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.
(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.
(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.
(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.
(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:
(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.
(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.''
(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.
(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.
(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:
(1)(i) The cumulative exposure for an 8-hour work shift shall be computed as follows: E = (Ca Ta+Cb Tb+. . .Cn Tn)/8 Where: E is the equivalent exposure for the working shift.C is the concentration during any period of time T where the
(i) The cumulative exposure for an 8-hour work shift shall be computed as follows: E = (Ca Ta+Cb Tb+. . .Cn Tn)/8 Where: E is the equivalent exposure for the working shift.C is the concentration during any period of time T where the
concentration remains constant.T is the duration in hours of the exposure at the concentration C. The 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.
(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: Two hours exposure at 150 ppmTwo hours exposure at 75 ppmFour hours exposure at 50 ppm
Substituting this information in the formula, we have (2x150+2x75+4x50)/8=81.25 ppm
Since 81.25 ppm is less than 100 ppm, the 8-hour time weighted average limit, the exposure is acceptable.
(2)(i) In case of a mixture of air contaminants an employer shall compute the equivalent exposure as follows: Em=(C1/L1+C2/L2)+. . .(Cn/Ln) Where: Em is the equivalent exposure for the mixture.C is the concentration of a particular contaminant.L is the exposure limit for that substance specified in subpart Z of 29
(i) In case of a mixture of air contaminants an employer shall compute the equivalent exposure as follows: Em=(C1/L1+C2/L2)+. . .(Cn/Ln) Where: Em is the equivalent exposure for the mixture.C is the concentration of a particular contaminant.L is the exposure limit for that substance specified in subpart Z of 29
CFR part 1910. The value of Em shall not exceed unity (1).
(ii) To illustrate the formula prescribed in paragraph (d)(2)(i) of this section, consider the following exposures: ------------------------------------------------------------------------
Actual
concentration
Substance of 8-hour 8-hour TWA
exposure PEL (ppm)
(ppm)------------------------------------------------------------------------B........................................... 500 1,000C........................................... 45 200D........................................... 40 200------------------------------------------------------------------------
Substituting in the formula, we have: Em=500/1,000+45/200+40/200Em=0.500+0.225+0.200Em=0.925 Since Em is less than unity (1), the exposure combination is within acceptable limits.
(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.
Table Z-1--Limits for Air Contaminants----------------------------------------------------------------------------------------------------------------
mg/m\3\ (b)
Substance CAS No. (c) ppm (a) \1\ \1\ Skin designation----------------------------------------------------------------------------------------------------------------Acetaldehyde.............................. 75-07-0 200 360Acetic acid............................... 64-19-7 10 25Acetic anhydride.......................... 108-24-7 5 20Acetone................................... 67-64-1 1000 2400Acetonitrile.............................. 75-05-8 40 702-Acetylaminofluorine; see 1910.1014...... 53-96-3Acetylene dichloride; see 1,2-
Dichloroethylene.Acetylene tetrabromide.................... 79-27-6 1 14Acrolein.................................. 107-02-8 0.1 0.25Acrylamide................................ 79-06-1 ............ 0.3 XAcrylonitrile; see 1910.1045.............. 107-13-1Aldrin.................................... 309-00-2 ............ 0.25 XAllyl alcohol............................. 107-18-6 2 5 XAllyl chloride............................ 107-05-1 1 3Allyl glycidyl ether (AGE)................ 106-92-3 (C)10 (C)45Allyl propyl disulfide.................... 2179-59-1 2 12alpha-Alumina............................. 1344-28-1
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5Aluminum, metal (as Al)................... 7429-90-5
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 54-Aminodiphenyl; see 1910.1011............ 92-67-12-Aminoethanol; see Ethanolamine.2-Aminopyridine........................... 504-29-0 0.5 2Ammonia................................... 7664-41-7 50 35Ammonium sulfamate........................ 7773-06-0
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5n-Amyl acetate............................ 628-63-7 100 525sec-Amyl acetate.......................... 626-38-0 125 650Aniline and homologs...................... 62-53-3 5 19 XAnisidine (o-, p-isomers)................. 29191-52-4 ............ 0.5 XAntimony and compounds (as Sb)............ 7440-36-0 ............ 0.5ANTU (alpha Naphthylthiourea)............. 86-88-4 ............ 0.3Arsenic, inorganic compounds (as As); see 7440-38-2
