{"data":{"id":"us/29-cfr-1926.55","jurisdiction":"us","citation":"29 CFR 1926.55","heading":"Gases, vapors, fumes, dusts, and mists.","body":"(a) Employers must limit an employee's exposure to any substance listed in Table 1 or 2 of this section in accordance with the following:\n(1) Substances with limits preceded by (C)—Ceiling Values. An employee's exposure, as determined from breathing-zone air samples, to any substance in Table 1 of this section with a permissible exposure limit preceded by (C) must at no time exceed the exposure limit specified for that substance. If instantaneous monitoring is not feasible, then the employer must assess the ceiling as a 15-minute time-weighted average exposure that the employer cannot exceed at any time during the working day.\n(2) Other substances—8-hour Time Weighted Averages. An employee's exposure, as determined from breathing-zone air samples, to any substance in Table 1 or 2 of this section with a permissible exposure limit not preceded by (C) must not exceed the limit specified for that substance measured as an 8-hour time-weighted average in any work shift.\n(b) To achieve compliance with paragraph (a) of this section, administrative or engineering controls must first be implemented whenever feasible. When such controls are not feasible to achieve full compliance, protective equipment or other protective measures shall be used to keep the exposure of employees to air contaminants within the limits prescribed in this section. Any equipment and technical measures used for this purpose must first be approved for each particular use by a competent industrial hygienist or other technically qualified person. Whenever respirators are used, their use shall comply with § 1926.103.\n(c) Paragraphs (a) and (b) of this section do not apply to the exposure of employees to airborne asbestos, tremolite, anthophyllite, or actinolite dust. Whenever any employee is exposed to airborne asbestos, tremolite, anthophyllite, or actinolite dust, the requirements of § 1926.1101 shall apply.\n(d) Paragraphs (a) and (b) of this section do not apply to the exposure of employees to formaldehyde. Whenever any employee is exposed to formaldehyde, the requirements of § 1910.1048 of this title shall apply.\nTable 1 to § 1926.55—Permissible Exposure Limits for Airborne Contaminants\nSubstance CAS No. d ppm a mg/m 3 b Skin designation *\nAbate; see Temephos\nAcetaldehyde 75-07-0 200 360 —\nAcetic acid 64-19-7 10 25 —\nAcetic anhydride 108-24-7 5 20 —\nAcetone 67-64-1 1000 2400 —\nAcetonitrile 75-05-8 40 70 —\n2-Acetylaminofluorine; see § 1926.1114 53-96-3\nAcetylene 74-86-2 E\nAcetylene dichloride; see 1,2-Dichloroethylene\nAcetylene tetrabromide 79-27-6 1 14 —\nAcrolein 107-02-8 0.1 0.25 —\nAcrylamide 79-06-1 — 0.3 X\nAcrylonitrile; see § 1926.1145 107-13-1\nAldrin 309-00-2 — 0.25 X\nAllyl alcohol 107-18-6 2 5 X\nAllyl chloride 107-05-1 1 3 —\nAllyl glycidyl ether (AGE) 106-92-3 (C)10 (C)45 —\nAllyl propyl disulfide 2179-59-1 2 12 —\nalpha-Alumina 1344-28-1\nTotal dust — —\nRespirable fraction — —\nAlundum; see alpha-Alumina\n4-Aminodiphenyl; see § 1926.1111 92-67-1\n2-Aminoethanol; see Ethanolamine\n2-Aminopyridine 504-29-0 0.5 2 —\nAmmonia 7664-41-7 50 35 —\nAmmonium sulfamate 7773-06-0\nTotal dust — 15 —\nRespirable fraction — 5 —\nn-Amyl acetate 628-63-7 100 525 —\nsec-Amyl acetate 626-38-0 125 650 —\nAniline and homologs 62-53-3 5 19 X\nAnisidine (o-, p-isomers) 29191-52-4 — 0.5 X\nAntimony and compounds (as Sb) 7440-36-0 — 0.5 —\nANTU (alpha Naphthylthiourea) 86-88-4 — 0.3 —\nArgon 7440-37-1 E\nArsenic, inorganic