OSHA enforces hundreds of permissible exposure limits (PELs) for toxic air contaminants found in U.S. workplaces. These PELs set enforceable limits on the magnitude and duration of employee exposure to each contaminant. The amount of exposure permitted by a given PEL depends on the toxicity and other characteristics of the particular substance. Two different types of measurement are used for PEL determination. The concentration of gases and liquids in the air is measured in parts per million (ppm). Solids and liquids in the form of mists, dusts, or fumes, are measured in milligrams per cubic meter (mg/m3).
Exposure limits called Threshold Limit Values (TLVs) were developed by the American Conference of Governmental Industral Hygienists (ACGIH). TLVs represent the level of chemicals in the ambient air that most workers can be exposed to on a daily basis without harmful effects.
OSHA’s PELs for air contaminants are located in §1910.1000, Tables Z-1, Z-2, and Z-3. The air contaminant limits were adopted by OSHA in 1971 from existing national consensus standards issued by the American Conference of Governmental Industrial Hygienists and the American National Standards Institute (ANSI). Consequently, these PELs, which have not been updated since 1971, reflect the results of research conducted in the 1950s and 1960s.
Substance
|
CAS No. (c)
|
ppm (a)[a]
|
mg/m3(b)[a]
|
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
| |||
|
15
| |||
|
5
| |||
Aluminum, metal (as Al)
|
7429-90-5
| |||
|
15
| |||
|
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
| |||
|
15
| |||
|
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 compound (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
|
([b])
| |||
Azinphos-methyl
|
86-50-0
|
0.2
|
X
| |
Barium, soluble compounds (as Ba)
|
7440-39-3
|
0.5
| ||
Barium sulfate
|
7727-43-7
| |||
|
15
| |||
|
5
| |||
Benomyl
|
17804-35-2
| |||
|
15
| |||
|
5
| |||
Benzene; see 1910.1028
|
71-43-2
| |||
| ||||
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
|
([c])
| ||
Biphenyl; see Diphenyl.
| ||||
Bismuth telluride, Undoped
|
1304-82-1
| |||
|
15
| |||
|
5
| |||
Boron oxide
|
1303-86-2
| |||
|
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
|
1ppm/5ppm 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 Cr03)
|
1189-85-1
|
(C)0.1
|
X
| |
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
| |||
|
15
| |||
|
5
| |||
Calcium hydroxide
|
1305-62-0
| |||
|
15
| |||
|
5
| |||
Calcium oxide
|
1305-78-8
|
5
| ||
Calcium silicate
|
1344-95-2
| |||
|
15
| |||
|
5
| |||
Calcium sulfate
|
7778-18-9
| |||
|
15
| |||
|
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
|
([c])
| ||
Carbon monoxide
|
630-08-0
|
50
|
55
| |
Carbon tetrachloride
|
56-23-5
|
([c])
| ||
Cellulose
|
9004-34-6
| |||
|
15
| |||
|
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 (Phenacylchloride)
|
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
|
(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
| |||
|
15
| |||
|
5
| |||
Chromic acid and chromates (as CR03)
|
([b])
|
([c])
| ||
Chromium (II) compounds. (as CR)
|
7440-47-3
|
0.5
| ||
Chromium (III) compounds. (as CR)
|
7440-47-3
|
0.5
| ||
Chromium metal and insoluble salts (as CR)
|
7440-47-3
|
1
| ||
Chrysene; see Coal tarpitch volatiles.
| ||||
Clopidol
|
2971-90-6
| |||
|
15
| |||
|
5
| |||
Coal dust (less than 5% Si02), respirable fraction
|
([d])
| |||
Coal dust (greater than or equal to 5% Si02), respirable fraction
|
([d])
| |||
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
| |||
|
0.1
| |||
|
1
| |||
Cotton duste, see 1910.1043
|
1
| |||
Crag herbicide (Sesone)
|
136-78-7
| |||
|
15
| |||
|
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)
|
([b])
|
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
| |
3,3'-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
| |
Dicyclopentadienyl iron
|
102-54-5
| |||
|
15
| |||
|
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
| ||
|
528-29-0
| |||
|
99-65-0
| |||
|
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
| |||
|
15
| |||
|
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
|
25
| |
Ethylene dibromide
|
106-93-4
|
([c])
| ||
Ethylene dichloride (1,2-Dichloroethane)
|
107-06-2
|
([c])
| ||
Ethylene glycol dinitrate
|
628-96-6
|
(C)0.2
|
(C)1
|
X
|
Ethylene glycol methyl acetate; see Methyl cellosolve acetate.
| ||||
Ethyleneimine; see 1910.1012
|
151-56-4
| |||
Ethylene oxide; see 1910.1047
|
75-21-8
| |||
Ethylidene chloride; see 1,1-Dichloroethane.