1910.1018.Arsenic, organic compounds (as As)........ 7440-38-2 ............ 0.5Arsine.................................... 7784-42-1 0.05 0.2Asbestos; see 1910.1001................... (\4\)Azinphos-methyl........................... 86-50-0 ............ 0.2 XBarium, soluble compounds (as Ba)......... 7440-39-3 ............ 0.5Barium sulfate............................ 7727-43-7
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5Benomyl................................... 17804-35-2
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5Benzene; see 1910.1028.................... 71-43-2
See Table Z-2 for the limits
applicable in the operations or
sectors excluded in 1910.1028 \d\
Benzidine; see 1910.1010.................. 92-87-5p-Benzoquinone; see Quinone.Benzo(a)pyrene; see Coal tar pitch
volatiles..Benzoyl peroxide.......................... 94-36-0 ............ 5Benzyl chloride........................... 100-44-7 1 5Beryllium and beryllium compounds (as Be). 7440-41-7 ............ (\2\)Biphenyl; see Diphenyl.Bismuth telluride, Undoped................ 1304-82-1
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5Boron oxide............................... 1303-86-2
Total dust............................ .............. ............ 15Boron trifluoride......................... 7637-07-2 (C)1 (C)3Bromine................................... 7726-95-6 0.1 0.7Bromoform................................. 75-25-2 0.5 5 XButadiene (1,3-Butadiene); See 29 CFR 106-99-0 1 ppm/5 ppm
1910.1051; 29 CFR 1910.19(l). STEL
Butanethiol; see Butyl mercaptan.2-Butanone (Methyl ethyl ketone).......... 78-93-3 200 5902-Butoxyethanol........................... 111-76-2 50 240 Xn-Butyl-acetate........................... 123-86-4 150 710sec-Butyl acetate......................... 105-46-4 200 950tert-Butyl acetate........................ 540-88-5 200 950n-Butyl alcohol........................... 71-36-3 100 300sec-Butyl alcohol......................... 78-92-2 150 450tert-Butyl alcohol........................ 75-65-0 100 300Butylamine................................ 109-73-9 (C)5 (C)15 Xtert-Butyl chromate (as CrO3); see 1189-85-1
1910.1026 \6\.n-Butyl glycidyl ether (BGE).............. 2426-08-6 50 270Butyl mercaptan........................... 109-79-5 10 35p-tert-Butyltoluene....................... 98-51-1 10 60Cadmium (as Cd); see 1910.1027............ 7440-43-9Calcium carbonate......................... 1317-65-3
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5Calcium hydroxide......................... 1305-62-0
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5Calcium oxide............................. 1305-78-8 ............ 5Calcium silicate.......................... 1344-95-2
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5Calcium sulfate........................... 7778-18-9
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5Camphor, synthetic........................ 76-22-2 ............ 2Carbaryl (Sevin).......................... 63-25-2 ............ 5Carbon black.............................. 1333-86-4 ............ 3.5Carbon dioxide............................ 124-38-9 5000 9000Carbon disulfide.......................... 75-15-0 ............ (\2\)Carbon monoxide........................... 630-08-0 50 55Carbon tetrachloride...................... 56-23-5 ............ (\2\)Cellulose................................. 9004-34-6
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5Chlordane................................. 57-74-9 ............ 0.5 XChlorinated camphene...................... 8001-35-2 ............ 0.5 XChlorinated diphenyl oxide................ 55720-99-5 ............ 0.5Chlorine.................................. 7782-50-5 (C)1 (C)3Chlorine dioxide.......................... 10049-04-4 0.1 0.3Chlorine trifluoride...................... 7790-91-2 (C)0.1 (C)0.4Chloroacetaldehyde........................ 107-20-0 (C)1 (C)3a-Chloroacetophenone (Phenacyl chloride).. 532-27-4 0.05 0.3Chlorobenzene............................. 108-90-7 75 350o-Chlorobenzylidene malononitrile......... 2698-41-1 0.05 0.4Chlorobromomethane........................ 74-97-5 200 10502-Chloro-1,3-butadiene; see beta-
Chloroprene.Chlorodiphenyl (42% Chlorine) (PCB)....... 53469-21-9 ............ 1 XChlorodiphenyl (54% Chlorine) (PCB)....... 11097-69-1 ............ 0.5 X1-Chloro-2,3-epoxypropane; see
Epichlorohydrin.2-Chloroethanol; see Ethylene
chlorohydrin.Chloroethylene; see Vinyl chloride.Chloroform (Trichloromethane)............. 67-66-3 (C)50 (C)240bis(Chloromethyl) ether; see 1910.1008.... 542-88-1Chloromethyl methyl ether; see 1910.1006.. 107-30-21-Chloro-1-nitropropane................... 600-25-9 20 100Chloropicrin.............................. 76-06-2 0.1 0.7beta-Chloroprene.......................... 126-99-8 25 90 X2-Chloro-6-(trichloromethyl) pyridine..... 1929-82-4
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5Chromium (II) compounds.
(as Cr)............................... 7440-47-3 ............ 0.5Chromium (III) compounds.
