Wherever this section applies, an employee's exposure to any substance listed in Table Z - Shipyards of this section shall be limited in accordance with the requirements of the following paragraphs of this section.

1. (a)

   1. (1) Substances with limits preceded by “C” - Ceiling values. An employee's exposure to any substance in Table Z - Shipyards, 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 over a working day.
   2. (2) Other Substances - 8-hour Time Weighted Averages. An employee's exposure to any substance in Table Z - Shipyards, 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.
2. (b) -(c) [Reserved]
3. (d) Computation formula. 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 1915 in order to determine whether an employee is exposed over the regulatory limit is as follows:

4. (1)

   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 1915 for the material involved.

   2. (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 - Shipyards. 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.

5. (2)

   1. (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 1915. The value of Em shall not exceed unity (1).

   2. (ii) To illustrate the formula prescribed in paragraph (d)(2)(i) of this section, consider the following exposures:

      Substance Actual concentration of 8 hour exposure (ppm) 8 hr. TWA PEL (ppm) B5001000 C45200 D40200 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.

      Table Z - ShipyardsSubstance CAS No. d ppm a * mg/m 3 b * Skin Designation Abate; see Temephos Acetaldehyde75-07-0200360 - Acetic acid64-19-71025 - Acetic anhydride108-24-7520 - Acetone67-64-110002400 - Acetonitrile75-05-84070 - 2-Acetylaminofluorine; see § 1915.101453-96-3 Acetylene74-86-2E Acetylene dichloride; see 1,2-Dichloroethylene Acetylene tetrabromide79-27-6114 - Acrolein107-02-80.10.25 - Acrylamide79-06-1 - 0.3X Acrylonitrile; see § 1915.1045107-13-1 Aldrin309-00-2 - 0.25X 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, (as Al) Metal7429-90-5 Total dust - 15 - Respirable fraction - 5 - Alundum; see alpha-Alumina 4-Aminodiphenyl; see § 1915.101192-67-1 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)29191-52-4 - 0.5X Antimony and compounds (as Sb)7440-36-0 - 0.5 - ANTU (alpha Naphthylthiourea)86-88-4 - 0.3 - Argon7440-37-1E Arsenic, inorganic compounds (as As); see § 1915.10187440-38-2 - - - Arsenic, organic compounds (as As)7440-38-2 - 0.5 - Arsine7784-42-10.050.2 - Asbestos; see 1915.1001 Azinphos-methyl86-50-0 - 0.2X Barium, soluble compounds (as Ba)7440-39-3 - 0.5 - Barium sulfate7727-43-7 Total dust - 15 - Respirable fraction - 5 - Benomyl17804-35-2 Total dust - 15 - Respirable fraction - 5 - Benzene g; see § 1915.102871-43-2 Benzidine; see § 1915.101092-87-5 p-Benzoquinone; see Quinone Benzo(a)pyrene; see Coal tar pitch volatiles Benzoyl peroxide94-36-0 - 5 - Benzyl chloride100-44-715 - Beryllium and beryllium compounds (as Be); see 1915.1024 (q)7440-41-70.002 Biphenyl; see Diphenyl Bismuth telluride, Undoped1304-82-1 Total dust - 15 - Respirable fraction - 5 - Bisphenol A; see Diglycidyl ether Boron oxide1303-86-2 Total dust - 15 - Boron tribromide10294-33-4110 - Boron trifluoride7637-07-2(C)1(C)3 - Bromine7726-95-60.10.7 - Bromine pentafluoride7789-30-20.10.7 - 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 1915.1026 n1189-85-1 n-Butyl glycidyl ether (BGE)2426-08-650270 - Butyl mercaptan109-79-50.51.5 - p-tert-Butyltoluene98-51-11060 - Cadmium dust fume (as Cd); see 1915.10277440-43-9 - - - Calcium carbonate1317-65-3 Total dust - 15 - Respirable fraction - 5 - Calcium hydroxide1305-62-0 - - - Calcium hydroxide Total dust - 15 - Respirable fraction - 5 - Calcium oxide1305-78-8 - 5 - Calcium silicate1344-95-2 Total dust - 15 - Respirable fraction - 5 - Calcium sulfate7778-18-9 Total dust - 15 - Respirable fraction - 5 - Camphor, synthetic76-22-2 - 2 - Carbaryl (Sevin)63-25-2 - 5 - Carbon black1333-86-4 - 3.5 - Carbon dioxide124-38-950009000 - Carbon disulfide75-15-02060X Carbon monoxide630-08-05055 - Carbon tetrachloride56-23-51065X Cellulose9004-34-6 Total dust - 15 - Respirable fraction - 5 - Chlordane57-74-9 - 0.5X Chlorinated camphene8001-35-2 - 0.5X Chlorinated diphenyl oxide55720-99-5 - 0.5 - Chlorine7782-50-513 - 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)53469-21-9 - 1X Chlorodiphenyl (54% Chlorine) (PCB)11097-69-1 - 0.5X 1-Chloro,2,3-epoxypropane; see Epichlorohydrin 2-Chloroethanol; see Ethylene chlorohydrin Chloroethylene; see Vinyl chloride Chloroform (Trichloromethane)67-66-350240 - bis(Chloromethyl) ether; see § 1915.1008542-88-1 Chloromethyl methyl ether; see § 1915.1006107-30-2 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)7440-47-3 - 0.5 - Chromium (III) compounds (as Cr)7440-47-3 - 0.5 - Chromium (VI) compounds; see 1915.1026 o Chromium metal and insol. salts (as Cr)7440-47-3 - 1 - Chrysene; see Coal tar pitch volatiles Clopidol2971-90-6 Total dust - 15 - Respirable fraction - 5 - Coal tar pitch volatiles (benzene soluble fraction), anthracene, BaP, phenanthrene, acridine, chrysene, pyrene65966-93-2 - 0.2 - Cobalt metal, dust, and fume (as Co)7440-48-4 - 0.1 - Copper7440-50-8 Fume (as Cu) - 0.1 - Dusts and mists (as Cu) - 1 - Corundum; see Emery Cotton dust (raw) - 1 Crag herbicide (Sesone)136-78-7 Total dust - 15 - Respirable fraction - 5 - Cresol, all isomers1319-77-3522X Crotonaldehyde123-73-9;26 4170-30-3 Cumene98-82-850245X Cyanides (as CN)Varies with Compound - 5 - Cyanogen460-19-510 - - Cyclohexane110-82-73001050 - Cyclohexanol108-93-050200 - Cyclohexanone108-94-150200 - Cyclohexene110-83-83001015 - Cyclonite121-82-4 - 1.5X Cyclopentadiene542-92-775200 - 2,4-D (Dichlorophenoxyacetic acid)94-75-7 - 10 - Decaborane17702-41-90.050.3X Demeton (Systox)8065-48-3 - 0.1X 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 (CBCP); see § 1915.104496-12-8 - 1,2-Dibromoethane; see Ethylene dibromide Dibutyl phosphate107-66-415 - Dibutyl phthalate84-74-2 - 5 - Dichloroacetylene7572-29-4(C)0.1(C)0.4 - o-Dichlorobenzene95-50-1(C)50(C)300 - p-Dichlorobenzene106-46-775450 - 3,3′-Dichlorobenzidine; see § 1915.100791-94-1 Dichlorodifluoromethane75-71-810004950 - 1,3-Dichloro-5,5-dimethyl hydantoin118-52-5 - 0.2 - Dichlorodiphenyltrichloroethane (DDT)50-29-3 - 1X 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)62-73-7 - 1X Dicyclopentadienyl iron102-54-5 Total dust - 15 - Respirable fraction - 5 - Dieldrin60-57-1 - 0.25X Diethylamine109-89-72575 - 2-Diethylaminoethanol100-37-81050 - Diethylene triamine111-40-0(C)10(C)42X 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 § 1915.101560-11-7 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 phosphate300-76-5 - 3 - Dimethylformamide68-12-21030X 2,6-Dimethyl-4-heptanone; see Diisobutyl ketone 1,1-Dimethylhydrazine57-14-70.51X Dimethylphthalate131-11-3 - 5 - Dimethyl sulfate77-78-315X Dinitrobenzene (all isomers) 1X (ortho)528-29-0 (meta)99-65-0 (para)100-25-4 Dinitro-o-cresol534-52-1 - 0.2X Dinitrotoluene25321-14-6 - 1.5X Dioxane (Diethylene dioxide)123-91-1100360X Diphenyl (Biphenyl)92-52-40.21 - Diphenylamine122-39-4 - 10 - Diphenylmethane diisocyanate; see Methylene bisphenyl isocyanate Dipropylene glycol methyl ether34590-94-8100600X Di-sec octyl phthalate (Di-(2-ethylhexyl) phthalate)117-81-7 - 5 - Emery12415-34-8 Total dust - 15 - Respirable fraction - 5 - Endosulfan115-29-7 - 0.1X Endrin72-20-8 - 0.1X Epichlorohydrin106-89-8519X EPN2104-64-5 - 0.5X 1,2-Epoxypropane; see Propylene oxide 2,3-Epoxy-1-propanol; see Glycidol Ethane74-84-0E 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 mercaptan75-08-10.51 - Ethyl silicate78-10-4100850 - Ethylene74-85-1E Ethylene chlorohydrin107-07-3516X Ethylenediamine107-15-31025 - Ethylene dibromide106-93-4(C)25(C)190X Ethylene dichloride (1,2-Dichloroethane)107-06-250200 - Ethylene glycol dinitrate628-96-6(C)0.2(C)1X Ethylene glycol methyl acetate; see Methyl cellosolve acetate Ethyleneimine; see § 1915.1012151-56-4 Ethylene oxide; see § 1915.104775-21-8 Ethylidene chloride; see 1,1-Dichloroethane N-Ethylmorpholine100-74-32094X Ferbam14484-64-1 Total dust - 15 - Ferrovanadium dust12604-58-9 - 1 - Fibrous Glass Total dust 15 - Respirable fraction - 5 - Fluorides (as F)Varies with compound - 2.5 - Fluorine7782-41-40.10.2 - Fluorotrichloromethane (Trichlorofluoromethane)75-69-410005600 - Formaldehyde; see § 1915.104850-00-0 Formic acid64-18-659 - Furfural98-01-1520X Furfuryl alcohol98-00-050200 - Gasoline8006-61-9 A 3 - 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( 2)( 2)( 2) Graphite, synthetic Total dust - 15 - Respirable fraction - 5 - Guthion; see Azinphos methyl Gypsum13397-24-5 Total dust - 15 - Respirable fraction - 5 - Hafnium7440-58-6 - 0.5 - Helium7440-59-7E Heptachlor76-44-8 - 0.5X Heptane (n-Heptane)142-82-55002000 - Hexachloroethane67-72-1110X Hexachloronaphthalene1335-87-1 - 0.2X 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 Hydrogen1333-74-0E Hydrogen bromide10035-10-6310 - Hydrogen chloride7647-01-0(C)5(C)7 - Hydrogen cyanide74-90-81011X Hydrogen fluoride (as F)7664-39-332 - Hydrogen peroxide7722-84-111.4 - Hydrogen selenide (as Se)7783-07-50.05 Hydrogen sulfide7783-06-41015 - Hydroquinone123-31-9 - 2 - Indene95-13-61045 - Indium and compounds (as In)7440-74-6 - 0.1 - Iodine7553-56-2(C)0.1(C)1 - Iron oxide fume1309-37-1 - 10 - Iron salts (soluble) (as Fe)Varies with compound - 1 - 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 § 1915.10257439-92-1 - - - Limestone1317-65-3 Total dust - 15 - Respirable fraction - 5 - Lindane58-89-9 - 0.5X Lithium hydride7580-67-8 - 0.025 - 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 anhydride108-31-60.25 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 0.1X Mercury (organo) alkyl compounds (as Hg)7439-97-6 - 0.01X Mercury (vapor) (as Hg)7439-97-6 - 0.1X Mesityl oxide141-79-725100 - Methane74-82-8E 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 chloride74-87-3100210 - Methyl chloroform (1,1,1-Trichloroethane)71-55-63501900 - Methylcyclohexane108-87-25002000 - Methylcyclohexanol25639-42-3100470 - o-Methylcyclohexanone583-60-8100460X Methylene chloride; see § 1910.1052 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 mercaptan74-93-10.51 - Methyl methacrylate80-62-6100410100 Methyl propyl ketone; see 2-Pentanone Methyl silicate681-84-5530 - 