When performing risk assessment on chemical hazards, such as fire and explosion, it is necessary to comprehensively identify the hazards and the scenarios leading to the occurrence of fire and explosion in order to consider specific risk reduction measures. It is required to utilize specialized knowledge about the characteristics of chemical substances related to the reaction process, ignition phenomena, and associated functions. Especially in medium-sized enterprises (SMEs), it is difficult to perform risk assessments for hazardous chemicals. This paper proposes a simple hazard scenario identification method focusing on the three elements of combustion (fire triangle), that is fuels, ignition source, and oxygen. Hazard scenarios of causing a fire or explosion when combustible chemicals are handled in an open area can be classified into four patterns. Based on the confirmed pattern for hazard scenarios, the triggering event could be comprehensively identified, and the hazard scenario leading to the occurrence of fire and explosion could be easily identified. Furthermore, by considering workplace condition, etc., the occurrence of industrial accidents and the spread of damage to the surrounding area could be included in the hazard scenario.