(as Cr)............................... 7440-47-3 ............ 0.5Chromium (VI) compounds; See 1910.1026 \5\Chromium metal and insol. salts (as Cr)... 7440-47-3 ............ 1Chrysene; see Coal tar pitch volatiles.Clopidol.................................. 2971-90-6
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5Coal dust (less than 5% SiO2), respirable .............. ............ (\3\)
fraction.Coal dust (greater than or equal to 5% .............. ............ (\3\)
SiO2), respirable fraction.Coal tar pitch volatiles (benzene soluble 65966-93-2 ............ 0.2
fraction), anthracene, BaP, phenanthrene,
acridine, chrysene, pyrene.Cobalt metal, dust, and fume (as Co)...... 7440-48-4 ............ 0.1Coke oven emissions; see 1910.1029.Copper.................................... 7440-50-8
Fume (as Cu).......................... .............. ............ 0.1
Dusts and mists (as Cu)............... .............. ............ 1Cotton dust \e\; see 1910.1043............ .............. ............ 1Crag herbicide (Sesone)................... 136-78-7
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5Cresol, all isomers....................... 1319-77-3 5 22 XCrotonaldehyde............................ 123-73-9; 2 6
4170-30-3Cumene.................................... 98-82-8 50 245 XCyanides (as CN).......................... (\4\) ............ 5 XCyclohexane............................... 110-82-7 300 1050Cyclohexanol.............................. 108-93-0 50 200Cyclohexanone............................. 108-94-1 50 200Cyclohexene............................... 110-83-8 300 1015Cyclopentadiene........................... 542-92-7 75 2002,4-D (Dichlorophenoxyacetic acid)........ 94-75-7 ............ 10Decaborane................................ 17702-41-9 0.05 0.3 XDemeton (Systox).......................... 8065-48-3 ............ 0.1 XDiacetone alcohol (4-Hydroxy-4-methyl-2- 123-42-2 50 240
pentanone).1,2-Diaminoethane; see Ethylenediamine.Diazomethane.............................. 334-88-3 0.2 0.4Diborane.................................. 19287-45-7 0.1 0.11,2-Dibromo-3-chloropropane (DBCP); see 96-12-8
1910.1044.1,2-Dibromoethane; see Ethylene dibromide.Dibutyl phosphate......................... 107-66-4 1 5Dibutyl phthalate......................... 84-74-2 ............ 5o-Dichlorobenzene......................... 95-50-1 (C)50 (C)300p-Dichlorobenzene......................... 106-46-7 75 4503,'-Dichlorobenzidine; see 1910.1007...... 91-94-1Dichlorodifluoromethane................... 75-71-8 1000 49501,3-Dichloro-5,5-dimethyl hydantoin....... 118-52-5 ............ 0.2Dichlorodiphenyltrichloroethane (DDT)..... 50-29-3 ............ 1 X1,1-Dichloroethane........................ 75-34-3 100 4001,2-Dichloroethane; see Ethylene
dichloride.1,2-Dichloroethylene...................... 540-59-0 200 790Dichloroethyl ether....................... 111-44-4 (C)15 (C)90 XDichloromethane; see Methylene chloride.Dichloromonofluoromethane................. 75-43-4 1000 42001,1-Dichloro-1-nitroethane................ 594-72-9 (C)10 (C)601,2-Dichloropropane; see Propylene
dichloride.Dichlorotetrafluoroethane................. 76-14-2 1000 7000Dichlorvos (DDVP)......................... 62-73-7 ............ 1 XDicyclopentadienyl iron................... 102-54-5
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5Dieldrin.................................. 60-57-1 ............ 0.25 XDiethylamine.............................. 109-89-7 25 752-Diethylaminoethanol..................... 100-37-8 10 50 XDiethyl ether; see Ethyl ether.Difluorodibromomethane.................... 75-61-6 100 860Diglycidyl ether (DGE).................... 2238-07-5 (C)0.5 (C)2.8Dihydroxybenzene; see Hydroquinone.Diisobutyl ketone......................... 108-83-8 50 290Diisopropylamine.......................... 108-18-9 5 20 X4-Dimethylaminoazobenzene; see 1910.1015.. 60-11-7Dimethoxymethane; see Methylal.Dimethyl acetamide........................ 127-19-5 10 35 XDimethylamine............................. 124-40-3 10 18Dimethylaminobenzene; see Xylidine........Dimethylaniline (N,N-Dimethylaniline)..... 121-69-7 5 25 XDimethylbenzene; see Xylene.
Dimethyl-1,2-dibromo-2,2-dichloroethyl 300-76-5 ............ 3
phosphate.Dimethylformamide......................... 68-12-2 10 30 X2,6-Dimethyl-4-heptanone; see Diisobutyl
ketone.1,1-Dimethylhydrazine..................... 57-14-7 0.5 1 XDimethylphthalate......................... 131-11-3 ............ 5Dimethyl sulfate.......................... 77-78-1 1 5 XDinitrobenzene (all isomers).............. .............. ............ 1 X
(ortho)............................... 528-29-0
(meta)................................ 99-65-0
(para)................................ 100-25-4Dinitro-o-cresol.......................... 534-52-1 ............ 0.2 XDinitrotoluene............................ 25321-14-6 ............ 1.5 XDioxane (Diethylene dioxide).............. 123-91-1 100 360 XDiphenyl (Biphenyl)....................... 92-52-4 0.2 1Diphenylmethane diisocyanate; see
Methylene bisphenyl isocyanate.Dipropylene glycol methyl ether........... 34590-94-8 100 600 XDi-sec octyl phthalate (Di-(2-ethylhexyl) 117-81-7 ............ 5
phthalate).Emery..................................... 12415-34-8
