The cause of a significant part of technogenic catastrophes is destruction of hazardous objects. This destruction occurs as a result of: catastrophic failures, operator errors, natural influences; terrorist activities. A methodology of modeling and investigation of safety for Complex Technical Systems is proposed. Complex Technical Systems are considered as unique technogenic objects which are designed in one or two instances, implementing extreme technologies and are subjected to influence of mechanical, physical and chemical factors. The generalized cause-and-effect complex and the scenario of violation of reliability and safety for such systems are formulated. Dynamic models related to formation of system's states are grounded – from the initial defectiveness of the construction to the damages, destruction, failure, pre-emergency, -emergency and possible technogenic catastrophe. A concept of an intelligent program system, which is intended for computer-aided investigation of reliability and safety at all stages of existence, has been developed. The results obtained provide for efficient and qualitative investigation of revealing of hazards and grounding techniques and aids for provision of reliability and safety.