MEMORANDUM

SUBJECT:  Definition of Regulated Air Pollutant for Purposes of
          Title V 

FROM:     Lydia N. Wegman, Deputy Director
          Office of Air Quality Planning and Standards  (MD-10)

TO:       Air Division Director, Regions I-X


     In response to requests for guidance on the definition of
"regulated air pollutant," this memorandum clarifies the approach
set forth by the definition in the 40 CFR part 70 regulations and
indicates the ways in which the class of regulated air pollutants
can change.  The attachment provides a compilation of the lists
of pollutants which are considered "regulated air pollutants" for
purposes of the operating permits programs under title V of the
Clean Air Act (Act).  This memorandum also provides guidance on
the Environmental Protection Agency's (EPA) definition of "air
pollutant," as that term is used in determining major source
status pursuant to section 302 of the Act.  Finally, this
memorandum emphasizes the ability of permitting authorities to
designate certain quantities of emissions of regulated air
pollutants as "insignificant" with respect to the obligation to
report emissions of those pollutants in permit applications.  The
policies set out in this memorandum and attachment are intended
solely as guidance, not final agency action, and cannot be relied
upon to create any rights enforceable by any party.


I. Regulated Air Pollutant

     The definition of regulated air pollutant, found at 40 
CFR 70.2 is important because it determines which pollutants and
emissions units must be addressed in a source's title V permit
application.  In addition, this definition can affect whether a
State's fee revenue is presumed adequate to fund its title V
program and in some cases, the amount of permit fees a source
must pay.  Each of these roles is discussed below.  

     Once a source is subject to a title V permitting program,
its emissions of all regulated air pollutants (except those which
meet the permitting authority's criteria for "insignificant"
emissions) must be described in the permit application along with
all emissions of pollutants for which the source is considered
major.  Similarly, applications must describe all emissions units
which emit regulated air pollutants (except those deemed
insignificant).

     In addition, the concept of regulated air pollutant plays an
important role in the area of permit fees.  First, regulated air
pollutants are the starting point for determining which
pollutants must be included when relying on the $25 ton per year
(as adjusted by the consumer price index) presumptive minimum
program cost as a basis for demonstrating the adequacy of a
State's projected fee revenue.  As part of this demonstration,
the State projects its revenue using a subset of regulated air
pollutants [i.e., regulated pollutant (for presumptive fee
calculation)].  Second, many States are developing fee schedules
which impose fees based on emissions of regulated air
pollutants."

     The population of regulated air pollutants is composed of
the following categories of pollutants: 

(1) Nitrogen oxides (NOx) and volatile organic compounds (VOC's). 
The definition of regulated air pollutant specifically includes
these two significant precursors to ozone formation.  This
approach is consistent with the Act's treatment of VOC's and NOx
pursuant to part D of title I of the Act.  (These ozone
precursors are combined with the criteria pollutants for purposes
of the attached list of regulated pollutants);

(2) Any pollutant for which a national ambient air quality
standard has been promulgated [i.e., particulate matter (measured
as PM-10: particles with an aerodynamic diameter less than or
equal to a nominal 10 micrometers), sulfur dioxide, ozone,
nitrogen dioxide, carbon monoxide, and lead];

(3) Any pollutant that is subject to a new source performance
standard promulgated under section 111 of the Act [including
section 111(d)], which require new and modified sources to
satisfy emissions standards, work practice standards, and other
requirements; 

(4) Any of the ozone depleting substances specified as a Class I
(primarily chlorofluorocarbons) or Class II substance
(hydrochlorofluorocarbons) under title VI of the Act [all of
which became regulated pollutants when they became subject to 
standards and requirements for (1) servicing of motor vehicle air
conditioners and (2) restrictions on the sale of ozone-depleting
substances promulgated into 40 CFR part 82 (57 FR 31242, July 14,
1992)]; and

(5) Any pollutant subject to a standard promulgated under section
112 or other requirements established under section 112 of the
Act, including sections 112(g)(2), (j), and (r) of the Act.  
     
