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Title 29Subtitle BChapter XVIIPart 1910Subpart Z → §1910.1000


Title 29: Labor
PART 1910—OCCUPATIONAL SAFETY AND HEALTH STANDARDS (CONTINUED)
Subpart Z—Toxic and Hazardous Substances


§1910.1000   Air contaminants.

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.

(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 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 ppm

Two hours exposure at 75 ppm

Four hours exposure at 50 ppm

Substituting this information in the formula, we have

(2 × 150 + 2 × 75 + 4 × 50) ÷ 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 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:

SubstanceActual concentration of 8-hour exposure (ppm)8-hour TWA PEL (ppm)
B5001,000
C45200
D40200

Substituting in the formula, we have:

Em = 500 ÷ 1,000 + 45 ÷ 200 + 40 ÷ 200

Em = 0.500 + 0.225 + 0.200

Em = 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

SubstanceCAS No. (c)ppm (a)1mg/m3 (b)1Skin designation
Acetaldehyde75-07-0200360
Acetic acid64-19-71025
Acetic anhydride108-24-7520
Acetone67-64-110002400
Acetonitrile75-05-84070
2-Acetylaminofluorine; see 1910.101453-96-3
Acetylene dichloride; see 1,2-Dichloroethylene.
Acetylene tetrabromide79-27-6114
Acrolein107-02-80.10.25
Acrylamide79-06-10.3X
Acrylonitrile; see 1910.1045107-13-1
Aldrin309-00-20.25X
Allyl alcohol107-18-625X
Allyl chloride107-05-113
Allyl glycidyl ether (AGE)106-92-3(C)10(C)45
Allyl propyl disulfide2179-59-1212
alpha-Alumina1344-28-1
Total dust   15
Respirable fraction   5
Aluminum, metal (as Al)7429-90-5
Total dust   15
Respirable fraction   5
4-Aminodiphenyl; see 1910.101192-67-1
2-Aminoethanol; see Ethanolamine.
2-Aminopyridine504-29-00.52
Ammonia7664-41-75035
Ammonium sulfamate7773-06-0
Total dust   15
Respirable fraction   5
n-Amyl acetate628-63-7100525
sec-Amyl acetate626-38-0125650
Aniline and homologs62-53-3519X
Anisidine (o-, p-isomers)29191-52-40.5X
Antimony and compounds (as Sb)7440-36-00.5
ANTU (alpha Naphthylthiourea)86-88-40.3
Arsenic, inorganic compounds (as As); see 1910.10187440-38-2
Arsenic, organic compounds (as As)7440-38-20.5
Arsine7784-42-10.050.2
Asbestos; see 1910.1001(4)
Azinphos-methyl86-50-00.2X
Barium, soluble compounds (as Ba)7440-39-30.5
Barium sulfate7727-43-7
Total dust   15
Respirable fraction   5
Benomyl17804-35-2
Total dust   15
Respirable fraction   5
Benzene; see 1910.102871-43-2
See Table Z-2 for the limits applicable in the operations or sectors excluded in 1910.1028d
Benzidine; see 1910.101092-87-5
p-Benzoquinone; see Quinone.
Benzo(a)pyrene; see Coal tar pitch volatiles.
Benzoyl peroxide94-36-05
Benzyl chloride100-44-715
Beryllium and beryllium compounds (as Be); see 1926.112487440-41-7
Biphenyl; see Diphenyl.
Bismuth telluride, Undoped1304-82-1
Total dust   15
Respirable fraction   5
Boron oxide1303-86-2
Total dust   15
Boron trifluoride7637-07-2(C)1(C)3
Bromine7726-95-60.10.7
