Factories Act, 1948 :
PERMISSIBLE LEVELS OF CERTAIN CHEMICAL SUBSTANCES IN WORK ENVIRONMENT
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Sl. No.
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Substance
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Permissible limits of exposure
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|||
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Time-Weighted average concentration (TWA) (8 hrs.)
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Short-term exposure limit (STEL) (15 min.)*
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PPm
|
mg/m3**
|
PPm
|
mg/m3**
|
|
1
|
2
|
3
|
4
|
5
|
6
|
|
(1)
|
Acetaldehyde
|
100
|
180
|
150
|
270
|
|
(2)
|
Acetic Acid
|
10
|
25
|
15
|
37
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|
(3)
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Acetone
|
750
|
1780
|
1000
|
2375
|
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(4)
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Acrolein
|
01
|
0.25
|
0.3
|
0.8
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(5)
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Acrylonitrile-skin (S.C.)
|
2
|
4.5
|
–
|
–
|
|
(6)
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Aldrin-skin
|
–
|
0.25
|
–
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–
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|
(7)
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Allyl Chloride
|
1
|
3
|
2
|
6
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(8)
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Ammonia
|
0.25
|
18
|
35
|
27
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(9)
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Aniline-skin
|
2
|
10
|
–
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–
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(10)
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Anisidine (o-P-isomers)-skin
|
0.1
|
0.5
|
–
|
–
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(11)
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Arsenic & soluble compounds (as As)
|
–
|
0.2
|
–
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–
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[(12)
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Benzene (H.C.)
|
0.5
|
1.5
|
25
|
7.5]
|
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(13)
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Beryllium & Compounds (as Be) (S.C.)
|
–
|
0.002
|
–
|
–
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|
(14)
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Boron trifluoride C
|
1
|
3
|
–
|
–
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(15)
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Bromine
|
0.1
|
0.7
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0.3
|
2
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(16)
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Butane
|
800
|
1900
|
–
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–
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(17)
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2-Butanone (Methyle ethyle Ketone MEK)
|
200
|
590
|
300
|
885
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(18)
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n-Butyl acetate
|
150
|
710
|
200
|
950
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(19)
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n-Butyl alcohol-skin-C
|
50
|
150
|
–
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–
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(20)
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Sce/tert, Butyl acetate
|
200
|
950
|
–
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–
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(21)
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Butyl Mercaptan
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0.5
|
1.5
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–
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–
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(22)
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Cadmium-dust and salts (as Cd)
|
–
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0.05
|
–
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–
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(23)
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Calcium oxide
|
–
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2
|
–
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–
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(24)
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Carbaryl (Sevin)
|
–
|
5
|
–
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–
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(25)
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Carbofuran (Furadan)
|
–
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0.1
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–
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–
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(26)
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Carbon disulphide-skin
|
10
|
30
|
–
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–
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(27)
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Carbon monoxide
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50
|
55
|
400
|
440
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(28)
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Carbon tetrachloride-skin (S.C.)
|
5
|
30
|
–
|
–
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|
(29)
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Chlordane-skin
|
–
|
0.5
|
–
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2
|
|
(30)
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Chlorine
|
1
|
3
|
3
|
9
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(31)
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Chlorobenzene (monochlorobenzene)
|
75
|
350
|
–
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–
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(32)
|
Chloroform (S.C.)
|
10
|
50
|
–
|
–
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|
(33)
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bis-(Chloromethyl) ether (H.C.)
|
0.001
|
0.005
|
–
|
–
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(34)
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Chromic acid and chromates (as Cr) (Water soluble)
|
–
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0.05
|
–
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–
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(35)
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Chromous Salts (as Cr)
|
–
|
0.5
|
–
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–
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(36)
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Copper fume
|
–
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0.2
|
–
|
–
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(37)
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Cotton dust, raw
|
–
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0.2*
|
–
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–
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(38)
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Cresoal, all isomers-skin
|
5
|
22
|
–
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–
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|
(39)
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Cyanides (as Cn)-skin
|
–
|
5
|
–
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–
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|
(40)
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Cyanogen
|
10
|
20
|
–
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–
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(41)
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DDT (Dichlorodiphenyl Trichloroethane)
|
–
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1
|
–
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–
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(42)
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Demeton-skin
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0.01
|
0.1
|
–
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–
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(43)
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Diazinon-skin
|
–
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0.1
|
–
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–
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(44)
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Dibutyl Phythalate
|
–
|
5
|
–
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–
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(45)
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Dichlorous (DDVP)-skin
|
–
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1
|
–
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–
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(46)
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Dieldrin-skin
|
–
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0.25
|
–
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–
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(47)
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Dinitrobenzene (all isomers)-skin
|
0.15
|
1
|
–
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–
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(48)
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Dinitrotoluene-skin
|
–
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1.5
|
–
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–
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(49)
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Diphenyl (Biphenyl)
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0.2
|
1.5
|
–
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–
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(50)
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Endosulfan (Thiodan)-skin
|
–
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0.1
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–
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–
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(51)
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Endrin-skin
|
–
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0.1
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–
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–
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(52)
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Ethyl acetat
|
400
|
1400
|
–
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–
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(53)
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Ethyl alcohol
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1000
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1900
|
–
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–
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(54)
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Ethylamin
|
10
|
18
|
–
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–
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(55)
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Fluorides (as F)
|
–
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2.5
|
–
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–
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(56)
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Fluorine
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1
|
2
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2
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4
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(57)
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Formaldehyde (S.C.)