     It is important to note that, if a pollutant is regulated
for one source category by a standard or other requirement, then
the pollutant is considered a regulated air pollutants for all
source categories.  This rule is relevant to all the pollutants
listed under items (3),(4), and (5) above with one exception:
those which are the subject of case-by-case MACT determinations
under section 112(g)(2). 

     The issue of when a substance regulated under section 112
becomes a regulated air pollutants merits further discussion:

    When a permitting authority makes a case-by-case MACT
     determination under section 112(g)(2), then the pollutant
     for which the determination is made is regulated even though
     EPA has not issued a standard for that pollutant.  However,
     the pollutant is considered regulated only with respect to
     the individual source for which the MACT determination was
     made. 

    A pollutant will become regulated under section 112(j) of
     the Act (the "MACT hammer") if the Administrator fails to
     promulgate a standard by the date established pursuant to
     section 112(e) of the Act.  Pursuant to section 112(j),
     permitting authorities will be required to make case-by-case
     MACT equivalent determinations.  The pollutants become
     regulated nationwide upon the date this provision takes
     effect for the pollutant (i.e., 18 months after the missed
     deadline for the standard but not prior to 42 months after
     the enactment of the Act Amendments of 1990).  Pollutants so
     regulated are considered regulated air pollutants for all
     sources that emit the pollutant because the hammer provision
     is a broadly applicable surrogate for the promulgation of a
     MACT standard.  This is in contrast to the section 112(g)(2)
     determinations which are triggered only for the single
     source subject to the requirement, rather than nationwide.

    The EPA's proposed rule required by section 112(r)(3), lists
     substances which could cause or may reasonably be
     anticipated to cause death, injury, or serious adverse
     effects to human health or the environment if accidentally
     released, was published in the Federal Register on January
     19, 1993 (58 FR 5102).  All of the listed pollutants will
     become regulated air pollutants upon promulgation of the
     list.

     The attachment to this memorandum contains a list of
pollutants which are regulated as well as a list of pollutants
which are subject to regulation under section 112 in the future,
as discussed above.  It is also important to note that the
attached lists are dynamic and subject to change.  For example,
the EPA is required to review periodically the statutory list of
pollutants in section 112(b) and is authorized to delete and add
substances if the scientific data demonstrate that such a change
is appropriate.  

     We have attempted to note the likely near-term changes in
the regulations that determine which pollutants are "regulated
air pollutants," and we will provide updates to this guidance
periodically.  

     The definition of regulated air pollutants does not limit
the air pollutants which a State may choose to regulate nor does
it limit the information (such as for permit applications) which
a State may require of a source.  States are free to adopt more
expansive approaches to the regulation of toxic air pollutants
than is required by part 70. 


II. Definition of "Air Pollutant" Pursuant to Section 302

     Considerable interest has been expressed in a related, but
distinct, area: the definition of "air pollutant" contained in
section 302(g) of the Act.  This definition governs which
pollutants are to be considered in determining whether a source
is "major" pursuant to section 302(j) of the Act.  This is
important to the operating permit program because all major
sources must obtain a title V permit.  Although section 302(g)
can be read quite broadly, so as to encompass virtually any
substance emitted into the atmosphere, EPA believes that it is
more consistent with the intent of Congress to interpret this
provision more narrowly.  Were this not done, a variety of
sources that have no known prospect for future regulation under
the Act would nonetheless be classified as major sources and be
required to apply for title V permits.  Of particular concern
would be sources of carbon dioxide or methane.

     As a result, EPA is interpreting "air pollutant" for section
302(g) purposes as limited to all pollutants subject to
regulation under the Act.  This would include, of course, all
regulated air pollutants plus others specified by the Act or by
EPA rulemaking.  This approach results in the inclusion of the
pollutants on the list of hazardous air pollutants in section
112(b) that are not otherwise regulated.  It should be noted that
the 1990 Amendments to the Act did include provisions with
respect to carbon dioxide (section 821) and methane (section
603), but these requirements involve actions such as reporting
and study, not actual control of emissions.  Therefore, these
provisions do not preempt EPA's discretion to exclude these
pollutants in determining whether a source is major.  If the
results of the studies required by the 1990 Amendments to the Act
suggest the need for regulation, these pollutants could be
reconsidered at that time for classification as pollutants
subject to regulation under the Act.

