The combination of the frequency, or probability, of occurrence and the consequence of a specified hazardous event. Note: The concept of risk always has two elements: the frequency with which a hazardous event occurs and the consequences of the hazardous event. Reference: IEC 60300-3-9 The chance of something adverse happening where 'something' refers to a particular consequence of the manifestation of a hazard. Risk reflects both the likelihod that harm will occur and its severity in relation to the number of people who might be affected, and the consequences to them. Reference: HarsNet working group, 2002, HarsBook, A technical guide for the assessment of highly reactive chemical systems, Frankfurt. Risk should be expressed in the most suitable terms. Some of the commonly used outputs are: (1) predicted frequency of mortality or morbidity to an individual (individual risk); (2) frequency versus consequence plots (known as F-N curves where F stands for frequency and N the cumulative number of people suffering a specified level of harm or the cumulative cost of damage) forsocietal risk; (3) the statistically expected loss rate in terms of casualties, economic cost or environmental damage; (4) the distribution of the risk of a specific damage level, presented as a contour plot, displaying levels of equal damage