1

M E M ORA N D U M

D A TE: December 11, 2013

S UBJ E CT: Emiss i ons D a ta a nd A c u t e Risk Fac tor Us e d in Re sidual R isk M od e l i n g : Acrylic

and Modacrylic Fibers, Amino/Phenolic Resins, and Polycarbonate Production

F RO M : Lesley Stobert, EC/R Incorporated

TO: Nick Parsons, EPA/OAQPS

The pur p ose o f this m e m o ra ndum i s to provide in f o r mation on t he Environm e ntal P rot ec t i on

Ag e n c y ( E P A) Risk and T ec hno l o g y R e vi e w ( RTR) d a ta used to estimate r e s idual r isk for the

Acrylic and Modacrylic Fibers Production (AMF), Amino/Phenolic Resins Production (APR),

a nd Polycarbonate Production (PC) M a x i m um A c hiev a ble Control T ec hnol o g y ( MAC T ) sou r c e

ca t e gori e s.

1.0 BACKGROUND

S ec t i on 112 of the Cl ea n Air Ac t (CAA) e stablishes a tw o

- st a g e r e g ulato r y pro c e ss t o a dd r e ss

e m i ss i ons of h a z a rdous a ir pol l utants ( H APs) f r o m s t a t i on a r y sou r ce s. I n t he f irst s ta g e , s e c t i on

112( d ) directs the EPA to dev e lop t ec hnol o g y

- b a s e d st a nd a rds f o r c a t e g o r ies of industrial

sou rce s. I n the s ec ond st a g e , kn o wn a s the re sid u a l risk stag e , se c t i on 112 ( f ) ( 2 ) directs the E P A

to ass e ss t he h ea l t h a nd e nvironme n t a l risks that re main a ft e r s o u rce s co m e in t o c omp l ian c e with

MACT. I f a ddi t ional r isk r e du c t i ons a re n e ce ss a r y to prot ec t publ i c h ea l t h with an a m ple m a r g in

of s a f e t y or to p re v e nt ad v e rse e nviro n ment a l e f f ec ts, the E P A mu s t dev e lop s t a nd a rds to a d d r e ss

t h e se r e maining risks.

2.0 DEVELOPMENT OF THE DATA SETS USED IN RESIDUAL RISK MODELING

For the APR and PC source categories, the 2005 N a t i on a l Emis s ions I n v e nto r y ( N E I ) d a ta s e rved

a s the sta r t i ng point f

o r this ass e ss m e nt. Due to concerns about possible facility changes that may

have occurred after 2005 at the one operating major source in the AMF source category, 2008

NEI data served as the starting point for that source category. Using lists of operating facilities

known during MACT development in combination with pro c e ss MA C T c o d e s 1 in the NEI, lists

of fac i l i t ies in the APR, AMF and PC source categories were developed (MACT codes: AMF

– 1001, APR

– 1347, PC

– 1326). T hese f ac i l i t y l i sts were used to c r e a te a subset of the N E I for

each source category that c ontai n e d f a c i l i t y wi d e e m i ss i ons d a ta f or eac h f a c i l i t y in each sour c e

ca t e g o ry. F ac i l i t y info r mation w a s c h ec k e d a g a inst c omp l i a n c e d a ta b a s e s and p e rmit i n f o r mation

t o e nsure t h a t t h e fac i l i t ies w e re subj ec t t o the re le v a nt rules. Spe c ific c h a n g e s to d a ta w i t hin

e ac h so u r c e c a te g o r y a r e discuss e d in sections 2.1, 2.2, a nd 2.3. Additional information gathered

after the residual risk was modeled are discussed in section 2.4.

1 The NEI associates a specific code with emissions and emission points regulated by each MACT standard.2

Upon the re q u e st of indust r y tr a d e g roups su c h a s the A me r ic a n C h e m i st r y Coun c il ( AC C ) a nd

the S o c ie t y of Ch e m ic a l M a nuf a c tu r e rs & A f

filiat e s (S OCMA ) , the 2005 N E I d a ta w a s

volun t a ri l y r e vie we d b y i ndust r y f o r c o rr e c t n e ss of fac i l i t y n a mes, Source Classifi ca t i on Cod e s

(S C C), M A CT c od e s, emissions, loc a t i on (l a t i tude a nd lon g i t ude c oordin a t e s) a nd other

modeli n g p a r a met e rs c ontain e d in t he N E I . The p roposed r e v is i ons w e re re v i e w e d on a ca se b y

ca s e b a sis a nd w e re ac c e pted w h e re a p p rop r iat e

.

The EPA requested that the one facility in the AMF source category examine the 2008 NEI data,

identify process MACT codes for each emission point, and, where differences existed, correct or

update the data. After review of the data, the facility submitted updated information, and the

updated data formed the basis for the data set used for modeling.

