Exposure limits for harmful airborne substances

• Pages: 10-16

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3. Exposure limits for harmful airborne substances

3.1. Establishment of exposure limits

3.1.1. The principle of exposure limits in the working environment should be

established:

(a) by legislation; or

(b) by collective agreement or by any other agreements drawn up between the

employers and workers; or

(c) by any other channel approved by the competent authority after consulting the

employers’ and workers’ organisations.

3.1.2. When exposure limits have been established as in paragraph 3.1.1, the

wording of the relevant provisions should be sufficiently flexible to permit updating as

scientific knowledge, technology and socio-economic conditions progress.

3.1.3. The exposure limit system should be gradually extended to cover an

increasing number of chemicals and physical agents, starting with:

(a) those involving the most serious hazards; and

(b) those to which the greatest number of workers are exposed.

3.1.4. (1) When the exposure limits are established, allowance should be made

for:

(a) scientific knowledge with regard to all the hazards associated with exposure to the

substances in question;

(b) the subjective reactions of the human body; and

(c) the monitoring possibilities.

(2) Exposure limits should in general be established or modified through

consultation with the employers’ and workers’ organisations concerned.

3.1.5. Exposure limits should be based on a study of the dose-effect and dose-

response relationship. They should be established in the light of the following data:

(a) the physical and chemical properties of the substance, including the nature and

quantity of contaminants;

(b) the ways in which it is expected to use the substance, and features of the exposure

of workers;

(c) the results of experiments with laboratory animals designed to establish:

(i) the acute local and general effects (irritation and sensitisation);

(ii) the effects of repeated administration; and

(iii) the chronic general effects, including those affecting the central nervous

system (mutagenic, carcinogenic, gonadotropic and teratogenic effects); and

(d) the results of:

(i) routine medical examinations of exposed workers;