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:
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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:
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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:
| Substance | Actual concentration of 8-hour exposure (ppm) | 8-hour TWA PEL (ppm) |
|---|---|---|
| B | 500 | 1,000 |
| 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.
(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.
| Substance | CAS No. (c) | ppm (a) 1 | mg/m3 (b) 1 | Skin designation |
|---|---|---|---|---|
| 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 1910.1014 | 53-96-3 | |||
| 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 1910.1045 | 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, metal (as Al) | 7429-90-5 | |||
| Total dust | 15 | |||
| Respirable fraction | 5 | |||
| 4-Aminodiphenyl; see 1910.1011 | 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 | ||
| Arsenic, inorganic compounds (as As); see 1910.1018 | 7440-38-2 | |||
| Arsenic, organic compounds (as As) | 7440-38-2 | 0.5 | ||
| Arsine | 7784-42-1 | 0.05 | 0.2 | |
| Asbestos; see 1910.1001 | (4) | |||
| 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 | |||
| Benzene; see 1910.1028 | 71-43-2 | |||
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| See Table Z-2 for the limits applicable in the operations or sectors excluded in 1910.1028 d | ||||
| Benzidine; see 1910.1010 | 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) | 7440-41-7 | (2) | ||
| Biphenyl; see Diphenyl. | ||||
| Bismuth telluride, Undoped | 1304-82-1 | |||
| Total dust | 15 | |||
| Respirable fraction | 5 | |||
| Boron oxide | 1303-86-2 | |||
| Total dust | 15 | |||
| Boron trifluoride | 7637-07-2 | (C)1 | (C)3 | |
| Bromine | 7726-95-6 | 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 | 1 ppm/5 ppm STEL | ||
| 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 1910.1026 6 | 1189-85-1 | |||
| n-Butyl glycidyl ether (BGE) | 2426-08-6 | 50 | 270 | |
| Butyl mercaptan | 109-79-5 | 10 | 35 | |
| p-tert-Butyltoluene | 98-51-1 | 10 | 60 | |
| Cadmium (as Cd); see 1910.1027 | 7440-43-9 | |||
| Calcium carbonate | 1317-65-3 | |||
| Total dust | 15 | |||
| Respirable fraction | 5 | |||
| Calcium hydroxide | 1305-62-0 | |||
| 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 | (2) | ||
| Carbon monoxide | 630-08-0 | 50 | 55 | |
| Carbon tetrachloride | 56-23-5 | (2) | ||
| 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 | (C)1 | (C)3 | |
| Chlorine dioxide | 10049-04-4 | 0.1 | 0.3 | |
| 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. | ||||
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| 2-Chloroethanol; see Ethylene chlorohydrin. | ||||
| Chloroethylene; see Vinyl chloride. | ||||
| Chloroform (Trichloromethane) | 67-66-3 | (C)50 | (C)240 | |
| bis(Chloromethyl) ether; see 1910.1008 | 542-88-1 | |||
| Chloromethyl methyl ether; see 1910.1006 | 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 1910.1026 5 | ||||
| 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 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, pyrene | 65966-93-2 | 0.2 | ||
| Cobalt metal, dust, and fume (as Co) | 7440-48-4 | 0.1 | ||
| Coke oven emissions; see 1910.1029. | ||||
| Copper | 7440-50-8 | |||
| Fume (as Cu) | 0.1 | |||
| Dusts and mists (as Cu) | 1 | |||
| Cotton dust e; see 1910.1043 | 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;4170-30-3 | 2 | 6 | |
| Cumene | 98-82-8 | 50 | 245 | X |
| Cyanides (as CN) | (4) | 5 | X | |
| Cyclohexane | 110-82-7 | 300 | 1050 | |
| Cyclohexanol | 108-93-0 | 50 | 200 | |
| Cyclohexanone | 108-94-1 | 50 | 200 | |
| Cyclohexene | 110-83-8 | 300 | 1015 | |
| 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 (DBCP); see 1910.1044 | 96-12-8 | |||
| 1,2-Dibromoethane; see Ethylene dibromide. | ||||
| Dibutyl phosphate | 107-66-4 | 1 | 5 | |
| Dibutyl phthalate | 84-74-2 | 5 | ||
| o-Dichlorobenzene | 95-50-1 | (C)50 | (C)300 | |
| p-Dichlorobenzene | 106-46-7 | 75 | 450 | |
| 3,′-Dichlorobenzidine; see 1910.1007 | 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 | |
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| 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 | 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 1910.1015 | 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 | 77-78-1 | 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 | |
| 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 | |||
| 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. | ||||
| 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 | (C)10 | (C)25 | |
| Ethyl silicate | 78-10-4 | 100 | 850 | |
| Ethylene chlorohydrin | 107-07-3 | 5 | 16 | X |
| Ethylenediamine | 107-15-3 | 10 | ||