Monitoring progress of accident scenarios, and effectiveness of control measures is a main goal of safety indicators. From an overview of scientific literature one may conclude that indicators do not logically relate to current safety theories and models, their relation with accident processes is far from perfect, and a a "silver bulleta " has not been identified yet. Professional literature shows another picture, and divides indicators in leading and lagging. This distinction seems convincing. Not only companies, but also regulations adopted this division. Currently many indicators used in industry generate a number, while the relation with accident processes is questionable at least. In addition, it can be expected that regulators of major hazard companies will ask to identify and implement both lagging and leading indicators, and anchor these indicators in a safety management system. The subject a "safety indicators" will remain in the spotlight in the time to come. This presentation will focus on a review of scientific and professional literature. This article is written in a "praesens historicuma ", and based upon recent articles (Oostendorp et al., 2016, Swuste et al., 2010, 2014, 2016 a,b, 2018).