{"data":{"id":"us/29-cfr-1910.1000","jurisdiction":"us","citation":"29 CFR 1910.1000","heading":"Air contaminants.","body":"An employee's exposure to any substance listed in Tables Z-1, Z-2, or Z-3 of this section shall be limited in accordance with the requirements of the following paragraphs of this section.\n(a) Table Z-1—(1) Substances with limits preceded by “C”—Ceiling Values. An employee's exposure to any substance in Table Z-1, the exposure limit of which is preceded by a “C”, shall at no time exceed the exposure limit given for that substance. If instantaneous monitoring is not feasible, then the ceiling shall be assessed as a 15-minute time weighted average exposure which shall not be exceeded at any time during the working day.\n(2) Other substances—8-hour Time Weighted Averages. An employee's exposure to any substance in Table Z-1, the exposure limit of which is not preceded by a “C”, shall not exceed the 8-hour Time Weighted Average given for that substance in any 8-hour work shift of a 40-hour work week.\n(b) Table Z-2. An employee's exposure to any substance listed in Table Z-2 shall not exceed the exposure limits specified as follows:\n(1) 8-hour time weighted averages. An employee's exposure to any substance listed in Table Z-2, in any 8-hour work shift of a 40-hour work week, shall not exceed the 8-hour time weighted average limit given for that substance in Table Z-2.\n(2) Acceptable ceiling concentrations. An employee's exposure to a substance listed in Table Z-2 shall not exceed at any time during an 8-hour shift the acceptable ceiling concentration limit given for the substance in the table, except for a time period, and up to a concentration not exceeding the maximum duration and concentration allowed in the column under “acceptable maximum peak above the acceptable ceiling concentration for an 8-hour shift.”\n(3) Example. During an 8-hour work shift, an employee may be exposed to a concentration of Substance A (with a 10 ppm TWA, 25 ppm ceiling and 50 ppm peak) above 25 ppm (but never above 50 ppm) only for a maximum period of 10 minutes. Such exposure must be compensated by exposures to concentrations less than 10 ppm so that the cumulative exposure for the entire 8-hour work shift does not exceed a weighted average of 10 ppm.\n(c) Table Z-3. An employee's exposure to any substance listed in Table Z-3, in any 8-hour work shift of a 40-hour work week, shall not exceed the 8-hour time weighted average limit given for that substance in the table.\n(d) Computation formulae. The computation formula which shall apply to employee exposure to more than one substance for which 8-hour time weighted averages are listed in subpart Z of 29 CFR part 1910 in order to determine whether an employee is exposed over the regulatory limit is as follows:\n(1)(i) The cumulative exposure for an 8-hour work shift shall be computed as follows:\nE = (Ca Ta + Cb Tb + . . .Cn Tn) ÷ 8\nWhere:\nE is the equivalent exposure for the working shift.\nC is the concentration during any period of time T where the concentration remains constant.\nT is the duration in hours of the exposure at the concentration C.\nThe value of E shall not exceed the 8-hour time weighted average specified in subpart Z of 29 CFR part 1910 for the substance involved.\n(ii) To illustrate the formula prescribed in paragraph (d)(1)(i) of this section, assume that Substance A has an 8-hour time weighted average limit of 100 ppm noted in Table Z-1. Assume that an employee is subject to the following exposure:\nTwo hours exposure at 150 ppm\nTwo hours exposure at 75 ppm\nFour hours exposure at 50 ppm\nSubstituting this information in the formula, we have\n(2 × 150 + 2 × 75 + 4 × 50) ÷ 8 = 81.25 ppm\nSince 81.25 ppm is less than 100 ppm, the 8-hour time weighted average limit, the exposure is acceptable.