Bromoform75-25-20.55X
Butadiene (1,3-Butadiene); See 29 CFR 1910.1051; 29 CFR 1910.19(l)106-99-01 ppm/5 ppm STEL
Butanethiol; see Butyl mercaptan.
2-Butanone (Methyl ethyl ketone)78-93-3200590
2-Butoxyethanol111-76-250240X
n-Butyl-acetate123-86-4150710
sec-Butyl acetate105-46-4200950
tert-Butyl acetate540-88-5200950
n-Butyl alcohol71-36-3100300
sec-Butyl alcohol78-92-2150450
tert-Butyl alcohol75-65-0100300
Butylamine109-73-9(C)5(C)15X
tert-Butyl chromate (as CrO3); see 1910.102661189-85-1
n-Butyl glycidyl ether (BGE)2426-08-650270
Butyl mercaptan109-79-51035
p-tert-Butyltoluene98-51-11060
Cadmium (as Cd); see 1910.10277440-43-9
Calcium carbonate1317-65-3
Total dust   15
Respirable fraction   5
Calcium hydroxide1305-62-0
Total dust   15
Respirable fraction   5
Calcium oxide1305-78-85
Calcium silicate1344-95-2
Total dust   15
Respirable fraction   5
Calcium sulfate7778-18-9
Total dust   15
Respirable fraction   5
Camphor, synthetic76-22-22
Carbaryl (Sevin)63-25-25
Carbon black1333-86-43.5
Carbon dioxide124-38-950009000
Carbon disulfide75-15-0   (2)
Carbon monoxide630-08-05055
Carbon tetrachloride56-23-5   (2)
Cellulose9004-34-6
Total dust   15
Respirable fraction   5
Chlordane57-74-90.5X
Chlorinated camphene8001-35-20.5X
Chlorinated diphenyl oxide55720-99-50.5
Chlorine7782-50-5(C)1(C)3
Chlorine dioxide10049-04-40.10.3
Chlorine trifluoride7790-91-2(C)0.1(C)0.4
Chloroacetaldehyde107-20-0(C)1(C)3
a-Chloroacetophenone (Phenacyl chloride)532-27-40.050.3
Chlorobenzene108-90-775350
o-Chlorobenzylidene malononitrile2698-41-10.050.4
Chlorobromomethane74-97-52001050
2-Chloro-1,3-butadiene; see beta-Chloroprene.
Chlorodiphenyl (42% Chlorine) (PCB)53469-21-91X
Chlorodiphenyl (54% Chlorine) (PCB)11097-69-10.5X
1-Chloro-2,3-epoxypropane; see Epichlorohydrin.
2-Chloroethanol; see Ethylene chlorohydrin.
Chloroethylene; see Vinyl chloride.
Chloroform (Trichloromethane)67-66-3(C)50(C)240
bis(Chloromethyl) ether; see 1910.1008542-88-1
Chloromethyl methyl ether; see 1910.1006107-30-2
1-Chloro-1-nitropropane600-25-920100
Chloropicrin76-06-20.10.7
beta-Chloroprene126-99-82590X
2-Chloro-6-(trichloromethyl) pyridine1929-82-4
Total dust   15
Respirable fraction   5
Chromium (II) compounds.
(as Cr)7440-47-30.5
Chromium (III) compounds.
(as Cr)7440-47-30.5
Chromium (VI) compounds; See 1910.10265
Chromium metal and insol. salts (as Cr)7440-47-31
Chrysene; see Coal tar pitch volatiles.
Clopidol2971-90-6
Total dust   15
Respirable fraction   5
Coal dust (less than 5% SiO2), respirable fraction      (3)
Coal dust (greater than or equal to 5% SiO2), respirable fraction      (3)
Coal tar pitch volatiles (benzene soluble fraction), anthracene, BaP, phenanthrene, acridine, chrysene, pyrene65966-93-20.2
Cobalt metal, dust, and fume (as Co)7440-48-40.1
Coke oven emissions; see 1910.1029.
Copper7440-50-8
Fume (as Cu)   0.1
Dusts and mists (as Cu)   1
Cotton duste; see 1910.1043   1
Crag herbicide (Sesone)136-78-7
