From Risk Perception to Actionable Controls: A Hybrid Occupational Risk Analysis and Assessment Approach in a Combined Cycle Power Plant Construction

Occupational safety management in combined cycle power plant (CCPP) construction requires methods that can both prioritize multiple tasks and explain why critical scenarios arise. This article presents a hybrid case-study methodology integrating questionnaire-based semi-quantitative 5 × 5 risk matrices with task-focused HAZOP. An anonymous structured questionnaire was completed by 105 workers at a CCPP construction site (response rate 75.0%), covering eight major construction activities and four occupational groups. Likelihood and severity ratings were processed in RStudio 2025.09.2 to produce 5 × 5 risk matrices, distribution plots, and “High + Critical” prioritization indices. The highest-ranked tasks were then subjected to HAZOP in PHAWorks RA Edition (Version 1.0.9834). “Work at height” emerged as the highest-ranked perceived-risk activity across all groups, followed by lifting/load handling, chemicals/flammables, and electrical works. Safety technicians tended to assign more conservative ratings than labor personnel, indicating role-dependent differences in risk perception. The HAZOP analysis suggested that the plausible HAZOP-informed accident scenarios and control weaknesses were not only technical but also organizational, including failures in permit-to-work, lockout/tagout, exclusion-zone control, fall protection, and chemical handling discipline. The integrated hybrid workflow bridges rapid semi-quantitative prioritization and structured causal analysis, supporting the translation of field-based perceptions into targeted and actionable safety controls for dynamic energy-project worksites. The findings highlight the critical role of organizational discipline alongside technical measures and support the integration of structured risk assessment within occupational health and safety management systems in dynamic construction environments.