Safety of functioning of technological system is defined not only a condition of the system, but also the correct work of all personnel serving system. The main responsible for accidents is, as a rule, not the equipment, not the organization of work, and the working person. Each person at the level of interaction with system can make wrong actions, make the wrong decisions, show dishonesty and negligence in performance of the duties. Such mistakes and errors will surely affect safety of functioning of all system.
ergonomic (are caused by inconsistency of characteristics of the person and machine part of system which can be shown in the form of requirement of such efforts for impact on governing bodies which the person cannot make).