The EPA c ondu c ted a n e x tensive re view of the lo ca t i o n c oordin a t e s f o r a ll f a c i l i t ies in the 3

sour c e ca t e g o r ies. L o ca t i ons w e re plotted and visual l y r e vie w e d usi n g Go o g le E a rth.

A djus t ments w e re m a de where emission points were not located in industrialized areas or where

they did not match the facility address locations.

S ta c k a nd f

u g i t ive p a r a m e te r s that did not m ee t the E P A Q u a l i t y Assu r a n c e ( Q A ) r out i n e s and

stan d a r ds w e re c o r r ec ted. P e rmit d a ta a nd compliance databases were used to ma k e a r e a / m a jor

sou rc e d e si g n a t i ons. F inal l y

, a stand a rd Q A of the mod e l i ng f i l e w a s co n d u c ted. In some cases,

emissions were assigned to or removed from the AMF, APR or PC source category based on a

combination of inf

ormation available in the NEI database, such as the specific chemical emitted,

the MACT code the emissions were assigned to, the source of the NEI data (some data is from

state agencies where other data is from the Toxics Release Inventory (TRI)), and the method of

MACT code assignment in the NEI (data may be assigned by EPA, state agencies, or through

association with a specific source classification code (SCC)).

Risks a ssoci a ted w i t h f

a c i l i t ies c ov e r e d b y the AMF , APR, a nd PC M A CT stand a rds w e re

model e d using the r e sul t ing f i l es

. S p e c ific r e vis i ons to eac h d a t a set a r e disc u ssed b e low.

2.1 Development of the AMF data set

The 2008 N E I d a t a h a d one f a c i l i ty th a t was do c u m e nted a s h a ving e m i ss i ons sour ce s subje c t t o

the AMF MACT standard. I n t h e re v i e w of a ddi t ional info r mat i on f r om i ndust r y , tit l e V p e rmit s

, EPA compliance databases, a nd p e r m i t t ing a uthorities, this l i st w a s confirmed.

2.2 Development of the APR data set

The 2005 N E I d a t a h a d 22 f a c i l i t ies th a t w e re do c u m e nted a s h a ving e m i ss i ons sour ce s sub j ec t t o

the APR MACT. I

n the r e vi e w of a ddi t ional info r mat i on f r om i ndust r y , tit l e V p e rmit s , EPA

compliance databases, and p e r m i t t ing a uthorities, three additional facilities were added and

seven were removed from the list due to facility closures, not being subject to the APR MACT

standard or not being a major source of HAP. The resulting list included 18 f a c i l i t ies.

Some emissions were reassigned to the APR source category for 10 facilities based on a3

combination of information related to the spe cific chemical emitted, the SCC, the MACT code

the emissions were assigned to, the source of the NEI data, and the method of MACT code

assignment in the NEI. As methanol, formaldehyde, phenol, and triethylamine are commonly

used and can be expected from AP R production, principally, emissions of these chemicals were

scrutinized. Using this combination of information, emissions were also reassigned away from

the APR source category to the MACT code for the Hazardous Organic NESHAP for one

facility. These emis sions changes resulted in the addition of emissions to the APR source

category of approximately 8 tpy methanol, 3 tpy phenol, 2 tpy formaldehyde, 2 tpy triethylamine,

and less than 1 tpy of other chemicals.

S upplem e ntal e m i ss i ons i n f o r mation wi t hin t he s our c e c a t e g o r y w a s r ece i v e d f r om and ac c e pted

f or NEI11136. S ome e m i ss i ons sour ce s at NEI11136 w e re r e a ss i g n e d out of the so u r c e c a t e g o r y

a ft e r input f

r om t he fac i l i t y

.

2.3 Development of the PC data set

The 2005 N E I d a t a h a d 4 f a c i l i t ies th a t w e re do c u m e nted a s h a ving e m i ss i ons sour ce s sub j ec t t o

the PC M A CT. I n t h e re v i e w of a ddi t ional info r mat i on f r om i ndust r y , tit l e V p e rmit s , EPA

compliance databases, a nd p e r m i t t ing a uthorities, this l i st w a s confirmed.

Some emissions were reassigned to the PC source category for each facility based on combined

information related to the specific chemical emitted, the SCC, the MACT code the emissions

were assigned to, the source of the NEI data, and the method of MACT cod e assignment in the

NEI. As methylene chloride and phosgene are commonly used, and emissions of these chemicals

can be expected from PC production, emissions of these chemicals were scrutinized. In addition,

emissions of triethylamine and ethyl chloride ma y be expected from this source category.

