ytes t i nassessin g th e nee dfo r a regulator yflexibilit yanalysis . Significan t economi c effect s mus t als o b e likely , otherwis e a regulator yflexibilit yanalysi s i s no t required . Th e EP Adoe s no t expec t suc heffects . Therefore , fo r th e reason s cite dabove , th e regulator yflexibilit ydiscussio ncurrentl yi nth e economi c analysi s i nth e BI D doe s no t requir e an ychanges . Commen t Economi c Impac t o f Standar d Th e commente r (IV-D-3 ) state dtha t cost s require dt o compl ywit hth e VC standar dhav e a negativ e impac t o nth e industry' s profitabilit yan dcompetitiv e situatio ni nregar dt o foreig nproducers .

!-6 EP.7 5

f , > PN s

Respons e Th e commente r discusse s thre e subject s i nit s commen t andit s supplementar yinformation :

• th e genera l economi c conditio no f th e domesti c VCM/PV C industr y » th e economi c conditio nfo r th e commenter' s facilit yspecificall y (bu t wit honl ya limite damoun t o f supportin g financia l information ;

• th e foreig ncompetition . Th e economi c analysi s presentl yavailabl e (Docke t Ite mIV-B-11 ) include s consideratio no f th e abov e subject s (wit hth e exceptio no f informatio n specifi c t o th e commenter' s facilit ybecaus e i t di dne t exis t a t th e time) . Consideratio no f th e genera l economi c conditio no f th e domesti c industr yrun s throughou t th e analysis . Foreig ncompetitio ni s als o specificall ydiscusse d i nSectio n8.1.8 . Mor e tha n2 year s hav e passe dsinc e th e economi c analysi s wa s completed , s c naturall ychange s hav e occurred.i nth e industr ydurin g th e interim . However , th e ne winformatio nsupplie db yth e commente r abou t th e industr yi ngenera l an dabou t foreig nproducer s i s no t significantl ydifferen t fro mwha t i s currentl yi nth e economi c analysis . Overall , th e economi c analysi s appear s t o b e reasonabl e i naddressin g th e impac t o f th e VC standar d o nth e VCM/PC V

industry . Th e financia l informatio npresente db yth e commente r concernin g it s specifi c situatio ni s insufficien t t o permi t a detaile dexamination . Also , becaus e th e fir m

i s onl yabou t 1-1/ 2 year s old , it s youn g ag e sharpl ylimit s th e valu e o f a nanalysi s o f historica l financia l performance . Tw o point s indicat e tha t th e curren t economi c analysi s i s reasonable . Th e firs t poin t i s that , i ngeneral , th e commenter' s situatio nseem s t o b e reasonabl ysimila r t o th e mode l plan t analysi s presente di nth e economi c analysis . Fo r example , a calculatio no f th e cos t increase s pe r kilogra mo f capacit yindicate s tha t th e cos t increase s presente dar e approximatel yth e sam e a s thos e fo r th e mode l plants . Th e secon dpoin t i s tha t th e owner s an dmanager s o f th e commenter' s facilit yar e no t newcomer s t o th e industry . Therefore , becaus e th e owner s an dmanager s ha da hig hdegre e o f prio r knowledg e abou t th e industry , considerabl e importanc e shoul db e attache dt o th e fac t tha t the y electe dt o procee dan dpurchas e th e plant s i nquestio na s recentl ya s Jul y1984 . 2-6 6P.7 6

Commen t V C Emission s fro mLandfill s Th e commente r (IV-D-10 ) agree dwit hth e EPA' s approac ho f requirin g plant s tha t generat e off-specificatio nPV C resin s t o mee t standard s designe d t o facilitate'th e ultimat e dispose r o f th e off-specificatio nresi ni ncomplyin g wit hth e environmenta l regulation s applicabl e t o hazardou s wast e disposal . Th e commente r expresse dconcer ntha t strippin g requirement s fo r of**-

