Large numbers and quantities of hazardous and noxious substances (HNS) are transported by sea. For this reason, the prioritisation of risk from HNS becomes an important element to emergency planning and preparedness. The colleagues of ARCOPOL Plus project implemented a methodology to prioritise potential acute public health risks associated with incidents involving maritime transport of hazardous and noxious substances (HNS). To this end, authors have developed a tool and database with toxicology and behaviour statistics for over 300 HNS. The methodology does not provide a process for assessing risks for specific incidents but instead aims to provide strategic risk information for public health planning and preparedness. Whilst chronic effects are important public health considerations, acute health impacts have been used as the risk driver for this assessment. This decision has been taken in order to reflect the type of incident scenario envisaged, i.e. associated with large chemical releases, and additionally because of the inherent difficulties associated with attributing chronic effects such as excess cancers to specific events / agents. With this index, regional planners or port operators have the possibility of identify risk of most relevance to the region by reviewing statistical data on maritime transport and handling of HNS.