\n(2)(i) In case of a mixture of air contaminants an employer shall compute the equivalent exposure as follows:\nEm = (C1 ÷ L1 + C2 ÷ L2) + . . .(Cn ÷ Ln)\nWhere:\nEm is the equivalent exposure for the mixture.\nC is the concentration of a particular contaminant.\nL is the exposure limit for that substance specified in subpart Z of 29 CFR part 1910.\nThe value of Em shall not exceed unity (1).\n(ii) To illustrate the formula prescribed in paragraph (d)(2)(i) of this section, consider the following exposures:\nSubstance Actual concentration of 8-hour exposure (ppm) 8-hour TWA PEL (ppm)\nB 500 1,000\nC 45 200\nD 40 200\nSubstituting in the formula, we have:\nEm = 500 ÷ 1,000 + 45 ÷ 200 + 40 ÷ 200\nEm = 0.500 + 0.225 + 0.200\nEm = 0.925\nSince Em is less than unity (1), the exposure combination is within acceptable limits.\n(e) To achieve compliance with paragraphs (a) through (d) of this section, administrative or engineering controls must first be determined and implemented whenever feasible. When such controls are not feasible to achieve full compliance, protective equipment or any 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/or technical measures used for this purpose must 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 1910.134.\nTable Z-1—Limits for Air Contaminants\nSubstance CAS No. (c) ppm (a) 1 mg/m3 (b) 1 Skin designation\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 1910.1014 53-96-3\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 1910.1045 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 15\nRespirable fraction 5\nAluminum, metal (as Al) 7429-90-5\nTotal dust 15\nRespirable fraction 5\n4-Aminodiphenyl; see 1910.1011 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\nArsenic, inorganic compounds (as As); see 1910.1018 7440-38-2\nArsenic, organic compounds (as As) 7440-38-2 0.5\nArsine 7784-42-1 0.05 0.2\nAsbestos; see 1910.1001 (4)\nAzinphos-methyl 86-50-0 0.2 X\nBarium, soluble compounds (as Ba) 7440-39-3 0.5\nBarium sulfate 7727-43-7\nTotal dust 15\nRespirable fraction 5\nBenomyl 17804-35-2\nTotal dust 15\nRespirable fraction 5\nBenzene; see 1910.1028 71-43-2\nSee Table Z-2 for the limits applicable in the operations or sectors excluded in 1910.1028 d\nBenzidine; see 1910.1010 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 8 7440-41-7\nBiphenyl; see Diphenyl.\nBismuth telluride, Undoped 1304-82-1\nTotal dust 15\nRespirable fraction 5\nBoron oxide 1303-86-2\nTotal dust 15\nBoron trifluoride 7637-07-2 (C)1 (C)3\nBromine 7726-95-6 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 1 ppm/5 ppm STEL\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 1910.1026 6 1189-85-1\nn-Butyl glycidyl ether (BGE) 2426-08-6 50 270\nButyl mercaptan 109-79-5 10 35\np-tert-Butyltoluene 98-51-1 10 60\nCadmium (as Cd); see 1910.1027 7440-43-9\nCalcium carbonate 1317-65-3\nTotal dust 15\nRespirable fraction 5\nCalcium hydroxide 1305-62-0\nTotal dust 15\nRespirable fraction 5\nCalcium oxide 1305-78-8 5\nCalcium silicate 1344-95-2\nTotal dust 15\nRespirable fraction 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 (2)\nCarbon monoxide 630-08-0 50 55\nCarbon tetrachloride 56-23-5 (2)\nCellulose 9004-34-6\nTotal dust 15\nRespirable fraction 5\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 (C)1 (C)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 1910.1008 542-88-1\nChloromethyl methyl ether; see 1910.1006 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\n2-Chloro-6-(trichloromethyl) pyridine 1929-82-4\nTotal dust 15\nRespirable fraction 5\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 1910.1026 5\nChromium metal and insol. salts (as Cr) 7440-47-3 1\nChrysene; see Coal tar pitch volatiles.