§ 1926.55 Gases, vapors, fumes, dusts, and mists.

(a) Employers must limit an employee's exposure to any substance listed in Table 1 or 2 of this section in accordance with the following:

(1)

Substances with limits preceded by (C)—Ceiling Values.

An employee's exposure, as determined from breathing-zone air samples, to any substance in Table 1 of this section with a permissible exposure limit preceded by (C) must at no time exceed the exposure limit specified for that substance. If instantaneous monitoring is not feasible, then the employer must assess the ceiling as a 15-minute time-weighted average exposure that the employer cannot exceed at any time during the working day.

(2)

Other substances—8-hour Time Weighted Averages.

An employee's exposure, as determined from breathing-zone air samples, to any substance in Table 1 or 2 of this section with a permissible exposure limit not preceded by (C) must not exceed the limit specified for that substance measured as an 8-hour time-weighted average in any work shift.

(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 § 1926.1101 shall apply.

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 § 1926.1101 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.

Table 1 to § 1926.55—Permissible Exposure Limits for Airborne Contaminants

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

—

Asbes

3-7

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 § 1926.1101

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); see 1926.1124

(q)

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 CrO

3

); 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 d

9-79-5

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

)

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

—

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-Dichloroetha

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

34

—

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

—

Fl

l 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 ace

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

M

etylene (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-

lpha-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 ethe

7-87-9

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

)

(

oluble 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, respirable dust

Cristobalite; see 1926.1153

14464-46-1

Quartz; see 1926.1153

5

14808-60-7

Tripoli (as quartz); see 1926.1153

5

1317-95-9

Tridymite; see 1926.1153

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); use asbestos limit; see § 1926.1101

Talc (containing no asbestos), respirable dust

14807-96-6

(

2

)

(

2

)

(

2

)

Tremolite, asbestiform; see § 1926.1101

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

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 Te

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 V

2

O

5

)

—

(C)0.5

—

Fume (as V

2

O

5

)

—

(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

Table 2 to § 1926.55—Mineral Dusts

Substance

mppcf

(j)

SILICA:

Crystalline

250

(k)

Quartz. Threshold Limit calculated from the formula

(p)

% SiO

2

+ 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:

26.55—Mineral Dusts

Substance

mppcf

(j)

SILICA:

Crystalline

250

(k)

Quartz. Threshold Limit calculated from the formula

(p)

% SiO

2

+ 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/m

3

whichever is the smaller) of total dust <1% SiO

2

[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 to Tables 1 and 2 of this section:

1

[Reserved]

2

See Table 2 of this section.

3

Use Asbestos Limit § 1926.1101.

4

[Reserved]

5

See Table 2 of this section for the exposure limit for any operations or sectors where the exposure limit in § 1926.1153 is stayed or is otherwise not in effect.

* An “X” designation in the “Skin Designation” column indicates that the substance is a dermal hazard.

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

al 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/m

3

.

o

If the exposure limit in § 1926.1126 is stayed or is otherwise not in effect, the exposure limit is 0.1 mg/m

3

(as CrO

3

) as an 8-hour TWA.

p

This standard applies to any operations or sectors for which the respirable crystalline silica standard, 1926.1153, is stayed or otherwise is not in effect.

q

This standard applies to any operations or sectors for which the beryllium standard, 1926.1124, is stayed or otherwise is not in effect.

The 1970 TLV uses letter designations instead of a numerical value as follows:

A

1

[Reserved]

A

2

Polytetrafluoroethylene decomposition products. Because these products decompose in part by hydrolysis in alkaline solution, they can be quantitatively determined in air as fluoride to provide an index of exposure. No TLV is recommended pending determination of the toxicity of the products, but air concentrations should be minimal.

A

3

Gasoline and/or Petroleum Distillates. The composition of these materials varies greatly and thus a single TLV for all types of these materials is no longer applicable. The content of benzene, other aromatics and additives should be determined to arrive at the appropriate TLV.

E Simple asphyxiants. The limiting factor is the available oxygen which shall be at least 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

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; 81 FR 16875, Mar. 25, 2016; 81 FR 31168, May 18, 2016; 81 FR 60273, Sept. 1, 2016; 82 FR 2750, Jan. 9, 2017; 84 FR 21576, May 14, 2019]