#### § 1915.1000 Air contaminants.

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.

(a)

(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) *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.

(b)-(c) [Reserved]

(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:

(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.

(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.

(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 1915.

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:

| Substance | Actual concentration of 8 hour exposure (ppm) | 8 hr. TWA PEL (ppm) |
| --- | --- | --- |
| B | 500 | 1000 |
| C | 45 | 200 |
| D | 40 | 200 |
| 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.

| Substance | CAS No.d | ppma * | mg/m3 b * | Skin Designation |
| --- | --- | --- | --- | --- |
| Abate; see Temephos | | | | |
| Acetaldehyde | 75-07-0 | 200 | 360 | — |
| Acetic acid | 64-19-7 | 10 | 25 | — |
| Acetic anhydride | 108-24-7 | 5 | 20 | — |
| Acetone | 67-64-1 | 1000 | 2400 | — |
| Acetonitrile | 75-05-8 | 40 | 70 | — |
| 2-Acetylaminofluorine; see § 1915.1014 | 53-96-3 | | | |
| Acetylene | 74-86-2 | E | | |
| Acetylene dichloride; see 1,2-Dichloroethylene | | | | |
| Acetylene tetrabromide | 79-27-6 | 1 | 14 | — |
| Acrolein | 107-02-8 | 0.1 | 0.25 | — |
| Acrylamide | 79-06-1 | — | 0.3 | X |
| Acrylonitrile; see § 1915.1045 | 107-13-1 | | | |
| Aldrin | 309-00-2 | — | 0.25 | X |
| Allyl alcohol | 107-18-6 | 2 | 5 | X |
| Allyl chloride | 107-05-1 | 1 | 3 | — |
| Allyl glycidyl ether (AGE) | 106-92-3 | (C)10 | (C)45 | — |
| Allyl propyl disulfide | 2179-59-1 | 2 | 12 | — |
| alpha-Alumina | 1344-28-1 | | | |
| Total dust | | — | 15 | — |
| Respirable fraction | | — | 5 | — |
| Aluminum, (as Al) Metal | 7429-90-5 | | | |
| Total dust | | — | 15 | — |
| Respirable fraction | | — | 5 | — |
| Alundum; see alpha-Alumina | | | | |
| 4-Aminodiphenyl; see § 1915.1011 | 92-67-1 | | | |
| 2-Aminoethanol; see Ethanolamine | | | | |
| 2-Aminopyridine | 504-29-0 | 0.5 | 2 | — |
| Ammonia | 7664-41-7 | 50 | 35 | — |
| Ammonium sulfamate | 7773-06-0 | | | |
| Total dust | | — | 15 | — |
| Respirable fraction | | — | 5 | — |
| n-Amyl acetate | 628-63-7 | 100 | 525 | — |
| sec-Amyl acetate | 626-38-0 | 125 | 650 | — |
| Aniline and homologs | 62-53-3 | 5 | 19 | X |
| Anisidine (o-, p-isomers) | 29191-52-4 | — | 0.5 | X |
| Antimony and compounds (as Sb) | 7440-36-0 | — | 0.5 | — |
| ANTU (alpha Naphthylthiourea) | 86-88-4 | — | 0.3 | — |
| Argon | 7440-37-1 | E | | |
| Arsenic, inorganic compounds (as As); see § 1915.1018 | 7440-38-2 | — | — | — |
| Arsenic, organic compounds (as As) | 7440-38-2 | — | 0.5 | — |
| Arsine | 7784-42-1 | 0.05 | 0.2 | — |
| Asbestos; see 1915.1001 | | | | |
| Azinphos-methyl | 86-50-0 | — | 0.2 | X |
| Barium, soluble compounds (as Ba) | 7440-39-3 | — | 0.5 | — |
| Barium sulfate | 7727-43-7 | | | |
| Total dust | | — | 15 | — |
| Respirable fraction | | — | 5 | — |
| Benomyl | 17804-35-2 | | | |
| Total dust | | — | 15 | — |
| Respirable fraction | | — | 5 | — |
| Benzeneg; see § 1915.1028 | 71-43-2 | | | |
| Benzidine; see § 1915.1010 | 92-87-5 | | | |
| p-Benzoquinone; see Quinone | | | | |
| Benzo(a)pyrene; see Coal tar pitch volatiles | | | | |
| Benzoyl peroxide | 94-36-0 | — | 5 | — |
| Benzyl chloride | 100-44-7 | 1 | 5 | — |
| Beryllium and beryllium compounds (as Be); see 1915.1024(q) | 7440-41-7 | | 0.002 | |
| Biphenyl; see Diphenyl | | | | |
| Bismuth telluride, Undoped | 1304-82-1 | | | |
| Total dust | | — | 15 | — |
| Respirable fraction | | — | 5 | — |
| Bisphenol A; see Diglycidyl ether | | | | |
| Boron oxide | 1303-86-2 | | | |
| Total dust | | — | 15 | — |
| Boron tribromide | 10294-33-4 | 1 | 10 | — |
| Boron trifluoride | 7637-07-2 | (C)1 | (C)3 | — |
| Bromine | 7726-95-6 | 0.1 | 0.7 | — |
| Bromine pentafluoride | 7789-30-2 | 0.1 | 0.7 | — |
