Safety engineering is a cross-domain discipline that requires knowledge and information of different kinds. Process safety engineering for example needs knowledge of fields like mechanical engineering, chemistry, chemical engineering, control and automation, etc. Knowledge of these domains along with the specific concepts related to the safety discipline allows to perform process safety design, analysis and management. In order to increase the efficiency of these processes and use and reuse information available from the safety community a common understanding of the concepts and its relations is needed. In this work, a chemical process safety ontology, OntoSafe, is presented. It has concepts of very different topics related to safety, from toxicology to safety instrumented systems. It is intended to be a live project that is available to the safety community.