ABSTRACT
The use of control charts in a system to prevent the risk of accidents is discussed here. Data of offshore operational units of an oil company are analyzed and trends of the process of generation of accidents are evaluated employing the charts built. The practical limits to the possibility of treating each type of accident separately are discussed. To develop a single measure aggregating occurrences of different severity is explored the idea that all types of accidents occur due to working conditions typical of the operational environment that affect individuals as a group. The assignment of numerical values to importance of occurrences of different types of accident is based on the value of the risk of a fatal accident, the protection against which is composed by a number of basic elements of security. The loss of a fraction of such protection determines the risk of each other kind of accident.