| Bromoform | 75-25-2 | 0.5 | 5 | X |
| Butadiene (1,3-Butadiene); see 29 CFR 1910.1051; 29 CFR 1910.19(l) | 106-99-0 | 1ppm/5ppmSTEL | — | — |
| Butanethiol; see Butyl mercaptan | | | | |
| 2-Butanone (Methyl ethyl ketone) | 78-93-3 | 200 | 590 | — |
| 2-Butoxyethanol | 111-76-2 | 50 | 240 | X |
| n-Butyl-acetate | 123-86-4 | 150 | 710 | — |
| sec-Butyl acetate | 105-46-4 | 200 | 950 | — |
| tert-Butyl acetate | 540-88-5 | 200 | 950 | — |
| n-Butyl alcohol | 71-36-3 | 100 | 300 | — |
| sec-Butyl alcohol | 78-92-2 | 150 | 450 | — |
| tert-Butyl alcohol | 75-65-0 | 100 | 300 | — |
| Butylamine | 109-73-9 | (C)5 | (C)15 | X |
| tert-Butyl chromate (as CrO3); see 1915.1026n | 1189-85-1 | | | |
| n-Butyl glycidyl ether (BGE) | 2426-08-6 | 50 | 270 | — |
| Butyl mercaptan | 109-79-5 | 0.5 | 1.5 | — |
| p-tert-Butyltoluene | 98-51-1 | 10 | 60 | — |
| Cadmium dust fume (as Cd); see 1915.1027 | 7440-43-9 | — | — | — |
| Calcium carbonate | 1317-65-3 | | | |
| Total dust | | — | 15 | — |
| Respirable fraction | | — | 5 | — |
| Calcium hydroxide | 1305-62-0 | — | — | — |
| Calcium hydroxide | | | | |
| Total dust | | — | 15 | — |
| Respirable fraction | | — | 5 | — |
| Calcium oxide | 1305-78-8 | — | 5 | — |
| Calcium silicate | 1344-95-2 | | | |
| Total dust | | — | 15 | — |
| Respirable fraction | | — | 5 | — |
| Calcium sulfate | 7778-18-9 | | | |
| Total dust | | — | 15 | — |
| Respirable fraction | | — | 5 | — |
| Camphor, synthetic | 76-22-2 | — | 2 | — |
| Carbaryl (Sevin) | 63-25-2 | — | 5 | — |
| Carbon black | 1333-86-4 | — | 3.5 | — |
| Carbon dioxide | 124-38-9 | 5000 | 9000 | — |
| Carbon disulfide | 75-15-0 | 20 | 60 | X |
| Carbon monoxide | 630-08-0 | 50 | 55 | — |
| Carbon tetrachloride | 56-23-5 | 10 | 65 | X |
| Cellulose | 9004-34-6 | | | |
| Total dust | | — | 15 | — |
| Respirable fraction | | — | 5 | — |
| Chlordane | 57-74-9 | — | 0.5 | X |
| Chlorinated camphene | 8001-35-2 | — | 0.5 | X |
| Chlorinated diphenyl oxide | 55720-99-5 | — | 0.5 | — |
| Chlorine | 7782-50-5 | 1 | 3 | — |
| Chlorine trifluoride | 7790-91-2 | (C)0.1 | (C)0.4 | — |
| Chloroacetaldehyde | 107-20-0 | (C)1 | (C)3 | — |
| a-Chloroacetophenone (Phenacyl chloride) | 532-27-4 | 0.05 | 0.3 | — |
| Chlorobenzene | 108-90-7 | 75 | 350 | — |
| o-Chlorobenzylidene malononitrile | 2698-41-1 | 0.05 | 0.4 | — |
| Chlorobromomethane | 74-97-5 | 200 | 1050 | — |
| 2-Chloro-1,3-butadiene; see beta-Chloroprene | | | | |
| Chlorodiphenyl (42% Chlorine) (PCB) | 53469-21-9 | — | 1 | X |
| Chlorodiphenyl (54% Chlorine) (PCB) | 11097-69-1 | — | 0.5 | X |
| 1-Chloro,2,3-epoxypropane; see Epichlorohydrin | | | | |
| 2-Chloroethanol; see Ethylene chlorohydrin | | | | |
| Chloroethylene; see Vinyl chloride | | | | |
| Chloroform (Trichloromethane) | 67-66-3 | 50 | 240 | — |
| bis(Chloromethyl) ether; see § 1915.1008 | 542-88-1 | | | |
| Chloromethyl methyl ether; see § 1915.1006 | 107-30-2 | | | |
| 1-Chloro-1-nitropropane | 600-25-9 | 20 | 100 | — |
| Chloropicrin | 76-06-2 | 0.1 | 0.7 | |
| beta-Chloroprene | 126-99-8 | 25 | 90 | X |
| 2-Chloro-6-(trichloromethyl) pyridine | 1929-82-4 | | | |
| 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 1915.1026o | | | | |
| Chromium metal and insol. salts (as Cr) | 7440-47-3 | — | 1 | — |
| Chrysene; see Coal tar pitch volatiles | | | | |
| Clopidol | 2971-90-6 | | | |
| Total dust | | — | 15 | — |
| Respirable fraction | | — | 5 | — |
| Coal tar pitch volatiles (benzene soluble fraction), anthracene, BaP, phenanthrene, acridine, chrysene, pyrene | 65966-93-2 | — | 0.2 | — |
| Cobalt metal, dust, and fume (as Co) | 7440-48-4 | — | 0.1 | — |
| Copper | 7440-50-8 | | | |
| 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 isomers | 1319-77-3 | 5 | 22 | X |
| Crotonaldehyde | 123-73-9; | 2 | 6 | |
| | 4170-30-3 | | | |
| Cumene | 98-82-8 | 50 | 245 | X |
| Cyanides (as CN) | Varies with Compound | — | 5 | — |