|
1.0
|
1.5
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2
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3
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(58)
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Formic Acid
|
5
|
9
|
–
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–
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(59)
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Gasoline
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300
|
900
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500
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1500
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(60)
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Hydrazine-skin (S.C.)
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0.1
|
0.1
|
–
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–
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|
(61)
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Hydrogen Chloride-C
|
5
|
7
|
–
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–
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(62)
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Hydrogen Cyanide skin-C
|
10
|
10
|
–
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–
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|
(63)
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Hydrogen Fluoride (as F)-C
|
3
|
2.5
|
–
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–
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(64)
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Hydrogen Peroxide
|
1
|
1.5
|
–
|
–
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(65)
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Hydrogen Sulphide
|
10
|
14
|
15
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21
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|
(66)
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lodine-C
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0.1
|
1
|
–
|
–
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|
(67)
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Iron Oxide Fume (FO2O3) (as Fe)
|
–
|
5
|
–
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–
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|
(68)
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Isoamyl acetate
|
100
|
525
|
–
|
–
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|
(69)
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Isoamyl alcohol
|
100
|
360
|
125
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450
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(70)
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Isobutyl alcohol
|
50
|
150
|
–
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–
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(71)
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Lead, inorg, dusts, dusts and fumes (as Pb)
|
–
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0.15
|
–
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–
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|
(72)
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Lindane-skin
|
–
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0.5
|
–
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–
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|
(73)
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Malathion-skin
|
–
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10
|
–
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–
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(74)
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Manganese dust and compounds (as (Mn)-C
|
–
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5
|
–
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–
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(75)
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Manganese Fume (as Mn)
|
–
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1
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–
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3
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(76)
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Mercury (as Hg)-skin
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|
|
|
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(i) Alkyle compounds
|
–
|
0.01
|
–
|
0.03
|
|
|
(ii) All forms except alkyle vapour
|
–
|
0.05
|
–
|
–
|
|
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(iii) Aryle and inorganic compounds
|
–
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0.1
|
–
|
–
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|
(77)
|
Methyl alcohol (Methanol)-skin
|
200
|
260
|
250
|
310
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|
(78)
|
Methyl cellosolve (2-methoxyethanol)-skin
|
5
|
16
|
–
|
–
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|
(79)
|
Methyl isobutyl Ketone
|
50
|
205
|
75
|
300
|
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(80)
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Methyl Isocyanate-skin
|
0.02
|
0.05
|
–
|
–
|
|
(81)
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Naphthalene
|
10
|
50
|
15
|
75
|
|
(82)
|
Nickel carbonyl (as Ni)
|
0.05
|
0.35
|
–
|
–
|
|
(83)
|
Nitric acid
|
2
|
5
|
4
|
10
|
|
(84)
|
Nitric Oxide
|
25
|
30
|
–
|
–
|
|
(85)
|
Nitrobenzene-skin
|
1
|
5
|
–
|
–
|
|
(86)
|
Nitrogen dioxide
|
3
|
6
|
5
|
10
|
|
(87)
|
Oil mist mineral
|
–
|
5
|
–
|
10
|
|
(88)
|
Ozone
|
0.1
|
0.2
|
0.3
|
0.6
|
|
(89)
|
Parathion-skin
|
–
|
0.1
|
–
|
–
|
|
(90)
|
Phenol-skin
|
5
|
19
|
–
|
–
|
|
(91)
|
Phorate (Thimet)-skin
|
–
|
0.05
|
–
|
0.2
|
|
(92)
|
Phosgene (Carbonyl Chloride)
|
0.1
|
0.4
|
–
|
–
|
|
(93)
|
Phosphine
|
0.3
|
0.4
|
1
|
1
|
|
(94)
|
Phosphoric acid
|
–
|
1
|
–
|
3
|
|
(95)
|
Phosphorus (yellow)
|
–
|
0.1
|
–
|
–
|
|
(96)
|
Phosphorus penta-chloride
|
0.1
|
1
|
–
|
–
|
|
(97)
|
Phosphorus trichloride
|
0.2
|
1.5
|
0.5
|
3
|
|
(98)
|
Picric acid-skin
|
–
|
0.1
|
–
|
0.3
|
|
(99)
|
Pyridine
|
5
|
15
|
–
|
–
|
|
(100)
|
Silans (silicon tetrahydride)
|
5
|
7
|
–
|
–
|
|
(101)
|
Sodium hydroxide-C
|
–
|
2
|
–
|
|
|
(102)
|
Styrene, monomer (phanylethlene)
|
50
|
215
|
100
|
425
|
|
(103)
|
Sulphur dioxide
|
2
|
5
|
5
|
10
|
|
(104)
|
Sulphur hexafluoride
|
1000
|
6000
|
–
|
–
|
|
(105)
|
Sulphuric acid
|
–
|
1
|
–
|
–
|
|
(106)
|
Tetraethyl lead (as Pb) – Skin
|
–
|
0.1
|
–
|
–
|
|
(107)
|
Toluene (Toluol)
|
100
|
375
|
150
|
560
|
|
(108)
|
O-Toluidine-skin (S.C.)