Triethylamine is a catalyst that can be used in the PC production process, and ethyl chloride can

be a by

- product of the polymerization reaction, depending on the solvents and other chemicals

used in the process. Th e scrutiny and reassignment of some of these emissions to the PC source

category resulted in the addition of 74 tpy of ethyl chloride, 40 tpy triethylamine, 6 tpy

methylene chloride and 0.2 tpy phosgene to the source category.

2.4 NACAA and State Review

On February 4, 2013, after residual risk modeling had been conducted for these three source

categories, the EPA asked the National Association of Clean Air Agencies (NACAA) to review

the emissions data for APR and PC facilities in several states. The stat e of Texas was also asked

to review emissions data for the APR and PC facilities in their state. The results of this review

are discussed in further detail below. A list of all of the facilities subject to this review can be

found in Appendix A.

The state of North Carolina confirmed that the three APR facilities in that state were still active

and subject to the APR MACT standards. For one facility (NEI56485), they indicated that

several emission points previously assigned to the APR source category were s ubject to a

different MACT standard. For another facility (NEI46350), they also indicated that two minor

emission points previously assigned to the APR source category were subject to a different4

MACT standard.

The state of South Carolina confirmed that t he one APR facility in that state was still active and

subject to the APR MACT standards. The state provided 2005 NEI emissions data for this

facility to confirm the data used by the EPA.

The state of Texas confirmed that the one APR facility and two PC f acilities in that state were

still active and subject to the APR and PC MACT standards, respectively. There were no

revisions to the emissions data.

As the revisions provided by these states was either only to confirm that the facilities were still

active and subject to the applicable MACT standard, or to remove emission points from the

source category, the EPA made the decision not to remodel the risk for these categories. Should

the EPA choose to remodel the residual risk for these source categories in t he future, the revised

dataset will reflect the changes described above.

3.0 ACUTE R I S K

As outlined in App e ndix B : A nalysis of Data on Shor t

- T e rm E m is s ion Rat e s R e la t ive to L on g

T e rm Emission Rat e s (Palma a nd S m i th, 2009), sho r t

- te r m emission r a tes ca n b e e st i mat e d b a s e d

on a nnu a l av e ra g e r a tes in o rd e r to a ssess risk a ssoci a ted w i t h ac ute e x posur e

. F or RTR

rulem a ki n g s, unless more d e tailed in f o rm a t i on is a v a i l a ble, it i s g e n e r a l l y a ssu m e d t h a t t he 1

-

hour e m i ss i on r a te for e a c h fa c i l i t y e x c e e ds the a nnu a l a v e rage hou r l y e m i ss i on r a te b y t e n f o l d,

a nd that th i s ten f

old e m i ss i on spike c ould coin c ide w i t h wo r s t

- c a se m e teo r olo g i c a l condit i ons

a nd the p re s e n c e of a human re c e ptor a t t he f a c i l i t y bou nd a r y . This m e t h od w a s de ve lo p e d a s a

m ea ns of s c r e e ni n g for potential l y si g n i fi ca nt a c ute e x posur e s. This fac t o r of ten wa s a ppl i e d to

all av e rage a nn u a l hour l y e m i ss i on r a tes f or a so u rc e , with one e x ce pt i on, as described below.

A fac tor o f two f

or ac ute risk w a s ch o s e n for e m i s sions f rom e quip m e nt l e a ks. Ho we v e r, this

f a c tor w a s ch o s e n a ft e r most of the r isk ass e ss me nt w a s al r e a d y c omp l e te a nd w a s the r e fo r e on l y

a ppl i e d to s e v e r a l f

a c i l i t ies showing the h i g h e st risk. The f a c tor of t w o w a s ch o s e n b eca use

e m i ss i ons f

r om equipment le a ks a r e inh e r e nt l y di f f e r e nt f r om o t h e r e m i ss i on sour ce s a t ch e m i ca l

m a n u f a c turi n g f ac i l i t ies. W hi l e we b e l i e ve that it is poss i ble th a t wo r s t

- ca se short

- te r m emission

episodes f rom sou r c e s such a s pro ce ss vents, s t ac ks, o r fl a r e s m a y be a s hi g h a s ten times the

a n n u a l av e ra g e due to e v e nts such a s upsets or p r o ce s s flow v a ri a bi l i t y , th i s do e s not a pp l y to

e q uip m e nt l ea ks. Equip m e nt l ea ks a r e not a f f ec ted ac ute l y b y v a ri a ble flow in a s y s t e m and thus

ca nnot emit in t he same w a y a s a fo re mentioned e m i ss i on sour ce s during a l a r g e

- s ca l e ups e t. In

addition , a large uncertain t y factor has already been incorporated into the emission rate estimates

from equipment leaks

.