| Cyanogen | 460-19-5 | 10 | — | — |
| Cyclohexane | 110-82-7 | 300 | 1050 | — |
| Cyclohexanol | 108-93-0 | 50 | 200 | — |
| Cyclohexanone | 108-94-1 | 50 | 200 | — |
| Cyclohexene | 110-83-8 | 300 | 1015 | — |
| Cyclonite | 121-82-4 | — | 1.5 | X |
| Cyclopentadiene | 542-92-7 | 75 | 200 | — |
| 2,4-D (Dichlorophenoxyacetic acid) | 94-75-7 | — | 10 | — |
| Decaborane | 17702-41-9 | 0.05 | 0.3 | X |
| Demeton (Systox) | 8065-48-3 | — | 0.1 | X |
| Diacetone alcohol (4-Hydroxy-4-methyl-2-pentanone) | 123-42-2 | 50 | 240 | — |
| 1,2-Diaminoethane; see Ethylenediamine | | | | |
| Diazomethane | 334-88-3 | 0.2 | 0.4 | — |
| Diborane | 19287-45-7 | 0.1 | 0.1 | — |
| 1,2-Dibromo-3-chloropropane (CBCP); see § 1915.1044 | 96-12-8 | | — | |
| 1,2-Dibromoethane; see Ethylene dibromide | | | | |
| Dibutyl phosphate | 107-66-4 | 1 | 5 | — |
| Dibutyl phthalate | 84-74-2 | — | 5 | — |
| Dichloroacetylene | 7572-29-4 | (C)0.1 | (C)0.4 | — |
| o-Dichlorobenzene | 95-50-1 | (C)50 | (C)300 | — |
| p-Dichlorobenzene | 106-46-7 | 75 | 450 | — |
| 3,3′-Dichlorobenzidine; see § 1915.1007 | 91-94-1 | | | |
| Dichlorodifluoromethane | 75-71-8 | 1000 | 4950 | — |
| 1,3-Dichloro-5,5-dimethyl hydantoin | 118-52-5 | — | 0.2 | — |
| Dichlorodiphenyltrichloroethane (DDT) | 50-29-3 | — | 1 | X |
| 1,1-Dichloroethane | 75-34-3 | 100 | 400 | — |
| 1,2-Dichloroethane; see Ethylene dichloride | | | | |
| 1,2-Dichloroethylene | 540-59-0 | 200 | 790 | — |
| Dichloroethyl ether | 111-44-4 | (C)15 | (C)90 | X |
| Dichloromethane; see Methylene chloride | | | | |
| Dichloromonofluoromethane | 75-43-4 | 1000 | 4200 | — |
| 1,1-Dichloro-1-nitroethane | 594-72-9 | (C)10 | (C)60 | — |
| 1,2-Dichloropropane; see Propylene dichloride | | | | |
| Dichlorotetrafluoroethane | 76-14-2 | 1000 | 7000 | — |
| Dichlorvos (DDVP) | 62-73-7 | — | 1 | X |
| Dicyclopentadienyl iron | 102-54-5 | | | |
| Total dust | | — | 15 | — |
| Respirable fraction | | — | 5 | — |
| Dieldrin | 60-57-1 | — | 0.25 | X |
| Diethylamine | 109-89-7 | 25 | 75 | — |
| 2-Diethylaminoethanol | 100-37-8 | 10 | 50 | — |
| Diethylene triamine | 111-40-0 | (C)10 | (C)42 | X |
| Diethyl ether; see Ethyl ether | | | | |
| Difluorodibromomethane | 75-61-6 | 100 | 860 | — |
| Diglycidyl ether (DGE) | 2238-07-5 | (C)0.5 | (C)2.8 | — |
| Dihydroxybenzene; see Hydroquinone | | | | |
| Diisobutyl ketone | 108-83-8 | 50 | 290 | — |
| Diisopropylamine | 108-18-9 | 5 | 20 | X |
| 4-Dimethylaminoazobenzene; see § 1915.1015 | 60-11-7 | | | |
| Dimethoxymethane; see Methylal | | | | |
| Dimethyl acetamide | 127-19-5 | 10 | 35 | X |
| Dimethylamine | 124-40-3 | 10 | 18 | — |
| Dimethylaminobenzene; see Xylidine | | | | |
| Dimethylaniline (N,N-Dimethylaniline) | 121-69-7 | 5 | 25 | X |
| Dimethylbenzene; see Xylene | | | | |
| Dimethyl-1,2-dibromo- 2,2-dichloroethyl phosphate | 300-76-5 | — | 3 | — |
| Dimethylformamide | 68-12-2 | 10 | 30 | X |
| 2,6-Dimethyl-4-heptanone; see Diisobutyl ketone | | | | |
| 1,1-Dimethylhydrazine | 57-14-7 | 0.5 | 1 | X |
| Dimethylphthalate | 131-11-3 | — | 5 | — |
| Dimethyl sulfate | 77-78-3 | 1 | 5 | X |
| Dinitrobenzene (all isomers) | | | 1 | X |
| (ortho) | 528-29-0 | | | |
| (meta) | 99-65-0 | | | |
| (para) | 100-25-4 | | | |
| Dinitro-o-cresol | 534-52-1 | — | 0.2 | X |
| Dinitrotoluene | 25321-14-6 | — | 1.5 | X |
| Dioxane (Diethylene dioxide) | 123-91-1 | 100 | 360 | X |
| Diphenyl (Biphenyl) | 92-52-4 | 0.2 | 1 | — |
| Diphenylamine | 122-39-4 | — | 10 | — |
| Diphenylmethane diisocyanate; see Methylene bisphenyl isocyanate | | | | |
| Dipropylene glycol methyl ether | 34590-94-8 | 100 | 600 | X |
| Di-sec octyl phthalate (Di-(2-ethylhexyl) phthalate) | 117-81-7 | — | 5 | — |
| Emery | 12415-34-8 | | | |
| Total dust | | — | 15 | — |
| Respirable fraction | | — | 5 | — |
| Endosulfan | 115-29-7 | — | 0.1 | X |
| Endrin | 72-20-8 | — | 0.1 | X |
