The safety of a chemical process plant can be achieved through plant-lifecycle engineering (Plant-LCE), which is performed from research and development to plant safety design, construction, and manufacturing (production and maintenance) stages, as well as at each engineering stage. To expressly provide a framework that can perform coherent decision making through the plant-lifecycle and at each stage, it is effective to develop a business process model that systematizes the activities related to engineering, production, etc. and represents the ideal and consistent business flow for each company. The safety division of the Society of Chemical Engineers Japan (SCEJ) has advanced the development of a business process model of Plant-LCE which consists of the business process models for process safety design, production management, plant maintenance, and process safety management (PSM). The original business flow for each company can be developed by referring to these business process models as reference models. This business flow can clarify what kind of activities should be performed at each stage, what kind of information on an activity should be collected, how it should be conveyed to other engineering activities, etc. In this paper, we review the challenges in developing business process models to realize a PSM environment logically.