- specificatio nPV C resin s prio r t o remova l t o landfill s ma yno t b e sufficien t t o preven t subsequen t exceedence s o f th e propose ddrinkin g wate r standar dfo r VC . Th e commente r explaine dtha t V C contaminatio no f drinkin g wate r i s likel ybecaus e PV C resi ni s no t legall ya hazardou s wast e and'i s therefor e no t require dt o b e dispose di nfacilitie s regulate dunde r Subtitl e C o f th e Resourc e Conservatio nan dRecover yAc t (RCRA) . Th e commente r urge dEP At o bette r coordinat e al l regulator yactivitie s pertainin g t o VC . Respons e Thi s rulemakin g i s limite di nscop e t o th e regulatio no f atmospheri c emission s o f V C fro moff-specificatio nPV C resin s i nlandfills . I nthi s context , th e strippin g requirement s i nth e standar dfo r off-specificatio nPV C resin s ar e believe dt o b e th e mos t effectiv e wa yo f limitin g V C emission s fro mPV C resi ni nlandfills . I f ther e ar e othe r environmenta l consequence s o f th e disposa l o f off-specificatio nPV C resins , appropriat e restriction s ca n b e applie dunde r othe r statutes . Commen t Offe r t o Assis t RCRA . Tas k Forc e Th e commente r (IV-D-1 ) offere dt o provid e assistanc e t o th e Tas k Forc e establishe dunde r Subtitl e D o f RCR Ai nthei r assessmen t o f emission s o f V C fro mhazardou s wast e facilities , municipa l landfill s an dothe r ai r emissio n sources . .Further , h e requeste dtha t hi s organizatio nb e kep t informe do nth e tas k force' s activities . Respons e Th e commenters ' reques t ha s bee nforwarde dt o th e RCR ATas k Force .

• 6 7P.7 7

r . ix .

Commen t Reportin g o f Desig nCapacit y Th e commente r (IV-D-3 ) state d tha t th e requirement s i npropose d 4 0 CF R 61.70(f ) fo r plant s t o repor t desig ncapacit yinformatio ni s inappropriat e a s thi s informatio ni s proprietary . Further , plant s tha t stri p i nth e reacto r shoul d no t b e require d t o provid e desig ncapacit yinformatio nbecaus e i t i s irrelevant , fo r complianc e determination,..an d othe r plant s shoul d b e allowe d t o provid e desig ncapacit yi na separat e confidential document . Respons e Th e informatio nbein g requeste d i nthi s provisio no f th e standar d i s th e desig ncapacit yo f a PVC plan t i nterm s o f a nestimat e o f th e numbe r o f polymerizatio nbatche s th e plan t i s capabl e o f producing , rathe r tha nspecifi c batc hsize s o r rates . Suc hinformatio nwoul d no t revea l significan t informa

tio no nactua l productio nand , consequently , woul d no t ordinaril yinvolv e confidentialit yproblems . However , i f th e owne r o r operato r o f a naffecte d facilit yha s reaso nt o believ e tha t thi s o r an yothe r informatio nsubmitte d t o EP Ashoul d b e treate d a s confidential , suc htreatmen t ca nb e requeste d a t th e tim e o f submitta l an d a decisio no nth e reques t ca nb e mad e byEPA . I nth e cas e o f plant s tha t stri p i nth e reactor , n o reportin g o f desig n capacit ydat a i s required . Fo r th e adde d complianc e metho d fo r in-reactor

strippers , plant s nee d onl yrepor t VC emission s calculate d t o b e i nexces s o f th e combine d limi t fo r reacto r openin g los s an d source s followin g th e stripper . Informatio no ndesig ncapacit yneede d fo r th e calculatio nmetho d nee d onl yb e retaine d a t th e plan t i nth e record s fo r complianc e calculations . Commen t CERCL AReportin g Requirement s Thre e commenter s (IV-D-1 , IV-D-6 , IV-D-14 ) requeste d clarificatio no n th e applicabilit yo f th e Comprehensiv e Environmenta l Response , Compensatio n an d Liabilit yAc t (CERCLA ) reportin g requirement s t o source s regulate d unde r th e VC standard , specifyin g whethe r VC release s fro mEDC/V C an d PVC plant s ar e require d t o b e reporte d unde r CERCLA . Commente r IV-D-1 4 specificall y questione d whethe r emission s belo wth e threshol d concentratio ndefinin g a n actionabl e lea k ar e intende d t o b e reporte d unde r CERCLA . Athir d commente r

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(IV-D-12 ) state d tha t relie f valv e discharge s o f VC ar e reportabl e unde r