| Epichlorohydrin | 106-89-8 | 5 | 19 | X |
| EPN | 2104-64-5 | — | 0.5 | X |
| 1,2-Epoxypropane; see Propylene oxide | | | | |
| 2,3-Epoxy-1-propanol; see Glycidol | | | | |
| Ethane | 74-84-0 | E | | |
| Ethanethiol; see Ethyl mercaptan | | | | |
| Ethanolamine | 141-43-5 | 3 | 6 | — |
| 2-Ethoxyethanol (Cellosolve) | 110-80-5 | 200 | 740 | X |
| 2-Ethoxyethyl acetate (Cellosolve acetate) | 111-15-9 | 100 | 540 | X |
| Ethyl acetate | 141-78-6 | 400 | 1400 | — |
| Ethyl acrylate | 140-88-5 | 25 | 100 | X |
| Ethyl alcohol (Ethanol) | 64-17-5 | 1000 | 1900 | — |
| Ethylamine | 75-04-7 | 10 | 18 | — |
| Ethyl amyl ketone (5-Methyl-3-heptanone) | 541-85-5 | 25 | 130 | — |
| Ethyl benzene | 100-41-4 | 100 | 435 | — |
| Ethyl bromide | 74-96-4 | 200 | 890 | — |
| Ethyl butyl ketone (3-Heptanone) | 106-35-4 | 50 | 230 | — |
| Ethyl chloride | 75-00-3 | 1000 | 2600 | — |
| Ethyl ether | 60-29-7 | 400 | 1200 | — |
| Ethyl formate | 109-94-4 | 100 | 300 | — |
| Ethyl mercaptan | 75-08-1 | 0.5 | 1 | — |
| Ethyl silicate | 78-10-4 | 100 | 850 | — |
| Ethylene | 74-85-1 | E | | |
| Ethylene chlorohydrin | 107-07-3 | 5 | 16 | X |
| Ethylenediamine | 107-15-3 | 10 | 25 | — |
| Ethylene dibromide | 106-93-4 | (C)25 | (C)190 | X |
| Ethylene dichloride (1,2-Dichloroethane) | 107-06-2 | 50 | 200 | — |
| Ethylene glycol dinitrate | 628-96-6 | (C)0.2 | (C)1 | X |
| Ethylene glycol methyl acetate; see Methyl cellosolve acetate | | | | |
| Ethyleneimine; see § 1915.1012 | 151-56-4 | | | |
| Ethylene oxide; see § 1915.1047 | 75-21-8 | | | |
| Ethylidene chloride; see 1,1-Dichloroethane | | | | |
| N-Ethylmorpholine | 100-74-3 | 20 | 94 | X |
| Ferbam | 14484-64-1 | | | |
| Total dust | | — | 15 | — |
| Ferrovanadium dust | 12604-58-9 | — | 1 | — |
| Fibrous Glass | | | | |
| Total dust | | | 15 | — |
| Respirable fraction | | — | 5 | — |
| Fluorides (as F) | Varies with compound | — | 2.5 | — |
| Fluorine | 7782-41-4 | 0.1 | 0.2 | — |
| Fluorotrichloromethane (Trichlorofluoromethane) | 75-69-4 | 1000 | 5600 | — |
| Formaldehyde; see § 1915.1048 | 50-00-0 | | | |
| Formic acid | 64-18-6 | 5 | 9 | — |
| Furfural | 98-01-1 | 5 | 20 | X |
| Furfuryl alcohol | 98-00-0 | 50 | 200 | — |
| Gasoline | 8006-61-9 | | A3 | — |
| Glycerin (mist) | 56-81-5 | | | |
| Total dust | | — | 15 | — |
| Respirable fraction | | — | 5 | — |
| Glycidol | 556-52-5 | 50 | 150 | — |
| Glycol monoethyl ether; see 2-Ethoxyethanol | | | | |
| Graphite, natural, respirable dust | 7782-42-5 | (2) | (2) | (2) |
| Graphite, synthetic | | | | |
| Total dust | | — | 15 | — |
| Respirable fraction | | — | 5 | — |
| Guthion; see Azinphos methyl | | | | |
| Gypsum | 13397-24-5 | | | |
| Total dust | | — | 15 | — |
| Respirable fraction | | — | 5 | — |
| Hafnium | 7440-58-6 | — | 0.5 | — |
| Helium | 7440-59-7 | E | | |
| Heptachlor | 76-44-8 | — | 0.5 | X |
| Heptane (n-Heptane) | 142-82-5 | 500 | 2000 | — |
| Hexachloroethane | 67-72-1 | 1 | 10 | X |
| Hexachloronaphthalene | 1335-87-1 | — | 0.2 | X |
| n-Hexane | 110-54-3 | 500 | 1800 | — |
| 2-Hexanone (Methyl n-butyl ketone) | 591-78-6 | 100 | 410 | — |
| Hexone (Methyl isobutyl ketone) | 108-10-1 | 100 | 410 | — |
| sec-Hexyl acetate | 108-84-9 | 50 | 300 | — |
| Hydrazine | 302-01-2 | 1 | 1.3 | X |
| Hydrogen | 1333-74-0 | E | | |
| Hydrogen bromide | 10035-10-6 | 3 | 10 | — |
| Hydrogen chloride | 7647-01-0 | (C)5 | (C)7 | — |
| Hydrogen cyanide | 74-90-8 | 10 | 11 | X |
| Hydrogen fluoride (as F) | 7664-39-3 | 3 | 2 | — |
| Hydrogen peroxide | 7722-84-1 | 1 | 1.4 | — |
| Hydrogen selenide (as Se) | 7783-07-5 | 0.05 | | |
| Hydrogen sulfide | 7783-06-4 | 10 | 15 | — |
| Hydroquinone | 123-31-9 | — | 2 | — |
| Indene | 95-13-6 | 10 | 45 | — |
| Indium and compounds (as In) | 7440-74-6 | — | 0.1 | — |
| Iodine | 7553-56-2 | (C)0.1 | (C)1 | — |
| Iron oxide fume | 1309-37-1 | — | 10 | — |
