p. 1



# OAR Box 1875
Prepped by Ollie Stewart



### Document

Number: 

# 75 ) ll-F-2 2
Docket Number: 

# A-90-1 9

Printed 12/1/200811:12:48AM

Sheet 75of 86P. 2 

# A-90-1 9 ll-F-2 2

TO : Fran

k Hodsol l FROM : Michae l Shapiro DATE : Octobe r 16 , 199 2

Attache d pleas e fin

d ou r writ e u

p o f th e rational e fo

r th e contro l leve l decisio no n proces s vents . W e believ

e thi s reflect s th

e result s o f ou

r discussion s earlie r thi s week . I n orde r th

e understan

d th e firs t paragrap

hoptio n 1 represent s th

e floor leve l o f control , optio n 2 represent s the CT G level , optio

n 3 represent s th

e NSP S leve l an

d optio n4 represent s EPA' s orgina l proposal . The one change w e hav e mad e i s t o reques t comment o n th e ful l range o f option s betwee nth e floor an

d EPA' s origina l proposa l o f proces s vent s bu t w e are focusin

g ou r reques t fo

r comment s o

noption s 1 throug

h3 . Pleas e cal l eithe r mysel f 260 - 730 4 o r (703 ) 351-9389 , or Lydi a Wegma na t (919 ) 541-5504 . Thi s writ e u p ha s no t ye t bee

nreviewe

d b y EPA' s attorneys .



## 8 

## i B 

## l l w I F r* A


# L 1 U DEC f | I96 e EPAAI R PQCKET jP. 3

Draf t Rational e fo

r Decisio

no n Existin

g Sourc e Proces s Vent s

I nselectio

no f th e propose

d standar

d fo r existin

g sources , EP A determine

d tha t a leve l of emissio nreductio

nfro m proces s vent s mor e stringent tha n th e leve l associate

d wit hth

e floor i s achievable . Th

e EP A i s proposin

g t o require contro l leve l i n Optio n2 , whic

hha s a nincrementa l cost-effectivenes s o f $1,800/M

g an d contro l vent s tha t hav e TRE cost-effectivenes s value s o f les s tha

n$2,000/Mg . Althoug hEP A i s proposin

g thi s specifi c contro l level , EP A i s requestin

g comment o

nth e range o f option s fro

m l t o 4 whic

hwoul d requir e contro l o f vent s wit hTRE cost-effectivenes s value s o f les s tha n$1,500/M

g t o les s tha

n $5,000/Mg . Th

e EP A anticipate s -tha

t in consideratio

no f th e fina l decisio

nEP A wil l giv

e mor e weight t o option s 1 t o 3 . A s discusse

d mor e fully

below , thi s decisio ni s based o

n consideration s specifi c t o th e SOCM I categor

y an d woul d no t necessaril y

b e appropriat e fo

r other sourc e categories . Therefore , i t shoul d no t b e viewe d a s a benchmar

k for decision s
o nother standards . Th e EP A recognize s tha t ther e ar e differin g view s regardin

g th e appropriat e criteri a fo r determinin

g th e contro l level . Consequently , EP A i s requestin

g comment s o

nth e appropriatenes s of particular contro l choice s withi nth e rang e o f option s describe

d abov e an d ask s tha t commenter s provide supportin

g rational e fo

r thei r preferences . The EP A selecte

d th e propose

d contro l criteri a considerin g th e criteri a enumerate d i n Sectio

n112(d ) o f the Act : th e cos t
o f achievin

g suc hreductions ; an

y non-ai r qualit

y healt han

d lP. 4

environmenta l impacts ; an d energ y requirements . A s a matte r of genera l policy

indecision s t o selec t contro l level s abov e th e floor , EP

A believe s tha t a compariso n of benefits , both quantifiabl e an

d nonquantifiable , an d cost s i s a

nimportant consideration . Suc ha n approac

hprovide s a mean s fo r determinin g th e poin t a t whichth e cost s an

d other impact s becom e unreasonabl e relativ e to th e healt hprotectio

n benefits . I nthi s
case , however , ou

r abilit

y t o d o suc ha compariso

nwa s severel y limite d due t o th

e limite

d dat a o

n th e characteristic s o f the emissio nsource s an

d th e complexit

y o f th e sourc e category . Specifically , ther e wa s insufficient dat a t o d o a scientificall y credibl e analysi s of th e cancer healthbenefits . Furthermore , ther e ar e n

o model s t o evaluat e the non-cancer healtheffect s o f th e comple

xmixture s of HAP' s emitte d b y HO N facilities . Consequently , EP

A use d benchmark s fro

m previou s ai r toxic s regulator

y decision s an

d pas t ai r toxic s benefit s studie s a s a surrogat e measur e fo r benefit s consideration s i n th e decisio

