§ 1926.55
Gases, vapors, fumes, dusts, and mists.
(a) Exposure of employees to inhalation, ingestion, skin absorption, or contact with any material or substance at a concentration above those specified in the “Threshold Limit Values of Airborne Contaminants for 1970” of the American Conference of Governmental Industrial Hygienists, shall be avoided. See appendix A to this section.
(b) To achieve compliance with paragraph (a) of this section, administrative or engineering controls must first be implemented whenever feasible. When such controls are not feasible to achieve full compliance, protective equipment or 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 technical measures used for this purpose must first 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 § 1926.103.
(c) Paragraphs (a) and (b) of this section do not apply to the exposure of employees to airborne asbestos, tremolite, anthophyllite, or actinolite dust. Whenever any employee is exposed to airborne asbestos, tremolite, anthophyllite, or actinolite dust, the requirements of § 1910.1101 or § 1926.58 of this title shall apply.
(d) Paragraphs (a) and (b) of this section do not apply to the exposure of employees to formaldehyde. Whenever any employee is exposed to formaldehyde, the requirements of § 1910.1048 of this title shall apply.
Appendix A to § 1926.55—1970 American Conference of Governmental Industrial Hygienists' Threshold Limit Values of Airborne Contaminants
Threshold Limit Values of Airborne Contaminants for Construction
Substance
CAS No. d
ppm a
mg/m 3 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 § 1926.1114
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 § 1926.1145
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
—
—
Respirable fraction
—
—
Alundum; see alpha-Alumina
4-Aminodiphenyl; see § 1926.1111
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 § 1926.1118
7440-38-2
—
—
—
Arsenic, organic compounds (as As)
7440-38-2
—
0.5
—
Arsine
7784-42-1
0.05
0.2
—
Asbestos; see 1926.58
Azinphos-methyl
86-50-0
—
0.2
X
Barium, soluble compounds (as Ba)
7440-39-3
—
0.5
—
Benzene g; see § 1926.1128
71-43-2
Benzidine; see § 1926.1110
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
—
0.002
—
Biphenyl; see Diphenyl
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
STEL 1 ppm/5 ppm
—
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 1926.1126 n
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 (as Cd); see 1926.1127
7440-43-9
Calcium carbonate
1317-65-3
Total dust
—
—
Respirable fraction
—
—
Calcium oxide
1305-78-8
—
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
—
—
Respirable fraction
—
—
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 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
2-Chloroethanol; see Ethylene chlorohydrin
Chloroethylene; see Vinyl chloride
Chloroform (Trichloromethane)
67-66-3
(C)50
(C)240
—
bis(Chloromethyl) ether; see § 1926.1108
542-88-1
Chloromethyl methyl ether; see § 1926.1106
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
Chromium (II) compounds
(as Cr)
7440-47-3
—
0.5
—
Chromium (III) compounds
(as Cr)
7440-47-3
—
0.5
—
Chromium (VI) compounds; See 1926.1126 o
Chromium metal and insol. salts (as Cr)
7440-47-3
—
1
—
Chrysene; see Coal tar pitch volatiles
Coal tar pitch volatiles (benzene soluble fraction), anthracene, BaP, phenanthrene, acridine, chrysene, pyrene
65996-93-2
—
0.2
—
Cobalt metal, dust, and fume (as Co)
7440-48-4
—
0.1
—
Coke oven emissions; see § 1926.1129
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
—
—
Respirable fraction
—
—
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
X
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
—
DDT, see Dichlorodiphenyltrichloroethane
DDVP, see Dichlorvos
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 § 1926.1144
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 § 1926.1107
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
Dieldrin
60-57-1
—
0.25
X
Diethylamine
109-89-7
25
75
—
2-Diethylaminoethanol
100-37-8
10
50
X
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 § 1926.1115
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
—
—
Respirable fraction
—
—
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 § 1926.1112
151-56-4
Ethylene oxide; see § 1926.1147
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
—
Respirable fraction
—
—
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 § 1926.1148
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
A 3
—
Glycerin (mist)
56-81-5
Total dust
—
—
Respirable fraction
—
—
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
—
—
Respirable fraction
—
—
Guthion; see Azinphos methyl
Gypsum
13397-24-5
Total dust
—
—
Respirable fraction
