Under the Clean Air Act, EPA is required to regulate emissions of hazardous air pollutants. This original list included 189 pollutants. Since 1990, EPA has modified the list through rulemaking to include 188 hazardous air pollutants.
CAS NumberChemical Name75070Acetaldehyde60355Acetamide75058Acetonitrile98862Acetophenone539632-Acetylaminofluorene107028Acrolein79061Acrylamide79107Acrylic acid107131Acrylonitrile107051Allyl chloride926714-Aminobiphenyl62533Aniline90040o-Anisidine1332214Asbestos71432Benzene (including benzene from gasoline)92875Benzidine98077Benzotrichloride100447Benzyl chloride92524Biphenyl117817Bis(2-ethylhexyl)phthalate (DEHP)542881Bis(chloromethyl)ether75252Bromoform1069451-Bromopropane (See Modification)1069901,3-Butadiene156627Calcium cyanamide105602Caprolactam (See Modification)133062Captan63252Carbaryl75150Carbon disulfide56235Carbon tetrachloride463581Carbonyl sulfide120809Catechol133904Chloramben57749Chlordane7782505Chlorine79118Chloroacetic acid5322742-Chloroacetophenone108907Chlorobenzene510156Chlorobenzilate67663Chloroform107302Chloromethyl methyl ether126998Chloroprene1319773Cresols/Cresylic acid (isomers and mixture)95487o-Cresol108394m-Cresol106445p-Cresol98828Cumene947572,4-D, salts and esters3547044DDE334883Diazomethane132649Dibenzofurans961281,2-Dibromo-3-chloropropane84742Dibutylphthalate1064671,4-Dichlorobenzene(p)919413,3-Dichlorobenzidene111444Dichloroethyl ether (Bis(2-chloroethyl)ether)5427561,3-Dichloropropene62737Dichlorvos111422Diethanolamine121697N,N-Dimethylaniline64675Diethyl sulfate1199043,3-Dimethoxybenzidine60117Dimethyl aminoazobenzene1199373,3′-Dimethyl benzidine79447Dimethyl carbamoyl chloride68122Dimethyl formamide571471,1-Dimethyl hydrazine131113Dimethyl phthalate77781Dimethyl sulfate5345214,6-Dinitro-o-cresol, and salts512852,4-Dinitrophenol1211422,4-Dinitrotoluene1239111,4-Dioxane (1,4-Diethyleneoxide)1226671,2-Diphenylhydrazine106898Epichlorohydrin (l-Chloro-2,3-epoxypropane)1068871,2-Epoxybutane140885Ethyl acrylate100414Ethyl benzene51796Ethyl carbamate (Urethane)75003Ethyl chloride (Chloroethane)106934Ethylene dibromide (Dibromoethane)107062Ethylene dichloride (1,2-Dichloroethane)107211Ethylene glycol151564Ethylene imine (Aziridine)75218Ethylene oxide96457Ethylene thiourea75343Ethylidene dichloride (1,1-Dichloroethane)50000Formaldehyde76448Heptachlor118741Hexachlorobenzene87683Hexachlorobutadiene77474Hexachlorocyclopentadiene67721Hexachloroethane822060Hexamethylene-1,6-diisocyanate680319Hexamethylphosphoramide110543Hexane302012Hydrazine7647010Hydrochloric acid7664393Hydrogen fluoride (Hydrofluoric acid)7783064Hydrogen sulfide (See Modification)123319Hydroquinone78591Isophorone58899Lindane (all isomers)108316Maleic anhydride67561Methanol72435Methoxychlor74839Methyl bromide (Bromomethane)74873Methyl chloride (Chloromethane)71556Methyl chloroform (1,1,1-Trichloroethane)78933Methyl ethyl ketone (2-Butanone) (See Modification)60344Methyl hydrazine74884Methyl iodide (Iodomethane)108101Methyl isobutyl ketone (Hexone)624839Methyl isocyanate80626Methyl methacrylate1634044Methyl tert butyl ether1011444,4-Methylene bis(2-chloroaniline)75092Methylene chloride (Dichloromethane)101688Methylene diphenyl diisocyanate (MDI)1017794,4′-Methylenedianiline91203Naphthalene98953Nitrobenzene929334-Nitrobiphenyl1000274-Nitrophenol794692-Nitropropane684935N-Nitroso-N-methylurea62759N-Nitrosodimethylamine59892N-Nitrosomorpholine56382Parathion82688Pentachloronitrobenzene (Quintobenzene)87865Pentachlorophenol108952Phenol106503p-Phenylenediamine75445Phosgene7803512Phosphine7723140Phosphorus85449Phthalic anhydride1336363Polychlorinated biphenyls (Aroclors)11207141,3-Propane sultone57578beta-Propiolactone123386Propionaldehyde114261Propoxur (Baygon)78875Propylene dichloride (1,2-Dichloropropane)75569Propylene oxide755581,2-Propylenimine (2-Methyl aziridine)91225Quinoline106514Quinone100425Styrene96093Styrene oxide17460162,3,7,8-Tetrachlorodibenzo-p-dioxin793451,1,2,2-Tetrachloroethane127184Tetrachloroethylene (Perchloroethylene)7550450Titanium tetrachloride108883Toluene958072,4-Toluene diamine5848492,4-Toluene diisocyanate95534o-Toluidine8001352Toxaphene (chlorinated camphene)1208211,2,4-Trichlorobenzene790051,1,2-Trichloroethane79016Trichloroethylene959542,4,5-Trichlorophenol880622,4,6-Trichlorophenol121448Triethylamine1582098Trifluralin5408412,2,4-Trimethylpentane108054Vinyl acetate593602Vinyl bromide75014Vinyl chloride75354Vinylidene chloride (1,1-Dichloroethylene)1330207Xylenes (isomers and mixture)95476o-Xylenes108383m-Xylenes106423p-Xylenes0Antimony Compounds0Arsenic Compounds (inorganic including arsine)0Beryllium Compounds0Cadmium Compounds0Chromium Compounds0Cobalt Compounds0Coke Oven Emissions0Cyanide Compounds 10Glycol ethers 2 (See Modification)0Lead Compounds0Manganese Compounds0Mercury Compounds0Fine mineral fibers 30Nickel Compounds0Polycyclic Organic Matter 40Radionuclides (including radon) 50Selenium 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. Polymers are excluded from the glycol category. (See Modification)
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 ºC.
5 – A type of atom which spontaneously undergoes radioactive decay.
