ALARP—What does it really mean?

This paper examines the requirements that might reasonably be regarded as being implied by the ALARP principle. The principle stipulates that those responsible should reduce risks of death and injury for workers and members of the public to levels that are ‘As Low As Reasonably Practicable’. The main aim of the paper is to resolve the apparent conflict between the ALARP principle on the one hand and, on the other, conventional social cost–benefit analysis. In particular, cost–benefit analysis prescribes that a safety improvement should be undertaken only if the cost of doing so is less than or equal to the resultant benefits, whereas some regulatory agencies interpret ALARP as requiring that the improvement must be undertaken provided that costs are not in ‘gross disproportion’ to benefits, which would clearly include cases in which costs might substantially exceed benefits.