3.1.1. The competent authority, or a body approved or recognised by the competent authority, should establish systems and specific criteria for classifying a chemical as hazardous and should progressively extend these systems and their application. Existing criteria for classification established by other competent authorities or by international agreement may be followed, if they are consistent with the criteria and methods outlined in this code, and this is encouraged where it may assist uniformity of approach. The results of the work of the UNEP/ILO/WHO International Programme on Chemical Safety (IPCS) coordinating group for the harmonisation of classification of chemicals should be considered when appropriate. The responsibilities and role of competent authorities concerning classification systems are set out in paragraphs 2.1.8 (criteria and requirements), 2.1.9 (consolidated list) and 2.1.10 (assessment of new chemicals).

3.1.2. Suppliers should ensure that chemicals they supply have been classified or that they have been identified and their properties assessed (see paragraphs 2.4.3 (assessment) and 2.4.4 (classification)) .

3.1.3. Manufacturers or importers, unless exempted, should give to the competent authority information about chemical elements and compounds not yet included in the consolidated classification list compiled by the competent authority, prior to their use at work (see paragraph 2.1.10 (assessment of new chemicals)).

3.1.4. The limited quantities of a new chemical required for research and development purposes may be produced by, handled in, and transported between laboratories and pilot plant before all hazards of this chemical are known in accordance with national laws and regulations. All available information found in literature or known to the employer from his or her experience with similar chemicals and applications should be fully taken into account, and adequate protection measures should be applied, as if the chemical were hazardous. The workers involved must be informed about the actual hazard information as it becomes known.

3.2.1. The criteria for the classification of chemicals should be based upon their intrinsic health and physical hazards, including:

(a) toxic properties, including both acute and chronic health effects in all parts of the body;

(b) chemical or physical characteristics, including flammable, explosive, oxidising and dangerously reactive properties;

(c) corrosive and irritant properties;

(d) allergenic and sensitising effects;

(e) carcinogenic effects;

(f) teratogenic and mutagenic effects;

(g) effects on the reproductive system.

3.3.1. The classification of chemicals should be based on available sources of information, e.g.:

(a) test data;

(b) information provided by the manufacturer or importer, including information on research work done;

(c) information available as a result of international transport rules, e.g. the United Nations Recommendations on the transport of dangerous goods, which should be taken into account for the classification of chemicals in the case of transport, and the UNEP Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and their Disposal ( 1989), which should be taken into account in respect of hazardous wastes;

(d) reference books or literature;

(e) practical experience;

(f) in the case of mixtures, either on the test of the mixture or on the known hazards of their components;

(g) information provided as a result of the risk evaluation work performed by the International Agency for Research on Cancer (IARC), the UNEP/ILO/WHO International Programme on Chemical Safety (IPCS), the European Communities and various national and international institutions, as well as information available through systems such as the UNEP International Register of Potentially Toxic Chemicals (IRPTC).

3.3.2. Certain classification systems in use may be limited to particular classes of chemicals only. An example is the WHO Recommended classification of pesticides by hazard and guidelines to classification, which classifies pesticides by degree of toxicity only and principally by acute risks to health. Employers and workers should understand the limitations of any such system. Such systems can be useful to complement a more generally applicable system.

3.3.3. Mixtures of chemicals should be classified based on the hazards exhibited by the mixtures themselves. Only if mixtures have not been tested as a whole should they be classified on the basis of intrinsic hazards of their Component chemicals.