| Iron salts (soluble) (as Fe) | Varies with compound | — | 1 | — |
| Isoamyl acetate | 123-92-2 | 100 | 525 | — |
| Isoamyl alcohol (primary and secondary) | 123-51-3 | 100 | 360 | — |
| Isobutyl acetate | 110-19-0 | 150 | 700 | — |
| Isobutyl alcohol | 78-83-1 | 100 | 300 | — |
| Isophorone | 78-59-1 | 25 | 140 | — |
| Isopropyl acetate | 108-21-4 | 250 | 950 | — |
| Isopropyl alcohol | 67-63-0 | 400 | 980 | — |
| Isopropylamine | 75-31-0 | 5 | 12 | — |
| Isopropyl ether | 108-20-3 | 500 | 2100 | — |
| Isopropyl glycidyl ether (IGE) | 4016-14-2 | 50 | 240 | — |
| Kaolin | 1332-58-7 | | | |
| Total dust | | — | 15 | — |
| Respirable fraction | | — | 5 | — |
| Ketene | 463-51-4 | 0.5 | 0.9 | — |
| Lead, inorganic (as Pb); see § 1915.1025 | 7439-92-1 | — | — | — |
| Limestone | 1317-65-3 | | | |
| Total dust | | — | 15 | — |
| Respirable fraction | | — | 5 | — |
| Lindane | 58-89-9 | — | 0.5 | X |
| Lithium hydride | 7580-67-8 | — | 0.025 | — |
| L.P.G. (Liquefied petroleum gas) | 68476-85-7 | 1000 | 1800 | |
| Magnesite | 546-93-0 | | | |
| Total dust | | — | 15 | — |
| Respirable fraction | | — | 5 | — |
| Magnesium oxide fume | 1309-48-4 | | | |
| Total particulate | | 15 | — | — |
| Malathion | 121-75-5 | | | |
| Total dust | | — | 15 | X |
| Maleic anhydride | 108-31-6 | 0.25 | | |
| Manganese compounds (as Mn) | 7439-96-5 | — | (C)5 | — |
| Manganese fume (as Mn) | 7439-96-5 | — | (C)5 | — |
| Marble | 1317-65-3 | | | |
| Total dust | | — | 15 | — |
| Respirable fraction | | — | 5 | — |
| Mercury (aryl and inorganic)(as Hg) | 7439-97-6 | | 0.1 | X |
| Mercury (organo) alkyl compounds (as Hg) | 7439-97-6 | — | 0.01 | X |
| Mercury (vapor) (as Hg) | 7439-97-6 | — | 0.1 | X |
| Mesityl oxide | 141-79-7 | 25 | 100 | — |
| Methane | 74-82-8 | E | | |
| Methanethiol; see Methyl mercaptan | | | | |
| Methoxychlor | 72-43-5 | | | |
| Total dust | | — | 15 | — |
| 2-Methoxyethanol (Methyl cellosolve) | 109-86-4 | 25 | 80 | X |
| 2-Methoxyethyl acetate (Methyl cellosolve acetate) | 110-49-6 | 25 | 120 | X |
| Methyl acetate | 79-20-9 | 200 | 610 | — |
| Methyl acetylene (Propyne) | 74-99-7 | 1000 | 1650 | — |
| Methyl acetylene-propadiene mixture (MAPP) | | 1000 | 1800 | — |
| Methyl acrylate | 96-33-3 | 10 | 35 | X |
| Methylal (Dimethoxy-methane) | 109-87-5 | 1000 | 3100 | — |
| Methyl alcohol | 67-56-1 | 200 | 260 | — |
| Methylamine | 74-89-5 | 10 | 12 | — |
| Methyl amyl alcohol; see Methyl isobutyl carbinol | | | | |
| Methyl n-amyl ketone | 110-43-0 | 100 | 465 | — |
| Methyl bromide | 74-83-9 | (C)20 | (C)80 | X |
| Methyl butyl ketone; see 2-Hexanone | | | | |
| Methyl cellosolve; see 2-Methoxyethanol | | | | |
| Methyl cellosolve acetate; see 2-Methoxyethyl acetate | | | | |
| Methyl chloride | 74-87-3 | 100 | 210 | — |
| Methyl chloroform (1,1,1-Trichloroethane) | 71-55-6 | 350 | 1900 | — |
| Methylcyclohexane | 108-87-2 | 500 | 2000 | — |
| Methylcyclohexanol | 25639-42-3 | 100 | 470 | — |
| o-Methylcyclohexanone | 583-60-8 | 100 | 460 | X |
| Methylene chloride; see § 1910.1052 | | | | |
| Methyl ethyl ketone (MEK); see 2-Butanone | | | | |
| Methyl formate | 107-31-3 | 100 | 250 | — |
| Methyl hydrazine (Monomethyl hydrazine) | 60-34-4 | (C)0.2 | (C)0.35 | X |
| Methyl iodide | 74-88-4 | 5 | 28 | X |
| Methyl isoamyl ketone | 110-12-3 | 100 | 475 | — |
| Methyl isobutyl carbinol | 108-11-2 | 25 | 100 | X |
| Methyl isobutyl ketone; see Hexone | | | | |
| Methyl isocyanate | 624-83-9 | 0.02 | 0.05 | X |
| Methyl mercaptan | 74-93-1 | 0.5 | 1 | — |
| Methyl methacrylate | 80-62-6 | 100 | 410 | 100 |
| Methyl propyl ketone; see 2-Pentanone | | | | |
| Methyl silicate | 681-84-5 | 5 | 30 | — |
| alpha-Methyl styrene | 98-83-9 | (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 aniline | 100-61-8 | 2 | 9 | X |
| Monomethyl hydrazine; see Methyl hydrazine | | | | |
| Morpholine | 110-91-8 | 20 | 70 | X |