To c a lcul a te e m i ss i ons f

r om equipment le a ks for these source categories, testing for equipment

leaks is co n du c ted on a re g ular b a sis, a nd wh e n a l ea k is m ea s u r e d using EPA Method 21, a

pr e d e te r m i n e d e m i ss i on f a c tor f rom EPA’s Protocol for Equipm e nt L e ak Emission Est i mat e s

do c ument is a ppl i e d. W h e n these e m i ss i on r a tes f o r e q uip m e nt l ea ks w e re d e v e loped, the E P A

u s e d d a ta f

rom a number o f dif

fe r e nt s t udies of b a gg e d samples a t p e trol e um and s y nthetic

o r g a nic c h e m i ca l m a nu fa c turing f a c i l i t ies. I n these stud i e s, the E P A me a sur e d f o r le a ks us i n g5

EPA Method 21 a nd wh e re le a ks w e re foun d , the c on ce nt r a t i on w a s r e c o r d e d, the l e a k w a s

b a g g e d, a nd a n e st i mate of the m a ss emission r a te w a s c a lcul a t e d f r om the b a g g e d sample. F rom

the re sul t s of th e se stud i e s, mass e m i ss i on r a tes w e re found to v a r y up to five ord e rs o f

m a g n i t ude f

or a g iven E P A M e thod 21 con ce nt r a t i on re a din g . A c o rr e l a t i on w a s de ve lo p e d b a s e d

on these r e sul t s, which wa s inhe r e nt l y b i a s e d tow a rds hi g h e r e m i ss i on r a tes. 2

I f a n e v e nt c a usi n g a p r e ssure inc r ea se o cc u rre d in a p r o ce ss str ea m wh e r e a l e a k w a s p re s e nt, we

would not expect the concentration of HAP in the equipment leak to change b e ca use t h e HAP

c on c e ntr a t i on is on l y a fun c t i on o f the c omposi t ion of the pro c e ss s t re a m. The e m i s sions e st i mate

is b a s e d on a co nce nt r a t i on me a sur e ment using a toxic vapor analyzer (TVA) used as a part of

EPA Method 21, a nd h a s a lr ea d y inc o rpo ra t e d v a r i a bi l i t y

, a s discuss e d above. Therefore, we do

not believe that emissions from equipment leaks pose a large acute risk.

B a s e d on th i s info r mation, we do not b e l i e ve it is app r opri a te to a dd anoth e r o r d e r of m a g ni t ude

o f u n ce rt a in t y to emissions f r o m equipment le a ks, a n d t h a t a f a c tor of two is m o r e a ppro p ri a t e . A

list of fac i l i t ies w h e r e we u s e d the f a c tor of two inste a d of t e n is p r ovided in App e ndix 7 of the

r isk ass e ss m e nt d o c ument.

RE F ERENCES

P a l m a , T e d a nd R o y S m i th. App e ndix B : A nalysis of Data on Shor t

- T e rm E m is s ion Rat e s

R e la t ive to L ong

- T

e rm E m is s ion Rat e s . R i sk a nd T ec hnol o g y R e view ( RTR) R i sk

Ass e ss m e nt Methodolo g ies. Pr e p a r e d f or U.S. Environm e ntal P rot ec t i on Ag e n c y

. Res e a r c h T r i a n g le Pa r k, NC. P ubl i ca t i on No. EP A

- 452/ R

- 09

- 006. J une 2009.

1995 Protocol for Equipment Leak Emission Estimates . U.S. Environmental Protection Agency.

Research Triangle Park, NC. Publication No. EPA

- 453/R

- 95

- 017. November 1995.

2 M ore d e tailed dis c uss i on on how th e se c o rr e latio n s w e re d e v e loped ca n be f ound in App e nd i x

B of the E P A ’ s Protocol for Equipm e nt L e ak Emission Est i mat e s do c ument.6

Appendix A

– List of Facilities Subject to NACAA Review

Facility Nam e NEI ID City State Source Category

EMERALD CAROLINA CHEMICAL, LLC NEINC0595 Charlotte NC Amino and Phenolic Resins Production

GEORGIA

- PACIFIC CONWAY OPERATIONS NEI46350 CONWAY NC Amino and Phenolic Resins Production

HEXION SPECIALTY CHEMICALS, INC. NEI56485 FAYETTEVILLE NC Amino and Phenolic Resins Production

NEVAMAR CO LLC NEI7964 HAMPTON SC Amino and Phenolic Resins Production

LUFKIN RESIN PLANT NEI12810 LUFKIN TX Amino and Phenolic Resins Production

BAYTOWN PLANT NEI13287 BAYTOWN TX Polycarbonate Production

DOW CHEMICAL CO FREEPORT FACILITY NEI11295 Freeport TX Polycarbonate Production