The components of risk

The evaluation of environmental risks involves concepts more complex than the distinction between risk and danger. The definition of risk is based on probability and consequence. These are the foundation for Ineris using its expertise to develop and help improve such risk evaluation methods.

In France, the overall approach to risk evaluation originated at the end of the 1970s, with the decree of July 16, 1976, on installations classified for the protection of the environment.
The methods for evaluating chronic risk are based on different concepts, vocabulary and logic than those used in the field of accidental risks.

Accidental risk

The evaluation of accidental risk, whether technological or natural in origin, is based on the “probability of occurrence”, the “intensity” of a phenomenon and the “vulnerability” of targets (also known as “stakes”). The purpose of the evaluation is to determine the hazard (combination of the probability and intensity of the accident) and the level of severity (combination of the intensity of the phenomenon and the vulnerability of stakes).

> Definition of accidental risk

Chronic risk

The study of chronic risk is based on the concepts of danger, exposure and impact. The purpose of evaluation is to determine the probability of occurrence or the amplitude of impact of a substance on a living organism based on exposure level.

> Definition of chronic risk