| Naphtha (Coal tar) | 8030-30-6 | 100 | 400 | — |
| Naphthalene | 91-20-3 | 10 | 50 | — |
| alpha-Naphthylamine; see § 1915.1004 | 134-32-7 | | | |
| beta-Naphthylamine; see § 1915.1009 | 91-59-8 | | | — |
| Neon | 7440-01-9 | | | |
| Nickel carbonyl (as Ni) | 13463-39-3 | 0.001 | 0.007 | — |
| Nickel, metal and insoluble compounds (as Ni) | 7440-02-0 | — | 1 | — |
| Nickel, soluble compounds (as Ni) | 7440-02-0 | — | 1 | — |
| Nicotine | 54-11-5 | — | 0.5 | X |
| Nitric acid | 7697-37-2 | 2 | 5 | — |
| Nitric oxide | 10102-43-9 | 25 | 30 | — |
| p-Nitroaniline | 100-01-6 | 1 | 6 | X |
| Nitrobenzene | 98-95-3 | 1 | 5 | X |
| p-Nitrochlorobenzene | 100-00-5 | — | 1 | X |
| 4-Nitrodiphenyl; see § 1915.1003 | 92-93-3 | | | |
| Nitroethane | 79-24-3 | 100 | 310 | — |
| Nitrogen | 7727-37-9 | E | | |
| Nitrogen dioxide | 10102-44-0 | (C)5 | (C)9 | — |
| Nitrogen trifluoride | 7783-54-2 | 10 | 29 | — |
| Nitroglycerin | 55-63-0 | (C)0.2 | (C)2 | X |
| Nitromethane | 75-52-5 | 100 | 250 | — |
| 1-Nitropropane | 108-03-2 | 25 | 90 | — |
| 2-Nitropropane | 79-46-9 | 25 | 90 | — |
| N-Nitrosodimethylamine; see § 1915.1016 | 62-79-9 | | | — |
| Nitrotoluene (all isomers) | | 5 | 30 | X |
| o-isomer | 88-72-2; | | | |
| m-isomer | 99-08-1; | | | |
| p-isomer | 99-99-0 | | | |
| Nitrotrichloromethane; see Chloropicrin | | | | |
| Nitrous oxide | 10024-97-2 | E | | |
| Octachloronaphthalene | 2234-13-1 | — | 0.1 | X |
| Octane | 111-65-9 | 400 | 1900 | — |
| Oil mist, mineral | 8012-95-1 | — | 5 | — |
| Osmium tetroxide (as Os) | 20816-12-0 | — | 0.002 | — |
| Oxalic acid | 144-62-7 | — | 1 | — |
| Oxygen difluoride | 7783-41-7 | 0.05 | 0.1 | — |
| Ozone | 10028-15-6 | 0.1 | 0.2 | — |
| Paraquat, respirable dust | 4685-14-7; | — | 0.5 | X |
| | 1910-42-5; | | | |
| | 2074-50-2 | | | |
| Parathion | 56-38-2 | — | 0.1 | — |
| Particulates not otherwise regulated | | | | |
| Total dust organic and inorganic | | — | 15 | — |
| PCB; see Chlorodiphenyl (42% and 54% chlorine) | | | | |
| Pentaborane | 19624-22-7 | 0.005 | 0.01 | — |
| Pentachloronaphthalene | 1321-64-8 | — | 0.5 | X |
| Pentachlorophenol | 87-86-5 | — | 0.5 | X |
| Pentaerythritol | 115-77-5 | | | |
| Total dust | | — | 15 | — |
| Respirable fraction | | — | 5 | — |
| Pentane | 109-66-0 | 500 | 1500 | — |
| 2-Pentanone (Methyl propyl ketone) | 107-87-9 | 200 | 700 | — |
| Perchloroethylene (Tetrachloroethylene) | 127-18-4 | 100 | 670 | — |
| Perchloromethyl mercaptan | 594-42-3 | 0.1 | 0.8 | — |
| Perchloryl fluoride | 7616-94-6 | 3 | 13.5 | — |
| Perlite | 93763-70-3 | | | |
| Total dust | | — | 15 | — |
| Respirable fraction | | — | 5 | — |
| Petroleum distillates (Naphtha)(Rubber Solvent) | | | A3 | — |
| Phenol | 108-95-2 | 5 | 19 | X |
| p-Phenylene diamine | 106-50-3 | — | 0.1 | X |
| Phenyl ether, vapor | 101-84-8 | 1 | 7 | — |
| Phenyl ether-biphenyl mixture, vapor | | 1 | 7 | — |
| Phenylethylene; see Styrene | | | | |
| Phenyl glycidyl ether (PGE) | 122-60-1 | 10 | 60 | — |
| Phenylhydrazine | 100-63-0 | 5 | 22 | X |
| Phosdrin (Mevinphos) | 7786-34-7 | — | 0.1 | X |
| Phosgene (Carbonyl chloride) | 75-44-5 | 0.1 | 0.4 | — |
| Phosphine | 7803-51-2 | 0.3 | 0.4 | — |
| Phosphoric acid | 7664-38-2 | — | 1 | — |
| Phosphorus (yellow) | 7723-14-0 | — | 0.1 | — |
| Phosphorus pentachloride | 10026-13-8 | — | 1 | — |
| Phosphorus pentasulfide | 1314-80-3 | — | 1 | — |
| Phosphorus trichloride | 7719-12-2 | 0.5 | 3 | — |
| Phthalic anhydride | 85-44-9 | 2 | 12 | — |
| Picloram | 1918-02-1 | | | |
| Total dust | | — | 15 | — |
| Respirable fraction | | — | 5 | — |
| Picric acid | 88-89-1 | — | 0.1 | — |
| Piperazine dihydrochloride | 142-64-3 | — | — | X |
| Pindone (2-Pivalyl-1,3-indandione) | 83-26-1 | — | 0.1 | — |
| Plaster of Paris | 26499-65-0 | | | |
| Total dust | | — | 15 | — |
| Respirable fraction | | — | 5 | — |
| Platinum (as Pt) | 7440-06-4 | | | |