     This approach to interpreting section 302(g) is similar to
the traditional practice of the prevention of significant
deterioration (PSD) program under part C of title I of the Act
[see, e.g., Implementation of North County Resource Recovery PSD
Remand, Gerald Emison, Director, OAQPS, dated September 22,
1987].


III. De Minimis Thresholds

     With the 1990 Amendments, the Act expressly addresses a
significantly broader range of pollutants.  The EPA believes that
this will confer real benefits to air quality management and that
the title V permit program offers the flexibility for efficient
implementation of these requirements.  This function includes
providing information about emissions of these pollutants,
through the permit application process, even if the particular
pollutant is not currently required to be controlled at the
individual source.  The EPA also realizes, though, that in many
cases these pollutants are emitted in amounts of no significance
to air quality management.  It would be unduly burdensome to
require permit applicants to quantify all emissions of these
pollutants, especially given their considerable number and, in
some cases, difficulty in quantification.

     The part 70 promulgation recognized this fact but gave only
very general guidance as to the approvable options for States in
developing their part 70 programs.  Section 70.5(c) provides that
"[T]he Administrator may approve as part of a State program a
list of insignificant activities and emissions levels which need
not be included in permit applications."   The regulation further
provides that "[T]he permitting authority shall require
additional information related to the emissions of air pollutants
sufficient to verify which requirements are applicable to the
source, and other information needed to collect any permit fees
owed under the fee schedule approved pursuant to 70.9(b) of this
part."  70.5(c)(3)(i).

     The EPA understands the need for States to establish de
minimis thresholds for emissions reporting purposes in permit
applications and recognizes that the particular thresholds
selected by individual States can vary based on their air quality
management needs and professional judgement.  The EPA will work
with States to develop part 70 programs that will best meet their
program needs.


     For further information, call Kirt Cox at (919) 541-5399 or
Candace Carraway at (919) 541-3189. 

Attachment

cc:  Air Branch Chiefs, Regions I - X
     Regional Office Permit Program Contacts
     OAQPS Division Directors



                     LIST OF REGULATED AIR POLLUTANTS
                            (As of April 1993)

I. Pollutants for Which an NAAQS Has Been Established

lead 
sulfur dioxide
nitrogen dioxide
carbon monoxide
particulate matter (PM10)
ozone, including precursors:
     nitrogen oxides (NO, NO2, NO3, N2O, N2O3, N2O4, N2O5)
     volatile organic compounds (VOC's) 

     As defined in 40 CFR 51.100(s), the term VOC includes any
compound of carbon (excluding carbon monoxide, carbon dioxide,
carbonic acid, metallic carbides or carbonates, and ammonium
carbonate) which participates in atmospheric photochemical
reactions.  The EPA has developed a list of substances (which is
subject to change) which are excluded from the VOC definition
because of their negligible reactivity.  The EPA's proposal to
exclude perchloroethylene from the definition was published in 57
FR 48490 (October 26, 1992).  
  
     The following organic compounds are excluded from the
definition of VOC because of they have been determined to have
negligible photochemical reactivity: 

methane 
ethane 
methylene chloride (dichloromethane) 
1,1,1-trichloroethane (methyl chloroform)
1,1,1-trichloro-2,2,2-trifluoroethane (CFC-113)             
trichlorofluoromethane (CFC-11) 
dichlorodifluoromethane (CFC-12) 
chlorodifluoromethane (CFC-22) 
trifluoromethane (FC-23) 
1,2-dichloro 1,1,2,2-tetrafluoroethane (CFC-114)
chloropentafluoroethane (CFC-115) 
1,1,1-trifluoro 2,2-dichloroethane (HCFC-123)
1,1,1,2-tetrafluoroethane (HFC-134a) 
1,1-dichloro 1-fluoroethane (HCFC-141b) 
1-chloro 1,1-difluoroethane (HCFC-142b)
2-chloro-1,1,1,2-tetrafluoroethane (HCFC-124) 
pentafluoroethane (HFC-125) 
1,1,2,2-tetrafluoroethane (HFC-134) 
1,1,1-trifluoroethane (HFC-143a) 
1,1-difluoroethane (HFC-152a) 


perfluorocarbon compounds which fall into these classes:          
                                             