CERCLA , excep t t o th e extent , tha t the yar e th e resul t o f a genuin e emergency . Respons e Unde r th e provision s o f CERCLA , release s o f hazardou s substance s whic h ar e federall ypermitte d ar e no t subjec t t o CERCLA . notificatio nrequirement s and liabilities . Th e definitio no f "federall ypermitte d release " i nSectio n 101(10 ) o f CERCL Aspecificall yinclude s " . . .(H ) anyemissio nint o th e ai r subjec t t o a permi t o r contro l regulatio nunde r . . . Sectio n11 2 .. . o f th e Clea nAi r Ac t ... " therefore , emission s i ncomplianc e wit hthi s standar d ar e no t subjec t t o CERCLA . However , emission s exceedin g thi s standar d and th e reportabl e quantit yprovision s o f CERCL Aar e subjec t t o bot hstatutes . Commen t Reportin g an d Recordkeepin g Requirement s Fou r commenter s (IV-D-3 , IV-D-8 , IV-D-12 , IV-D-13 ) addresse d th e propose d reportin g an d recordkeepin g requirements . Th e firs t commente r (IV-D-3 ) disagree d wit hth e EP Aestimate s tha t th e annua l paperwor k burde nwil l b e reduce d by2. 8 perso nyear s b yth e propose d revisions . Th e commente r claime d tha t th e inclusio no f th e Subpar t V requirement s woul d necessaril yincreas e th e paperwor k burden . Th e secon d commente r (IV-D-8 ) state d tha t th e propose d change s i nreportin g requirement s represen t a nemphasi s o nemissio nreductio n rathe r tha nincreasin g paperwork . Th e thir d commente r (IV-D-12 ) state d tha t al l tes t result s shoul d b e reported , no t jus t thos e tha t excee d th e standards . Suc ha requiremen t woul d promot e accurac yand completenes s and permi t EP At o buil d a dat a bas e fo r futur e revision s o f th e standard . Respons e Th e reportin g an d recordkeepin g burde nresultin g fro mth e revise d standar d wa s evaluate d byEP Ausin g standar d Agenc yprocedure s t o arriv e a t th e estimat e tha t th e burde nwoul d b e reduce d b y2. 8 person-years . Basically , thi s estimat e reflect s th e reductio ni nreportin g an d recordkeepin g require

ment s i nth e revise d standard . Th e calculation s o nwhic hthi s estimat e i s base d hav e bee nreviewe d b yOM B a s a par t o f th e Informatio nCollectio n

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• » t-J- * t

Request , whic hi s availabl e fo r inspectio ni nth e docke t (Docke t Ite mIV-F-1) . Th e ccm.mente r ha s suggeste d n o specifi c error s i nthi s analysi s no r recommende d a nalternativ e analysis . Th e submissio no f al l tes t dat a associated wit hth e standar d ha s no t bee nrequire d becaus e suc ha requiremen t woul d impos e anunnecessar yburde n o nbot hth e responden t and EPA . I t i s mer e productiv e t o chec k int o th e accurac yan d completenes s o f calculation s a s th e nee d arise s (usin g th e authorit yo f Sectio n114 ) tha nt o handl e a quantit yo f routin e reports . Th e calculation s ar e require d t o b e maintaine d fo r a 3-yea r period . Further , a n adecuat e dat a bas e fo r futur e revie wo f th e standar d ca nb e obtaine d withou t suc hextensiv e commitmen t o f resource s t o reporting . Sinc e proposal , EP Adecide d t o retai n10-da yreportin g requirement s fo r relie f valv e discharges . I naddition , quarterl yreportin g o f exces s emission s wil l b e require d instea d o f semiannua l reporting. , a s proposed . Th e ne t resul t o f th e promulgate d change s t o reportin g and recordkeepin g requirement s i s no t expecte d t o significantl yincreas e o r decreas e th e paperwor k burde ncompare d t o th e existin g standard . Commen t Typographical Error s Fiv e commenter s (IV-D-1 , IV-D-3 , IV-D-6 , IV-D-8 , IV-D-9 ) pointe d ou t typographica l error s i nth e Federa l Registe r notice . Respons e Th e typographica l error s hav e bee nnote d an d thos e containe d i nth e regulatio nwil l b e correcte d a t promulgation .

