The rapid growth in digitalization and automation results in industrial plants increasingly interconnected through IT (Information Technology) and OT (Operational Technology) networks. While this interconnectedness offers significant operational advantages, it also makes plants vulnerable to cyber-physical attacks. Such attacks can lead to major accidents like fires or explosions. Currently, scenarios resulting from cyber-physical attacks are inadequately considered in process hazard analyses, such as HAZOP studies. To protect plants against these threats, a comprehensive combined safety and security analysis is required. Therefore, the novel Safety-Cyber-Security-Evaluation (sCSE) methodology is presented, which builds upon existing HAZOP studies. The sCSE methodology identifies potential safety-relevant scenarios resulting from cyber-physical attacks, determines potential attack vectors, and derives appropriate security countermeasures. Finally, the security countermeasures are prioritized for implementation.