In the paper, on the basis of the conducted analysis of the dynamics of the spread of dangers in the context of evolutionary development of society, it is determined that the global problems have become complex, which appears in interdependence of natural, technogenic, socio-political, economic, scientific-technological and other risks. The main source of danger, at the present stage of development of society, is an industrial environment.The analysis of known theoretical studies to appearance of dangerous is carried out and it is defined that none of considered theories can be treated as absolutely correct and generally accepted. First of all the conceptuality of given theories that is, limited practical usage, second of all the insufficient attention and underestimation of the role of the "human factor" as a fundamental factor in the process of creating dangers are the meanest drawbacks. Notice, that in the European Countries exist around 100 differents methods of assessment of the risk of occurrence dangers, according them quantitative measurement of the risks is carried out by the three meanest methods: statistical, expert and analog.British Standard BS-8800 (GB), risk assessment based on probability-loss matrix (GB, France, Latvia, the USA, Australia), construction of risk assessment scales (Germany, Finland), the methodology of the National Research Institute of Occupational Safety and Health (NRIOS) in Ukraine, risk score (the USA), risk assessment code (GB), method of verbal functions (European Union),assessment of occupational risks by the Elmer system, risk assessment based on requirements level ranking (OIR index) are the most often used methods for the risks evaluation. On basis of the analysis of the above mentioned methods, two main problems were identified. The first problem that exists in the risks evaluation of occurrence dangerous is the lack of a unique unified methodology.The second problem is the underestimation of the significance of the "human factor" in the "man-machine" system. It is pointed out that due to underestimating the role of the "human factor" as a key component of risk one cannot consider any of the known risk assessment methods to be effective and universally accepted. Based on conducted research, the need for a principallynew universal and effective methodology for quantitative risk assessment is identified.
Quantitative Risk Assessment of Biogas Plant – Determination of Assumptions and Estimation of Selected Top Event