     (i)  Cyclic, branched, or linear, completely
          fluorinated alkanes; 
                                                                  
    (ii)  Cyclic, branched, or linear, completely
          fluorinated ethers with no unsaturations;

   (iii)  Cyclic, branched, or linear, completely
          fluorinated tertiary amines with no
          unsaturations; and
                                  
    (iv)  Sulfur containing perfluorocarbons with no
          unsaturations and with sulfur bonds only to
          carbon and fluorine.                          
                                           


II. Pollutants Regulated Under New Source Performance Standards

Criteria pollutants (including VOC's and NOx) plus:

dioxin/furan (defined in 40 CFR 60.53a to mean total tetra
through octachlorinated dibenzo-p-dioxins and dibenzofurans)*
fluorides
hydrogen chloride*
hydrogen sulfide (H2S)
sulfuric acid mist
total reduced sulfur
reduced sulfur compounds
total suspended particulate 

*  The new source performance standard (NSPS) for municipal waste
combustors (MWC) controls emissions of dioxin/furans and hydrogen
chloride gas (40 CFR 60.53a and 60.54a) as surrogates for
controlling emissions of organic compounds and acid gases which
are emitted in the exhaust gases from MWC units.  Thus, the
indicated dioxin/furan compounds and hydrogen chloride are
regulated pollutants.

     Note that the EPA has drafted a proposed revision to the
NSPS for MWC's which will regulate substances like cadmium which
are not currently regulated air pollutants.  As this revised NSPS
and other standards are developed, there may be additions to the
list of regulated pollutants.



III. Class I and Class II Substances Under Title VI


Class I Substances

carbon tetrachloride                                              
chlorofluorocarbon-11 (CFC-11)
chlorofluorocarbon-12 (CFC-12)
chlorofluorocarbon-13 (CFC-13)                                    
chlorofluorocarbon-111 (CFC-111)                                  
chlorofluorocarbon-112 (CFC-112)                                  
chlorofluorocarbon-113 (CFC-113)
chlorofluorocarbon-114 (CFC-114)
chlorofluorocarbon-115 (CFC-115)                                  
chlorofluorocarbon-211 (CFC-211)                                  
chlorofluorocarbon-212 (CFC-212)                                  
chlorofluorocarbon-213 (CFC-213)                                  
chlorofluorocarbon-214 (CFC-214)                                  
chlorofluorocarbon-215 (CFC-215)                                  
chlorofluorocarbon-216 (CFC-216)                                  
chlorofluorocarbon-217 (CFC-217)                                 
halon-1211                                                        
halon-1301                                                        
halon-2402                                                        
methyl chloroform                                                





Class II Substances                                              

hydrochlorofluorocarbon-21 (HCFC-21)                              
hydrochlorofluorocarbon-22 (HCFC-22)                              
hydrochlorofluorocarbon-31 (HCFC-31)                             
hydrochlorofluorocarbon-121 (HCFC-121)                            
hydrochlorofluorocarbon-122 (HCFC-122)                           
hydrochlorofluorocarbon-123 (HCFC-123)                           
hydrochlorofluorocarbon-124 (HCFC-124)                            
hydrochlorofluorocarbon-131 (HCFC-131)                           
hydrochlorofluorocarbon-132 (HCFC-132)                            
hydrochlorofluorocarbon-133 (HCFC-133)                            
hydrochlorofluorocarbon-141 (HCFC-141)                            
hydrochlorofluorocarbon-142 (HCFC-142)                            
hydrochlorofluorocarbon-221 (HCFC-221)                            
hydrochlorofluorocarbon-222 (HCFC-222)                            
hydrochlorofluorocarbon-223 (HCFC-223)                            
hydrochlorofluorocarbon-224 (HCFC-224)                            
hydrochlorofluorocarbon-225 (HCFC-225)                           
hydrochlorofluorocarbon-226 (HCFC-226)                            
hydrochlorofluorocarbon-231 (HCFC-231)                            
hydrochlorofluorocarbon-232 (HCFC-232)                            
hydrochlorofluorocarbon-233 (HCFC-233)                            
hydrochlorofluorocarbon-234 (HCFC-234)                            
hydrochlorofluorocarbon-235 (HCFC-235)                            
hydrochlorofluorocarbon-241 (HCFC-241)                            
hydrochlorofluorocarbon-242 (HCFC-242)                            
hydrochlorofluorocarbon-243 (HCFC-243)                            
hydrochlorofluorocarbon-244 (HCFC-244)                            
hydrochlorofluorocarbon-251 (HCFC-251)                            
hydrochlorofluorocarbon-252 (HCFC-252)                            
hydrochlorofluorocarbon-253 (HCFC-253)                            
hydrochlorofluorocarbon-261 (HCFC-261)                            
hydrochlorofluorocarbon-262 (HCFC-262)                            
hydrochlorofluorocarbon-271 (HCFC-271)                           