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5Endrin.................................... 72-20-8 ............ 0.1 XEpichlorohydrin........................... 106-89-8 5 19 XEPN....................................... 2104-64-5 ............ 0.5 X1,2-Epoxypropane; see Propylene oxide.2,3-Epoxy-1-propanol; see Glycidol.Ethanethiol; see Ethyl mercaptan.Ethanolamine.............................. 141-43-5 3 62-Ethoxyethanol (Cellosolve).............. 110-80-5 200 740 X2-Ethoxyethyl acetate (Cellosolve acetate) 111-15-9 100 540 XEthyl acetate............................. 141-78-6 400 1400Ethyl acrylate............................ 140-88-5 25 100 XEthyl alcohol (Ethanol)................... 64-17-5 1000 1900Ethylamine................................ 75-04-7 10 18Ethyl amyl ketone (5-Methyl-3-heptanone).. 541-85-5 25 130Ethyl benzene............................. 100-41-4 100 435Ethyl bromide............................. 74-96-4 200 890Ethyl butyl ketone (3-Heptanone).......... 106-35-4 50 230Ethyl chloride............................ 75-00-3 1000 2600Ethyl ether............................... 60-29-7 400 1200Ethyl formate............................. 109-94-4 100 300Ethyl mercaptan........................... 75-08-1 (C)10 (C)25Ethyl silicate............................ 78-10-4 100 850Ethylene chlorohydrin..................... 107-07-3 5 16 XEthylenediamine........................... 107-15-3 10 25Ethylene dibromide........................ 106-93-4 ............ (\2\)Ethylene dichloride (1,2-Dichloroethane).. 107-06-2 ............ (\2\)Ethylene glycol dinitrate................. 628-96-6 (C)0.2 (C)1 XEthylene glycol methyl acetate; see Methyl
cellosolve acetate.Ethyleneimine; see 1910.1012.............. 151-56-4Ethylene oxide; see 1910.1047............. 75-21-8Ethylidene chloride; see 1,1-
Dichloroethane.N-Ethylmorpholine......................... 100-74-3 20 94 XFerbam.................................... 14484-64-1
Total dust............................ .............. ............ 15Ferrovanadium dust........................ 12604-58-9 ............ 1Fluorides (as F).......................... (\4\) ............ 2.5Fluorine.................................. 7782-41-4 0.1 0.2Fluorotrichloromethane 75-69-4 1000 5600
(Trichlorofluoromethane).Formaldehyde; see 1910.1048............... 50-00-0Formic acid............................... 64-18-6 5 9Furfural.................................. 98-01-1 5 20 XFurfuryl alcohol.......................... 98-00-0 50 200Grain dust (oat, wheat, barley)........... .............. ............ 10Glycerin (mist)........................... 56-81-5
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5Glycidol.................................. 556-52-5 50 150Glycol monoethyl ether; see 2-
Ethoxyethanol.Graphite, natural, respirable dust........ 7782-42-5 ............ (\3\)Graphite, synthetic.......................
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5Guthion; see Azinphos methyl.Gypsum.................................... 13397-24-5
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5Hafnium................................... 7440-58-6 ............ 0.5Heptachlor................................ 76-44-8 ............ 0.5 XHeptane (n-Heptane)....................... 142-82-5 500 2000Hexachloroethane.......................... 67-72-1 1 10 XHexachloronaphthalene..................... 1335-87-1 ............ 0.2 Xn-Hexane.................................. 110-54-3 500 18002-Hexanone (Methyl n-butyl ketone)........ 591-78-6 100 410Hexone (Methyl isobutyl ketone)........... 108-10-1 100 410sec-Hexyl acetate......................... 108-84-9 50 300Hydrazine................................. 302-01-2 1 1.3 XHydrogen bromide.......................... 10035-10-6 3 10Hydrogen chloride......................... 7647-01-0 (C)5 (C)7Hydrogen cyanide.......................... 74-90-8 10 11 XHydrogen fluoride (as F).................. 7664-39-3 ............ (\2\)Hydrogen peroxide......................... 7722-84-1 1 1.4Hydrogen selenide (as Se)................. 7783-07-5 0.05 0.2Hydrogen sulfide.......................... 7783-06-4 ............ (\2\)Hydroquinone.............................. 123-31-9 ............ 2Iodine.................................... 7553-56-2 (C)0.1 (C)1Iron oxide fume........................... 1309-37-1 ............ 10Isoamyl acetate........................... 123-92-2 100 525Isoamyl alcohol (primary and secondary)... 123-51-3 100 360Isobutyl acetate.......................... 110-19-0 150 700Isobutyl alcohol.......................... 78-83-1 100 300Isophorone................................ 78-59-1 25 140Isopropyl acetate......................... 108-21-4 250 950Isopropyl alcohol......................... 67-63-0 400 980Isopropylamine............................ 75-31-0 5 12Isopropyl ether........................... 108-20-3 500 2100Isopropyl glycidyl ether (IGE)............ 4016-14-2 50 240Kaolin.................................... 1332-58-7
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5Ketene.................................... 463-51-4 0.5 0.9Lead, inorganic (as Pb); see 1910.1025.... 7439-92-1Limestone................................. 1317-65-3
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5Lindane................................... 58-89-9 ............ 0.5 XLithium hydride........................... 7580-67-8 ............ 0.025L.P.G. (Liquefied petroleum gas).......... 68476-85-7 1000 1800Magnesite................................. 546-93-0
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5Magnesium oxide fume...................... 1309-48-4