compounds (as As); see § 1926.1118 7440-38-2 — — —\nArsenic, organic compounds (as As) 7440-38-2 — 0.5 —\nArsine 7784-42-1 0.05 0.2 —\nAsbestos; see § 1926.1101\nAzinphos-methyl 86-50-0 — 0.2 X\nBarium, soluble compounds (as Ba) 7440-39-3 — 0.5 —\nBenzene g; see § 1926.1128 71-43-2\nBenzidine; see § 1926.1110 92-87-5\np-Benzoquinone; see Quinone\nBenzo(a)pyrene; see Coal tar pitch volatiles\nBenzoyl peroxide 94-36-0 — 5 —\nBenzyl chloride 100-44-7 1 5 —\nBeryllium and beryllium compounds (as Be); see 1926.1124 (q) 7440-41-7 — 0.002 —\nBiphenyl; see Diphenyl\nBisphenol A; see Diglycidyl ether\nBoron oxide 1303-86-2\nTotal dust — 15 —\nBoron tribromide 10294-33-4 1 10 —\nBoron trifluoride 7637-07-2 (C)1 (C)3 —\nBromine 7726-95-6 0.1 0.7 —\nBromine pentafluoride 7789-30-2 0.1 0.7 —\nBromoform 75-25-2 0.5 5 X\nButadiene (1,3-Butadiene); see 29 CFR 1910.1051; 29 CFR 1910.19(l) 106-99-0 STEL 1 ppm/5 ppm —\nButanethiol; see Butyl mercaptan\n2-Butanone (Methyl ethyl ketone) 78-93-3 200 590 —\n2-Butoxyethanol 111-76-2 50 240 X\nn-Butyl-acetate 123-86-4 150 710 —\nsec-Butyl acetate 105-46-4 200 950 —\ntert-Butyl acetate 540-88-5 200 950 —\nn-Butyl alcohol 71-36-3 100 300 —\nsec-Butyl alcohol 78-92-2 150 450 —\ntert-Butyl alcohol 75-65-0 100 300 —\nButylamine 109-73-9 (C)5 (C)15 X\ntert-Butyl chromate (as CrO3); see 1926.1126 n 1189-85-1\nn-Butyl glycidyl ether (BGE) 2426-08-6 50 270 —\nButyl mercaptan 109-79-5 0.5 1.5 —\np-tert-Butyltoluene 98-51-1 10 60 —\nCadmium (as Cd); see 1926.1127 7440-43-9\nCalcium carbonate 1317-65-3\nTotal dust — —\nRespirable fraction — —\nCalcium oxide 1305-78-8 — 5 —\nCalcium sulfate 7778-18-9\nTotal dust — 15 —\nRespirable fraction — 5 —\nCamphor, synthetic 76-22-2 — 2 —\nCarbaryl (Sevin) 63-25-2 — 5 —\nCarbon black 1333-86-4 — 3.5 —\nCarbon dioxide 124-38-9 5000 9000 —\nCarbon disulfide 75-15-0 20 60 X\nCarbon monoxide 630-08-0 50 55 —\nCarbon tetrachloride 56-23-5 10 65 X\nCellulose 9004-34-6\nTotal dust — —\nRespirable fraction — —\nChlordane 57-74-9 — 0.5 X\nChlorinated camphene 8001-35-2 — 0.5 X\nChlorinated diphenyl oxide 55720-99-5 — 0.5 —\nChlorine 7782-50-5 1 3 —\nChlorine dioxide 10049-04-4 0.1 0.3\nChlorine trifluoride 7790-91-2 (C)0.1 (C)0.4 —\nChloroacetaldehyde 107-20-0 (C)1 (C)3 —\na-Chloroacetophenone (Phenacyl chloride) 532-27-4 0.05 0.3 —\nChlorobenzene 108-90-7 75 350 —\no-Chlorobenzylidene malononitrile 2698-41-1 0.05 0.4 —\nChlorobromomethane 74-97-5 200 1050 —\n2-Chloro-1,3-butadiene; see beta-Chloroprene\nChlorodiphenyl (42% Chlorine) (PCB) 53469-21-9 — 1 X\nChlorodiphenyl (54% Chlorine) (PCB) 11097-69-1 — 0.5 X\n1-Chloro,2,3-epoxypropane; see Epichlorohydrin\n2-Chloroethanol; see Ethylene chlorohydrin\nChloroethylene; see Vinyl chloride\nChloroform (Trichloromethane) 67-66-3 (C)50 (C)240 —\nbis(Chloromethyl) ether; see § 1926.1108 542-88-1\nChloromethyl methyl ether; see § 1926.1106 107-30-2\n1-Chloro-1-nitropropane 600-25-9 20 100 —\nChloropicrin 76-06-2 0.1 0.7 —\nbeta-Chloroprene 126-99-8 25 90 X\nChromium (II) compounds\n(as Cr) 7440-47-3 — 0.5 —\nChromium (III) compounds\n(as Cr) 7440-47-3 — 0.5 —\nChromium (VI) compounds; See 1926.1126 o\nChromium metal and insol. salts (as Cr) 7440-47-3 — 1 —\nChrysene; see Coal tar pitch volatiles\nCoal tar pitch volatiles (benzene soluble fraction), anthracene, BaP, phenanthrene, acridine, chrysene, pyrene 65996-93-2 — 0.2 —\nCobalt metal, dust, and fume (as Co) 7440-48-4 — 0.1 —\nCopper 7440-50-8\nFume (as Cu) — 0.1 —\nDusts and mists (as Cu) — 1 —\nCorundum; see Emery\nCotton dust (raw) — 1\nCrag herbicide (Sesone) 136-78-7\nTotal dust — —\nRespirable