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3. 0 PETITIO NFORRECONSIDERATIO N

I nrespons e t o th e EPA' s notic e tha t th e Agenc ydi dno t inten dt o promulgat e th e amendment s t o th e VC standar dwhic hwer e propose di n197 7 , th e Natura l Resource s Defens e Counci l (NRDC ) andth e Environmenta l Defens e Fund (EDF ) submitte da petitio nfo r reconsideratio nt o th e Agency . Th e NRDC/ED F petitio nwa s base do nfou r mai nobjections . First , NRDC/FD F state dtha t th e EPA' s announcemen t tha t i t di dno t inten dt o promulgat e th e propose damendment s wa s a fina l administrativ e action , whic hwa s no t precede d b ya notic e proposin g th e withdrawa l andallowin g fo r publi c commen t o nth e action . Second , NRDC/ED F objecte dt o th e EPA' s us e o f cos t informatio ni n th e standard s settin g process , statin g tha t th e balancin g o f th e cost s and benefit s o f VC emission s contro l i s i nconflic t wit hth e requirement s o f Sectio n11 2 o f th e Clea nAi r Act . Third , NRDC/ETJ F objecte dt o an yinterpre

tatio no f Sectio n11 2 tha t establishe s a requiremen t tha t a leve l o f emissio n contro l b e "consistentl yachieved " i norde r t o for mth e basi s o f a standard . Finally , NRDC/ED F state dtha t th e EPA' s decision s o nspecifi c portion s o f th e propose damendment s wer e i nconflic t wit hth e evidenc e befor e th e Agenc yo n thos e issues . Th e criteri a establishe dfo r grantin g suc ha petitio nfo r reconsideratio n are : (1 ) th e petitio nmus t b e base do ninformatio nwhic hwa s no t andcoul d no t reasonabl yhav e bee npresente dduring th e origina l rulemaking ; an d(2 ) th e petitio nmus t provid e substantia l suppor t fo r th e argumen t tha t th e challenge dactio nshoul db e changed . Se e Denia l o f Petitio nt o Revis e NSP S fo r Stationar yGa s Turbines , 4 5 FR8165 3 (Decembe r 11 , 1980) . Th e objection s raise di nth e petitio nsubmitte db yNRDC/ED F i nthi s rulemaking d o no t mee t eithe r criterion . Th e firs t objectio nraise db yNRDC/EDF , tha t ther e wa s inadequat e opportunit yfo r publi c commen t concernin g th e Agency' s decisio nno t t o



### 3-1P.8 1

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promulgat e th e propose d VC regulations , i s no t supporte d b yth e recor d o f thi s rulemaking . Betwee nth e proposa l o f th e amendment s t o th e VC standar d an d th e decisio nno t t o promulgat e them , 8 year s hav e elapsed . Durin g thi s time , th e amendments , thei r potentia l consequences , and th e alternativ e action s befor e th e Agenc ywer e al l i nth e publi c record , and specificall y communicate d t o NRD C and EO F prio r t o th e NAPCTA C meeting . Inligh t o f thi s record , EP Adoe s no t believ e tha t a nadditiona l publi c commen t perio d woul d b e eithe r necessar yo r helpfu l i nth e resolutio nc f thes e issues . Th e secon d issu e raise d b yNRDC/FD F i nth e petitio nfo r reconsideratio n concerne d th e consideratio no f cost s o f contro l i nsettin g th e standard . I t i s th e EPA' s judgmen t tha t th e VC standar d satisfie s th e requiremen t o f Sectio n11 2 o f th e Clea nAi r Ac t tha t th e standar d b e se t a t a leve l whic h provide s a n"ampl e margi no f safety " t o th e public . Further , EP Abelieve s tha t cos t and feasibilit yma yb e considere d i nsettin g th e standard . Thi s argumen t ha s bee nfull yexamine d b yth e Agency , a s discusse d i nth e 1975-197 6 VC rulemakin g and discusse d i nth e Agency' s brie f i nNRD C v . EP A, No . 85-115 0 (D.C . Cir) . N o additiona l informatio ni nsuppor t o f thei r argumen t ha s bee n pu t forwar d b

