What is the object of safety science?

•There are ten kinds of main viewpoints on the object of safety science.•There is yet no universally accepted object of safety science.•Four evaluation criteria of a proper object of scientific research are proposed.•No proper object of safety science completely fulfilled the four evaluation criteria.•The new term “hazard-target system” can be viewed as the object of safety science. One of the symbols of a mature science is that it has an explicit object of scientific research. It is necessary for safety science to have a well-defined object that can be studied. The aim of this paper is to answer the question “What is the object of safety science?” Many safety researchers are concerned about this issue. The main viewpoints on this issue are reviewed, classified and discussed. However, there is yet no universally accepted object of safety science. Four evaluation criteria of a proper object of scientific research are proposed to avoid falling into the trap of solipsism. According to these evaluation criteria, there is no proper object of safety science at present. Although the focuses of safety science have been dynamic in its history, the object of safety science should be clear and uniform in the future. Therefore, a new term called a “hazard-target system” as the object of safety science is introduced and discussed based on related safety models. It is concluded that a hazard-target system can be viewed as the proper object of safety science.