1. In activities or operations where workers are exposed to chemical agents, the characterization of hazards will occur when the exposure limits listed in Table No. 1 of this Annex are exceeded.
2. All values set forth in Table No. 1 – Tolerance Limits Table are valid for absorption only through the respiratory route.
3. All values set forth in Table No. 1 as “Simple Asphyxiants” indicate that in the presence of these substances in the workplace, the minimum oxygen concentration must be 18 (eighteen) percent by volume. Situations where the oxygen concentration is below this value will be considered a serious and imminent risk.
4. The “CEILING VALUE” column lists the chemical agents whose tolerance limits must not be exceeded at any time during the workday.
5. The “ALSO ABSORBED THROUGH THE SKIN” column lists the chemical agents that can be absorbed through the skin, thereby requiring the use of suitable gloves during handling, in addition to the necessary PPE to protect other parts of the body.
6. The assessment of chemical agent concentrations through instantaneous sampling methods, whether direct-reading or not, must be carried out with at least 10 (ten) samples at each point – at the worker’s respiratory level. There must be a minimum interval of 20 (twenty) minutes between each sampling.
7. Each of the concentrations obtained in these samples must not exceed the values obtained in the following equation, otherwise, it will be considered a situation of serious and imminent risk.
- Maximum Value = T.L. x D.F.
- Where:
- T.L. = tolerance limit for the chemical agent, according to Table No. 1.
- D.F. = deviation factor, as defined in Table No. 2.
Table 2
| T.L. (ppm or mg/m³) | D.F. |
|---|---|
| 0 to 1 | 3 |
| 1 to 10 | 2 |
| 10 to 100 | 1.5 |
| 100 to 1000 | 1.25 |
| above 1000 | 1.1 |
8. The tolerance limit will be considered exceeded when the arithmetic mean of the concentrations exceeds the values set in Table No. 1.
9. For chemical agents that have a “CEILING VALUE” indicated in Table No. 1 (Tolerance Limits Table), the tolerance limit will be considered exceeded when any of the concentrations obtained in the samples exceed the values set in the same table.
10. The tolerance limits set in Table No. 1 are valid for workweeks of up to 48 (forty-eight) hours.
10.1 For workweeks exceeding 48 (forty-eight) hours, the provisions of Article 60 of the CLT must be followed.
Table 1 – Table of Tolerance Limits
| CHEMICAL AGENTS | Ceiling Limit | Absoroption through skin | Up to 48 hours per week | Unhealthiness degree to be considered in characterization | ||
| ppm* | mg/m3** | |||||
| Acetaldehyde | 78 | 140 | maximum | |||
| Cellosolve acetate | + | 78 | 420 | medium | ||
| Ethylene glycol monoethyl ether acetate (see Cellosolve acetate) | – | – | – | |||
| Ethyl acetate | 310 | 1090 | minimum | |||
| Ethyl 2-ethoxy ethyl (see Cellosolve ethyl) | – | – | – | |||
| Acetylene | Asphyxiant | simple | – | |||
| Acetone | 780 | 1870 | minimum | |||
| Acetonitrile | 30 | 55 | maximum | |||
| Acetic acid | 8 | 20 | medium | |||
| Hydrogen cyanide | + | 8 | 9 | maximum | ||
| Hydrochloric acid | + | 4 | 5,5 | maximum | ||
| Chromic acid (mist) | – | 0,04 | maximum | |||