| Metal | | — | — | — |
| Soluble salts | | — | 0.002 | — |
| Polytetrafluoroethylene decomposition products | | | A2 | |
| Portland cement | 65997-15-1 | | | |
| Total dust | | 15 | — | 10 |
| Respirable fraction | | 5 | — | — |
| Propargyl alcohol | 107-19-7 | 1 | — | X |
| beta-Propriolactone; see § 1915.1013 | 57-57-8 | | | |
| Propionic acid | 79-09-4 | — | — | — |
| n-Propyl acetate | 109-60-4 | 200 | 840 | — |
| n-Propyl alcohol | 71-23-8 | 200 | 500 | — |
| n-Propyl nitrate | 627-13-4 | 25 | 110 | — |
| Propylene dichloride | 78-87-5 | 75 | 350 | — |
| Propylene imine | 75-55-8 | 2 | 5 | X |
| Propylene oxide | 75-56-9 | 100 | 240 | — |
| Propyne; see Methyl acetylene | | | | |
| Pyrethrum | 8003-34-7 | — | 5 | — |
| Pyridine | 110-86-1 | 5 | 15 | — |
| Quinone | 106-51-4 | 0.1 | 0.4 | — |
| RDX; see Cyclonite | | | | |
| Rhodium (as Rh), metal fume and insoluble compounds | 7440-16-6 | — | 0.1 | — |
| Rhodium (as Rh), soluble compounds | 7440-16-6 | — | 0.001 | — |
| Ronnel | 299-84-3 | — | 10 | — |
| Rotenone | 83-79-4 | — | 5 | — |
| Rouge | | — | | |
| Total dust | | — | 15 | — |
| Respirable fraction | | — | 5 | — |
| Selenium compounds (as Se) | 7782-49-2 | — | 0.2 | — |
| Selenium hexafluoride (as Se) | 7783-79-1 | 0.05 | 0.4 | — |
| Silica, amorphous, precipitated and gel | 112926-00-8 | (2) | (2) | (2) |
| Silica, amorphous, diatomaceous earth, containing less than 1% crystalline silica | 61790-53-2 | (2) | (2) | (2) |
| Silica, crystalline, respirable dust | | | | |
| Cristobalite; see 1915.1053 | 14464-46-1 | | | |
| Quartz; see 1915.10535 | 14808-60-7 | | | |
| Tripoli (as quartz); see 1915.10535 | 1317-95-9 | | | |
| Tridymite; see 1915.1053 | 15468-32-3 | | | |
| Silica, fused, respirable dust | 60676-86-0 | (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 dust | 14807-96-6 | (2) | (2) | (2) |
| Tremolite, asbestiform | | (3) | (3) | (3) |
| Silicon | 7440-21-3 | | | |
| Total dust | | — | 15 | — |
| Respirable fraction | | — | 5 | — |
| Silicon carbide | 409-21-2 | | | |
| Total dust | | — | 15 | — |
| Respirable fraction | | — | 5 | — |
| Silver, metal and soluble compounds (as Ag) | 7440-22-4 | — | 0.01 | — |
| Soapstone; see Silicates | | | | |
| Sodium fluoroacetate | 62-74-8 | — | 0.05 | X |
| Sodium hydroxide | 1310-73-2 | — | 2 | — |
| Starch | 9005-25-8 | | | |
| Total dust | | — | 15 | — |
| Respirable fraction | | — | 5 | — |
| Stibine | 7803-52-3 | 0.1 | 0.5 | — |
| Stoddard solvent | 8052-41-3 | 200 | 1150 | — |
| Strychnine | 57-24-9 | — | 0.15 | — |
| Styrene | 100-42-5 | 100 | 420 | 50 |
| Sucrose | 57-50-1 | | | |
| Total dust | | — | 15 | — |
| Respirable fraction | | — | 5 | — |
| Sulfur dioxide | 7446-09-5 | 5 | 13 | — |
| Sulfur hexafluoride | 2551-62-4 | 1000 | 6000 | — |
| Sulfuric acid | 7664-93-9 | — | 1 | — |
| Sulfur monochloride | 10025-67-9 | 1 | 6 | — |
| Sulfur pentafluoride | 5714-22-7 | 0.025 | 0.25 | — |
| Sulfuryl fluoride | 2699-79-8 | 5 | 20 | — |
| Systox, see Demeton | | | | |
| 2,4,5-T (2,4,5-trichlorophenoxyacetic acid) | 93-76-5 | — | 10 | — |
| Talc; see Silicates— | | | | |
| Tantalum, metal and oxide dust | 7440-25-7 | — | 5 | — |
| TEDP (Sulfotep) | 3689-24-5 | — | 0.2 | X |
| Teflon decomposition products | | | A2 | |
| Tellurium and compounds (as Te) | 13494-80-9 | — | 0.1 | — |
| Tellurium hexafluoride (as Te) | 7783-80-4 | 0.02 | 0.2 | — |
| Temephos | 3383-96-8 | | | |
| Total dust | | — | 15 | — |
| Respirable fraction | | — | 5 | — |
| TEPP (Tetraethyl pyrophosphate) | 107-49-3 | — | 0.05 | X |
| Terphenyls | 26140-60-3 | (C)1 | (C)9 | — |
| 1,1,1,2-Tetrachloro-2,2-difluoroethane | 76-11-9 | 500 | 4170 | — |
| 1,1,2,2-Tetrachloro-1,2-difluoroethane | 76-12-0 | 500 | 4170 | — |
| 1,1,2,2-Tetrachloroethane | 79-34-5 | 5 | 35 | X |
| Tetrachloroethylene; see Perchloroethylene | | | | |
| Tetrachloromethane; see Carbon tetrachloride | | | | |