fraction — —\nCresol, all isomers 1319-77-3 5 22 X\nCrotonaldehyde 123-73-9; 2 6\n4170-30-3\nCumene 98-82-8 50 245 X\nCyanides (as CN) Varies with Compound — 5 X\nCyanogen 460-19-5 10 — —\nCyclohexane 110-82-7 300 1050 —\nCyclohexanol 108-93-0 50 200 —\nCyclohexanone 108-94-1 50 200 —\nCyclohexene 110-83-8 300 1015 —\nCyclonite 121-82-4 — 1.5 X\nCyclopentadiene 542-92-7 75 200 —\nDDT, see Dichlorodiphenyltrichloroethane\nDDVP, see Dichlorvos\n2,4-D (Dichlorophenoxyacetic acid) 94-75-7 — 10 —\nDecaborane 17702-41-9 0.05 0.3 X\nDemeton (Systox) 8065-48-3 — 0.1 X\nDiacetone alcohol (4-Hydroxy-4-methyl-2-pentanone) 123-42-2 50 240 —\n1,2-Diaminoethane; see Ethylenediamine\nDiazomethane 334-88-3 0.2 0.4 —\nDiborane 19287-45-7 0.1 0.1 —\n1,2-Dibromo-3-chloropropane (DBCP); see § 1926.1144 96-12-8 —\n1,2-Dibromoethane; see Ethylene dibromide\nDibutyl phosphate 107-66-4 1 5 —\nDibutyl phthalate 84-74-2 — 5 —\nDichloroacetylene 7572-29-4 (C)0.1 (C)0.4 —\no-Dichlorobenzene 95-50-1 (C)50 (C)300 —\np-Dichlorobenzene 106-46-7 75 450 —\n3,3′-Dichlorobenzidine; see § 1926.1107 91-94-1\nDichlorodifluoromethane 75-71-8 1000 4950 —\n1,3-Dichloro-5,5-dimethyl hydantoin 118-52-5 — 0.2 —\nDichlorodiphenyltrichloroethane (DDT) 50-29-3 — 1 X\n1,1-Dichloroethane 75-34-3 100 400 —\n1,2-Dichloroethane; see Ethylene dichloride\n1,2-Dichloroethylene 540-59-0 200 790 —\nDichloroethyl ether 111-44-4 (C)15 (C)90 X\nDichloromethane; see Methylene chloride\nDichloromonofluoromethane 75-43-4 1000 4200 —\n1,1-Dichloro-1-nitroethane 594-72-9 (C)10 (C)60 —\n1,2-Dichloropropane; see Propylene dichloride\nDichlorotetrafluoroethane 76-14-2 1000 7000 —\nDichlorvos (DDVP) 62-73-7 — 1 X\nDieldrin 60-57-1 — 0.25 X\nDiethylamine 109-89-7 25 75 —\n2-Diethylaminoethanol 100-37-8 10 50 X\nDiethylene triamine 111-40-0 (C)10 (C)42 X\nDiethyl ether; see Ethyl ether\nDifluorodibromomethane 75-61-6 100 860 —\nDiglycidyl ether (DGE) 2238-07-5 (C)0.5 (C)2.8 —\nDihydroxybenzene; see Hydroquinone\nDiisobutyl ketone 108-83-8 50 290 —\nDiisopropylamine 108-18-9 5 20 X\n4-Dimethylaminoazobenzene; see § 1926.1115 60-11-7\nDimethoxymethane; see Methylal\nDimethyl acetamide 127-19-5 10 35 X\nDimethylamine 124-40-3 10 18 —\nDimethylaminobenzene; see Xylidine\nDimethylaniline (N,N-Dimethylaniline) 121-69-7 5 25 X\nDimethylbenzene; see Xylene\nDimethyl-1,2-dibromo- 2,2-dichloroethyl phosphate 300-76-5 — 3 —\nDimethylformamide 68-12-2 10 30 X\n2,6-Dimethyl-4-heptanone; see Diisobutyl ketone\n1,1-Dimethylhydrazine 57-14-7 0.5 1 X\nDimethylphthalate 131-11-3 — 5 —\nDimethyl sulfate 77-78-3 1 5 X\nDinitrobenzene (all isomers) 1 X\n(ortho) 528-29-0\n(meta) 99-65-0\n(para) 100-25-4\nDinitro-o-cresol 534-52-1 — 0.2 X\nDinitrotoluene 25321-14-6 — 1.5 X\nDioxane (Diethylene dioxide) 123-91-1 100 360 X\nDiphenyl (Biphenyl) 92-52-4 0.2 1 —\nDiphenylamine 122-39-4 — 10 —\nDiphenylmethane diisocyanate; see Methylene bisphenyl isocyanate\nDipropylene glycol methyl ether 34590-94-8 100 600 X\nDi-sec octyl phthalate (Di-(2-ethylhexyl) phthalate) 117-81-7 — 5 —\nEmery 12415-34-8\nTotal dust — —\nRespirable fraction — —\nEndosulfan 115-29-7 — 0.1 X\nEndrin 72-20-8 — 0.1 X\nEpichlorohydrin 106-89-8 5 19 X\nEPN 2104-64-5 — 0.5 X\n1,2-Epoxypropane; see Propylene oxide\n2,3-Epoxy-1-propanol; see Glycidol\nEthane 74-84-0 E\nEthanethiol; see Ethyl mercaptan\nEthanolamine 141-43-5 3 6 —\n2-Ethoxyethanol (Cellosolve) 110-80-5 200 740 X\n2-Ethoxyethyl acetate (Cellosolve acetate) 111-15-9 100 540 X\nEthyl acetate 141-78-6 400 1400 —\nEthyl acrylate 140-88-5 25 100 X\nEthyl alcohol (Ethanol) 64-17-5 1000 1900 —\nEthylamine 