Total dust   15
Respirable fraction   5
Cresol, all isomers1319-77-3522X
Crotonaldehyde123-73-9;
4170-30-3
26
Cumene98-82-850245X
Cyanides (as CN)(4)5X
Cyclohexane110-82-73001050
Cyclohexanol108-93-050200
Cyclohexanone108-94-150200
Cyclohexene110-83-83001015
Cyclopentadiene542-92-775200
2,4-D (Dichlorophenoxyacetic acid)94-75-710
Decaborane17702-41-90.050.3X
Demeton (Systox)8065-48-30.1X
Diacetone alcohol (4-Hydroxy-4-methyl-2-pentanone)123-42-250240
1,2-Diaminoethane; see Ethylenediamine.
Diazomethane334-88-30.20.4
Diborane19287-45-70.10.1
1,2-Dibromo-3-chloropropane (DBCP); see  1910.104496-12-8
1,2-Dibromoethane; see Ethylene dibromide.
Dibutyl phosphate107-66-415
Dibutyl phthalate84-74-25
o-Dichlorobenzene95-50-1(C)50(C)300
p-Dichlorobenzene106-46-775450
3,′-Dichlorobenzidine; see 1910.100791-94-1
Dichlorodifluoromethane75-71-810004950
1,3-Dichloro-5,5-dimethyl hydantoin118-52-50.2
Dichlorodiphenyltrichloroethane (DDT)50-29-31X
1,1-Dichloroethane75-34-3100400
1,2-Dichloroethane; see Ethylene dichloride.
1,2-Dichloroethylene540-59-0200790
Dichloroethyl ether111-44-4(C)15(C)90X
Dichloromethane; see Methylene chloride.
Dichloromonofluoromethane75-43-410004200
1,1-Dichloro-1-nitroethane594-72-9(C)10(C)60
1,2-Dichloropropane; see Propylene dichloride.
Dichlorotetrafluoroethane76-14-210007000
Dichlorvos (DDVP)62-73-71X
Dicyclopentadienyl iron102-54-5
Total dust   15
Respirable fraction   5
Dieldrin60-57-10.25X
Diethylamine109-89-72575
2-Diethylaminoethanol100-37-81050X
Diethyl ether; see Ethyl ether.
Difluorodibromomethane75-61-6100860
Diglycidyl ether (DGE)2238-07-5(C)0.5(C)2.8
Dihydroxybenzene; see Hydroquinone.
Diisobutyl ketone108-83-850290
Diisopropylamine108-18-9520X
4-Dimethylaminoazobenzene; see 1910.101560-11-7
Dimethoxymethane; see Methylal.
Dimethyl acetamide127-19-51035X
Dimethylamine124-40-31018
Dimethylaminobenzene; see Xylidine
Dimethylaniline (N,N-Dimethylaniline)121-69-7525X
Dimethylbenzene; see Xylene.
Dimethyl-1,2-dibromo-2,2-dichloroethyl phosphate300-76-53
Dimethylformamide68-12-21030X
2,6-Dimethyl-4-heptanone; see Diisobutyl ketone.
1,1-Dimethylhydrazine57-14-70.51X
Dimethylphthalate131-11-35
Dimethyl sulfate77-78-115X
Dinitrobenzene (all isomers)      1X
(ortho)528-29-0
(meta)99-65-0
(para)100-25-4
Dinitro-o-cresol534-52-10.2X
Dinitrotoluene25321-14-61.5X
Dioxane (Diethylene dioxide)123-91-1100360X
Diphenyl (Biphenyl)92-52-40.21
Diphenylmethane diisocyanate; see Methylene bisphenyl isocyanate.
Dipropylene glycol methyl ether34590-94-8100600X
Di-sec octyl phthalate (Di-(2-ethylhexyl) phthalate)117-81-75
Emery12415-34-8
Total dust   15
Respirable fraction   5
Endrin72-20-80.1X
Epichlorohydrin106-89-8519X
EPN2104-64-50.5X
1,2-Epoxypropane; see Propylene oxide.
2,3-Epoxy-1-propanol; see Glycidol.
Ethanethiol; see Ethyl mercaptan.
Ethanolamine141-43-536
2-Ethoxyethanol (Cellosolve)110-80-5200740X
2-Ethoxyethyl acetate (Cellosolve acetate)111-15-9100540X