Total particulate..................... .............. ............ 15Malathion................................. 121-75-5
Total dust............................ .............. ............ 15 XMaleic anhydride.......................... 108-31-6 0.25 1Manganese compounds (as Mn)............... 7439-96-5 ............ (C)5Manganese fume (as Mn).................... 7439-96-5 ............ (C)5Marble.................................... 1317-65-3
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5Mercury (aryl and inorganic) (as Hg)...... 7439-97-6 ............ (\2\)Mercury (organo) alkyl compounds (as Hg).. 7439-97-6 ............ (\2\)Mercury (vapor) (as Hg)................... 7439-97-6 ............ (\2\)Mesityl oxide............................. 141-79-7 25 100Methanethiol; see Methyl mercaptan.Methoxychlor.............................. 72-43-5
Total dust............................ .............. ............ 152-Methoxyethanol (Methyl cellosolve)...... 109-86-4 25 80 X2-Methoxyethyl acetate (Methyl cellosolve 110-49-6 25 120 X
acetate).Methyl acetate............................ 79-20-9 200 610Methyl acetylene (Propyne)................ 74-99-7 1000 1650Methyl acetylene-propadiene mixture (MAPP) .............. 1000 1800
Methyl acrylate........................... 96-33-3 10 35 XMethylal (Dimethoxy-methane).............. 109-87-5 1000 3100Methyl alcohol............................ 67-56-1 200 260Methylamine............................... 74-89-5 10 12Methyl amyl alcohol; see Methyl isobutyl
carbinol.Methyl n-amyl ketone...................... 110-43-0 100 465Methyl bromide............................ 74-83-9 (C)20 (C)80 XMethyl butyl ketone; see 2-Hexanone.Methyl cellosolve; see 2-Methoxyethanol.Methyl cellosolve acetate; see 2-
Methoxyethyl acetate.Methyl chloride........................... 74-87-3 ............ (\2\)Methyl chloroform (1,1,1-Trichloroethane). 71-55-6 350 1900Methylcyclohexane......................... 108-87-2 500 2000Methylcyclohexanol........................ 25639-42-3 100 470o-Methylcyclohexanone..................... 583-60-8 100 460 XMethylene chloride........................ 75-09-2 ............ (\2\)Methyl ethyl ketone (MEK); see 2-Butanone.Methyl formate............................ 107-31-3 100 250Methyl hydrazine (Monomethyl hydrazine)... 60-34-4 (C)0.2 (C)0.35 XMethyl iodide............................. 74-88-4 5 28 XMethyl isoamyl ketone..................... 110-12-3 100 475Methyl isobutyl carbinol.................. 108-11-2 25 100 XMethyl isobutyl ketone; see Hexone.Methyl isocyanate......................... 624-83-9 0.02 0.05 XMethyl mercaptan.......................... 74-93-1 (C)10 (C)20Methyl methacrylate....................... 80-62-6 100 410Methyl propyl ketone; see 2-Pentanone.alpha-Methyl styrene...................... 98-83-9 (C)100 (C)480Methylene bisphenyl isocyanate (MDI)...... 101-68-8 (C)0.02 (C)0.2Mica; see Silicates.Molybdenum (as Mo)........................ 7439-98-7
Soluble compounds..................... .............. ............ 5
Insoluble compounds.
Total dust......................... .............. ............ 15Monomethyl aniline........................ 100-61-8 2 9 XMonomethyl hydrazine; see Methyl
hydrazine.Morpholine................................ 110-91-8 20 70 XNaphtha (Coal tar)........................ 8030-30-6 100 400Naphthalene............................... 91-20-3 10 50alpha-Naphthylamine; see 1910.1004........ 134-32-7beta-Naphthylamine; see 1910.1009......... 91-59-8Nickel carbonyl (as Ni)................... 13463-39-3 0.001 0.007Nickel, metal and insoluble compounds (as 7440-02-0 ............ 1
Ni).Nickel, soluble compounds (as Ni)......... 7440-02-0 ............ 1Nicotine.................................. 54-11-5 ............ 0.5 XNitric acid............................... 7697-37-2 2 5Nitric oxide.............................. 10102-43-9 25 30p-Nitroaniline............................ 100-01-6 1 6 XNitrobenzene.............................. 98-95-3 1 5 Xp-Nitrochlorobenzene...................... 100-00-5 ............ 1 X4-Nitrodiphenyl; see 1910.1003............ 92-93-3Nitroethane............................... 79-24-3 100 310Nitrogen dioxide.......................... 10102-44-0 (C)5 (C)9Nitrogen trifluoride...................... 7783-54-2 10 29Nitroglycerin............................. 55-63-0 (C)0.2 (C)2 XNitromethane.............................. 75-52-5 100 2501-Nitropropane............................ 108-03-2 25 902-Nitropropane............................ 79-46-9 25 90N-Nitrosodimethylamine; see 1910.1016.Nitrotoluene (all isomers)................ .............. 5 30 X
o-isomer.............................. 88-72-2
m-isomer.............................. 99-08-1
p-isomer.............................. 99-99-0Nitrotrichloromethane; see Chloropicrin.Octachloronaphthalene..................... 2234-13-1 ............ 0.1 XOctane.................................... 111-65-9 500 2350Oil mist, mineral......................... 8012-95-1 ............ 5Osmium tetroxide (as Os).................. 20816-12-0 ............ 0.002Oxalic acid............................... 144-62-7 ............ 1Oxygen difluoride......................... 7783-41-7 0.05 0.1Ozone..................................... 10028-15-6 0.1 0.2
Paraquat, respirable dust................. 4685-14-7; ............ 0.5 X
1910-42-5;
2074-50-2Parathion................................. 56-38-2 ............ 0.1 XParticulates not otherwise regulated
(PNOR) \f\.