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 Mineral wool Total dust - 15 - Respirable dust - 5 - 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 § 1915.1004134-32-7 beta-Naphthylamine; see § 1915.100991-59-8 - Neon7440-01-9Nickel carbonyl (as Ni)13463-39-30.0010.007 - Nickel, metal and insoluble compounds (as Ni)7440-02-0 - 1 - Nickel, soluble compounds (as Ni)7440-02-0 - 1 - Nicotine54-11-5 - 0.5X Nitric acid7697-37-225 - Nitric oxide10102-43-92530 - p-Nitroaniline100-01-616X Nitrobenzene98-95-315X p-Nitrochlorobenzene100-00-5 - 1X 4-Nitrodiphenyl; see § 1915.100392-93-3 Nitroethane79-24-3100310 - Nitrogen7727-37-9E 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 § 1915.101662-79-9 - Nitrotoluene (all isomers) 530X o-isomer88-72-2; m-isomer99-08-1; p-isomer99-99-0 Nitrotrichloromethane; see Chloropicrin Nitrous oxide10024-97-2E Octachloronaphthalene2234-13-1 - 0.1X Octane111-65-94001900 - Oil mist, mineral8012-95-1 - 5 - Osmium tetroxide (as Os)20816-12-0 - 0.002 - Oxalic acid144-62-7 - 1 - Oxygen difluoride7783-41-70.050.1 - Ozone10028-15-60.10.2 - Paraquat, respirable dust4685-14-7; - 0.5X 1910-42-5; 2074-50-2 Parathion56-38-2 - 0.1 - Particulates not otherwise regulated Total dust organic and inorganic - 15 - PCB; see Chlorodiphenyl (42% and 54% chlorine) Pentaborane19624-22-70.0050.01 - Pentachloronaphthalene1321-64-8 - 0.5X Pentachlorophenol87-86-5 - 0.5X Pentaerythritol115-77-5 Total dust - 15 - Respirable fraction - 5 - Pentane109-66-05001500 - 2-Pentanone (Methyl propyl ketone)107-87-9200700 - Perchloroethylene (Tetrachloroethylene)127-18-4100670 - Perchloromethyl mercaptan594-42-30.10.8 - Perchloryl fluoride7616-94-6313.5 - Perlite93763-70-3 Total dust - 15 - Respirable fraction - 5 - Petroleum distillates (Naphtha)(Rubber Solvent) A 3 - Phenol108-95-2519X p-Phenylene diamine106-50-3 - 0.1X 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)7786-34-7 - 0.1X Phosgene (Carbonyl chloride)75-44-50.10.4 - Phosphine7803-51-20.30.4 - Phosphoric acid7664-38-2 - 1 - Phosphorus (yellow)7723-14-0 - 0.1 - Phosphorus pentachloride10026-13-8 - 1 - Phosphorus pentasulfide1314-80-3 - 1 - Phosphorus trichloride7719-12-20.53 - Phthalic anhydride85-44-9212 - Picloram1918-02-1 Total dust - 15 - Respirable fraction - 5 - Picric acid88-89-1 - 0.1 - Piperazine dihydrochloride142-64-3 - - X Pindone (2-Pivalyl-1,3-indandione)83-26-1 - 0.1 - Plaster of Paris26499-65-0 Total dust - 15 - Respirable fraction - 5 - Platinum (as Pt)7440-06-4 Metal - - - Soluble salts - 0.002 - Polytetrafluoroethylene decomposition products A 2 Portland cement65997-15-1 Total dust 15 - 10 Respirable fraction 5 - - Propargyl alcohol107-19-71 - X beta-Propriolactone; see § 1915.101357-57-8 Propionic acid79-09-4 - - - 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 Pyrethrum8003-34-7 - 5 - Pyridine110-86-1515 - Quinone106-51-40.10.4 - RDX; see Cyclonite Rhodium (as Rh), metal fume and insoluble compounds7440-16-6 - 0.1 - Rhodium (as Rh), soluble compounds7440-16-6 - 0.001 - Ronnel299-84-3 - 10 - Rotenone83-79-4 - 5 - Rouge - Total dust - 15 - Respirable fraction - 5 - Selenium compounds (as Se)7782-49-2 - 0.2 - Selenium hexafluoride (as Se)7783-79-10.050.4 - Silica, amorphous, precipitated and gel112926-00-8( 2)( 2)( 2) Silica, amorphous, diatomaceous earth, containing less than 1% crystalline silica61790-53-2( 2)( 2)( 2) Silica, crystalline, respirable dust Cristobalite; see 1915.105314464-46-1 Quartz; see 1915.1053 