| Ethanoic acid (see Acetic acid) | – | – | – | |||
| Hydrofluoric acid | 2,5 | 1,5 | maximum | |||
| Formic acid | 4 | 7 | medium | |||
| Methanoic acid (see Formic acid) | – | – | – | |||
| Methyl acrylate | + | 8 | 27 | maximum | ||
| Acrylonitrile | + | 16 | 35 | maximum | ||
| Iso-amyl alcohol | 78 | 280 | minimum | |||
| N-Butyl alcohol | + | + | 40 | 115 | maximum | |
| Isobutyl alcohol | 40 | 115 | medium | |||
| Sec-butyl alcohol (2-butanol) | 115 | 350 | medium | |||
| Tert-butyl alcohol | 78 | 235 | medium | |||
| Ethyl alcohol | 780 | 1480 | minimum | |||
| Furfuryl alcohol | + | 4 | 15,5 | medium | ||
| Methyl amyl alcohol (see Methyl isobutyl carbinol) | – | – | – | |||
| Methyl alcohol | + | 156 | 200 | maximum | ||
| N-Propyl alcohol | + | 156 | 390 | medium | ||
| Isopropyl alcohol | + | 310 | 765 | medium | ||
| Acetic aldehyde (see Acetaldehyde) | – | – | – | |||
| Formic aldehyde (see Formaldehyde) | – | – | – | |||
| Ammonia | 20 | 14 | medium | |||
| Anhydrous sulfur (see Sulfur dioxide) | – | – | – | |||
| Aniline | + | 4 | 15 | maximum | ||
| Argon | Asphyxiant | simple | – | |||
| Arsine | 0,04 | 0,16 | maximum | |||
| Ethyl bromide | 156 | 695 | maximum | |||
| Methyl bromide | + | 12 | 47 | maximum | ||
| Bromine | 0,08 | 0,6 | maximum | |||
| Bromoethane (see Ethyl bromide) | – | – | – | |||
| Bromoform | + | 0,4 | 4 | medium | ||
| Bromomethane (see Methyl bromide) | – | – | – | |||
| 1,3 Butadiene | 780 | 1720 | medium | |||
| n-Butane | 470 | 1090 | medium | |||
| n-Butane (see N-butyl alcohol) | – | – | – | |||
| sec-Butanol (see Sec-butyl alcohol) | – | – | – | |||
| Butanone (see Methyl ethyl ketone) | – | – | – | |||
| 1-Butanethiol (see Butyl mercaptan) | – | – | – | |||
| n-Butylamine | + | + | 4 | 12 | maximum | |
| Cellosolve butyl | + | 39 | 190 | medium | ||
| n-Butil mercaptana | 0,4 | 1,2 | medium | |||
| 2-Butoxyethanol (see Cellosolve butyl) | – | – | – | |||
| Cellosolve (see 2-ethoxy ethanol) | – | – | – | |||
| Lead | – | 0,1 | maximum | |||
| Methyl cyanide (see Acetonitrile) | – | – | – | |||
| Vinyl cyanide (see Acrylonitrile) | – | – | – | |||
| Cyanogen | 8 | 16 | maximum | |||
| Cyclohexane | 235 | 820 | medium | |||
| Cyclohexanol | 40 | 160 | maximum | |||
| Cyclohexylamine | + | 8 | 32 | maximum | ||
| Carbonyl chloride (see Phosgene) | – | – | – | |||
| Ethyl chloride | 780 | 2030 | medium | |||
| Phenyl chloride (see Chloro benzene) | – | – | – | |||
| Methyl chloride | 78 | 165 | maximum | |||
| Methylene chloride | 156 | 560 | maximum | |||
| Vinyl chloride | + | 156 | 398 | maximum | ||
| Vinylidene chloride | 8 | 31 | maximum | |||
| Chlorine | 0,8 | 2,3 | maximum | |||
| Chlorobenzene | 59 | 275 | medium | |||
| Clorobromomethane | 156 | 820 | maximum | |||
| Chloroethane (see Ethyl chloride) | – | – | – | |||
| Chloroethyl (see Vinyl chloride) | – | – | – | |||
| Chlorodifluomethane (Freon 22) | 780 | 2730 | minimum | |||
| Chloroform | 20 | 94 | maximum | |||
| 1-chloro-1-nitropropane | 16 | 78 | maximum | |||
| Chloroprene | + | 20 | 70 | maximum | ||
| Cumene | + | 39 | 190 | maximum | ||
| Decaborane | + | 0,04 | 0,25 | maximum | ||
| Demeton | + | 0,008 | 0,08 | maximum | ||
