Chemical process industries are threatened with accidental and intentional adverse events because of the storage and operation of large quantities of hazardous substances. Safety and security barriers play important roles in protecting the chemical plants from safety and security-related undesired events and mitigating the potentially catastrophic consequences. Aiming to identify major accident scenarios in terms of both safety and security and determine the corresponding safety and security barriers, a novel approach based on MIMAH (methodology for identifying major accident hazards) and historical data analysis is proposed. In this approach, the MIMAH is extended to identify accident scenarios related to safety, physical security, and cyber security by using a combination of bow-tie analysis and attack tree analysis. Then, data analysis is conducted to supplement the identified major accident scenarios before the critical safety and security barriers can be identified and illustrated based on an integrated bow-tie and attack tree model. This study helps to identify major hazards considering both safety and security perspectives and supports the integrated assessment and management of safety and security barriers in the chemical process industries.