| ||||
N-Ethylmorpholine
|
100-74-3
|
20
|
94
|
X
|
Ferbam
|
14484-64-1
| |||
|
15
| |||
Ferrovanadium dust
|
12604-58-9
|
1
| ||
Fluorides (as F)
|
([b])
|
2.5
| ||
Fluorine
|
7782-41-4
|
0.1
|
0.2
| |
Fluorotrichloromethane (Trichlorofluoromethane)
|
75-69-4
|
1000
|
5600
| |
Formaldehyde; see 1910.1048
|
50-00-0
| |||
Formic acid
|
64-18-6
|
5
|
9
| |
Furfural
|
98-01-1
|
5
|
20
|
X
|
Furfuryl alcohol
|
98-00-0
|
50
|
200
| |
Grain dust (oat, wheat, barley)
|
10
| |||
Glycerin (mist)
|
56-81-5
| |||
|
15
| |||
|
5
| |||
Glycidol
|
556-52-5
|
50
|
150
| |
Glycol monoethyl ether; see 2-Ethoxyethanol
| ||||
Graphite, natural respirable dust
|
7782-42-5
|
([d])
| ||
Graphite, synthetic
| ||||
|
15
| |||
|
5
| |||
Guthion; see Azinphos methyl.
| ||||
Gypsum
|
13397-24-5
| |||
|
15
| |||
|
5
| |||
Hafnium
|
7440-58-6
|
0.5
| ||
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 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
|
([c])
| ||
Hydrogen peroxide
|
7722-84-1
|
1
|
1.4
| |
Hydrogen selenide (as Se)
|
7783-07-5
|
0.05
|
0.2
| |
Hydrogen sulfide
|
7783-06-4
|
([c])
| ||
Hydroquinone
|
123-31-9
|
2
| ||
Iodine
|
7553-56-2
|
(C)0.1
|
(C)1
| |
Iron oxide fume
|
1309-37-1
|
10
| ||
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
| |||
|
15
| |||
|
5
| |||
Ketene
|
463-51-4
|
0.5
|
0.9
| |
Lead inorganic (as Pb); see 1910.1025
|
7439-92-1
| |||
Limestone
|
1317-65-3
| |||
|
15
| |||
|
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
| |||
|
15
| |||
|
5
| |||
Magnesium oxide fume
|
1309-48-4
| |||
|
15
| |||
Malathion
|
121-75-5
| |||
|
15
|
X
| ||
Maleic anhydride
|
108-31-6
|
0.25
|
1
| |
Manganese compounds (as Mn)
|
7439-96-5
|
(C)5
| ||
Manganese fume (as Mn)
|
7439-96-5
|
(C)5
| ||
Marble
|
1317-65-3
| |||
|
15
| |||
|
5
| |||
Mercury (aryl and inorganic) (as Hg)
|
7439-97-6
|
([c])
| ||
Mercury (organo) alkyl compounds (as Hg)
|
7439-97-6
|
([c])
| ||
Mercury (vapor) (as Hg)
|
7439-97-6
|
([c])
| ||
Mesityl oxide
|
141-79-7
|
25
|
100
| |
Methanethiol; see methyl mercaptan.
| ||||
Methoxychlor
|
72-43-5
| |||
|
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
|
([c])
| ||
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
|
75-09-2
|
([c])
| ||
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
|
(C)10
|
(C)20
| |
Methyl methacrylate
|
80-62-6
|
100
|
410
| |
Methyl propyl ketone; see 2-Pentanone.
| ||||
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.
| ||||
Molybdenum (as Mo)
|
7439-98-7
| |||
|
5
| |||
|
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 1910.1004
|
134-32-7
| |||
beta-Naphthylamine; see 1910.1009
|
91-59-8
| |||
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 1910.1003
|
92-93-3
| |||
Nitroethane
|
79-24-3
|
100
|
310
| |
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 1910.1016.
| ||||
Nitrotoluene (all isomers)
|
5
|
30
|
X
| |
|
88-72-2
| |||
|
99-08-1
| |||
|
99-99-0
| |||
Nitrotrichloromethane; see Chloropicrin.
| ||||
Octachioronaphthalene
|
2234-13-1
|
0.1
|
X
| |
Octane
|
111-65-9
|
500
|
2350
| |
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; 1910-42-5; 2074-50-2
|
0.5
|
X
| |
Parathion
|
56-38-2
|
0.1
|
X
| |
Particulates not otherwise regulated (PNOR)f.
