Flexibility and reduced time-to-market are very important for the future of the process industries. The concept of modularization can address these challenges but requires new approaches for the engineering workflow of process plants, particularly for safety engineering. One of the major challenges stems from the fact that the modules are engineered before the modular plant is composed. Consequently, important information for safety engineering of the modules is not yet available. An approach to overcome this by integrating safety engineering into the engineering process of modular plants is presented in [17]. It is based on a structured handover of safety knowledge from the module designer to the modular plant owner. This paper discusses the handover process using the module type package in more detail with special focus on the representation of safety related knowledge. Adequate representation of safety knowledge enables fast and seamless integration during the engineering of the modular plant and allows for efficient selection of appropriate safety functions in the modules used. A survey of approaches for safety knowledge representation is presented and the various options are evaluated in light of collected requirements. The conducted research shows that existing approaches for knowledge representation have to be extended to meet the requirements of modular plant safety engineering.