Chapter 3: The Scientific Basis of Chemical Risk Assessment

The risk assessment of chemicals has conventionally been based on four elements:

1. Hazard identification: the identification of the inherent capacity of a chemical to cause one or more adverse effects, without regard to the likelihood or severity of such effects.

2. Hazard characterisation: the (semi-)quantitative evaluation of the nature of adverse effects following the exposure to a chemical, including the assessment of toxic potency (the relative toxicity of a chemical) and, where possible, a dose.response assessment.

3. Exposure assessment: the (semi-)quantitative evaluation of the likely exposure of man and/or the environment to a chemical.

4. Risk characterisation: the (semi-)quantitative estimation of the probability that an adverse effect will occur, and of its severity and duration in a given population under defined exposure conditions, based on elements 1.3.