| ||||
|
15
| |||
|
5
| |||
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
| |||
|
15
| |||
|
5
| |||
Pentane
|
109-66-0
|
1000
|
2950
| |
2-Pentanone (Methyl propyl ketone)
|
107-87-9
|
200
|
700
| |
Perchloroethylene (Tetrachloroethylene)
|
127-18-4
|
([c])
| ||
Perchloromethyl mercaptan
|
594-42-3
|
0.1
|
0.8
| |
Perchloryl fluoride
|
7616-94-6
|
3
|
13.5
| |
Petroleum distillates (Naphtha) (Rubber Solvent)
|
500
|
2000
| ||
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, vapors
|
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
| |||
|
15
| |||
|
5
| |||
Picric acid
|
88-89-1
|
0.1
|
X
| |
Pindone (2-Pivalyl-1,3-indandione)
|
83-26-1
|
0.1
| ||
Plaster of Paris
|
26499-65-0
| |||
|
15
| |||
|
5
| |||
Platinum (as Pt)
|
7440-06-4
| |||
| ||||
|
0.002
| |||
Portland cement
|
65997-15-1
| |||
|
15
| |||
|
5
| |||
Propane
|
74-98-6
|
1000
|
1800
| |
beta-Propiolactone; see 1910.1013
|
57-57-8
| |||
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
|
15
| ||
Rotenone
|
83-79-4
|
5
| ||
Rouge
| ||||
|
15
| |||
|
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
|
([d])
| ||
Silica, amorphous, diatomaceous earth, containing less than 1% crystalline silica.
|
61790-53-2
|
([d])
| ||
Silica, crystalline cristobalite, respirable dust
|
14464-46-1
|
([d])
| ||
Silica, crystalline quartz, respirable dust
|
14808-60-7
|
([d])
| ||
Silica, crystalline tripoli (as quartz) respirable dust
|
1317-95-9
|
([d])
| ||
Silica, crystalline tridymite, respirable dust
|
15468-32-3
|
([d])
| ||
Silica, fused, respirable dust
|
60676-86-0
|
([d])
| ||
Silicates (less than 1% crystalline silica)
| ||||
|
12001-26-2
|
([d])
| ||
|
([d])
| |||
|
([d])
| |||
|
([d])
| |||
|
14807-96-6
|
([d])
| ||
| ||||
Silicon
|
7440-21-3
| |||
|
15
| |||
|
5
| |||
Silicon carbide
|
409-21-2
| |||
|
15
| |||
|
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
| |||
|
15
| |||
|
5
| |||
Stibine
|
7803-52-3
|
0.1
|
0.5
| |
Stoddard solvent
|
8052-41-3
|
500
|
2900
| |
Strychnine
|
57-24-9
|
0.15
| ||
Styrene
|
100-42-5
|
([c])
| ||
Sucrose
|
57-50-1
| |||
|
15
| |||
|
5
| |||
Sulfur dioxide
|
7446-09-5
|
5
|
13
| |
Sulfur hexafluoride
|
2551-62-4
|
1000
|
6000
| |
Sulfur 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
| |
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
| |||
|
15
| |||
|
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
|
0.075
|
X
| |
Tetrahydrofuran
|
109-99-9
|
200
|
590
| |
Tetramethyl lead, (as Pb)
|
75-74-1
|
0.075
|
X
| |
Tetramethyl succinonitrile
|
3333-52-6
|
0.5
|
3
|
X
|
Tetranitromethane
|
509-14-8
|
1
|
8
| |
Tetryl (2,4,6-TrinitrophenylmethyInitramine)
|
479-45-8
|
1.5
|
X
| |
Thallium, soluble compounds (as TI)
|
7440-28-0
|
0.1
|
X
| |
4,4'-Thiobis (6-tert, Butyl-m-cresol)
|
96-69-5
| |||
|
15
| |||
|
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
| ||
Titanium dioxide
|
13463-67-7
| |||
|
15
| |||
Toluene
|
108-88-3
|
([c])
| ||
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
|
([c])
| ||
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
| |
2,4,6-Trinitrophenol; see Picric acid.
| ||||
2,4,6-Trinitrophenylmethyl nitramine; 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
| ||
Turpentine
|
8006-64-2
|
100
|
560
| |
Uranium (as U)
|
7440-61-1
| |||
|
0.05
| |||
|
0.25
| |||
Vanadium
|
1314-62-1
| |||
|
(C)0.5
| |||
|
(C)0.1
| |||
Vegetable oil mist
| ||||
|
15
| |||
|
5
| |||
Vinyl benzene; see Styrene.
| ||||
Vinyl chloride; see 1910.1017
|
75-01-4
| |||
Vinyl cyanide; see Acrylonitrile.
| ||||
Vinyl toluene
|
25013-15-4
|
100
|
480
| |
Warfarin
|
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
| |||
|
15
| |||
|
5
| |||
Zinc stearate
|
557-05-1
| |||
|
15
| |||
|
5
| |||
Zirconium compounds (as Zr)
|
7440-67-7
|
5
| ||
[a]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.