| Diamine (see Hydrazine) | – | – | – | |||
| Diborane | 0,08 | 0,08 | maximum | |||
| 1,2-Dibramoetano | + | 16 | 110 | medium | ||
| o-Dichlorobenzene | 39 | 235 | maximum | |||
| Dichlorodifluoromethane (Freon 12) | + | 780 | 3860 | minimum | ||
| 1,1 Dichloroethane | 156 | 640 | medium | |||
| 1,2 Dichloroethane | 39 | 156 | maximum | |||
| 1,1 Dichloroethylene (see Vinylidene chloride) | – | – | – | |||
| 1,2 Dichloroethylene | 155 | 615 | medium | |||
| Dichloromethane (see Methyl chloride) | – | – | – | |||
| 1,1 Dichloro-1-nitroethane | + | 8 | 47 | maximum | ||
| 1.2 Dichloropropane | 59 | 275 | maximum | |||
| Dichlorotetrafluoroethane (Freon 114) | 780 | 5460 | minimum | |||
| Diethylamine | 20 | 59 | medium | |||
| Diethyl ether (see Ethyl ether) | – | – | – | |||
| 2,4 Toluene diisocyanate (TDI) | + | 0,016 | 0,11 | maximum | ||
| Diisopropylamine | + | 4 | 16 | maximum | ||
| Dimethylacetamide | + | 8 | 28 | maximum | ||
| Dimethylamine | 8 | 14 | medium | |||
| Dimethylformamide | 8 | 24 | medium | |||
| l, l Dimethyl hydrazine | + | 0,4 | 0,8 | maximum | ||
| Carbon dioxide | 3900 | 7020 | minimum | |||
| Chlorine dioxide | 0,08 | 0,25 | maximum | |||
| Sulphur dioxide | 4 | 10 | maximum | |||
| Nitrogen dioxide | + | 4 | 7 | maximum | ||
| Carbon disulfide | + | 16 | 47 | maximum | ||
| Stibnite | 0,08 | 0,4 | maximum | |||
| Styrene | 78 | 328 | medium | |||
| Ethanol (see Acetaldehyde) | _ | _ | _ | |||
| Ethane | Asphyxiant | simples | _ | |||
| Ethanol (see Ethyl) | _ | _ | _ | |||
| Ethanethiol (see Ethyl mercaptan) | _ | _ | _ | |||
| Dichloroethyl ether | + | 4 | 24 | maximum | ||
| Ethyl ether | 310 | 940 | medium | |||
| Ethylene glycol monobutyl ether (see Cellosolve buthyl) | _ | _ | _ | |||
| Ethylene glycol monoethyl ether (see Cellosolve) | _ | _ | _ | |||
| Ethylene glycol monomethyl ether (see Cellosolve methyl) | _ | _ | _ | |||
| Ethylamine | 8 | 14 | maximum | |||
| Ethylbenzene | 78 | 340 | medium | |||
| Ethylene | Asphyxiant | simples | _ | |||
| Ethyleneimine | + | 0,4 | 0,8 | maximum | ||
| Ethyl mercaptan | 0,4 | 0,8 | medium | |||
| n-Ethyl morpholine | + | 16 | 74 | medium | ||
| 2-Ethoxyethanol | + | 78 | 290 | medium | ||
| Phenol | + | 4 | 15 | maximum | ||
| Fluorotrichloromethane (Freon 11) | 780 | 4370 | medium | |||
| Formaldehyde (formalin) | + | 1,6 | 2,3 | maximum | ||
| Phosphine | 0,23 | 0,3 | maximum | |||
| Fosgênio | 0,08 | 0,3 | maximum | |||
| Freon 11 (see Fluortrichloromethano) | _ | _ | _ | |||
| Freon 12 (see Dichlorodifluoromethane) | _ | _ | _ | |||
| Freon 22 (see Chlorodifluoromethane) | _ | _ | _ | |||
| Freon 113 (see 1,1,2, 1,2,2-trichlorotrifluoroethane) | _ | _ | _ | |||
| Freon 114 (see Dichlrorotetrafluorethane) | _ | _ | _ | |||
| Ammonia gas (see Ammonia) | _ | _ | _ | |||
| Carbonic gas (see Carbon dioxide) | _ | _ | _ | |||
| Hydrocyanic gas (see Hydrocyanic acid) | _ | _ | _ | |||
| Chlorine gas (see Hydrochloric acid) | _ | _ | _ | |||
| Sulfide gas | 8 | 12 | maximum | |||
| Helium | Asphyxiant | simples | _ | |||
| Hydrazine | + | 0,08 | 0,08 | maximum | ||
| Antimony hydride antimony (see Stibnite) | _ | _ | _ | |||
| Hydrogen | Asphyxiant | simples | _ | |||