75-04-7 10 18 —\nEthyl amyl ketone (5-Methyl-3-heptanone) 541-85-5 25 130 —\nEthyl benzene 100-41-4 100 435 —\nEthyl bromide 74-96-4 200 890 —\nEthyl butyl ketone (3-Heptanone) 106-35-4 50 230 —\nEthyl chloride 75-00-3 1000 2600 —\nEthyl ether 60-29-7 400 1200 —\nEthyl formate 109-94-4 100 300 —\nEthyl mercaptan 75-08-1 0.5 1 —\nEthyl silicate 78-10-4 100 850 —\nEthylene 74-85-1 E\nEthylene chlorohydrin 107-07-3 5 16 X\nEthylenediamine 107-15-3 10 25 —\nEthylene dibromide 106-93-4 (C)25 (C)190 X\nEthylene dichloride (1,2-Dichloroethane) 107-06-2 50 200 —\nEthylene glycol dinitrate 628-96-6 (C)0.2 (C)1 X\nEthylene glycol methyl acetate; see Methyl cellosolve acetate\nEthyleneimine; see § 1926.1112 151-56-4\nEthylene oxide; see § 1926.1147 75-21-8\nEthylidene chloride; see 1,1-Dichloroethane\nN-Ethylmorpholine 100-74-3 20 94 X\nFerbam 14484-64-1\nTotal dust — 15 —\nFerrovanadium dust 12604-58-9 — 1 —\nFibrous Glass\nTotal dust —\nRespirable fraction — —\nFluorides (as F) Varies with compound — 2.5 —\nFluorine 7782-41-4 0.1 0.2 —\nFluorotrichloromethane (Trichlorofluoromethane) 75-69-4 1000 5600 —\nFormaldehyde; see § 1926.1148 50-00-0\nFormic acid 64-18-6 5 9 —\nFurfural 98-01-1 5 20 X\nFurfuryl alcohol 98-00-0 50 200 —\nGasoline 8006-61-9 A 3 —\nGlycerin (mist) 56-81-5\nTotal dust — —\nRespirable fraction — —\nGlycidol 556-52-5 50 150 —\nGlycol monoethyl ether; see 2-Ethoxyethanol\nGraphite, natural, respirable dust 7782-42-5 (2) (2) (2)\nGraphite, synthetic\nTotal dust — —\nRespirable fraction — —\nGuthion; see Azinphos methyl\nGypsum 13397-24-5\nTotal dust — —\nRespirable fraction — —\nHafnium 7440-58-6 — 0.5 —\nHelium 7440-59-7 E\nHeptachlor 76-44-8 — 0.5 X\nHeptane (n-Heptane) 142-82-5 500 2000 —\nHexachloroethane 67-72-1 1 10 X\nHexachloronaphthalene 1335-87-1 — 0.2 X\nn-Hexane 110-54-3 500 1800 —\n2-Hexanone (Methyl n-butyl ketone) 591-78-6 100 410 —\nHexone (Methyl isobutyl ketone) 108-10-1 100 410 —\nsec-Hexyl acetate 108-84-9 50 300 —\nHydrazine 302-01-2 1 1.3 X\nHydrogen 1333-74-0 E\nHydrogen bromide 10035-10-6 3 10 —\nHydrogen chloride 7647-01-0 (C)5 (C)7 —\nHydrogen cyanide 74-90-8 10 11 X\nHydrogen fluoride (as F) 7664-39-3 3 2 —\nHydrogen peroxide 7722-84-1 1 1.4 —\nHydrogen selenide (as Se) 7783-07-5 0.05 .02 —\nHydrogen sulfide 7783-06-4 10 15 —\nHydroquinone 123-31-9 — 2 —\nIndene 95-13-6 10 45 —\nIndium and compounds (as In) 7440-74-6 — 0.1 —\nIodine 7553-56-2 (C)0.1 (C)1 —\nIron oxide fume 1309-37-1 — 10 —\nIron salts (soluble) (as Fe) Varies with compound — 1 —\nIsoamyl acetate 123-92-2 100 525 —\nIsoamyl alcohol (primary and secondary) 123-51-3 100 360 —\nIsobutyl acetate 110-19-0 150 700 —\nIsobutyl alcohol 78-83-1 100 300 —\nIsophorone 78-59-1 25 140 —\nIsopropyl acetate 108-21-4 250 950 —\nIsopropyl alcohol 67-63-0 400 980 —\nIsopropylamine 75-31-0 5 12 —\nIsopropyl ether 108-20-3 500 2100 —\nIsopropyl glycidyl ether (IGE) 4016-14-2 50 240 —\nKaolin 1332-58-7\nTotal dust — —\nRespirable fraction — —\nKetene 463-51-4 0.5 0.9 —\nLead, inorganic (as Pb); see 1926.62 7439-92-1\nLimestone 1317-65-3\nTotal dust — —\nRespirable fraction — —\nLindane 58-89-9 — 0.5 X\nLithium hydride 7580-67-8 — 0.025 —\nL.P.G. (Liquefied petroleum gas) 68476-85-7 1000 1800\nMagnesite 546-93-0\nTotal dust — —\nRespirable fraction — —\nMagnesium oxide fume 1309-48-4\nTotal particulate 15 — —\nMalathion 121-75-5\nTotal dust — 15 X\nMaleic anhydride 108-31-6 0.25\nManganese compounds (as Mn) 7439-96-5 — (C)5 —\nManganese fume (as Mn) 7439-96-5 — (C)5 —\nMarble 1317-65-3\nTotal dust — —\nRespirable fraction — —\nMercury (aryl and inorganic)(as