Ethyl acetate141-78-64001400
Ethyl acrylate140-88-525100X
Ethyl alcohol (Ethanol)64-17-510001900
Ethylamine75-04-71018
Ethyl amyl ketone (5-Methyl-3-heptanone)541-85-525130
Ethyl benzene100-41-4100435
Ethyl bromide74-96-4200890
Ethyl butyl ketone (3-Heptanone)106-35-450230
Ethyl chloride75-00-310002600
Ethyl ether60-29-74001200
Ethyl formate109-94-4100300
Ethyl mercaptan75-08-1(C)10(C)25
Ethyl silicate78-10-4100850
Ethylene chlorohydrin107-07-3516X
Ethylenediamine107-15-31025
Ethylene dibromide106-93-4   (2)
Ethylene dichloride (1,2-Dichloroethane)107-06-2   (2)
Ethylene glycol dinitrate628-96-6(C)0.2(C)1X
Ethylene glycol methyl acetate; see Methyl cellosolve acetate.
Ethyleneimine; see 1910.1012151-56-4
Ethylene oxide; see 1910.104775-21-8
Ethylidene chloride; see 1,1-Dichloroethane.
N-Ethylmorpholine100-74-32094X
Ferbam14484-64-1
Total dust   15
Ferrovanadium dust12604-58-91
Fluorides (as F)(4)2.5
Fluorine7782-41-40.10.2
Fluorotrichloromethane (Trichlorofluoromethane)75-69-410005600
Formaldehyde; see 1910.104850-00-0
Formic acid64-18-659
Furfural98-01-1520X
Furfuryl alcohol98-00-050200
Grain dust (oat, wheat, barley)10
Glycerin (mist)56-81-5
Total dust   15
Respirable fraction   5
Glycidol556-52-550150
Glycol monoethyl ether; see 2-Ethoxyethanol.
Graphite, natural, respirable dust7782-42-5   (3)
Graphite, synthetic
Total dust   15
Respirable fraction   5
Guthion; see Azinphos methyl.
Gypsum13397-24-5
Total dust   15
Respirable fraction   5
Hafnium7440-58-60.5
Heptachlor76-44-80.5X
Heptane (n-Heptane)142-82-55002000
Hexachloroethane67-72-1110X
Hexachloronaphthalene1335-87-10.2X
n-Hexane110-54-35001800
2-Hexanone (Methyl n-butyl ketone)591-78-6100410
Hexone (Methyl isobutyl ketone)108-10-1100410
sec-Hexyl acetate108-84-950300
Hydrazine302-01-211.3X
Hydrogen bromide10035-10-6310
Hydrogen chloride7647-01-0(C)5(C)7
Hydrogen cyanide74-90-81011X
Hydrogen fluoride (as F)7664-39-3   (2)
Hydrogen peroxide7722-84-111.4
Hydrogen selenide (as Se)7783-07-50.050.2
Hydrogen sulfide7783-06-4   (2)
Hydroquinone123-31-92
Iodine7553-56-2(C)0.1(C)1
Iron oxide fume1309-37-110
Isoamyl acetate123-92-2100525
Isoamyl alcohol (primary and secondary)123-51-3100360
Isobutyl acetate110-19-0150700
Isobutyl alcohol78-83-1100300
Isophorone78-59-125140
Isopropyl acetate108-21-4250950
Isopropyl alcohol67-63-0400980
Isopropylamine75-31-0512
Isopropyl ether108-20-35002100
Isopropyl glycidyl ether (IGE)4016-14-250240
Kaolin1332-58-7
Total dust   15
Respirable fraction   5
Ketene463-51-40.50.9
Lead, inorganic (as Pb); see 1910.10257439-92-1
Limestone1317-65-3
Total dust   15
Respirable fraction   5
Lindane58-89-90.5X
Lithium hydride7580-67-80.025
L.P.G. (Liquefied petroleum gas)68476-85-710001800
Magnesite546-93-0
Total dust   15
Respirable fraction   5
Magnesium oxide fume1309-48-4
Total particulate   15
Malathion121-75-5
Total dust   15X
Maleic anhydride108-31-60.251
Manganese compounds (as Mn)7439-96-5(C)5