—
—
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
.02
—
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
—
—
Respirable fraction
—
—
Ketene
463-51-4
0.5
0.9
—
Lead, inorganic (as Pb); see 1926.62
7439-92-1
Limestone
1317-65-3
Total dust
—
—
Respirable fraction
—
—
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
—
—
Respirable fraction
—
—
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
—
—
Respirable fraction
—
—
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
Methylene chloride; see § 1910.1052
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
500
1740
—
Methylenedianiline (MDA)
101-77-9
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
—
Methyl propyl ketone; see 2-Pentanone
Methyl silicate
681-84-5
(C)5
(C)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
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 § 1926.1104
134-32-7
beta-Naphthylamine; see § 1926.1109
91-59-8
—
Neon
7440-01-9
E
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 § 1926.1103
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 § 1926.1116
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
X
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
—
—
Respirable fraction
—
—
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
—
Petroleum distillates (Naphtha)(Rubber Solvent)
A 3
—
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
—
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
Total dust
—
—
Respirable fraction
—
—
Platinum (as Pt)
7440-06-4
Metal
—
—
—
Soluble salts
—
0.002
—
Polytetrafluoroethylene decomposition products
A 2
Portland cement
65997-15-1
Total dust
—
15
—
Respirable fraction
5
—
Propane
74-98-6
E
Propargyl alcohol
107-19-7
1
—
X
beta-Propriolactone; see § 1926.1113
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
—
10
—
Rotenone
83-79-4
—
5
—
Rouge
Total dust
—
—
Respirable fraction
—
—
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 cristobalite, respirable dust
14464-46-1
(2)
(2)
(2)
Silica, crystalline quartz, respirable dust
14808-60-7
(2)
(2)
(2)
Silica, crystalline tripoli (as quartz), respirable dust
1317-95-9
(2)
(2)
(2)
Silica, crystalline tridymite, respirable dust
15468-32-3
(2)
(2)
(2)
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); use asbestos limit; see 1926.58
Talc (containing no asbestos), respirable dust
14807-96-6
(2)
(2)
(2)
Tremolite, asbestiform; see 1926.58
Silicon carbide
409-21-2
Total dust
—
—
Respirable fraction
—
—
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
—
—
Respirable fraction
—
—
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
(C)100
(C)420
—
Sucrose
57-50-1
Total dust
—
—
Respirable fraction
—
—
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
—
—
Respirable fraction
—
—
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
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
—
—
Respirable fraction
—
—
Titanium dioxide
13463-67-7
Total dust
—
—
Toluene
108-88-3
200
750
—
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-Trinitrophenol; 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
—
—
Respirable fraction
—
—
Vinyl benzene; see Styrene
Vinyl chloride; see § 1926.1117
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
—
Zirconium compounds (as Zr)
7440-67-7
—
5
Mineral Dusts
Substance
mppcf (j)
SILICA:
Crystalline
Quartz. Threshold Limit calculated from the formula
250 (k)
%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
[Inert or Nuisance Dusts includes all mineral, inorganic, and organic dusts as indicated by examples in TLV's appendix D]
Conversion factors
mppcf × 35.3 = million particles per cubic meter = particles per c.c.
Footnotes
1 [Reserved]
2 See Mineral Dusts Table.
3 Use Asbestos Limit § 1926.58.
4 See 1926.58.
* The PELs are 8-hour TWAs unless otherwise noted; a (C) designation denotes a ceiling limit.
** As 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 § 1926.1128 the limit is 10 ppm TWA.
h-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.
l [Reserved]
m Covers all organic and inorganic particulates not otherwise regulated. Same as Particulates Not Otherwise Regulated.
n If the exposure limit in § 1926.1126 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 § 1926.1126 is stayed or is otherwise not in effect, the exposure limit is 0.1 mg/m3 (as CrO3) as an 8-hour TWA.
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 19.5% and be within the requirements addressing explosion in part 1926.
[39 FR 22801, June 24, 1974, as amended at 51 FR 37007, Oct. 17, 1986; 52 FR 46312, Dec. 4, 1987; 58 FR 35089, June 30, 1993; 61 FR 9249, 9250, Mar. 7, 1996; 61 FR 56856, Nov. 4, 1996; 62 FR 1619, Jan. 10, 1997; 71 FR 10381, Feb. 28, 2006; 71 FR 36009, June 23, 2006]