Hg) 7439-97-6 0.1 X\nMercury (organo) alkyl compounds (as Hg) 7439-97-6 — 0.01 X\nMercury (vapor) (as Hg) 7439-97-6 — 0.1 X\nMesityl oxide 141-79-7 25 100 —\nMethane 74-82-8 E\nMethanethiol; see Methyl mercaptan\nMethoxychlor 72-43-5\nTotal dust — 15 —\n2-Methoxyethanol (Methyl cellosolve) 109-86-4 25 80 X\n2-Methoxyethyl acetate (Methyl cellosolve acetate) 110-49-6 25 120 X\nMethyl acetate 79-20-9 200 610 —\nMethyl acetylene (Propyne) 74-99-7 1000 1650 —\nMethyl acetylene-propadiene mixture (MAPP) 1000 1800 —\nMethyl acrylate 96-33-3 10 35 X\nMethylal (Dimethoxy-methane) 109-87-5 1000 3100 —\nMethyl alcohol 67-56-1 200 260 —\nMethylamine 74-89-5 10 12 —\nMethyl amyl alcohol; see Methyl isobutyl carbinol\nMethyl n-amyl ketone 110-43-0 100 465 —\nMethyl bromide 74-83-9 (C)20 (C)80 X\nMethyl butyl ketone; see 2-Hexanone\nMethyl cellosolve; see 2-Methoxyethanol\nMethyl cellosolve acetate; see 2-Methoxyethyl acetate\nMethylene chloride; see § 1910.1052\nMethyl chloroform (1,1,1-Trichloroethane) 71-55-6 350 1900 —\nMethylcyclohexane 108-87-2 500 2000 —\nMethylcyclohexanol 25639-42-3 100 470 —\no-Methylcyclohexanone 583-60-8 100 460 X\nMethylene chloride 75-09-2 500 1740 —\nMethylenedianiline (MDA) 101-77-9\nMethyl ethyl ketone (MEK); see 2-Butanone\nMethyl formate 107-31-3 100 250 —\nMethyl hydrazine (Monomethyl hydrazine) 60-34-4 (C)0.2 (C)0.35 X\nMethyl iodide 74-88-4 5 28 X\nMethyl isoamyl ketone 110-12-3 100 475 —\nMethyl isobutyl carbinol 108-11-2 25 100 X\nMethyl isobutyl ketone; see Hexone\nMethyl isocyanate 624-83-9 0.02 0.05 X\nMethyl mercaptan 74-93-1 0.5 1 —\nMethyl methacrylate 80-62-6 100 410 —\nMethyl propyl ketone; see 2-Pentanone\nMethyl silicate 681-84-5 (C)5 (C)30 —\nalpha-Methyl styrene 98-83-9 (C)100 (C)480 —\nMethylene bisphenyl isocyanate (MDI) 101-68-8 (C)0.02 (C)0.2 —\nMica; see Silicates\nMolybdenum (as Mo) 7439-98-7\nSoluble compounds — 5 —\nInsoluble compounds\nTotal dust — 15 —\nMonomethyl aniline 100-61-8 2 9 X\nMonomethyl hydrazine; see Methyl hydrazine\nMorpholine 110-91-8 20 70 X\nNaphtha (Coal tar) 8030-30-6 100 400 —\nNaphthalene 91-20-3 10 50 —\nalpha-Naphthylamine; see § 1926.1104 134-32-7\nbeta-Naphthylamine; see § 1926.1109 91-59-8 —\nNeon 7440-01-9 E\nNickel carbonyl (as Ni) 13463-39-3 0.001 0.007 —\nNickel, metal and insoluble compounds (as Ni) 7440-02-0 — 1 —\nNickel, soluble compounds (as Ni) 7440-02-0 — 1 —\nNicotine 54-11-5 — 0.5 X\nNitric acid 7697-37-2 2 5 —\nNitric oxide 10102-43-9 25 30 —\np-Nitroaniline 100-01-6 1 6 X\nNitrobenzene 98-95-3 1 5 X\np-Nitrochlorobenzene 100-00-5 — 1 X\n4-Nitrodiphenyl; see § 1926.1103 92-93-3\nNitroethane 79-24-3 100 310 —\nNitrogen 7727-37-9 E\nNitrogen dioxide 10102-44-0 (C)5 (C)9 —\nNitrogen trifluoride 7783-54-2 10 29 —\nNitroglycerin 55-63-0 (C)0.2 (C)2 X\nNitromethane 75-52-5 100 250 —\n1-Nitropropane 108-03-2 25 90 —\n2-Nitropropane 79-46-9 25 90 —\nN-Nitrosodimethylamine; see § 1926.1116 62-79-9 —\nNitrotoluene (all isomers) 5 30 X\no-isomer 88-72-2;\nm-isomer 99-08-1;\np-isomer 99-99-0\nNitrotrichloromethane; see Chloropicrin\nNitrous oxide 10024-97-2 E\nOctachloronaphthalene 2234-13-1 — 0.1 X\nOctane 111-65-9 400 1900 —\nOil mist, mineral 8012-95-1 — 5 —\nOsmium tetroxide (as Os) 20816-12-0 — 0.002 —\nOxalic acid 144-62-7 — 1 —\nOxygen difluoride 7783-41-7 0.05 0.1 —\nOzone 10028-15-6 0.1 0.2 —\nParaquat, respirable dust 4685-14-7; — 0.5 X\n1910-42-5;\n2074-50-2\nParathion 56-38-2 — 0.1 X\nParticulates not otherwise regulated\nTotal dust organic and inorganic — 15 —\nPCB; see Chlorodiphenyl (42% and 54% chlorine)\nPentaborane 19624-22-7 0.005 0.01 —\nPentachloronaphthalene 1321-64-8 — 0.5 X\nPentachlorophenol 87-86-5 — 0.5 X\nPentaerythritol 115-77-5\nTotal dust — —\nRespirable fraction — —\nPentane 109-66-0 500 1500 —\n2-Pentanone (Methyl propyl ketone) 107-87-9 200 700 —\nPerchloroethylene (Tetrachloroethylene) 127-18-4 100 670 —\nPerchloromethyl mercaptan 594-42-3 0.1 0.8 —\nPerchloryl fluoride 7616-94-6 3 13.5 —\nPetroleum distillates (Naphtha)(Rubber Solvent) A 3 —\nPhenol 108-95-2 5 19 X\np-Phenylene diamine 106-50-3 — 0.1 X\nPhenyl ether, vapor 101-84-8 1 7 —\nPhenyl ether-biphenyl mixture, vapor 1 7 —\nPhenylethylene; see Styrene\nPhenyl glycidyl ether (PGE) 122-60-1 10 60 —\nPhenylhydrazine 100-63-0 5 22 X\nPhosdrin (Mevinphos) 7786-34-7 — 0.1 X\nPhosgene (Carbonyl chloride) 75-44-5 0.1 0.4 —\nPhosphine 7803-51-2 0.3 0.4 —\nPhosphoric acid 7664-38-2 — 1 —\nPhosphorus (yellow) 7723-14-0 — 0.1 —\nPhosphorus pentachloride 10026-13-8 — 1 —\nPhosphorus pentasulfide 1314-80-3 — 1 —\nPhosphorus trichloride 7719-12-2 0.5 3 —\nPhthalic anhydride 85-44-9 2 12 —\nPicric acid 88-89-1 — 0.1 X\nPindone (2-Pivalyl-1,3-indandione) 83-26-1 — 0.1 —\nPlaster of Paris 26499-65-0\nTotal dust — —\nRespirable fraction — —\nPlatinum (as Pt) 7440-06-4\nMetal — — —\nSoluble salts — 0.002 —\nPolytetrafluoroethylene decomposition products A 2\nPortland cement 65997-15-1\nTotal dust — 15 —\nRespirable fraction 5 —\nPropane 74-98-6 E\nPropargyl alcohol 107-19-7 1 — X\nbeta-Propriolactone; see § 1926.1113 57-57-8\nn-Propyl acetate 109-60-4 200 840 —\nn-Propyl alcohol 71-23-8 200 500 —\nn-Propyl nitrate 627-13-4 25 110 —\nPropylene dichloride 78-87-5 75 350 —\nPropylene imine 75-55-8 2 5 X\nPropylene oxide 75-56-9 100 240 —\nPropyne; see Methyl acetylene\nPyrethrum 8003-34-7 — 5 —\nPyridine 110-86-1 5 15 —\nQuinone 106-51-4 0.1 0.4 —\nRDX; see Cyclonite\nRhodium (as Rh), metal fume and insoluble compounds 7440-16-6 — 0.1 —\nRhodium (as Rh), soluble compounds 7440-16-6 — 0.001 —\nRonnel 299-84-3 — 10 —\nRotenone 83-79-4 — 5 —\nRouge\nTotal dust — —\nRespirable fraction — —\nSelenium compounds (as Se) 7782-49-2 — 0.2 —\nSelenium hexafluoride (as Se) 7783-79-1 0.05 0.4 —\nSilica, amorphous, precipitated and gel 112926-00-8 (2) (2) (2)\nSilica, amorphous, diatomaceous earth, containing less than 1% crystalline silica 61790-53-2 (2) (2) (2)\nSilica, crystalline, respirable dust\nCristobalite; see 1926.1153 14464-46-1\nQuartz; see 1926.1153 5 14808-60-7\nTripoli (as quartz); see 1926.1153 5 1317-95-9\nTridymite; see 1926.1153 15468-32-3\nSilica, fused, respirable dust 60676-86-0 (2) (2) (2)\nSilicates (less than 1% crystalline silica)\nMica (respirable dust) 12001-26-2 (2) (2) (2)\nSoapstone, total dust (2) (2) (2)\nSoapstone, respirable dust (2) (2) (2)\nTalc (containing asbestos); use asbestos limit; see § 1926.1101\nTalc (containing no asbestos), respirable dust 14807-96-6 (2) (2) (2)\nTremolite, asbestiform; see § 1926.1101\nSilicon carbide 409-21-2\nTotal dust — —\nRespirable fraction — —\nSilver, metal and soluble compounds (as Ag) 7440-22-4 — 0.01 —\nSoapstone; see Silicates\nSodium fluoroacetate 62-74-8 — 0.05 X\nSodium hydroxide 1310-73-2 — 2 —\nStarch 9005-25-8\nTotal dust — —\nRespirable fraction — —\nStibine 7803-52-3 0.1 0.5 —\nStoddard solvent 8052-41-3 200 1150 —\nStrychnine 57-24-9 — 0.15 —\nStyrene 100-42-5 (C)100 (C)420 —\nSucrose 57-50-1\nTotal dust — —\nRespirable fraction — —\nSulfur dioxide 7446-09-5 5 13 —\nSulfur hexafluoride 2551-62-4 1000 6000 —\nSulfuric acid 7664-93-9 — 1 —\nSulfur monochloride 10025-67-9 1 6 —\nSulfur pentafluoride 5714-22-7 0.025 0.25 —\nSulfuryl fluoride 2699-79-8 