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5PCB; see Chlorodiphenyl (42% and 54%
chlorine).Pentaborane............................... 19624-22-7 0.005 0.01Pentachloronaphthalene.................... 1321-64-8 ............ 0.5 XPentachlorophenol......................... 87-86-5 ............ 0.5 XPentaerythritol........................... 115-77-5
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5Pentane................................... 109-66-0 1000 29502-Pentanone (Methyl propyl ketone)........ 107-87-9 200 700Perchloroethylene (Tetrachloroethylene)... 127-18-4 ............ (\2\)Perchloromethyl mercaptan................. 594-42-3 0.1 0.8Perchloryl fluoride....................... 7616-94-6 3 13.5Petroleum distillates (Naphtha) (Rubber .............. 500 2000
Solvent).Phenol.................................... 108-95-2 5 19 Xp-Phenylene diamine....................... 106-50-3 ............ 0.1 XPhenyl ether, vapor....................... 101-84-8 1 7Phenyl ether-biphenyl mixture, vapor...... .............. 1 7Phenylethylene; see Styrene.Phenyl glycidyl ether (PGE)............... 122-60-1 10 60Phenylhydrazine........................... 100-63-0 5 22 XPhosdrin (Mevinphos)...................... 7786-34-7 ............ 0.1 XPhosgene (Carbonyl chloride).............. 75-44-5 0.1 0.4Phosphine................................. 7803-51-2 0.3 0.4Phosphoric acid........................... 7664-38-2 ............ 1Phosphorus (yellow)....................... 7723-14-0 ............ 0.1Phosphorus pentachloride.................. 10026-13-8 ............ 1Phosphorus pentasulfide................... 1314-80-3 ............ 1Phosphorus trichloride.................... 7719-12-2 0.5 3Phthalic anhydride........................ 85-44-9 2 12Picloram.................................. 1918-02-1
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5Picric acid............................... 88-89-1 ............ 0.1 XPindone (2-Pivalyl-1,3-indandione)........ 83-26-1 ............ 0.1Plaster of Paris.......................... 26499-65-0
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5Platinum (as Pt).......................... 7440-06-4
Metal.................................
Soluble salts......................... .............. ............ 0.002Portland cement........................... 65997-15-1
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5Propane................................... 74-98-6 1000 1800beta-Propriolactone; see 1910.1013........ 57-57-8n-Propyl acetate.......................... 109-60-4 200 840n-Propyl alcohol.......................... 71-23-8 200 500n-Propyl nitrate.......................... 627-13-4 25 110Propylene dichloride...................... 78-87-5 75 350Propylene imine........................... 75-55-8 2 5 XPropylene oxide........................... 75-56-9 100 240Propyne; see Methyl acetylene.Pyrethrum................................. 8003-34-7 ............ 5Pyridine.................................. 110-86-1 5 15Quinone................................... 106-51-4 0.1 0.4RDX; see Cyclonite.Rhodium (as Rh), metal fume and insoluble 7440-16-6 ............ 0.1
compounds.Rhodium (as Rh), soluble compounds........ 7440-16-6 ............ 0.001Ronnel.................................... 299-84-3 ............ 15Rotenone.................................. 83-79-4 ............ 5Rouge.....................................
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5Selenium compounds (as Se)................ 7782-49-2 ............ 0.2Selenium hexafluoride (as Se)............. 7783-79-1 0.05 0.4
Silica, amorphous, precipitated and gel... 112926-00-8 ............ (\3\)Silica, amorphous, diatomaceous earth, 61790-53-2 ............ (\3\)
containing less than 1% crystalline
silica.Silica, crystalline cristobalite, 14464-46-1 ............ (\3\)
respirable dust.Silica, crystalline quartz, respirable 14808-60-7 ............ (\3\)
dust.Silica, crystalline tripoli (as quartz), 1317-95-9 ............ (\3\)
respirable dust.Silica, crystalline tridymite, respirable 15468-32-3 ............ (\3\)
dust.Silica, fused, respirable dust............ 60676-86-0 ............ (\3\)Silicates (less than 1% crystalline
silica).
Mica (respirable dust)................ 12001-26-2 ............ (\3\)
Soapstone, total dust................. .............. ............ (\3\)
Soapstone, respirable dust............ .............. ............ (\3\)
Talc (containing asbestos); use .............. ............ (\3\)
asbestos limit; see 29 CFR 1910.1001.
Talc (containing no asbestos), 14807-96-6 ............ (\3\)
respirable dust.