Manganese fume (as Mn)7439-96-5(C)5
Marble1317-65-3
Total dust   15
Respirable fraction   5
Mercury (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 oxide141-79-725100
Methanethiol; see Methyl mercaptan.
Methoxychlor72-43-5
Total dust   15
2-Methoxyethanol (Methyl cellosolve)109-86-42580X
2-Methoxyethyl acetate (Methyl cellosolve acetate)110-49-625120X
Methyl acetate79-20-9200610
Methyl acetylene (Propyne)74-99-710001650
Methyl acetylene-propadiene mixture (MAPP)   10001800
Methyl acrylate96-33-31035X
Methylal (Dimethoxy-methane)109-87-510003100
Methyl alcohol67-56-1200260
Methylamine74-89-51012
Methyl amyl alcohol; see Methyl isobutyl carbinol.
Methyl n-amyl ketone110-43-0100465
Methyl bromide74-83-9(C)20(C)80X
Methyl butyl ketone; see 2-Hexanone.
Methyl cellosolve; see 2-Methoxyethanol.
Methyl cellosolve acetate; see 2-Methoxyethyl acetate.
Methyl chloride74-87-3   (2)
Methyl chloroform (1,1,1-Trichloroethane)71-55-63501900
Methylcyclohexane108-87-25002000
Methylcyclohexanol25639-42-3100470
o-Methylcyclohexanone583-60-8100460X
Methylene chloride75-09-2   (2)
Methyl ethyl ketone (MEK); see 2-Butanone.
Methyl formate107-31-3100250
Methyl hydrazine (Monomethyl hydrazine)60-34-4(C)0.2(C)0.35X
Methyl iodide74-88-4528X
Methyl isoamyl ketone110-12-3100475
Methyl isobutyl carbinol108-11-225100X
Methyl isobutyl ketone; see Hexone.
Methyl isocyanate624-83-90.020.05X
Methyl mercaptan74-93-1(C)10(C)20
Methyl methacrylate80-62-6100410
Methyl propyl ketone; see 2-Pentanone.
alpha-Methyl styrene98-83-9(C)100(C)480
Methylene bisphenyl isocyanate (MDI)101-68-8(C)0.02(C)0.2
Mica; see Silicates.
Molybdenum (as Mo)7439-98-7
Soluble compounds   5
      Insoluble compounds.
   Total dust   15
Monomethyl aniline100-61-829X
Monomethyl hydrazine; see Methyl hydrazine.
Morpholine110-91-82070X
Naphtha (Coal tar)8030-30-6100400
Naphthalene91-20-31050
alpha-Naphthylamine; see 1910.1004134-32-7
beta-Naphthylamine; see 1910.100991-59-8
Nickel carbonyl (as Ni)13463-39-30.0010.007
Nickel, metal and insoluble compounds (as Ni)7440-02-01
Nickel, soluble compounds (as Ni)7440-02-01
Nicotine54-11-50.5X
Nitric acid7697-37-225
Nitric oxide10102-43-92530
p-Nitroaniline100-01-616X
Nitrobenzene98-95-315X
p-Nitrochlorobenzene100-00-51X
4-Nitrodiphenyl; see 1910.100392-93-3
Nitroethane79-24-3100310
Nitrogen dioxide10102-44-0(C)5(C)9
Nitrogen trifluoride7783-54-21029
Nitroglycerin55-63-0(C)0.2(C)2X
Nitromethane75-52-5100250
1-Nitropropane108-03-22590
2-Nitropropane79-46-92590
N-Nitrosodimethylamine; see 1910.1016.
Nitrotoluene (all isomers)   530X
o-isomer88-72-2
m-isomer99-08-1
p-isomer99-99-0
Nitrotrichloromethane; see Chloropicrin.
Octachloronaphthalene2234-13-10.1X
Octane111-65-95002350
Oil mist, mineral8012-95-15
Osmium tetroxide (as Os)20816-12-00.002
Oxalic acid144-62-71
Oxygen difluoride7783-41-70.050.1
Ozone10028-15-60.10.2
Paraquat, respirable dust4685-14-7;
1910-42-5;
2074-50-2
0.5X
Parathion56-38-20.1X