yNRDC/EDF . Th e thir d issu e raise d b yNRDC/ED F concern s whethe r a nemissio nleve l mus t b e "consistentl yachieved " i norde r t o for mth e basi s o f th e standard . Thi s issu e wa s raise d wit hspecifi c referenc e t o th e 1 0 ppm vstandar d fo r exhaus t ga s VC emissions . Thi s standar d wa s selecte d becaus e i t wa s determine d tha t i t provide s th e publi c wit hth e ampl e margi no f safet yrequire d b y Sectio n112 . Althoug ha lowe r emissio nlimi t migh t b e assume d t o increas e tha t margin , suc ha leve l ha s no t bee nshow nt o b e achievabl e o na long-term , never-to-be-exceede d basis . N o additiona l informatio nha s bee nsubmitte d b y NRDC/ED F t o refut e th e findin g tha t th e 1 0 ppm vemissio nlimi t fo r exhaus t gase s provide s th e require d margi no f safet yfo r th e public . Finally , th e petitio npoint s t o thre e action s mad e byth e Agenc yi nthi s rulemakin g whic hNRDC/ED F believ e t o b e contrar yt o th e evidenc e befor e th e Agenc yo nthos e issues . Thes e action s are : (1 ) th e decisio nno t t o promulgat e th e 5 ppm

vstandar d fo r exhaus t gase s i nfavo r o f th e existin g 1 0 ppm v standard ; (2 ) th e decisio nno t t o promulgat e th e 5 ppm vstandar d fo r



### 3- 2P.8 2

oxychlorinatio nvents ; and(3 ) th e decisio nno t t o lowe r th e residua l V C limi t fo r ne wdispersio nresin s fro m2,00 0 ppmt o 50 0 ppm , o r t o lowe r th e limi t fo r othe r resinsfro m40 0 ppmt o 10 0 ppm . I neac hcase , th e petitioner s presente dn o ne winformatio ni nth e petitio nfo r reconsideratio nrelevan t t o th e decisio nt o retai nth e existin nstandards .



### 3-3P.8 3

*:••' « TECHNICA LREPOR TDAT A (Please read

Instructionson the reverse before completing) 1

. REPOR T,\I0

. EPA450/3-86-00 4 3

. RECIPIENT' S ACCESSIO N NO

. 4

. TITL E AN O SUBTITL E Viny l chlorid e standard : Response s t o Comment s o n Januar y198 5 Propose d Revision s 5 . REPOR T OAT E Septembe r 198 6 6

. PERFORMIN G ORGANIZATIO N COD E

7

. AUTHOR(S ) 8

. PERFORMIN G ORGANIZATIO N REPOR T\ i

9

. PERFORMIN G ORGANIZATIO N NAM E AN O ACORES 3 110

. PROGRA M ELEMEN T'. O

2

. SPOiNSORlN G AGcNC vNAM E AN O ADDRES S Offic e o f Ai r and Radiatio n U.S . Environmenta l Protectio n Agenc y Washington , D.C . XXoO ,13

. TYP E C F Fi=.PQRT AN O F = = i I i 1A

. SPONSORIN G AGENC YCOD E

15

. SUPPLE.ME.NTA R YNOTE S

16

. ABSTRAC T Thi s documen t summarize s and respond s t o comment s o n th e propose d revision s t o th e viny l chlorid e standar d se t unde r Sectio n 11 2 o f th e Clea n Ai r Act .

KE YWORD S AN O DOCUMEN TANALYSI S DESCRIPTOR S b.lOENTIFlERS/OPE N ENOE D TERM S c . COSAT I '•'idil/Grou p NESHA P Hazardou s Ai r Pollutant s Viny l chlorid e

18

. DISTRIBUTIO N STATEMEN T Unlimite d 19

. SECURIT YCLAS S /This Report) Unclassifie d 2 1

. O F PAG E 120

. SECURIT YCLAS S iTIiispa.nei IUnclassifie d 122

. PRIC E

EP AFor m 2220- 1 (Rev

. J-77 ) =BEVIOU S EDITIO N I S OBSOLET EUnite d SUHH S Environmenta l Protectio n Agenc y l Ui n < •n ( Ai r.KM ! K;idi;iH--i i OHif.i ! o fAi rOunhi yri;iniitm j ;*n d Standard s Researc h lri.niiil e Patk

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