Identifying the causes of disasters, emergency situations, and incidents is a necessary condition for avoiding similar situations in the future. The methods of the theory of catastrophes are constantly being improved, there is a need to return to some historical negative events, the analysis of which contributes to the discovery of new grounds, facts, consequences that update the essence of the emergence of an emergency situation, and allow managers, specialists and employees of any industry, association, enterprises or organizations to make security decisions. This study revealed cause-and-effect relationships in the chronology of events that led to the "Nedelin Disaster" - the worst and most fatal disaster in the rocket and space industry of the Soviet Union and the world, when the Soviet intercontinental ballistic missile R-16 exploded during a test at the start during launch preparation. The assessment of the occupational risk of hazards was carried out on the basis of the "bow-tie" model, which is a schematic method of describing and analyzing the ways of the development of a dangerous event from causes to consequences by combining the "fault tree analysis" and "event tree". This model is widely used because of its convenience and simplicity in representing the cause-and-effect relationship between a hazard, a hazardous event, and consequences. Its visualization helps to clearly demonstrate the process of managing occupational risks by determining the number of barriers (protective or preventive measures) that are placed on the path between danger and a dangerous event and a dangerous event and consequences. The number of barriers makes it possible, on the one hand, to establish an estimate of preventive and protective measures for labor protection, and on the other hand, to influence the probability of the occurrence of a dangerous event. The highlighted events, their analysis, understanding of the dangers and knowledge of the consequences of a dangerous event made it possible to build a model of the realized risk of danger with the definition of the main dangerous conditions that led to the disaster. In particular, the main dangerous conditions are: supplying fuel to the engine, installing the electric battery one hour before launch, giving an electric signal to start the rocket engine one minute before the crash and 15 minutes before launch. As a result of the combination of all three dangerous conditions, the probability of a dangerous event has increased to 100%. Another dangerous condition was the presence of a significant number of people to launch the rocket, which led to a significant severity of casualties - from 20 people to 100 or more. It is important that each of these factors alone could not affect the danger of preparing the rocket for launch, but their combination led to the disaster.
Keywords: disaster, danger, cause-and-effect relationships, risk, risk assessment.