IV. Pollutants Regulated Under Section 112

pollutants for which national emission standards for hazardous
air pollutants (NESHAP's) have been established:

arsenic
asbestos
beryllium
benzene
mercury
radionuclides
vinyl chloride




            POLLUTANTS SUBJECT TO REGULATION UNDER SECTION 112
                                     

I.   Pollutants listed in Section 112(b):

     The 189 pollutants listed in section 112(b) are not
considered regulated air pollutants until addressed in a
requirement that it be controlled by a source.  None of the
listed pollutants meets the definition except: asbestos, benzene,
and vinyl chloride (for which NESHAP's have been established);
and  hydrogen chloride (gas), dibenzofurans, and 2,3,7,8-
Tetrachlorodibenzo-p-dioxin (regulated under the municipal waste
combustor NSPS).  Most of the listed pollutants will become
regulated when EPA promulgates the Hazardous Organic NESHAP (HON)
which is discussed below.  The remaining pollutants will become
regulated: (1) when EPA promulgates a Maximum Achievable Control
Technology (MACT) standard for the pollutant under section
112(d), (2) for a particular source, when case-by-case MACT
determinations are made under section 112(g) for the source, or
(3) the later of June 15, 1994 or 18 months after EPA fails to
issue emissions standards for categories of sources in compliance
with the timetable promulgated pursuant to section 112(e) as
mandated by Section 112(j). 

     The section 112(b) list contains some technical errors which
will be corrected in subsequent rulemaking.  The majority of the
technical corrections likely to be made are noted below.  Also,
the pollutants from the 112(b) list which are addressed in the
proposed HON are followed by an asterisk.