|
2
|
9
|
–
|
–
|
|
(109)
|
Tributylphosphate
|
0.2
|
2.5
|
–
|
–
|
|
(110)
|
Trichloroethylene
|
50
|
270
|
200
|
1080
|
|
(111)
|
Uranium natural (as U)
|
–
|
0.2
|
–
|
0.6
|
|
(112)
|
Vinyl Chloride (H.C.)
|
5
|
10
|
–
|
–
|
|
(113)
|
Welding fumes
|
–
|
5
|
–
|
–
|
|
(114)
|
Xylene (0-m-P-isomers)
|
100
|
435
|
150
|
655
|
|
(115)
|
Zinc oxide
|
|
|
|
|
|
|
(i) Fume
|
–
|
5.0
|
–
|
10
|
|
|
(ii) Dust (Total dust)
|
–
|
10.00
|
–
|
–
|
|
(116)
|
Zirconium compounds (as Zr)
|
–
|
5
|
–
|
10
|
|
ppm
|
:
|
Parts of vapour or gas per million parts of contaminated air by volume at 25°C and 760 mm of Hg.
|
|
mg/m3
|
:
|
Milligram of substance per cubic metre of air
|
|
*
|
:
|
Not more than 4 times a day with at least 60 min. interval between successive exposures.
|
|
**
|
:
|
mg/m3 = Molecular weight/24.45 x ppm
|
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|
|
G : denotes ceiling limit
|
|
|
|
Skin : denotes potential contribution to the overall exposure by the cutaneous route including mucous membranes and eye.
|
|
|
|
S.C. : denotes suspected human carcinogen
|
|
|
|
H.C. : denotes confirmed human carcinogen.
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|
Substance
|
Permissible time weighted average concentration (TWA) (8 hours)
|
||||
|
Silica SiO2
|
|
||||
|
(a) Crystalline
|
|
||||
|
(i) Quartz
|
|
||||
|
(1) In terms of dust count
|
10600
|
mppcm
|
|||
|
|
% Quartz+10
|
||||
|
(2) In terms of respirable dust
|
10
|
mg/m3
|
|||
|
|
% respirable quartz +2
|
||||
|
(3) In terms of total dust
|
30
|
mg/m3
|
|||
|
|
% quartz + 3
|
||||
|
(ii) Cristoblite
|
: Half the limits given against quartz.
|
||||
|
(iii) Trioumite
|
: Half the limits given against quartz.
|
||||
|
(iv) Silica fused
|
: Same limit as for quartz.
|
||||
|
(v) Tripoli
|
: Same limit as in formula in item (2) given against quartz.
|
||||
|
[(b) Amorphous Silicates: 10 mg/m3, Total Dust
|
|||||
|
[Asbestos (H.C.
|
|
||||
|
(a) Amosite ……………………………….. 0.1 fibre/cc***
|
|||||
|
(b) Chrysotile ……………………………….0.1 fibre/cc***
|
|||||
|
(c) Crocidolite ………………………………0.1 fibre/cc*** ]
|
|||||
|
(c) Portland cement: 10 mg/m3 , Total dust containing less than 1% quartz.
|
|||||
|
(d) Coal Dust
|
: 2mg/m3 , respirable dust fraction containing less than 5% quartz.
|
||||
|
mppcm =
|
Millions particles per cubic metre of air, based on impinger samples counted by light field techniques.
|
||||
|
***(i)
|
For fibres greater than 5 μm in length and less than 5 μ m in breadth with length to breadth ratio equal to or greater than 3:1.
|
||||
|
(ii)
|
As determined by the membrane filter method at 400-450 x magnification (4mm objective) phase contrast illumination.]
|
||||