514808-60-7 Tripoli (as quartz); see 1915.1053 51317-95-9 Tridymite; see 1915.105315468-32-3 Silica, fused, respirable dust60676-86-0( 2)( 2)( 2) Silicates (less than 1% crystalline silica) Mica (respirable dust)12001-26-2( 2)( 2)( 2) Soapstone, total dust - ( 2)( 2)( 2) Soapstone, respirable dust - ( 2)( 2)( 2) Talc (containing asbestos) - ( 3)( 3)( 3) Talc (containing no asbestos), respirable dust14807-96-6( 2)( 2)( 2) Tremolite, asbestiform ( 3)( 3)( 3) 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)7440-22-4 - 0.01 - Soapstone; see Silicates Sodium fluoroacetate62-74-8 - 0.05X Sodium hydroxide1310-73-2 - 2 - Starch9005-25-8 Total dust - 15 - Respirable fraction - 5 - Stibine7803-52-30.10.5 - Stoddard solvent8052-41-32001150 - Strychnine57-24-9 - 0.15 - Styrene100-42-510042050 Sucrose57-50-1 Total dust - 15 - Respirable fraction - 5 - Sulfur dioxide7446-09-5513 - Sulfur hexafluoride2551-62-410006000 - Sulfuric acid7664-93-9 - 1 - 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)93-76-5 - 10 - Talc; see Silicates - Tantalum, metal and oxide dust7440-25-7 - 5 - TEDP (Sulfotep)3689-24-5 - 0.2X Teflon decomposition products A2 Tellurium and compounds (as Te)13494-80-9 - 0.1 - Tellurium hexafluoride (as Te)7783-80-40.020.2 - Temephos3383-96-8 Total dust - 15 - Respirable fraction - 5 - TEPP (Tetraethyl pyrophosphate)107-49-3 - 0.05X 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 Tetrachloronaphthalene1335-88-2 - 2X Tetraethyl lead (as Pb)78-00-2 - 0.1X Tetrahydrofuran109-99-9200590 - Tetramethyl lead, (as Pb)75-74-1 - 0.15X Tetramethyl succinonitrile3333-52-60.53X Tetranitromethane509-14-818 - Tetryl (2,4,6-Trinitrophenylmethylnitramine)479-45-8 - 1.5X Thallium, soluble compounds (as Tl)7440-28-0 - 0.1X 4,4′-Thiobis (6-tert, Butyl-m-cresol)96-69-5 Total dust - 15 - Respirable fraction - 5 - Thiram137-26-8 - 5 - Tin, inorganic compounds (except oxides) (as Sn)7440-31-5 - 2 - Tin, organic compounds (as Sn)7440-31-5 - 0.1 - Tin oxide (as Sn)21651-19-4 - - - Total dust - 15 - Respirable fraction - 5 - Titanium dioxide13463-67-7 Total dust - 15 - Toluene108-88-3200750100 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 phosphate126-73-8 - 5 - 1,1,1-Trichloroethane; see Methyl chloroform 1,1,2-Trichloroethane79-00-51045X Trichloroethylene79-01-6100535 - Trichloromethane; see Chloroform Trichloronaphthalene1321-65-9 - 5X 1,2,3-Trichloropropane96-18-450300 - 1,1,2-Trichloro-1,2,2-trifluoroethane76-13-110007600 - Triethylamine121-44-825100 - Trifluorobromomethane75-63-810006100 - Trimethyl benzene25551-13-725120 - 2,4,6-Trinitrophenyl; see Picric acid 2,4,6-Trinitrophenylmethylnitramine; see Tetryl 2,4,6-Trinitrotoluene (TNT)118-96-7 - 1.5X Triorthocresyl phosphate78-30-8 - 0.1 - Triphenyl phosphate115-86-6 - 3 - Tungsten (as W)7440-33-7 Insoluble compounds - 5 - Soluble compounds - 1 - Turpentine8006-64-2100560 - Uranium (as U)7440-61-1 Soluble compounds - 0.2 - Insoluble compounds - 0.2 - 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 § 1915.101775-01-4 Vinyl cyanide; see Acrylonitrile Vinyl toluene25013-15-4100480 - Warfarin81-81-2 - 0.1 - Xylenes (o-, m-, p-isomers)1330-20-7100435 - Xylidine1300-73-8525X Yttrium7440-65-5 - 1 - Zinc chloride fume7646-85-7 - 1 - Zinc oxide fume1314-13-2 - 5 - Zinc oxide1314-13-2 Total dust - 15 - Respirable fraction - 5 - Zinc stearate557-05-1 Total dust - 15 - Respirable fraction - 5 - Zirconium compounds (as Zr)7440-67-7 - 5