| ||||
Substance
|
8-hour time weighted average
|
Acceptable ceiling concentration
|
Acceptable maximum peak above the acceptable ceiling concentration for an 8-hour shift
| |
|---|---|---|---|---|
Concentration
|
Maximum duration
| |||
Benzene[a] Z37.40-1969
|
10 ppm
|
25 ppm
|
50 ppm
|
10 minutes.
|
Beryllium and beryllium compounds (Z37.29-1970)
|
2 μg/m3
|
5 μg/m3
|
25 μg/m3
|
30 minutes.
|
Cadmium fume[b] (Z37.5-1970)c
|
0.1 mg/m3
|
0.3 mg/m3
| ||
Cadmium dust[b] (Z37.5-1970)c
|
0.2 mg/m3
|
0.6 mg/m3
| ||
Carbon disulfide (Z37.3-1968)
|
20 ppm
|
30 ppm
|
100 ppm
|
30 minutes.
|
Carbon tetrachloride (Z37.17-1967)
|
10 ppm
|
25 ppm
|
200 ppm
|
5 minutes in any 4 hrs.
|
Chromic acid and chromates (Z37.7-1971)
|
1 mg/10m3
| |||
Ethylene dibromide (Z37.31-1970)
|
20 ppm
|
30 ppm
|
50 ppm
|
5 minutes.
|
Ethylene dichloride (Z37.21-1969)
|
50 ppm
|
100 ppm
|
200 ppm
|
5 minutes 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 (Z37.1966)
|
20 ppm
|
50 ppm
|
10 mins. once, only if no other meas, exp. occurs.
| |
Mercury (Z37.8-1971)
|
1 mg/10m3
| |||
Methyl chloride (Z37.18-1969)
|
100 ppm
|
200 ppm
|
300 ppm
|
5 minutes in any 3 hrs.
|
Methylene chloride: see §1910.1052
| ||||
Organo (alkyl) mercury (Z37.30-1969)
|
0.01 mg/m3
|
0.04 mg/m3
| ||
Styrene (Z37.15-1969)
|
100 ppm
|
200 ppm
|
600 ppm
|
5 minutes in any 3 hrs.
|
Tetrachloroethylene (Z37.22-1967)
|
100 ppm
|
200 ppm
|
300 ppm
|
5 minutes in any 3 hrs.
|
Toluene (Z37.12-1967)
|
200 ppm
|
300 ppm
|
500 ppm
|
10 minutes.
|
Trichloroethylene (Z37.19-1967)
|
100 ppm
|
200 ppm
|
300 ppm
|
5 minutes in any 2 hrs.
|
[a]This standard applies to the industry segments exempt from the 1 ppm 8 hour TWA and 5 ppm STEL of the benzene standard §1910.1028.
| ||||
Substance
|
Mppcf[a]
|
mg/m3
| ||||
|---|---|---|---|---|---|---|
Silica:
| ||||||
Crystalline
| ||||||
|
250[b]
|
10 mg/m3e
| ||||
%SiO2 + 5
|
%SiO2 + 2
| |||||
|
30mg/m3
| |||||
%SiO2 + 2
| ||||||
| ||||||
| ||||||
Amorphous, including natural diatomaceous earth
|
20
|
80 mg/m3
| ||||
%SiO2
| ||||||
Silicates (less than 1% crystalline silica):
| ||||||
|
20
| |||||
|
20
| |||||
|
20[c]
| |||||
| ||||||
| ||||||
|
50
| |||||
Graphite (natural)
|
15
| |||||
Coal dust:
| ||||||
|
2.4 mg/m3e
| |||||
|
10 mg/m3e
| |||||
%SiO2+2
| ||||||
Inert or Nuisance Dust:[d]
| ||||||
|
15
|
5mg/m3
| ||||
|
50
|
15mg/m3
| ||||
| ||||||
e Both concentration and percent quartz for the application of this limit are to be determined from the fraction passing a size-selector with the following characteristics:
| ||||||
Aerodynamic diameter (unit density sphere)
|
Percent passing selector
| |||||
2
|
90
| |||||
2.5
|
75
| |||||
3.5
|
50
| |||||
5.0
|
25
| |||||
10
|
0
| |||||
The measurements under this note refer to the use of an AEC (now NRC) instrument. The respirable fraction of coal dust is determined with a MRE; the figure corresponding to that of 2.4 mg/m3 in the table for coal dust is 4.5 mg/m3K.
| ||||||
[a]Millions of particles per cubic foot of air, based on impinger samples counted by light-field techniques.
[b]The percentage of crystalline silica in the formula is the amount determined from air-borne samples, except in those instances in which other methods have been shown to be applicable.
[c]Containing less than 1% quartz; if 1% quartz or more, use quartz limit.
[d]All inert or nuisance dusts, whether mineral, inorganic, or organic, not listed specifically by substance name are covered by this limit, which is the same as the Particulates Not Otherwise Regulated (PNOR) limit in Table Z-1.
| ||||||
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