Tremolite, asbestiform; see 1910.1001.Silicon................................... 7440-21-3
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5Silicon carbide........................... 409-21-2
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5Silver, metal and soluble compounds (as 7440-22-4 ............ 0.01
Ag).Soapstone; see Silicates.Sodium fluoroacetate...................... 62-74-8 ............ 0.05 XSodium hydroxide.......................... 1310-73-2 ............ 2Starch.................................... 9005-25-8
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5Stibine................................... 7803-52-3 0.1 0.5Stoddard solvent.......................... 8052-41-3 500 2900Strychnine................................ 57-24-9 ............ 0.15Styrene................................... 100-42-5 ............ (\2\)Sucrose................................... 57-50-1
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5Sulfur dioxide............................ 7446-09-5 5 13Sulfur hexafluoride....................... 2551-62-4 1000 6000Sulfuric acid............................. 7664-93-9 ............ 1Sulfur monochloride....................... 10025-67-9 1 6Sulfur pentafluoride...................... 5714-22-7 0.025 0.25Sulfuryl fluoride......................... 2699-79-8 5 20Systox; see Demeton.2,4,5-T (2,4,5-trichlorophenoxyacetic 93-76-5 ............ 10
acid).Talc; see Silicates.Tantalum, metal and oxide dust............ 7440-25-7 ............ 5TEDP (Sulfotep)........................... 3689-24-5 ............ 0.2 XTellurium and compounds (as Te)........... 13494-80-9 ............ 0.1Tellurium hexafluoride (as Te)............ 7783-80-4 0.02 0.2Temephos.................................. 3383-96-8
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5TEPP (Tetraethyl pyrophosphate)........... 107-49-3 ............ 0.05 XTerphenyls................................ 26140-60-3 (C)1 (C)91,1,1,2-Tetrachloro-2,2-difluoroethane.... 76-11-9 500 41701,1,2,2-Tetrachloro-1,2-difluoroethane.... 76-12-0 500 41701,1,2,2-Tetrachloroethane................. 79-34-5 5 35 XTetrachloroethylene; see
Perchloroethylene.Tetrachloromethane; see Carbon
tetrachloride.Tetrachloronaphthalene.................... 1335-88-2 ............ 2 XTetraethyl lead (as Pb)................... 78-00-2 ............ 0.075 XTetrahydrofuran........................... 109-99-9 200 590Tetramethyl lead (as Pb).................. 75-74-1 ............ 0.075 XTetramethyl succinonitrile................ 3333-52-6 0.5 3 XTetranitromethane......................... 509-14-8 1 8Tetryl (2,4,6- 479-45-8 ............ 1.5 X
Trinitrophenylmethylnitramine).Thallium, soluble compounds (as Tl)....... 7440-28-0 ............ 0.1 X4,4'-Thiobis (6-tert, Butyl-m-cresol)..... 96-69-5
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5Thiram.................................... 137-26-8 ............ 5Tin, inorganic compounds (except oxides) 7440-31-5 ............ 2
(as Sn).
Tin, organic compounds (as Sn)............ 7440-31-5 ............ 0.1Titanium dioxide.......................... 13463-67-7
Total dust............................ .............. ............ 15Toluene................................... 108-88-3 ............ (\2\)Toluene-2,4-diisocyanate (TDI)............ 584-84-9 (C)0.02 (C)0.14o-Toluidine............................... 95-53-4 5 22 XToxaphene; see Chlorinated camphene.Tremolite; see Silicates.Tributyl phosphate........................ 126-73-8 ............ 51,1,1-Trichloroethane; see Methyl
chloroform.1,1,2-Trichloroethane..................... 79-00-5 10 45 XTrichloroethylene......................... 79-01-6 ............ (\2\)Trichloromethane; see Chloroform.Trichloronaphthalene...................... 1321-65-9 ............ 5 X1,2,3-Trichloropropane.................... 96-18-4 50 3001,1,2-Trichloro-1,2,2-trifluoroethane..... 76-13-1 1000 7600Triethylamine............................. 121-44-8 25 100Trifluorobromomethane..................... 75-63-8 1000 61002,4,6-Trinitrophenol; see Picric acid.2,4,6-Trinitrophenylmethylnitramine; see
Tetryl.2,4,6-Trinitrotoluene (TNT)............... 118-96-7 ............ 1.5 XTriorthocresyl phosphate.................. 78-30-8 ............ 0.1Triphenyl phosphate....................... 115-86-6 ............ 3Turpentine................................ 8006-64-2 100 560Uranium (as U)............................ 7440-61-1
Soluble compounds..................... .............. ............ 0.05
Insoluble compounds................... .............. ............ 0.25Vanadium.................................. 1314-62-1
Respirable dust (as V2 O5)............ .............. ............ (C)0.5
Fume (as V2 O5)....................... .............. ............ (C)0.1Vegetable oil mist........................
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5Vinyl benzene; see Styrene.Vinyl chloride; see 1910.1017............. 75-01-4Vinyl cyanide; see Acrylonitrile.Vinyl toluene............................. 25013-15-4 100 480Warfarin.................................. 81-81-2 ............ 0.1Xylenes (o-, m-, p-isomers)............... 1330-20-7 100 435Xylidine.................................. 1300-73-8 5 25 XYttrium................................... 7440-65-5 ............ 1Zinc chloride fume........................ 7646-85-7 ............ 1Zinc oxide fume........................... 1314-13-2 ............ 5Zinc oxide................................ 1314-13-2
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5Zinc stearate............................. 557-05-1
Total dust............................ .............. ............ 15
Respirable fraction................... .............. ............ 5Zirconium compounds (as Zr)............... 7440-67-7 ............ 5----------------------------------------------------------------------------------------------------------------\1\ The PELs are 8-hour TWAs unless otherwise noted; a (C) designation denotes a ceiling limit. They are to be
(a) Parts of vapor or gas per million parts of contaminated air by volume at 25 [deg]C and 760 torr.(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.(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.(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.(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.(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.\2\ See Table Z-2.\3\ See Table Z-3.\4\ Varies with compound.\5\ See Table Z-2 for the exposure limit for any operations or sectors where the exposure limit in Sec.
1910.1026 is stayed or is otherwise not in effect.\6\ If the exposure limit inSec. 1910.1026 is stayed or is otherwise not in effect, the exposure limit is a
ceiling of 0.1 mg/m\3\.
