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 whichmeet 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 (NO ) and volatile organic compounds (VOC's).

x 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 NO

x 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 14,3

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 the4

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 section5

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).6

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, NO , NO , N O, N O , N O , N O ) 2 3 2 2 3 2 4 2 5 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:

methane7

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 NO ) plus:

x

dioxin/furan (defined in 40 CFR 60.53a to mean total tetra through octachlorinated dibenzo-p-dioxins and dibenzofurans) *
fluorides hydrogen chloride * hydrogen sulfide (H S) 2 sulfuric acid mist8

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 chloroform9

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 radionuclides10

vinyl chloride11

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 Asbestos12

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 *13

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,NDimethylformamide] 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 *14

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 *15

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 Compounds16

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) -OH. [recommended technical

n * correction: R-(OCH2CH2) -OH] Polymers are excluded from the

n 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 100 E C. * [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
100 E C.]17

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 variance18

with the guidance, based on an analysis of specific circumstances. The EPA may also change this guidance at any time without public notice.