\nClopidol 2971-90-6\nTotal dust 15\nRespirable fraction 5\nCoal dust (less than 5% SiO2), respirable fraction (3)\nCoal dust (greater than or equal to 5% SiO2), respirable fraction (3)\nCoal tar pitch volatiles (benzene soluble fraction), anthracene, BaP, phenanthrene, acridine, chrysene, pyrene 65966-93-2 0.2\nCobalt metal, dust, and fume (as Co) 7440-48-4 0.1\nCoke oven emissions; see 1910.1029.\nCopper 7440-50-8\nFume (as Cu) 0.1\nDusts and mists (as Cu) 1\nCotton dust e; see 1910.1043 1\nCrag herbicide (Sesone) 136-78-7\nTotal dust 15\nRespirable fraction 5\nCresol, all isomers 1319-77-3 5 22 X\nCrotonaldehyde 123-73-9; 4170-30-3 2 6\nCumene 98-82-8 50 245 X\nCyanides (as CN) (4) 5 X\nCyclohexane 110-82-7 300 1050\nCyclohexanol 108-93-0 50 200\nCyclohexanone 108-94-1 50 200\nCyclohexene 110-83-8 300 1015\nCyclopentadiene 542-92-7 75 200\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 1910.1044 96-12-8\n1,2-Dibromoethane; see Ethylene dibromide.\nDibutyl phosphate 107-66-4 1 5\nDibutyl phthalate 84-74-2 5\no-Dichlorobenzene 95-50-1 (C)50 (C)300\np-Dichlorobenzene 106-46-7 75 450\n3,′-Dichlorobenzidine; see 1910.1007 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\nDicyclopentadienyl iron 102-54-5\nTotal dust 15\nRespirable fraction 5\nDieldrin 60-57-1 0.25 X\nDiethylamine 109-89-7 25 75\n2-Diethylaminoethanol 100-37-8 10 50 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 1910.1015 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 77-78-1 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\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 15\nRespirable fraction 5\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.\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 (C)10 (C)25\nEthyl silicate 78-10-4 100 850\nEthylene chlorohydrin 107-07-3 5 16 X\nEthylenediamine 107-15-3 10 25\nEthylene dibromide 106-93-4 (2)\nEthylene dichloride (1,2-Dichloroethane) 107-06-2 (2)\nEthylene glycol dinitrate 628-96-6 (C)0.2 (C)1 X\nEthylene glycol methyl acetate; see Methyl cellosolve acetate.\nEthyleneimine; see 1910.1012 151-56-4\nEthylene oxide; see 1910.1047 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\nFluorides (as F) (4) 2.5\nFluorine 7782-41-4 0.1 0.2\nFluorotrichloromethane (Trichlorofluoromethane) 75-69-4 1000 5600\nFormaldehyde; see 1910.1048 50-00-0\nFormic acid 64-18-6 5 9\nFurfural 98-01-1 5 20 X\nFurfuryl alcohol 98-00-0 50 200\nGrain dust (oat, wheat, barley) 10\nGlycerin (mist) 56-81-5\nTotal dust 15\nRespirable fraction 5\nGlycidol 556-52-5 50 150\nGlycol monoethyl ether; see 2-Ethoxyethanol.\nGraphite, natural, respirable dust 7782-42-5 (3)\nGraphite, synthetic\nTotal dust 15\nRespirable fraction 5\nGuthion; see Azinphos methyl.\nGypsum 13397-24-5\nTotal dust 15\nRespirable fraction 5\nHafnium 7440-58-6 0.5\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 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 (2)\nHydrogen peroxide 7722-84-1 1 1.4\nHydrogen selenide (as Se) 7783-07-5 0.05 0.2\nHydrogen sulfide 7783-06-4 (2)\nHydroquinone 123-31-9 2\nIodine 7553-56-2 (C)0.1 (C)1\nIron oxide fume 1309-37-1 10\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 15\nRespirable fraction 5\nKetene 463-51-4 0.5 0.9\nLead, inorganic (as Pb); see 1910.1025 7439-92-1\nLimestone 1317-65-3\nTotal dust 15\nRespirable fraction 5\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 15\nRespirable fraction 5\nMagnesium oxide fume 1309-48-4\nTotal particulate 15\nMalathion 121-75-5\nTotal dust 15 X\nMaleic anhydride 108-31-6 0.25 1\nManganese compounds (as Mn) 7439-96-5 (C)5\nManganese fume (as Mn) 7439-96-5 (C)5\nMarble 1317-65-3\nTotal dust 15\nRespirable fraction 5\nMercury (aryl and inorganic) (as Hg) 7439-97-6 (2)\nMercury (organo) alkyl compounds (as Hg) 7439-97-6 (2)\nMercury (vapor) (as Hg) 7439-97-6 (2)\nMesityl oxide 141-79-7 25 100\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.