Classification, nature of hazard  

Health effects

Sources of chemical hazard

Exposure pathways and chemical detection

Protection measures

Regulation, legal basis

      From the health perspective, there are a number of ways of classifying chemical accidents, none of which is complete or mutually exclusive. For example, classification could be based on:

• the chemical(s) involved, the amount released, their physical form, and where and how the release occurred

• the sources of the release

• the extent of the contaminated area

• the number of people exposed or at risk

• the routes of exposure

• the health or medical consequences of exposure

The first and most essential step leading to the safe use of chemicals is to know their identity, their hazards to health and the environment and the means of controlling them. This knowledge should be available with reasonable effort and cost. Furthermore, this inherently complex knowledge must be organised in such a way that essential information on the hazards and corresponding protective measures can be identified and conveyed to the user in a form that is easy to understand.

The hazard classification and labelling process is an essential tool for establishing an effective information transfer so that the degree of the hazard the chemical represents for man and the environment can be recognised, the correct preventive actions be chosen, and safe use established.

International, regional, and national classification and labelling systems are already established and tested in practice.