5 20 —\nSystox, see Demeton\n2,4,5-T (2,4,5-trichlorophenoxyacetic acid) 93-76-5 — 10 —\nTalc; see Silicates—\nTantalum, metal and oxide dust 7440-25-7 — 5 —\nTEDP (Sulfotep) 3689-24-5 — 0.2 X\nTeflon decomposition products A2\nTellurium and compounds (as Te) 13494-80-9 — 0.1 —\nTellurium hexafluoride (as Te) 7783-80-4 0.02 0.2 —\nTemephos 3383-96-8\nTotal dust — —\nRespirable fraction — —\nTEPP (Tetraethyl pyrophosphate) 107-49-3 — 0.05 X\nTerphenyls 26140-60-3 (C)1 (C)9 —\n1,1,1,2-Tetrachloro-2,2-difluoroethane 76-11-9 500 4170 —\n1,1,2,2-Tetrachloro-1,2-difluoroethane 76-12-0 500 4170 —\n1,1,2,2-Tetrachloroethane 79-34-5 5 35 X\nTetrachloroethylene; see Perchloroethylene\nTetrachloromethane; see Carbon tetrachloride\nTetrachloronaphthalene 1335-88-2 — 2 X\nTetraethyl lead (as Pb) 78-00-2 — 0.1 X\nTetrahydrofuran 109-99-9 200 590 —\nTetramethyl lead, (as Pb) 75-74-1 — 0.15 X\nTetramethyl succinonitrile 3333-52-6 0.5 3 X\nTetranitromethane 509-14-8 1 8 —\nTetryl (2,4,6-Trinitrophenylmethylnitramine) 479-45-8 — 1.5 X\nThallium, soluble compounds (as Tl) 7440-28-0 — 0.1 X\nThiram 137-26-8 — 5 —\nTin, inorganic compounds (except oxides) (as Sn) 7440-31-5 — 2 —\nTin, organic compounds (as Sn) 7440-31-5 — 0.1 —\nTin oxide (as Sn) 21651-19-4 — — —\nTotal dust — —\nRespirable fraction — —\nTitanium dioxide 13463-67-7\nTotal dust — —\nToluene 108-88-3 200 750 —\nToluene-2,4-diisocyanate (TDI) 584-84-9 (C)0.02 (C)0.14 —\no-Toluidine 95-53-4 5 22 X\nToxaphene; see Chlorinated camphene\nTremolite; see Silicates\nTributyl phosphate 126-73-8 — 5 —\n1,1,1-Trichloroethane; see Methyl chloroform\n1,1,2-Trichloroethane 79-00-5 10 45 X\nTrichloroethylene 79-01-6 100 535 —\nTrichloromethane; see Chloroform\nTrichloronaphthalene 1321-65-9 — 5 X\n1,2,3-Trichloropropane 96-18-4 50 300 —\n1,1,2-Trichloro-1,2,2-trifluoroethane 76-13-1 1000 7600 —\nTriethylamine 121-44-8 25 100 —\nTrifluorobromomethane 75-63-8 1000 6100 —\nTrimethyl benzene 25551-13-7 25 120 —\n2,4,6-Trinitrophenol; see Picric acid\n2,4,6-Trinitrophenylmethylnitramine; see Tetryl\n2,4,6-Trinitrotoluene (TNT) 118-96-7 — 1.5 X\nTriorthocresyl phosphate 78-30-8 — 0.1 —\nTriphenyl phosphate 115-86-6 — 3 —\nTungsten (as W) 7440-33-7\nInsoluble compounds — 5 —\nSoluble compounds — 1 —\nTurpentine 8006-64-2 100 560 —\nUranium (as U) 7440-61-1\nSoluble compounds — 0.2 —\nInsoluble compounds — 0.2 —\nVanadium 1314-62-1\nRespirable dust (as V2 O5) — (C)0.5 —\nFume (as V2 O5) — (C)0.1 —\nVegetable oil mist\nTotal dust — —\nRespirable fraction — —\nVinyl benzene; see Styrene\nVinyl chloride; see § 1926.1117 75-01-4\nVinyl cyanide; see Acrylonitrile\nVinyl toluene 25013-15-4 100 480 —\nWarfarin 81-81-2 — 0.1 —\nXylenes (o-, m-, p-isomers) 1330-20-7 100 435 —\nXylidine 1300-73-8 5 25 X\nYttrium 7440-65-5 — 1 —\nZinc chloride fume 7646-85-7 — 1 —\nZinc oxide fume 1314-13-2 — 5 —\nZinc oxide 1314-13-2\nTotal dust — 15 —\nRespirable fraction — 5 —\nZirconium compounds (as Zr) 7440-67-7 — 5\nTable 2 to § 1926.55—Mineral Dusts\nSubstance mppcf (j)\nSILICA:\nCrystalline 250(k)\nQuartz. Threshold Limit calculated from the formula(p) % SiO2 + 5\nCristobalite\nAmorphous, including natural diatomaceous earth 20\nSILICATES (less than 1% crystalline silica)\nMica 20\nPortland cement 50\nSoapstone 20\nTalc (non-asbestiform) 20\nTalc (fibrous), use asbestos limit —\nGraphite (natural) 15\nInert or Nuisance Particulates: (m) 50 (or 15 mg/m3 whichever is the smaller) of total dust \u003c1% SiO2\n[Inert or Nuisance Dusts includes all mineral, inorganic, and organic dusts as indicated by examples in TLV's appendix D]\nConversion factors\nmppcf × 35.3 = million particles per cubic meter = particles per c.c.