\nMethyl chloride 74-87-3 (2)\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 (2)\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 (C)10 (C)20\nMethyl methacrylate 80-62-6 100 410\nMethyl propyl ketone; see 2-Pentanone.\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 1910.1004 134-32-7\nbeta-Naphthylamine; see 1910.1009 91-59-8\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 1910.1003 92-93-3\nNitroethane 79-24-3 100 310\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 1910.1016.\nNitrotoluene (all isomers) 5 30 X\no-isomer 88-72-2\nm-isomer 99-08-1\np-isomer 99-99-0\nNitrotrichloromethane; see Chloropicrin.\nOctachloronaphthalene 2234-13-1 0.1 X\nOctane 111-65-9 500 2350\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; 1910-42-5; 2074-50-2 0.5 X\nParathion 56-38-2 0.1 X\nParticulates not otherwise regulated (PNOR) f.\nTotal dust 15\nRespirable fraction 5\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 15\nRespirable fraction 5\nPentane 109-66-0 1000 2950\n2-Pentanone (Methyl propyl ketone) 107-87-9 200 700\nPerchloroethylene (Tetrachloroethylene) 127-18-4 (2)\nPerchloromethyl mercaptan 594-42-3 0.1 0.8\nPerchloryl fluoride 7616-94-6 3 13.5\nPetroleum distillates (Naphtha) (Rubber Solvent) 500 2000\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\nPicloram 1918-02-1\nTotal dust 15\nRespirable fraction 5\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 15\nRespirable fraction 5\nPlatinum (as Pt) 7440-06-4\nMetal\nSoluble salts 0.002\nPortland cement 65997-15-1\nTotal dust 15\nRespirable fraction 5\nPropane 74-98-6 1000 1800\nbeta-Propriolactone; see 1910.1013 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 15\nRotenone 83-79-4 5\nRouge\nTotal dust 15\nRespirable fraction 5\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 (3)\nSilica, amorphous, diatomaceous earth, containing less than 1% crystalline silica 61790-53-2 (3)\nSilica, crystalline, respirable dust\nCristobalite; see 1910.1053 7 14464-46-1\nQuartz; see 1910.1053 7 14808-60-7\nTripoli (as quartz); see 1910.1053 7 1317-95-9\nTridymite; see 1910.1053 7 15468-32-3\nSilica, fused, respirable dust 60676-86-0 (3)\nSilicates (less than 1% crystalline silica)\nMica (respirable dust) 12001-26-2 (3)\nSoapstone, total dust (3)\nSoapstone, respirable dust (3)\nTalc (containing asbestos); use asbestos limit; see 29 CFR 1910.1001 (3)\nTalc (containing no asbestos), respirable dust 14807-96-6 (3)\nTremolite, asbestiform; see 1910.1001.\nSilicon 7440-21-3\nTotal dust 15\nRespirable fraction 5\nSilicon carbide 409-21-2\nTotal dust 15\nRespirable fraction 5\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 15\nRespirable fraction 5\nStibine 7803-52-3 0.1 0.5\nStoddard solvent 8052-41-3 500 2900\nStrychnine 57-24-9 0.15\nStyrene 100-42-5 (2)\nSucrose 57-50-1\nTotal dust 15\nRespirable fraction 5\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\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 15\nRespirable fraction 5\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 0.075 X\nTetrahydrofuran 109-99-9 200 590\nTetramethyl lead (as Pb) 75-74-1 0.075 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\n4,4′-Thiobis (6-tert, Butyl-m-cresol) 96-69-5\nTotal dust 15\nRespirable fraction 5\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\nTitanium dioxide 13463-67-7\nTotal dust 15\nToluene 108-88-3 (2)\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 (2)\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\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\nTurpentine 8006-64-2 100 560\nUranium (as U) 7440-61-1\nSoluble compounds 0.05\nInsoluble compounds 0.25\nVanadium 1314-62-1\nRespirable dust (as V2 O5) (C)0.5\nFume (as V2 O5) (C)0.1\nVegetable oil mist\nTotal dust 15\nRespirable fraction 5\nVinyl benzene; see Styrene.