Particulates not otherwise regulated (PNOR)f.
Total dust   15
Respirable fraction   5
PCB; see Chlorodiphenyl (42% and 54% chlorine).
Pentaborane19624-22-70.0050.01
Pentachloronaphthalene1321-64-80.5X
Pentachlorophenol87-86-50.5X
Pentaerythritol115-77-5
Total dust   15
Respirable fraction   5
Pentane109-66-010002950
2-Pentanone (Methyl propyl ketone)107-87-9200700
Perchloroethylene (Tetrachloroethylene)127-18-4   (2)
Perchloromethyl mercaptan594-42-30.10.8
Perchloryl fluoride7616-94-6313.5
Petroleum distillates (Naphtha) (Rubber Solvent)   5002000
Phenol108-95-2519X
p-Phenylene diamine106-50-30.1X
Phenyl ether, vapor101-84-817
Phenyl ether-biphenyl mixture, vapor   17
Phenylethylene; see Styrene.
Phenyl glycidyl ether (PGE)122-60-11060
Phenylhydrazine100-63-0522X
Phosdrin (Mevinphos)7786-34-70.1X
Phosgene (Carbonyl chloride)75-44-50.10.4
Phosphine7803-51-20.30.4
Phosphoric acid7664-38-21
Phosphorus (yellow)7723-14-00.1
Phosphorus pentachloride10026-13-81
Phosphorus pentasulfide1314-80-31
Phosphorus trichloride7719-12-20.53
Phthalic anhydride85-44-9212
Picloram1918-02-1
Total dust   15
Respirable fraction   5
Picric acid88-89-10.1X
Pindone (2-Pivalyl-1,3-indandione)83-26-10.1
Plaster of Paris26499-65-0
Total dust   15
Respirable fraction   5
Platinum (as Pt)7440-06-4
Metal
Soluble salts   0.002
Portland cement65997-15-1
Total dust      15
Respirable fraction   5
Propane74-98-610001800
beta-Propriolactone; see 1910.101357-57-8
n-Propyl acetate109-60-4200840
n-Propyl alcohol71-23-8200500
n-Propyl nitrate627-13-425110
Propylene dichloride78-87-575350
Propylene imine75-55-825X
Propylene oxide75-56-9100240
Propyne; see Methyl acetylene.
Pyrethrum8003-34-75
Pyridine110-86-1515
Quinone106-51-40.10.4
RDX; see Cyclonite.
Rhodium (as Rh), metal fume and insoluble compounds7440-16-60.1
Rhodium (as Rh), soluble compounds7440-16-60.001
Ronnel299-84-315
Rotenone83-79-45
Rouge
Total dust   15
Respirable fraction   5
Selenium compounds (as Se)7782-49-20.2
Selenium hexafluoride (as Se)7783-79-10.050.4
Silica, amorphous, precipitated and gel112926-00-8   (3)
Silica, amorphous, diatomaceous earth, containing less than 1% crystalline silica61790-53-2   (3)
Silica, crystalline, respirable dust
Cristobalite; see 1910.1053714464-46-1
Quartz; see 1910.1053714808-60-7
Tripoli (as quartz); see 1910.105371317-95-9
Tridymite; see 1910.1053715468-32-3
Silica, fused, respirable dust60676-86-0   (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 asbestos limit; see 29 CFR 1910.1001   (3)
Talc (containing no asbestos), respirable dust14807-96-6   (3)
      Tremolite, asbestiform; see 1910.1001.
Silicon7440-21-3
Total dust   15
Respirable fraction   5
Silicon carbide409-21-2
Total dust   15
Respirable fraction   5
Silver, metal and soluble compounds (as Ag)7440-22-40.01
Soapstone; see Silicates.
Sodium fluoroacetate62-74-80.05X
Sodium hydroxide1310-73-22
Starch9005-25-8
Total dust   15
Respirable fraction   5