Table Z-2----------------------------------------------------------------------------------------------------------------
Acceptable maximum peak above the
acceptable ceiling concentration for an
Substance 8-hour time Acceptable ceiling 8-hr shift
weighted average concentration ----------------------------------------
Concentration Maximum duration----------------------------------------------------------------------------------------------------------------Benzene \a\ (Z37.40-1969)...... 10 ppm............ 25 ppm............ 50 ppm............ 10 minutes.Beryllium and beryllium 2 [micro]g/m\3\... 5 [micro]g/m\3\... 25 [micro]g/m\3\.. 30 minutes.
compounds (Z37.29-1970).Cadmium fume \b\ (Z37.5-1970).. 0.1 mg/m\3\....... 0.3 mg/m\3\.......Cadmium dust \b\ (Z37.5-1970).. 0.2 mg/m\3\....... 0.6 mg/m\3\.......Carbon disulfide (Z37.3-1968).. 20 ppm............ 30 ppm............ 100 ppm........... 30 minutes.Carbon tetrachloride (Z37.17- 10 ppm............ 25 ppm............ 200 ppm........... 5 min. in any 4
1967). hrs.Chromic acid and chromates .................. 1 mg/10m\3\.......
(Z37.7-1971) (as CrO3)\c\.Ethylene dibromide (Z37.31- 20 ppm............ 30 ppm............ 50 ppm............ 5 minutes.
1970).Ethylene dichloride (Z37.21- 50 ppm............ 100 ppm........... 200 ppm........... 5 min. in any 3
1969). hrs.Fluoride as dust (Z37.28-1969). 2.5 mg/m\3\.......Formaldehyde; see 1910.1048....Hydrogen fluoride (Z37.28-1969) 3 ppm.............Hydrogen sulfide (Z37.2-1966).. .................. 20 ppm............ 50 ppm............ 10 mins. once, only
if no other meas.
exp. occurs.Mercury (Z37.8-1971)........... .................. 1 mg/10m\3\.......Methyl chloride (Z37.18-1969).. 100 ppm........... 200 ppm........... 300 ppm........... 5 mins. in any 3
hrs.Methylene Chloride: See Sec.
1919.52..Organo (alkyl) mercury (Z37.30- 0.01 mg/m\3\...... 0.04 mg/m\3\......
1969).Styrene (Z37.15-1969).......... 100 ppm........... 200 ppm........... 600 ppm........... 5 mins. in any 3
hrs.Tetrachloroethylene (Z37.22- 100 ppm........... 200 ppm........... 300 ppm........... 5 mins. in any 3
1967). hrs.Toluene (Z37.12-1967).......... 200 ppm........... 300 ppm........... 500 ppm........... 10 minutes.Trichloroethylene (Z37.19-1967) 100 ppm........... 200 ppm........... 300 ppm........... 5 mins. in any 2
hrs.----------------------------------------------------------------------------------------------------------------\a\ 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.\b\ This standard applies to any operations or sectors for which the Cadmium standard, 1910.1027, is stayed or
otherwise not in effect.\c\ This standard applies to any operations or sectors for which the exposure limit in the Chromium (VI)
standard,Sec. 1910.1026, is stayed or is otherwise not in effect.
Table Z-3--Mineral Dusts------------------------------------------------------------------------
Substance mppcf \a\ mg/m\3\------------------------------------------------------------------------Silica:Crystalline
250 \b\ 10 mg/m\3\
\e\
Quartz (Respirable)....................... ---------- ----------
%SiO2+5 % SiO2 + 2
........... 30 mg/m\3\
Quartz (Total Dust)....................... ........... ----------
% SiO2 + 2
Cristobalite: Use \1/2\ the value calculated
from the count or mass formulae for quartz
Tridymite: Use \1/2\ the value calculated
from the formulae for quartz
........... 80 mg/m\3\Amorphous, including natural diatomaceous 20 ----------
earth........................................ %SiO2
Silicates (less than 1% crystalline silica):
Mica........................................ 20
Soapstone................................... 20
Talc (not containing asbestos).............. 20 \c\
Talc (containing asbestos) Use asbestos
limit......................................
Tremolite, asbestiform (see 29 CFR
1910.1001).................................
Portland cement............................. 50
Graphite (Natural)............................ 15
Coal Dust:
Respirable fraction less than 5% SiO2....... ........... 2.4 mg/
m\3\ \e\
........... 10 mg/m\3\
\e\
Respirable fraction greater than 5% SiO2.... ........... ----------
%SiO2+2
Inert or Nuisance Dust: \d\
Respirable fraction......................... 15 5 mg/m\3\
Total dust.................................. 50 15 mg/m\3\------------------------------------------------------------------------Note--Conversion factors - mppcf x 35.3 = million particles per cubic
meter = particles per c.c.
\a\ Millions of particles per cubic foot of air, based on impinger
samples counted by light-field techniques.\b\ 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.\c\ Containing less than 1% quartz; if 1% quartz or more, use quartz
limit.\d\ 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.\e\ 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: ------------------------------------------------------------------------
Percent passing
Aerodynamic diameter (unit density sphere) selector------------------------------------------------------------------------2.................................................... 902.5.................................................. 753.5.................................................. 505.0.................................................. 2510................................................... 0------------------------------------------------------------------------The 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/m\3\ in the table for
coal dust is 4.5 mg/m\3K\. [58 FR 35340, June 30. 1993; 58 FR 40191, July 27, 1993, as amended at 61 FR 56831, Nov. 4, 1996; 62 FR 1600, Jan. 10, 1997; 62 FR 42018, Aug. 4, 1997; 71 FR 10373, Feb. 28, 2006; 71 FR 16673, Apr. 3, 2006; 71 FR 36008, June 23, 2006]