The introduction of digital technology in industries creates new security threats that can lead to undesirable safety accidents. Thus, analyzing these threats during safety analysis becomes an important part for effective risk evaluation. However, nowadays, safety and security are assessed separately where they should not be. This is because a security threat can lead to the same dangerous phenomena as a safety accidental cause. In this paper, a new method that considers safety and security for probability evaluation during industrial risk analysis is proposed. This approach combines Bow-Tie Analysis (BTA), commonly used for safety analysis and the Attack Tree Analysis (ATA), recently introduced for security analysis of computer control systems.The combined use of BT and AT provides an exhaustive qualitative investigation of security and safety scenarios, and a qualitative evaluation of the likelihood of these scenarios. The definition of BT and AT combined, and the mathematical formulas for likelihood quantification are presented. The application of this approach is demonstrated using the case study of a risk scenario in a chemical facility.