     CAS number       Chemical name 

75070          Acetaldehyde*   
60355          Acetamide*                                         
75058          Acetonitrile*                                      
98862          Acetophenone*                                      
53963          2-Acetylaminofluorene*                             
107028         Acrolein*                                          
79061          Acrylamide*                                        
79107          Acrylic acid*                                      
107131         Acrylonitrile*                                     
107051         Allyl chloride*                                    
92671          4-Aminobiphenyl*                                   
62533          Aniline*                                           
90040          o-Anisidine*                                       
1332214        Asbestos                                          
71432          Benzene (including benzene from gasoline)*         
92875          Benzidine*                                         
98077          Benzotrichloride*                                  
100447         Benzyl chloride*                                   
92524          Biphenyl*                                          
117817         Bis(2-ethylhexyl)phthalate (DEHP)*                 
542881         Bis(chloromethyl)ether*                            
75252          Bromoform*                                         
106990         1,3-Butadiene*                                     
156627         Calcium cyanamide                                 
105602         Caprolactam*                                       
133062         Captan                                            
63252          Carbaryl                                         
75150          Carbon disulfide*                                 
56235          Carbon tetrachloride*                              
463581         Carbonyl sulfide*                                  
120809         Catechol*                                          
133904         Chloramben                                        
57749          Chlordane                                          
7782505        Chlorine                                          
79118          Chloroacetic acid*                                 
532274         2-Chloroacetophenone*                              
108907         Chlorobenzene*                                     
510156         Chlorobenzilate                                   
67663          Chloroform*                                        
107302         Chloromethyl methyl ether*                         
126998         Chloroprene*                                       
1319773        Cresols/Cresylic acid (isomers and mixture)*       
95487          o-Cresol*                                          
108394         m-Cresol*                                          
106445         p-Cresol*                                          
98828          Cumene*                                            
94757          2,4-D (2,4-Dichlorophenoxyacetic acid, including   
               salts and esters)*                                 
               DDE* [recommended technical correction: CAS number
              72559] (1,1-dichloro-2,2-bis(p-chlorophenyl)        
               ethylene)                                          
334883         Diazomethane*                                      
132649         Dibenzofurans* [recommended technical correction:                 
               Dibenzofuran]                                      
96128          1,2-Dibromo-3-chloropropane*                       
84742          Dibutylphthalate*                                  
106467         1,4-Dichlorobenzene(p)* [recommended technical    
              correction: 1,4-Dichlorobenzene]                   
91941          3,3-Dichlorobenzidene* [recommended technical     
              correction: 3,3'-Dichlorobenzidine]                
111444         Dichloroethyl ether (Bis(2-chloroethyl)ether)*     
542756         1,3-Dichloropropene*                               
62737          Dichlorvos                                         
111422         Diethanolamine*                                    
121697         N,N-Diethyl aniline (N,N-Dimethylaniline)*         
               [recommended technical correction: 
              N,N-Dimethylaniline]
64675          Diethyl sulfate*                                   
119904         3,3-Dimethoxybenzidine* [recommended technical    
              correction: 3,3'-Dimethoxybenzidine]               
60117          Dimethyl aminoazobenzene*                          
119937         3,3',-Dimethyl benzidine* [recommended technical  
              correction: 3,3',-Dimethylbenzidine]               
79447          Dimethyl carbamoyl chloride* [recommended         
              technical correction: Dimethylcarbamoyl chloride]  
68122          Dimethyl formamide* [recommended technical         
               correction: N,N-Dimethylformamide]                 
57147          1,1-Dimethyl hydrazine* [recommended technical    
              correction: 1,1-Dimethylhydrazine]                 
131113         Dimethyl phthalate*                                
77781          Dimethyl sulfate*                                  
               4,6-Dinitro-o-cresol, and salts* [recommended      
               technical correction to remove CAS number]
51285          2,4-Dinitrophenol*                                 
121142         2,4-Dinitrotoluene*                                
123911         1,4-Dioxane (1,4-Diethyleneoxide)*                 
122667         1,2-Diphenylhydrazine*                             
106898         Epichlorohydrin (l-Chloro-2,3-epoxypropane)*       
106887         1,2-Epoxybutane*                                   
140885         Ethyl acrylate*                                    
100414         Ethyl benzene* [recommended technical correction:                 
               Ethylbenzene]                                      
51796          Ethyl carbamate (Urethane)*                        
75003          Ethyl chloride (Chloroethane)*                     
106934         Ethylene dibromide (Dibromoethane)*                
107062         Ethylene dichloride (1,2-Dichloroethane)*          
107211         Ethylene glycol*                                   
151564         Ethylene imine (Aziridine) [recommended technical
              correction: Ethyleneimine (Aziridine)]             
75218          Ethylene oxide*                                    
96457          Ethylene thiourea*                                 
75343          Ethylidene dichloride (1,1-Dichloroethane)*        
50000          Formaldehyde*                                      
76448          Heptachlor                                        
118741         Hexachlorobenzene*                                 
87683          Hexachlorobutadiene*                               
77474          Hexachlorocyclopentadiene                         
67721          Hexachloroethane*                                  
822060         Hexamethylene-1,6-diisocyanate*                    
680319         Hexamethylphosphoramide*                           
110543         Hexane*                                            
302012         Hydrazine*                                         
