A qualitative approach to risk management of hazardous materials in the Netherlands: lessons learned from 7 sluice cases

The debate on risks related to hazardous materials has intensified in the Netherlands since the 1980s. Following the Bijlmer airplane disaster in Amsterdam in 1992 and the SE Fireworks disaster in the city of Enschede in 2000, society has become more aware of the risks involved in the production, storage and transport of hazardous materials. In order to prevent disasters and improve the safety of those living in the vicinity of risky activities, the Dutch government implemented its external safety policy ( externe veiligheidsbeleid ). External safety policy aims to control the risks for civilians relating to the production, storage and use of hazardous materials as well as transport by road, rail or water and through pipelines. The Dutch government has specified generic external safety norms to direct decision-making. However, risks are calculated with models which not only use transport of hazardous materials as their input but also population numbers in the adjacent area. Since not many people live directly adjacent to dams and sluices, it would seem improbable that an incident would create many problems due to low-population density. However, if sluices and floodgates were destroyed by an incident involving hazardous materials, the primary function would be diminished, resulting in new risks. The normally used quantitative approach does not therefore seem to be a sufficient means to control risks. In collaboration with Rijkswaterstaat , the executive arm of the Dutch Ministry of Infrastructure and the Environment, we conducted seven case studies to test an alternative approach. By using risk inventories and evaluations, questionnaires and interviews, we developed a new qualitative risk assessment method. This paper outlines our approach and presents the effectiveness of a qualitative risk analysis for controlling external safety risks related to water transport. We will particularly reflect on its effectiveness with regard to controlling risks at sluices and dams.