Stibine7803-52-30.10.5
Stoddard solvent8052-41-35002900
Strychnine57-24-90.15
Styrene100-42-5   (2)
Sucrose57-50-1
Total dust   15
Respirable fraction   5
Sulfur dioxide7446-09-5513
Sulfur hexafluoride2551-62-410006000
Sulfuric acid7664-93-91
Sulfur monochloride10025-67-916
Sulfur pentafluoride5714-22-70.0250.25
Sulfuryl fluoride2699-79-8520
Systox; see Demeton.
2,4,5-T (2,4,5-trichlorophenoxyacetic acid)93-76-510
Talc; see Silicates.
Tantalum, metal and oxide dust7440-25-75
TEDP (Sulfotep)3689-24-50.2X
Tellurium and compounds (as Te)13494-80-90.1
Tellurium hexafluoride (as Te)7783-80-40.020.2
Temephos3383-96-8
Total dust   15
Respirable fraction   5
TEPP (Tetraethyl pyrophosphate)107-49-30.05X
Terphenyls26140-60-3(C)1(C)9
1,1,1,2-Tetrachloro-2,2-difluoroethane76-11-95004170
1,1,2,2-Tetrachloro-1,2-difluoroethane76-12-05004170
1,1,2,2-Tetrachloroethane79-34-5535X
Tetrachloroethylene; see Perchloroethylene.
Tetrachloromethane; see Carbon tetrachloride.
Tetrachloronaphthalene1335-88-22X
Tetraethyl lead (as Pb)78-00-20.075X
Tetrahydrofuran109-99-9200590
Tetramethyl lead (as Pb)75-74-10.075X
Tetramethyl succinonitrile3333-52-60.53X
Tetranitromethane509-14-818
Tetryl (2,4,6-Trinitrophenylmethylnitramine)479-45-81.5X
Thallium, soluble compounds (as Tl)7440-28-00.1X
4,4′-Thiobis (6-tert, Butyl-m-cresol)96-69-5
Total dust   15
Respirable fraction   5
Thiram137-26-85
Tin, inorganic compounds (except oxides) (as Sn)7440-31-52
Tin, organic compounds (as Sn)7440-31-50.1
Titanium dioxide13463-67-7
Total dust   15
Toluene108-88-3   (2)
Toluene-2,4-diisocyanate (TDI)584-84-9(C)0.02(C)0.14
o-Toluidine95-53-4522X
Toxaphene; see Chlorinated camphene.
Tremolite; see Silicates.
Tributyl phosphate126-73-85
1,1,1-Trichloroethane; see Methyl chloroform.
1,1,2-Trichloroethane79-00-51045X
Trichloroethylene79-01-6   (2)
Trichloromethane; see Chloroform.
Trichloronaphthalene1321-65-95X
1,2,3-Trichloropropane96-18-450300
1,1,2-Trichloro-1,2,2-trifluoroethane76-13-110007600
Triethylamine121-44-825100
Trifluorobromomethane75-63-810006100
2,4,6-Trinitrophenol; see Picric acid.
2,4,6-Trinitrophenylmethylnitramine; see Tetryl.
2,4,6-Trinitrotoluene (TNT)118-96-71.5X
Triorthocresyl phosphate78-30-80.1
Triphenyl phosphate115-86-63
Turpentine8006-64-2100560
Uranium (as U)7440-61-1
Soluble compounds   0.05
Insoluble compounds   0.25
Vanadium1314-62-1
Respirable dust (as V2 O5)   (C)0.5
Fume (as V2 O5)   (C)0.1
Vegetable oil mist
Total dust   15
Respirable fraction   5
Vinyl benzene; see Styrene.
Vinyl chloride; see 1910.101775-01-4
Vinyl cyanide; see Acrylonitrile.
Vinyl toluene25013-15-4100480
Warfarin81-81-20.1
Xylenes (o-, m-, p-isomers)1330-20-7100435
Xylidine1300-73-8525X
Yttrium7440-65-51
Zinc chloride fume7646-85-71
Zinc oxide fume1314-13-25
Zinc oxide1314-13-2
Total dust   15
Respirable fraction   5
Zinc stearate557-05-1
Total dust   15
Respirable fraction   5
Zirconium compounds (as Zr)7440-67-75