| Isobutanol (see Isobutyl alcohol) | _ | _ | _ | |||
| Isopropylamine | 4 | 9,5 | medium | |||
| Isopropyl benzene (see Cumene) | _ | _ | _ | |||
| Mercury (all except organic forms) | _ | 0,04 | maximum | |||
| Methyl methacrylate | 78 | 320 | minimum | |||
| Methane | Asphyxiant | simples | _ | |||
| Methanol (see Methyl alcohol) | _ | _ | _ | |||
| Methylamine | 8 | 9,5 | maximum | |||
| Cellosolve methyl | + | 20 | 60 | maximum | ||
| Methyl cyclohexanol | 39 | 180 | medium | |||
| Methyl chloroform | 275 | 1480 | medium | |||
| Methyl demeton | + | _ | 0,4 | maximum | ||
| Methyl ethyl ketone | 155 | 460 | medium | |||
| Methyl isobutylcarbinol | + | 20 | 78 | maximum | ||
| Methyl mercaptan (methanethiol) | 0,04 | 0,8 | medium | |||
| 2-Methoxy ethanol (see Cellosolve methyl) | _ | _ | _ | |||
| Monomethyl hydrazine | + | + | 0,16 | 0,27 | maximum | |
| Carbon monoxide | 39 | 43 | maximum | |||
| Carbon black (1) | 3,5 | maximum | ||||
| Neon | Asphyxiant | simples | _ | |||
| Nickel carbonyl (Nickel tetracarbonyl) | 0,04 | 0,28 | maximum | |||
| N-propyl nitrate | 20 | 85 | maximum | |||
| Nitroethane | 78 | 245 | medium | |||
| Nitromethane | 78 | 195 | maximum | |||
| 1 – Nitropropane | 20 | 70 | medium | |||
| 2 – Nitropropane | 20 | 70 | medium | |||
| Ethylene oxide | 39 | 70 | maximo | |||
| Nitric oxide (NO) | 20 | 23 | maximum | |||
| Nitrous oxide (N2O) | Asphyxiant | simples | – | |||
| Ozone | 0,08 | 0,16 | maximum | |||
| Pentaborane | 0,004 | 0,008 | maximum | |||
| n-Pentane | + | 470 | 1400 | minimum | ||
| Perchloroethylene | 78 | 525 | medium | |||
| Pyridine | 4 | 12 | medium | |||
| n-Propane | Asphyxiant | simples | – | |||
| n-Propanol (see n-Propyl alcohol) | – | – | – | |||
| iso-Propanol (see Isopropyl alcohol) | – | – | – | |||
| Propanone (see Acetone) | – | – | – | |||
| Propylene | Asphyxiant | simples | – | |||
| Propylene imine | + | 1,6 | 4 | maximum | ||
| Dimethyl sulphate | + | + | 0,08 | 0,4 | maximum | |
| Hydrogene sulphide (see Sulfhydric gas) | – | – | – | |||
| Systox (see Demeton) | – | – | – | |||
| 1,1,2,2,Tetrabromoethane | 0,8 | 11 | medium | |||
| Carbon tetrachloride | + | 8 | 50 | maximum | ||
| Tetrachloroethane | + | 4 | 27 | maximum | ||
| Tetrachloroethylene (see Perchloroethylene) | – | – | – | |||
| Tetrahydrofuran | 156 | 460 | maximum | |||
| Toluene | + | 78 | 290 | medium | ||
| Tolueno-2,4-diisocyanate (TDI) (see 2,4 toluene diisocyanate) | – | – | – | |||
| Tribromomethane (see Bromoform) | – | – | – | |||
| Vinyl trichloride (see 1,1,2 trichloroethane) | – | – | – | |||
| 1,1,1 Trichloroethane (see Methyl chloroform) | – | – | – | |||
| 1,1,2 Trichloroethane | + | 8 | 35 | medium | ||
| Trichloroethylene | 78 | 420 | maximum | |||
| Trichloromethane (see Chloroform) | – | – | – | |||
| 1,2,3 Trichloropropane | 40 | 235 | maximum | |||
| 1,1,2 Trichloro-1,2,2 trifluoroethane (Freon 113) | 780 | 5930 | medium | |||
| Triethylamine | 20 | 78 | maximum | |||
| Trifluoro monobromo methane | 780 | 4760 | medium | |||
| Vinyl benzene (see Sytrene) | – | – | – | |||
| Xylene (Xylol) | 78 | 340 | medium | |||
* ppm – parts of vapor or gas per million parts of contaminated air.
** mg/m³ – milligrams per cubic meter of air.