n
over th e proposed contro l level . Th e informatio

nconsidere

d consiste

d of th e Benzen

e NESHA P decision s an

d th e Viny l Chlorid

e NESHAP . For example , a decisio ntha t reflecte

d consideratio

no f balancin

g emissio

n reduction s agains t cost s wa s th e benzene storage standard . I ntha t decision , th e cost-effectivenes s o f th e selecte

d optio nwa s estimate

d t o range fro

m $128/M g t o $909/M g (nee d t o b e adjuste

d t o 198 9 dollars) . However , i ntha t rulemakin

g i t wa s recognize

d tha t ther e wer e grea t uncertaintie s i nth e emissio

nestimate s an

d the cos t estimates .P. 5

Althoug hth e cost-effectivenes s measure s fro m pas t decision s
wer e examine d i n selectio no f th e propose d option , othe r factor s
wer e als o considere d du e t o limite d applicabilit y o f th e benzen e decision s t o thi s rulemaking . I nparticular , a t th e time o f th e benzen e decision s i t wa s recognize d tha t th e ris k assessment s
wer e incomplet e i n tha t no t al l healt hrisk s coul d b e quantifie d
an d tha t some cos t analyse s wer e ol d an d possibl y

understate d contro l costs . Th e ne t effec t o f thes e tw o factor s coul d no t b e quantifie d bu t wa s considere d i nth e genera l consideratio no f th e uncertainty . Th e cos t estimate s i n th e benzen e storag e decisio n reflec t thes e uncertaintie s an d i nfac t ar e believe d t o b e understated . Additiona l consideration s i nth e decisio nbein g mad e i nthi s proposa l include : (1 ) th e magnitud e o f th a emissio nreductio n availabl e a t a cos t tha t woul d no t resul t i nunreasonabl e economi c impacts ; (2 ) consistenc y wit hpas t decision s i norde r t o suppor t efficien t regulation ; an d (3 ) othe r non-quantifiabl e healt han

d environmenta l benefits , eg . non-cance r an d ecosyste

m effects . Further , technology capabl e o f meetin g thes e standard s i s widel y

applie d i n simila r sources . Existin g sourc e proces s vent s ar e th e singl e larges t contributo r o f HA P emission s fro m th e SOCM I sourc e category . Th e additiona l emissio n reductio nbeyon d tha t achieve d a t th e floo r tha t woul d resul t fro m th e propose d standar d i s abou t 400 0 Mg/yr , whic hEPA

consider s t o b e a substantia l reduction . Th e averag e
cos t effectivenes s o f th e selecte d alternativ e i s $230/Mg an d th eP. 6

additiona l increment o f contro l ha s a cos t effectivenes s of Sl,eoo/M

g o f HAP . Th

e cos t o f th

e selecte

d contro l requirement s
wa s judge

d t o be reasonabl e an d n o unreasonabl e economi c effect s
ar e expected . Th e EP A i s requestin

g commen

t o n a rang e o f contro l options becaus e o f the uncertaintie s i n th e measur e o f th

e benefit s of contro l an

d the uncertaintie s inth e cos t tha t woul d actuall y b e experienced . Becaus e o f th e conservativ

e assumption s use

d t o develo p th e contro l cost s an

d th e structur e o f the standard , i t i s unlikel y

tha t an

y sourc e woul d actuall y incu r cos t a t th

e TRE leve l (th

e criterio

n for definin

g vent s tha t mus t appl y control ) tha t i s equivalent t o $2,000/M g . Th e cos t analysi s use d in developin

g th e supportin

g informatio

n fo r thi s standar

d wa s base

d
o nus e o f a dedicate d contro l devic e for eac hvent . Actua l cost s woul d b e lower wher e on

e devic e coul d b

e use d t o contro l emission s fro

m severa l vents . Th e cos t o f contro l woul d als o b e lower i nthos e case s wher e i t i s feasibl e t o us e a boile r o r proces s heater . Finally , th e standar

d i s structure

d usin g a TRE inde xapproach . Sinc e th e standar

d i s in a TRE format , man y facilitie s ma

y b e abl e t o us e produc t recover y t o change vent strea m characteristic s s o tha t the y ar e belo

w th e relevant applicabilit

y criteria . Thi s flexibilit y i s expected t o allo w
som e source s throug

hchange s i

n eguipment or operation s t o lowe r thei r cos t o f compliance . As a result , th e impact s analysi s ma y overstat e th

e cost s o f complyin g withth

e proposed contro l requirement .