Supporting decision-making in the chemical industry by a dynamic interpretation of the ALARP principle

The selection of safety measures to reduce the risk level and environmental impacts in major-hazard industries is commonly supported by the ALARP (As Low As Reasonably Practicable) principle reinforced by cost-benefit analyses and the grossly disproportionate criterion. Nevertheless, decision-makers should also pay attention to the whole context and account for the level of uncertainty in and knowledge of the chemical process, the use of best available technologies, the potential of major losses due to the release of hazardous materials, and many other elements. Recently, a dynamic interpretation of the ALARP principle has been proposed, which involves considering decisions oscillating between two borderlines, where reference is made, in one case, to expected values and, in the other, to the precautionary principle, and deciding which is more appropriate. This contribution will provide some examples from the chemical industry, showing the appropriateness of a dynamic interpretation of the ALARP principle.