7647010        Hydrochloric acid [recommended technical           
               correction: Hydrochloric acid (hydrogen            
               chloride)(gas only)]                               
7664393        Hydrogen fluoride (Hydrofluoric acid)              
123319         Hydroquinone*                                      
78591          Isophorone*                                        
               Lindane (all isomers) [Recommended technical       
               correction: 1,2,3,4,5,6-Hexachlorocyclohexane (all 
               stereo isomers, including lindane)]                
108316         Maleic anhydride*                                  
67561          Methanol*                                          
72435          Methoxychlor                                      
74839          Methyl bromide (Bromomethane)*                     
74873          Methyl chloride (Chloromethane)*                   
71556          Methyl chloroform (1,1,1-Trichloroethane)*         
78933          Methyl ethyl ketone (2-Butanone)*                  
60344          Methyl hydrazine* [recommended technical           
               correction: Methylhydrazine]                       
74884          Methyl iodide (Iodomethane)*                       
108101         Methyl isobutyl ketone (Hexone)*                   
624839         Methyl isocyanate*                                 
80626          Methyl methacrylate*                               
1634044        Methyl tert butyl ether* [recommended technical
              correction: Methyl tert-butyl ether]               
101144         4,4-Methylene bis(2-chloroaniline)* [recommended
              technical correction: 4,4'-Methylenebis(2-          
               chloroaniline]         
75092          Methylene chloride (Dichloromethane)*              
101688         Methylene diphenyl diisocyanate (MDI)*             
               [recommended technical correction:                 
               4-4' Methylenediphenyl diisocyanate (MDI)]         
101779         4,4,-Methylenedianiline*                           
91203          Naphthalene*                                       
98953          Nitrobenzene*                                      
92933          4-Nitrobiphenyl*                                   
100027         4-Nitrophenol*                                     
79469          2-Nitropropane*                                    
684935         N-Nitroso-N-methylurea*                            
62759          N-Nitrosodimethylamine*                            
59892          N-Nitrosomorpholine*                               
56382          Parathion                                          
82688          Pentachloronitrobenzene (Quintobenzene)           
87865          Pentachlorophenol                                  
108952         Phenol*                                            
106503         p-Phenylenediamine*                                
75445          Phosgene*                                          
7803512        Phosphine                                          
7723140        Phosphorus                                        
85449          Phthalic anhydride*                                
1336363        Polychlorinated biphenyls (Aroclors)*              
1120714        1,3-Propane sultone*                               
57578          beta-Propiolactone*                                
123386         Propionaldehyde*                                   
114261         Propoxur (Baygon)*                                 
78875          Propylene dichloride (1,2-Dichloropropane)*        
75569          Propylene oxide*                                   
75558          1,2-Propylenimine (2-Methyl aziridine)*            
91225          Quinoline                                         
106514         Quinone*                                           
100425         Styrene*                                           
96093          Styrene oxide*                                     
1746016        2,3,7,8-Tetrachlorodibenzo-p-dioxin*               
79345          1,1,2,2-Tetrachloroethane*                         
127184         Tetrachloroethylene (Perchloroethylene)*           
7550450        Titanium tetrachloride                            
108883         Toluene*                                           
95807          2,4-Toluene diamine* [recommended technical        
               correction: 2,4-Toluenediamine]                    
584849         2,4-Toluene diisocyanate*                          
95534          o-Toluidine*                                       
8001352        Toxaphene (chlorinated camphene)                  
120821         1,2,4-Trichlorobenzene*                            
79005          1,1,2-Trichloroethane*                             
79016          Trichloroethylene*                                 
95954          2,4,5-Trichlorophenol*                             
88062          2,4,6-Trichlorophenol*                             
121448         Triethylamine*                                     
1582098        Trifluralin*                                       
540841         2,2,4-Trimethylpentane*                            
108054         Vinyl acetate*                                     
593602         Vinyl bromide*                                     
75014          Vinyl chloride*                                    
75354          Vinylidene chloride (1,1-Dichloroethylene)*        
1330207        Xylenes (isomers and mixture)*                     
95476          o-Xylenes* [recommended technical correction: 
               o-Xylene                                          
108383         m-Xylenes* [recommended technical correction:
               m-Xylene]
106423         p-Xylenes* [recommended technical correction:
               p-Xylene]
0              Antimony Compounds                                 
0              Arsenic Compounds (inorganic including arsine)     
0              Beryllium Compounds                                
0              Cadmium Compounds                                  
0              Chromium Compounds                                 
0              Cobalt Compounds                                   
0              Coke Oven Emissions                                
0              Cyanide Compounds [1]                              
0              Glycol ethers*  [2]                                
0              Lead Compounds                                     
0              Manganese Compounds                                
0              Mercury Compounds                                  
0              Fine mineral fibers [3]                            
0              Nickel Compounds                                   
0              Polycylic Organic Matter [4]* [recommended         
               technical correction: Polycyclic Organic Matter]
0              Radionuclides (including radon) [5]                
0              Selenium Compounds                                
   NOTE: For all listings above which contain the word
"compounds" and for glycol ethers, the following applies: Unless
otherwise specified, these listings are defined as including any
unique chemical substance that contains the named chemical (i.e.,
antimony, arsenic, etc.) as part of that chemical's
infrastructure.