      Mineral DustsSubstance mppcf (j) SILICA: Crystalline250 (k) Quartz. Threshold Limit calculated from the formula (p)% SiO2 + 5 Cristobalite Amorphous, including natural diatomaceous earth20 SILICATES (less than 1% crystalline silica) Mica20 Portland cement50 Soapstone20 Talc (non-asbestiform)20 Talc (fibrous), use asbestos limit-- Graphite (natural)15 Inert or Nuisance Particulates: (m)50 (or 15 mg/m 3 whichever is the smaller) of total dust <1% SiO2 Conversion factors mppcf × 35.3 = million particles per cubic meter = particles per c.c.

      Footnotes to Table Z - Shipyards: 1 [Reserved] 2 See Mineral Dusts Table. 3 Use Asbestos Limit § 1915.1001. 4 See 1915.1001. 5 See Mineral Dusts table for the exposure limit for any operations or sectors where the exposure limit in § 1915.1053 is stayed or is otherwise not in effect.* 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. 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 [Reserved] d 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.e-f [Reserved] g For sectors excluded from § 1915.1028 the limit is 10 ppm TWA. h Where OSHA has published a proposal for a substance but has not issued a final rule, the proposal is referenced and the existing limit is published. i [Reserved] j Millions of particles per cubic foot of air, based on impinger samples counted by light-field techniques. k 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. m Covers all organic and inorganic particulates not otherwise regulated. Same as Particulates Not Otherwise Regulated. n If the exposure limit in § 1915.1026 is stayed or is otherwise not in effect, the exposure limit is a ceiling of 0.1 mg/m 3. o If the exposure limit in § 1915.1026 is stayed or is otherwise not in effect, the exposure limit is 0.1 mg/m 3 (as CrO3) as an 8-hour TWA. p This standard applies to any operations or sectors for which the respirable crystalline silica standard, 1915.1053, is stayed or otherwise is not in effect. q This standard applies to any operations or sectors for which the beryllium standard, 1915.1024, is stayed or otherwise is not in effect.The 1970 TLV uses letter designations instead of a numerical value as follows:A 1 [Reserved]A 2 Polytetrafluoroethylene decomposition products. Because these products decompose in part by hydrolysis in alkaline solution, they can be quantitatively determined in air as fluoride to provide an index of exposure. No TLV is recommended pending determination of the toxicity of the products, but air concentrations should be minimal.A 3 Gasoline and/or Petroleum Distillates. The composition of these materials varies greatly and thus a single TLV for all types of these materials is no longer applicable. The content of benzene, other aromatics and additives should be determined to arrive at the appropriate TLV.E Simple asphyxiants. The limiting factor is the available oxygen which shall be at least 18% and be within the requirement addressing explosion in subpart B of part 1915.

[58 FR 35514, July 1, 1993, as amended at 61 FR 56856, Nov. 4, 1996; 62 FR 1619, Jan. 10, 1997; 67 FR 44545, July 3, 2002; 71 FR 10377, Feb. 28, 2006; 71 FR 36009, June 23, 2006; 76 FR 80740, Dec. 27, 2011; 81 FR 16874, Mar. 2 2016; 81 FR 31167, May 19, 2016; 81 FR 60273, Sept. 2, 2016; 82 FR 2744, Jan. 9, 2017]