A comprehensive analysis of the occurrence of Natech events in the process industry

Natural events triggering technological scenarios (Natech events) are an increasing concern for regulatory authorities and industry, in particular in areas prone to natural disasters. A comprehensive analysis of the occurrence of Natech scenarios affecting the process industry is presented. A dataset of 9100 past accidents that took place in the last 70 years was compiled and analysed, with the aim of understanding the trend of Natech events, their geographical distribution, the final technological scenarios, and the associated consequences in terms of human losses and asset damages. Meteorological events, such as storms, extreme temperatures and lightning were found to be the main trigger of Natech scenarios (86 %). Despite the difficulty in collecting homogeneous data worldwide, an increasing number of Natech events over the time is observed. Moreover, specific increases in the occurrence of Natech events correspond to the occurrence of severe natural disasters as the devastating hurricanes that affected the Gulf of Mexico in recent years. The societal risk curve associated to Natechs was calculated, evidencing the relevance of extremely severe accidents (> 100 deaths). The analysis of the dataset also allowed building quantified event trees for the evolution of Natech scenarios. Specific ignition probability values for Natech events were estimated.