\nVinyl chloride; see 1910.1017 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\nZinc stearate 557-05-1\nTotal dust 15\nRespirable fraction 5\nZirconium compounds (as Zr) 7440-67-7 5\n1 The PELs are 8-hour TWAs unless otherwise noted; a (C) designation denotes a ceiling limit. They are to be determined from breathing-zone air samples.\n(a) Parts of vapor or gas per million parts of contaminated air by volume at 25 °C and 760 torr.\n(b) 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.\n(c) 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.\n(d) The final benzene standard in 1910.1028 applies to all occupational exposures to benzene except in some circumstances the distribution and sale of fuels, sealed containers and pipelines, coke production, oil and gas drilling and production, natural gas processing, and the percentage exclusion for liquid mixtures; for the excepted subsegments, the benzene limits in Table Z-2 apply. See 1910.1028 for specific circumstances.\n(e) This 8-hour TWA applies to respirable dust as measured by a vertical elutriator cotton dust sampler or equivalent instrument. The time-weighted average applies to the cottom waste processing operations of waste recycling (sorting, blending, cleaning and willowing) and garnetting. See also 1910.1043 for cotton dust limits applicable to other sectors.\n(f) All inert or nuisance dusts, whether mineral, inorganic, or organic, not listed specifically by substance name are covered by the Particulates Not Otherwise Regulated (PNOR) limit which is the same as the inert or nuisance dust limit of Table Z-3.\n2 See Table Z-2.\n3 See Table Z-3.\n4 Varies with compound.\n5 See Table Z-2 for the exposure limit for any operations or sectors where the exposure limit in § 1910.1026 is stayed or is otherwise not in effect.\n6 If the exposure limit in § 1910.1026 is stayed or is otherwise not in effect, the exposure limit is a ceiling of 0.1 mg/m3.\n7 See Table Z-3 for the exposure limit for any operations or sectors where the exposure limit in § 1910.1053 is stayed or is otherwise not in effect.\n8 See Table Z-2 for the exposure limits for any operations or sectors where the exposure limits in § 1910.1024 are stayed or otherwise not in effect.\nTable Z-2\nSubstance 8-hour time weighted average Acceptable ceiling concentration Acceptable maximum peak above the acceptable ceiling concentration for an 8-hr shift\nConcentration Maximum duration\nBenzene a (Z37.40-1969) 10 ppm 25 ppm 50 ppm 10 minutes.\nBeryllium and beryllium compounds (Z37.29-1970) d 2 µg/m3 5 µg/m3 25 µg/m3 30 minutes.\nCadmium fume b (Z37.5-1970) 0.1 mg/m3 0.3 mg/m3\nCadmium dust b (Z37.5-1970) 0.2 mg/m3 0.6 mg/m3\nCarbon disulfide (Z37.3-1968) 20 ppm 30 ppm 100 ppm 30 minutes.\nCarbon tetrachloride (Z37.17-1967) 10 ppm 25 ppm 200 ppm 5 min. in any 4 hrs.\nChromic acid and chromates (Z37.7-1971) (as CrO3)c 1 mg/10m3\nEthylene dibromide (Z37.31-1970) 20 ppm 30 ppm 50 ppm 5 minutes.\nEthylene dichloride (Z37.21-1969) 50 ppm 100 ppm 200 ppm 5 min. in any 3 hrs.\nFluoride as dust (Z37.28-1969) 2.5 mg/m3\nFormaldehyde; see 1910.1048\nHydrogen fluoride (Z37.28-1969) 3 ppm\nHydrogen sulfide (Z37.2-1966) 20 ppm 50 ppm 10 mins. once, only if no other meas. exp. occurs.