1. ISO 31000:2018
Risk management — Guidelines. This international standard outlines the risk management process. In section 6.5.2 'Selection of risk treatment options
' it is established that 'avoiding the risk by deciding not to start or continue with the activity that gives rise to the risk' is a primary option
which is most applicable to risks assessed as having extremely high likelihood and impact.
2. Health and Safety Executive (HSE). (2001). Reducing risks
protecting people (R2P2). London: HSE Books. This official UK government publication discusses the concept of tolerability of risk. It explicitly defines a region of risk that is "intolerable" and cannot be justified in any ordinary circumstances (p. 10
para 39). High-likelihood
high-consequence hazards fall squarely into this intolerable region
reinforcing the choice.
3. Hopkin
P. (2018). Fundamentals of Risk Management: Understanding
Evaluating and Implementing Effective Risk Management. 5th ed. Kogan Page. This text
aligned with CIPS curriculum principles
describes the top-right quadrant of the risk matrix as containing risks that "will require immediate action" and where the response may be to "terminate the activity" (i.e.
avoidance). This aligns best with the concept of an intolerable hazard.