Background: Chemical process industries are among the most important industries which have been faced with many catastrophic accidents. This study aimed to analyze the root causes of the accidents in a chemical process industry. Methods: This study has been implemented in a chemical process industry using Tripod Delta technique in 2019. The implementation steps included forming an accident analysis team, reviewing accident documents and records, compiling Tripod Delta questionnaires, and determining the general failure types (GFTs) involved in the accident. Results: The results showed that procedures (PR), training (TR), and maintenance management (MM) have the most discrepancies in the accident (213, 212, and 202 respectively). In addition, communication (CO), hardware (HW), and design (DE) have the least discrepancies (33, 40, and 76 respectively). Conclusion: The findings indicated that training, standard, and safe procedures as well as maintenance management are determining factors in preventing industrial accidents. Therefore, in order to reduce the accident rates in industries, close attention should be paid to these areas and its indicators with a process and risk based approach.