Analysis of Natech accidents recorded in major accident databases

There is evidence that the impact of natural hazards on process plants as well as on infrastructures for energy supply may cause severe accidents involving the release of significant quantities of hazardous substances. These so-called “Natech” disasters deserve particular attention as they can result in multiple and simultaneous releases of hazardous materials. A further complication comes from the different consequences that may be related to different types of natural events that result in important differences in the expected damage to process equipment. Currently, there is only limited data available on Natech disasters, their prevalence, their triggering mechanisms, and the vulnerability of the various types of industry exposed. The present contribution is devoted to exploring the characteristics of different categories of Natech disasters, in particular those triggered by floods and earthquakes. Available data on Natech accidents were retrieved from several industrial accident databases in Europe and in the US. The analysis of accident data gives an indication of the expected damage of process equipment caused by the impact of natural events. Information was obtained on the expected loss of containment (LOC) events. The scenarios following the LOC events were related to substance hazard and to the intensity of LOCs. The presence and the role of safety barriers was investigated as well. The results allowed the identification of the critical equipment items with respect to the different Natech events and the definition of reference accident scenarios likely to be triggered by natural events in industrial plants.