This paper aims to develop a system dynamics model in order to formalize causal interdependencies between safety factors (technical, organizational and human). These factors define safety conditions in a complex industrial system. It is a systemic approach founded on the method of system dynamics and the case study is a storage unit for chemical products located in Morocco. System dynamics using VENSIM® software has been applied to assess the safety of the storage unit by modeling the activity of the industrial system. Through simulation, users can define deviant scenarios in order to improve safety of the industrial system and implement managerial tools involving organizational, technical and human factors.