1The 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.

(a) Parts of vapor or gas per million parts of contaminated air by volume at 25 °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.

2See Table Z-2.

3See Table Z-3.

4Varies with compound.

5See 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.

6If 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.

7See 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.

8See 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.

Table Z-2

Substance8-hour time weighted averageAcceptable ceiling concentrationAcceptable maximum peak above the acceptable ceiling concentration for an 8-hr shift
ConcentrationMaximum duration
Benzenea (Z37.40-1969)10 ppm25 ppm50 ppm10 minutes.
Beryllium and beryllium compounds (Z37.29-1970)d2 µg/m35 µg/m325 µg/m330 minutes.
Cadmium fumeb (Z37.5-1970)0.1 mg/m30.3 mg/m3
Cadmium dustb (Z37.5-1970)0.2 mg/m30.6 mg/m3
Carbon disulfide (Z37.3-1968)20 ppm30 ppm100 ppm30 minutes.
Carbon tetrachloride (Z37.17-1967)10 ppm25 ppm200 ppm5 min. in any 4 hrs.
Chromic acid and chromates (Z37.7-1971) (as CrO3)c   1 mg/10m3
Ethylene dibromide (Z37.31-1970)20 ppm30 ppm50 ppm5 minutes.
Ethylene dichloride (Z37.21-1969)50 ppm100 ppm200 ppm5 min. in any 3 hrs.
Fluoride as dust (Z37.28-1969)2.5 mg/m3
Formaldehyde; see 1910.1048
Hydrogen fluoride (Z37.28-1969)3 ppm
Hydrogen sulfide (Z37.2-1966)20 ppm50 ppm10 mins. once, only if no other meas. exp. occurs.
Mercury (Z37.8-1971)1 mg/10m3
Methyl chloride (Z37.18-1969)100 ppm200 ppm300 ppm5 mins. in any 3 hrs.
Methylene Chloride: See §1919.52.
Organo (alkyl) mercury (Z37.30-1969)0.01 mg/m30.04 mg/m3
Styrene (Z37.15-1969)100 ppm200 ppm600 ppm5 mins. in any 3 hrs.
Tetrachloroethylene (Z37.22-1967)100 ppm200 ppm300 ppm5 mins. in any 3 hrs.
Toluene (Z37.12-1967)200 ppm300 ppm500 ppm10 minutes.
Trichloroethylene (Z37.19-1967)100 ppm200 ppm300 ppm5 mins. in any 2 hrs.

aThis 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.

bThis standard applies to any operations or sectors for which the Cadmium standard, 1910.1027, is stayed or otherwise not in effect.

cThis 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.

dThis 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.

Table Z-3—Mineral Dusts

Substancemppcfamg/m3
Silica:
Crystalline
Quartz (Respirable)f250b10 mg/m3e
% SiO2 + 5% SiO2 + 2
Cristobalite: Use 12 the value calculated from the count or mass formulae for quartzf
Tridymite: Use 12 the value calculated from the formulae for quartzf
   
Amorphous, including natural diatomaceous earth2080 mg/m3
      %SiO2
   
Silicates (less than 1% crystalline silica):
Mica20
Soapstone20
Talc (not containing asbestos)20c
Talc (containing asbestos) Use asbestos limit
Tremolite, asbestiform (see 29 CFR 1910.1001)
Portland cement50
Graphite (Natural)15
Coal Dust:
   
Respirable fraction less than 5% SiO22.4 mg/m3 e
   
      10 mg/m3 e
Respirable fraction greater than 5% SiO2_____
%SiO2 + 2
   
Inert or Nuisance Dust:d
Respirable fraction155 mg/m3
Total dust5015 mg/m3

Note—Conversion factors - mppcf × 35.3 = million particles per cubic meter = particles per c.c.

aMillions of particles per cubic foot of air, based on impinger samples counted by light-field techniques.

bThe 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.

cContaining less than 1% quartz; if 1% quartz or more, use quartz limit.

dAll 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.

eBoth 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:

Aerodynamic diameter (unit density sphere)Percent passing selector
290
2.575
3.550
5.025
100

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/m3 in the table for coal dust is 4.5 mg/m3K.

fThis standard applies to any operations or sectors for which the respirable crystalline silica standard, 1910.1053, is stayed or is otherwise not in effect.

[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; 81 FR 16861, Mar. 25, 2016; 81 FR 31167, May 18, 2016; 81 FR 60272, Sept. 1, 2016; 82 FR 2735, Jan. 9, 2017]

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