Quantitative Risk Assessment for a Petroleum Storage and Distribution Terminal in Akwa Ibom State

This research conducts a quantitative risk assessment for a petroleum storage and distribution terminal in Akwa Ibom State, South South Nigeria, applying consequence modelling and frequency analysis techniques to characterise the risk profile of the facility and evaluate the adequacy of existing safety barriers. Petroleum storage terminals represent concentrations of hazardous inventory in proximity to populated areas, making rigorous quantitative risk assessment a regulatory and societal obligation. This study employs the Layer of Protection Analysis methodology for major loss-of-containment scenarios combined with consequence modelling using the PHAST software tool for fire, explosion, and toxic vapour dispersion scenarios. Individual and societal risk contours are calculated and benchmarked against international risk tolerability criteria adopted by the Nigerian upstream regulator as proxy standards. Frequency analysis draws on failure rate data from the European Loss Prevention Bulletin and offshore and onshore incident databases, adjusted for Nigerian operating conditions through expert judgement factors. Results indicate that three specific tank overfill scenarios present individual risk levels above the typical acceptability threshold at the facility boundary. Recommendations target the improvement of high-level alarm testing procedures, addition of an independent high-high level trip system for two product tanks, and revision of the emergency shutdown procedure for pipeline loading arms. Keywords: quantitative risk assessment, petroleum storage terminal, Layer of Protection Analysis, consequence modelling, Akwa Ibom State