Integrating Security Aspects in Multi-Hazard Risk Analysis for the Process Industries: a Quantitative Approach

Accidental scenarios connected to industrial activities are increasingly becoming more complex. These may stem from process upsets (safety), natural events (NaTech), or intentional attacks (security).Therefore, risk assessment should shift from single- to a multi-hazard approach. While safety-NaTech integration has advanced, security remains insufficiently addressed. This works aims at integrating security threats into multi-hazard risk analysis. It was structured in three phases. First, the attractiveness of process facilities to intentional attacks was studied by combining process safety with modern criminology approaches. Second, probabilistic tools for vulnerability assessment were developed, including event trees and fragility models. Third, the EU legislative framework for multi-hazard risk assessment was analyzed, focusing on Italy (deterministic approach) and the Netherlands (probabilistic approach). The analysis shows that safety and security are regulated separately, with land-use planning as the only connection to receptors. The three phases led to a quantitative methodology for integrated safety–security risk assessment, applying conventional metrics (e.g., local specific individual risk) to security for the first time. The findings confirm that a common quantitative framework is feasible and necessary to address evolving, interconnected threats driven by climate change and geopolitical instability.