Schedule ‘G’

(See Rule 70,84)

Permissible levels of certain chemical substances in work environment

Permissible limits of exposure

Time weighted average

Sl. No. Substance

concentration Short-term exposure limit

(8 hrs) (15 min)*

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

3. Acetone 750 1780 1000 2375

4. Acrolein 0.1 0.25 0.3 0.8

5. Acrylonitrile-skin 2 4.5 -- --

6. Aldrin-skin -- 0.25 -- --

7. Allyl Chloride 1 3 2 6

8. Ammonia 25 18 35 27

9. Aniline-skin 2 10 -- --

Anisidine

10. 0.1 0.5 -- --

(o-p- isomers)-skin

1 2 3 4 5 6

Arsenic &

11. -- 0.2 -- --

compounds (as As)

12. Benzene(H.C.) 10 20 25 7.5

Beryllium &

13. Compound (as Be) -- 0.002 -- --

(S.C.)

Bornon

14. 1 3 -- --

Trifluoride-C

15. Bromine 0.1 0.7 0.3 2

16. Butane 800 1900 -- --

2-Butanon (Methyl-

17. 200 590 300 885

ethyl Ketone MBK)

18. n-Butyl acetate 150 710 200 950

n-Butyl

19. 50 150 -- --

alcohol-skin-C

Sce/tert, Butyl

20. 200 950 -- --

acetate

21. Butyl Mercaptan 0.5 1.5 -- --

Cadmium-dust and

22. -- 0.05 -- --

salts (as Cd)

23. Calcium oxide -- 2 -- --

24. Carbaryl (Sevin) -- 5 -- --

Carbofuran

25. -- 0.1 -- --

(Furadan)

Carbon disulphide-

26. 10 30 -- --

skin

27. Carbon monoxide 50 55 400 440

Carbonate

28. 5 30 -- --

trachloride-skin

Carbonyl Chloride

29. 0.1 0.4 -- --

(Phosgene)

Chlorobenzene

30. (monochloro- 75 350 -- --

benzene)

31. Chloridane-skin -- 0.5 -- --

32. Chlorine 1 3 3 9

33. Chloroform (S.C.) 10 50 -- --

bis-(Chloromethyl)

34. 0.001 0.005 --

ether (H.C.)

Chromic acid and

35. chromates (as Cr) -- 0.05 -- --

water soluble

Chromous Salts

36. 0 05 -- --

(as Cr)

37. Copper fume -- 0.2 -- --

38. Cotton dust, raw -- 0.2 -- --

Cresol, all

39. 5 22 -- --

isomers-skin

Cyanides

40. -- 5 -- --

(as CN)-skin

1 2 3 4 5 6

41. Cyanogen 10 20 -- --

DDT(Dichloro

42. diphenyl -- 1 -- --

trichloroethane)

43. Demeron-skin 0.01 0.1 -- --

44. Diazinon-skin -- 0.1 -- --

45. Dibutyl pythalate -- 5 -- --

Dichiorvos

46. 0.1 1 -- --

(DDVP)-skin

47. Dieldrin-skin -- 0.25 -- --

Dinitrobenzene,

48. 0.15 1 -- --

(all isomers)- skin

49. Dinitrotoluene-skin -- 1.5 -- --

Diophenyl

50. 0.2 1.5 -- --

(Biphenyl)

Endosulfan

51. -- 0.1 -- --

(Thiadon)-skin

52. Endrin-skin -- 0.1 -- 0.3

53. Ethyl acetate 400 1400 -- --

54. Ethyl alcohol 1000 1900 -- --

55. Ethylamin 10 18 -- --

56. Fluorides (as F) -- 2.5 -- --

57. Fluorine 1 2 2 4

58. Formic Acid 5 9 -- --

Hydrazine-skin

59. 0.1 0.1 -- --

(S.C.)

Hydrogen

60. 5 7 -- --

Chloride-C

Hydrogen

61. 10 10 -- --

Cyanide-skin-C

Hydrogen fluoride

62. 3 2.5 -- --

(as F)-C

63. Hydrogen Peroxide 1 1.5 -- --

64. Hydrogen Sulphide 10 14 15 21

65. Gasoline 300 900 500 1500

66. Iodine -C 0.1 1 -- --

Iron Oxide Fume

67. - 5 -- --

(Fe O )(as Fe)

2 3

68. Isoamyl acetate 100 525 -- --

69. Isoamyl alcohol 100 360 125 450

70. Isobutyl alcohol 50 150 -- --

Lead, inorg, dusts

71. -- 0.15 -- --

and fumes (as Pb)

1 2 3 4 5 6

72. Lindane-skin -- 0.5 -- --

73. Malathion-skin -- 10 -- --

Manganese dust

74. and compounds(as -- 5 -- --

Mn)

Manganese Fume

75. -- 1 -- 3

(as Mn)

Mercury

76.

