Risk matrices are tools for comparing risks relative to one another (e.g. for a single system or single activity) and hence being able to rank. them for the purposes of risk mitigation and the allocation of safety resources. Risk matrices are not tools for determining the tolerability, or otherwise, of single risks. However, in some sectors risk matrices are being used to judge whether single risks. are tolerable, and ALARP arguments are being made for each separate single risk rather than an individual’s aggregate risk from all causes. This stretches the Risk Matrix concept beyond its breaking point, and is leading to potentially misinformed decisions by senior managers regarding the overall level of risk present, and hence whether risk reduction options are either needed or are reasonably practicable.