\nMercury (Z37.8-1971) 1 mg/10m3\nMethyl chloride (Z37.18-1969) 100 ppm 200 ppm 300 ppm 5 mins. in any 3 hrs.\nMethylene Chloride: See § 1919.52.\nOrgano (alkyl) mercury (Z37.30-1969) 0.01 mg/m3 0.04 mg/m3\nStyrene (Z37.15-1969) 100 ppm 200 ppm 600 ppm 5 mins. in any 3 hrs.\nTetrachloroethylene (Z37.22-1967) 100 ppm 200 ppm 300 ppm 5 mins. in any 3 hrs.\nToluene (Z37.12-1967) 200 ppm 300 ppm 500 ppm 10 minutes.\nTrichloroethylene (Z37.19-1967) 100 ppm 200 ppm 300 ppm 5 mins. in any 2 hrs.\na This standard applies to the industry segments exempt from the 1 ppm 8-hour TWA and 5 ppm STEL of the benzene standard at 1910.1028.\nb This standard applies to any operations or sectors for which the Cadmium standard, 1910.1027, is stayed or otherwise not in effect.\nc This standard applies to any operations or sectors for which the exposure limit in the Chromium (VI) standard, § 1910.1026, is stayed or is otherwise not in effect.\nd This standard applies to any operations or sectors for which the exposure limits in the beryllium standard, § 1910.1024, are stayed or is otherwise not in effect.\nTable Z-3—Mineral Dusts\nSubstance mppcf a mg/m3\nSilica:\nCrystalline\nQuartz (Respirable) f 250b 10 mg/m3 e\n% SiO2 + 5 % SiO2 + 2\nCristobalite: Use 1⁄2 the value calculated from the count or mass formulae for quartz f\nTridymite: Use 1⁄2 the value calculated from the formulae for quartz f\nAmorphous, including natural diatomaceous earth 20 80 mg/m3\n%SiO2\nSilicates (less than 1% crystalline silica):\nMica 20\nSoapstone 20\nTalc (not containing asbestos) 20 c\nTalc (containing asbestos) Use asbestos limit\nTremolite, asbestiform (see 29 CFR 1910.1001)\nPortland cement 50\nGraphite (Natural) 15\nCoal Dust:\nRespirable fraction less than 5% SiO2 2.4 mg/m 3 e\n10 mg/m 3 e\nRespirable fraction greater than 5% SiO2 _____ %SiO2 + 2\nInert or Nuisance Dust: d\nRespirable fraction 15 5 mg/m 3\nTotal dust 50 15 mg/m 3\nNote—Conversion factors - mppcf × 35.3 = million particles per cubic meter = particles per c.c.\na Millions of particles per cubic foot of air, based on impinger samples counted by light-field techniques.\nb 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.\nc Containing less than 1% quartz; if 1% quartz or more, use quartz limit.\nd All inert or nuisance dusts, whether mineral, inorganic, or organic, not listed specifically by substance name are covered by this limit, which is the same as the Particulates Not Otherwise Regulated (PNOR) limit in Table Z-1.\ne Both concentration and percent quartz for the application of this limit are to be determined from the fraction passing a size-selector with the following characteristics:\nAerodynamic diameter (unit density sphere) Percent passing selector\n2 90\n2.5 75\n3.5 50\n5.0 25\n10 0\nThe measurements under this note refer to the use of an AEC (now NRC) instrument. The respirable fraction of coal dust is determined with an MRE; the figure corresponding to that of 2.4 mg/m3 in the table for coal dust is 4.5 mg/m3K.\nf This standard applies to any operations or sectors for which the respirable crystalline silica standard, 1910.1053, is stayed or is otherwise not in effect.","path":["Title 29—Labor","Subtitle B—Regulations Relating to Labor","CHAPTER XVII—OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR","PART 1910—OCCUPATIONAL SAFETY AND HEALTH STANDARDS"],"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":"60fd42d94b71bd8790c418a665a3b88464811b484bf4e91671cb8f72e895ae0c","source_id":"us-cfr","stale":true,"prev":"us/29-cfr-1910.901-1910.999","next":"us/29-cfr-1910.1001"},"notice":"GroundRules: Original legal text. Not legal advice."}