(as Hg)-skin

(i) Alkyl

-- 0.01 -- 0.03

compounds

(ii) All forms

except alkyl -- 0.05 -- --

vapour

(iii) Aryl and

inorganic -- 0.1 -- --

compounds

Methyl alcohol

77. 200 260 250 310

(methanol)-skin

Methyl cellosolve-

78. skin (2 methoxy 5 16 -- --

ethanol)-scin

Methyl Isobutyl

79. 50 205 75 300

Ketone

80. Methyl Isocyanate 0.02 0.05 -- --

81. Naphthalene 10 50 15 75

Nickel carbonyl

82. 0.05 0.35 -- --

(as Ni)

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, minerals -- 5 -- 10

88. Ozone 0.1 0.2 0.3 0.6

89. Parathion-skin -- 0.1 -- --

90. Phenol-skin 5 19 -- --

Phorate

91. -- 0.05 -- 0.2

(Thimet)-skin

Phosgene

92. 0.1 0.4 -- --

(Carbonyl Chloride

93. Phosphine 0.3 0.4 1 1

Phosphoric acid

94. -- 1 -- --

(yellow)

1 2 3 4 5 6

95. Phosphorus (yellow) -- 0.1 -- --

Phosphorus

96. 0.1 1 -- --

pentachloride

Phosphorus

97. 0.2 1.5 0.5 3

trichloride

98. Picric acid-skin -- 0.1 -- 0.3

99. Pyridine 5 15 -- --

Silane (silicon

100. 5 7 -- --

tetrahydride)

Sodium

101. -- 2 -- --

hydroxide-C

Styrene, monomer

102. 50 215 100 425

(Phenylethylene)

103. Sulphur dioxide 2 5 5 10

Sulphur

104. 1000 6000 -- --

hexafluoride

105. Sulphuric acid -- 1 -- --

106. Toluene (Toluol) 100 375 150 560

O-Tuluiodine-skin

107. 2 9 -- --

(S.C.)

108. Tributyl phosphate 0.2 2.5 -- --

109. Trichloroethylene 50 270 200 1080

Uranium, natural (as

110. -- 0.2 -- --

U)

111. Vinyl chloride(H.C.) 5 10 -- --

112. Welding fumes -- 5 -- --

Xylene (o-, m, p-

113. 100 435 150 655

isomers)

114. Zinc oxide

(i)Fume -- 5 -- 10

(ii) Dust (Total dust) -- 10 -- --

Zironium

115. -- 5 -- 10

compounds (as Zr)

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

*Note more than 4 times a day with at least 60 min. interval between successive

exposures.

**mg/m^3 x (molecular weight)/24.45(ppm)

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

Permissible time-weighted average

Substance

concentration (TWA)(8 hrs)

1. Silica,SiO

2

(a) Crystaline

(i) Quartz

(1) In terms of dust count 10600 / (% Quartz + 10) mppcm

(2) In terms of respirable dust 10 / (% respirable quartz + 2) mg/m3

(3) In terms of total dust 30 / (% respirable quartz + 3) mg/m3

(ii) Cristabalite Half the limits given against quartz.

(iii) Tridymine 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: 10mg/m3 Total dust.

2. Asbestos (H.C.):

(a) Amosite......................................................... 0.1 fibre/cc***

(b) Chrystolite........................................................0.1 fibre/ cc***

(c) Crocidolite........................................................0.1 fibre/ cc***

(d) Portland Cement: 10 mg/mº, total dust containing less than 1% quartz

3. Coal Dust: 2 mg/mº, respirable dust fraction containing less than 5% quartz.

mppcm = Million particles per cubic metre of air, based on impinge samples counted by light-field

techniques.

***(i) For fibres greater than 5 µm in length and less than 5 µm in breadth with length to breadth

ration equal to or greater than 3:1.

(ii) As determined by the membrane filter method at 400-450 × magnification (4 µm ejective)

phase contrast illumination.

Respirable Dust :

Fraction passing a size-selector with the following characteristics:

Aerodynamic Diameter (µ m)

% passing selector

(Unit density sphere)

2 90

2.5 75

3.5 50

5.0 25

10 01

Permissible activity concentration levels for some of the radionuclide’s that are commonly

encountered in metal recycling industries as given below :

Radionuclide concentration

Radionuclide

(Bq/g*)

Co-60 0.1

Cs-137 0.1

Am-241 0.1

Ir-192 1.0”

Foot note :

1. Bq/g stands for Becquerel per gram. Becquerel means one transformation of a radionuclide per

second : and is the SI unit of radioactivity.

2. Measurement shall comprise external radiation levels on the metal scrap, semi-finished and

finished products as well as the background levels at the place of measurement and records of

the same shall be maintained. If the radiation level on the material exceeds the background

radiation level by 20 µ/hr (Micro Rad per hour).

The Atomic Energy Regulatory Board (AERB) Shall be promptly intimated.