| Tetrachloronaphthalene | 1335-88-2 | — | 2 | X |
| Tetraethyl lead (as Pb) | 78-00-2 | — | 0.1 | X |
| Tetrahydrofuran | 109-99-9 | 200 | 590 | — |
| Tetramethyl lead, (as Pb) | 75-74-1 | — | 0.15 | X |
| Tetramethyl succinonitrile | 3333-52-6 | 0.5 | 3 | X |
| Tetranitromethane | 509-14-8 | 1 | 8 | — |
| Tetryl (2,4,6-Trinitrophenylmethylnitramine) | 479-45-8 | — | 1.5 | X |
| Thallium, soluble compounds (as Tl) | 7440-28-0 | — | 0.1 | X |
| 4,4′-Thiobis (6-tert, Butyl-m-cresol) | 96-69-5 | | | |
| Total dust | | — | 15 | — |
| Respirable fraction | | — | 5 | — |
| Thiram | 137-26-8 | — | 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 dioxide | 13463-67-7 | | | |
| Total dust | | — | 15 | — |
| Toluene | 108-88-3 | 200 | 750 | 100 |
| Toluene-2,4-diisocyanate (TDI) | 584-84-9 | (C)0.02 | (C)0.14 | — |
| o-Toluidine | 95-53-4 | 5 | 22 | X |
| Toxaphene; see Chlorinated camphene | | | | |
| Tremolite; see Silicates | | | | |
| Tributyl phosphate | 126-73-8 | — | 5 | — |
| 1,1,1-Trichloroethane; see Methyl chloroform | | | | |
| 1,1,2-Trichloroethane | 79-00-5 | 10 | 45 | X |
| Trichloroethylene | 79-01-6 | 100 | 535 | — |
| Trichloromethane; see Chloroform | | | | |
| Trichloronaphthalene | 1321-65-9 | — | 5 | X |
| 1,2,3-Trichloropropane | 96-18-4 | 50 | 300 | — |
| 1,1,2-Trichloro-1,2,2-trifluoroethane | 76-13-1 | 1000 | 7600 | — |
| Triethylamine | 121-44-8 | 25 | 100 | — |
| Trifluorobromomethane | 75-63-8 | 1000 | 6100 | — |
| Trimethyl benzene | 25551-13-7 | 25 | 120 | — |
| 2,4,6-Trinitrophenyl; see Picric acid | | | | |
| 2,4,6-Trinitrophenylmethylnitramine; see Tetryl | | | | |
| 2,4,6-Trinitrotoluene (TNT) | 118-96-7 | — | 1.5 | X |
| Triorthocresyl phosphate | 78-30-8 | — | 0.1 | — |
| Triphenyl phosphate | 115-86-6 | — | 3 | — |
| Tungsten (as W) | 7440-33-7 | | | |
| Insoluble compounds | | — | 5 | — |
| Soluble compounds | | — | 1 | — |
| Turpentine | 8006-64-2 | 100 | 560 | — |
| Uranium (as U) | 7440-61-1 | | | |
| Soluble compounds | | — | 0.2 | — |
| Insoluble compounds | | — | 0.2 | — |
| Vanadium | 1314-62-1 | | | |
| 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 § 1915.1017 | 75-01-4 | | | |
| Vinyl cyanide; see Acrylonitrile | | | | |
| Vinyl toluene | 25013-15-4 | 100 | 480 | — |
| Warfarin | 81-81-2 | — | 0.1 | — |
| Xylenes (o-, m-, p-isomers) | 1330-20-7 | 100 | 435 | — |
| Xylidine | 1300-73-8 | 5 | 25 | X |
| Yttrium | 7440-65-5 | — | 1 | — |
| Zinc chloride fume | 7646-85-7 | — | 1 | — |
| Zinc oxide fume | 1314-13-2 | — | 5 | — |
| Zinc oxide | 1314-13-2 | | | |
| Total dust | | — | 15 | — |
| Respirable fraction | | — | 5 | — |
| Zinc stearate | 557-05-1 | | | |
| Total dust | | — | 15 | — |
| Respirable fraction | | — | 5 | — |
| Zirconium compounds (as Zr) | 7440-67-7 | — | 5 | |

Table Z—Shipyards

| Substance | mppcf(j) |
| --- | --- |
| SILICA: | |
| Crystalline | 250(k) |
| Quartz. Threshold Limit calculated from the formula(p) | % SiO2 + 5 |
| Cristobalite | |
| Amorphous, including natural diatomaceous earth | 20 |
| SILICATES (less than 1% crystalline silica) | |
| Mica | 20 |
| Portland cement | 50 |
| Soapstone | 20 |
| Talc (non-asbestiform) | 20 |
| Talc (fibrous), use asbestos limit | — |
| Graphite (natural) | 15 |
| Inert or Nuisance Particulates:(m) | 50 (or 15 mg/m3 whichever is the smaller) of total dust <1% SiO2 |
| Conversion factors | |
| mppcf × 35.3 = million particles per cubic meter = particles per c.c. | |

Mineral Dusts

| | | |
| --- | --- | --- |
| 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/m3. |
| o If the exposure limit in § 1915.1026 is stayed or is otherwise not in effect, the exposure limit is 0.1 mg/m3 (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: |
| A1 [Reserved] |
| A2 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. |
| A3 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]