   1 X'CN where X = H' or any other group where a formal
dissociation may occur.
For example KCN or Ca(CN)2                                        
             
   2 Includes mono- and di- ethers of ethylene glycol, diethylene
glycol, and triethylene glycol R-(OCH2CH2)n-OR' where             

   n = 1, 2, or 3                                                 
             
   R = alkyl or aryl groups                                       
             
   R' = R, H, or groups which, when removed, yield glycol ethers
with the structure: R-(OCH2CH)n-OH.* [recommended technical
correction: R-(OCH2CH2)n-OH]  Polymers are excluded from the
glycol category.
      
   3 Includes mineral fiber emissions from facilities
manufacturing or processing glass, rock, or slag fibers (or other
mineral derived fibers) of average diameter 1 micrometer or less. 

   4 Includes organic compounds with more than one benzene ring,
and which have a boiling point greater than or equal to 100øC.*
[recommended technical correction: Limited to, or refers to,
products from incomplete combustion of organic compounds (or
material) and pyrolysis processes having more than one benzene
ring, and which have a boiling point greater than or equal to
100øC.]
         
   5 A type of atom which spontaneously undergoes radioactive
decay. 


II.   Pollutants subject to the Hazardous Organic NESHAP (HON):

     As part of the effort to regulate pollutants listed in
section 112(b), the EPA has developed the (HON) which will apply
to the synthetic organic chemical manufacturing industry and will
control emissions of 149 volatile hazardous air pollutants
(HAP's).  All of the pollutants listed in the HON are among the
189 HAP's listed in section 112(b) and are identified (with an
asterisk) in the preceding section of this document.  Pollutants
addressed by the HON will become regulated on the effective date
specified in the HON.  

     
III. Pollutants listed under Section 112(r):

     Section 112(r)(3) requires that EPA promulgate an initial
list of at least 100 substances with threshold quantities which
would cause or may reasonably be anticipated to cause death,
injury, or serious adverse effects to human health or the
environment if accidentally released.  The EPA's proposed rule to
implement 112(r)(3) was published in the Federal Register on
January 19, 1993 (58 FR 5102).  The proposed list of substances
includes 100 acutely toxic substances, 62 flammable gases and
volatile flammable liquids, and commercial explosives (classified
by the Department of Transportation in Division 1.1).  The listed
pollutants will become "regulated" for purposes of title V upon
final promulgation of the list.

     The toxic and flammable substances listed in the proposed
rule are arranged alphabetically and by CAS number on the
attached lists.     


_________________________________________________________________

                                  NOTICE

     The policies set out in this guidance document are intended
     solely as guidance and do not represent final agency action
     and are not ripe for judicial review.  They are not
     intended, nor can they be relied upon, to create any rights
     enforceable by any party in litigation with the United
     States.  The EPA officials may decide to follow the guidance
     provided in this guidance document, or to act at variance
     with the guidance, based on an analysis of specific
     circumstances.  The EPA may also change this guidance at any
     time without public notice.

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