Conditional probabilities of post-release events for hazardous materials pipelines

Pipelines are commonly considered a safe alternative for the transportation of hazardous materials. However, in case of failure, pipelines still pose major risks to the environment and to the population potentially exposed. The aim of the present work is to provide occurrence probabilities of the intermediate and final events following the accidental release of hazardous materials from pipelines. A collection of incidents and accidents occurred worldwide in connection with the use of onshore long-distance pipeline networks, has been gathered to make up a specific database for the analysis of incidents in pipelines. A qualitative and quantitative analysis of the data has allowed to develop detailed event trees for the different classes of hazardous materials, and to calculate the probability of occurrence of the final outcomes. The investigation has also aimed at identifying, for each type of release, the relationship between the final events and the causes of the pipeline failure. The results obtained represent a useful and needed starting point in Quantitative Risk Analysis of hazardous materials transportation via pipelines.