\nFootnotes to Tables 1 and 2 of this section:\n1 [Reserved]\n2 See Table 2 of this section.\n3 Use Asbestos Limit § 1926.1101.\n4 [Reserved]\n5 See Table 2 of this section for the exposure limit for any operations or sectors where the exposure limit in § 1926.1153 is stayed or is otherwise not in effect.\n* An “X” designation in the “Skin Designation” column indicates that the substance is a dermal hazard.\na Parts of vapor or gas per million parts of contaminated air by volume at 25 °C and 760 torr.\nb Milligrams of substance per cubic meter of air. When entry is in this column only, the value is exact; when listed with a ppm entry, it is approximate.\nc [Reserved]\nd The CAS number is for information only. Enforcement is based on the substance name. For an entry covering more than one metal compound, measured as the metal, the CAS number for the metal is given—not CAS numbers for the individual compounds.\ne-f [Reserved]\ng For sectors excluded from § 1926.1128 the limit is 10 ppm TWA.\nh-i [Reserved]\nj Millions of particles per cubic foot of air, based on impinger samples counted by light-field techniques.\nk The percentage of crystalline silica in the formula is the amount determined from airborne samples, except in those instances in which other methods have been shown to be applicable.\nl [Reserved]\nm Covers all organic and inorganic particulates not otherwise regulated. Same as Particulates Not Otherwise Regulated.\nn If the exposure limit in § 1926.1126 is stayed or is otherwise not in effect, the exposure limit is a ceiling of 0.1 mg/m3.\no If the exposure limit in § 1926.1126 is stayed or is otherwise not in effect, the exposure limit is 0.1 mg/m3 (as CrO3) as an 8-hour TWA.\np This standard applies to any operations or sectors for which the respirable crystalline silica standard, 1926.1153, is stayed or otherwise is not in effect.\nq This standard applies to any operations or sectors for which the beryllium standard, 1926.1124, is stayed or otherwise is not in effect.\nThe 1970 TLV uses letter designations instead of a numerical value as follows:\nA 1 [Reserved]\nA 2 Polytetrafluoroethylene decomposition products. Because these products decompose in part by hydrolysis in alkaline solution, they can be quantitatively determined in air as fluoride to provide an index of exposure. No TLV is recommended pending determination of the toxicity of the products, but air concentrations should be minimal.\nA 3 Gasoline and/or Petroleum Distillates. The composition of these materials varies greatly and thus a single TLV for all types of these materials is no longer applicable. The content of benzene, other aromatics and additives should be determined to arrive at the appropriate TLV.\nE Simple asphyxiants. The limiting factor is the available oxygen which shall be at least 19.5% and be within the requirements addressing explosion in part 1926.","path":["Title 29—Labor","Subtitle B—Regulations Relating to Labor","CHAPTER XVII—OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR","PART 1926—SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION","Subpart D—Occupational Health and Environmental Controls"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-29.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:25:20Z","sha256":"e404845fa4311b7f219a18e65ca5e07e789e9539fd1360b76532396e37044aa1","source_id":"us-cfr","stale":true,"prev":"us/29-cfr-1926.54","next":"us/29-cfr-1926.56"},"notice":"GroundRules: Original legal text. Not legal advice."}