Hazard

A hazard is the source of potential harm — moving machinery, a chemical, a height, a pressurised system, a workload. Risk is the combination of likelihood and consequence when someone is exposed to the hazard. The distinction is operational: a hazard exists whether or not anyone is near it, and risk appears when a worker enters the hazard zone without sufficient control. Programs reduce risk by removing or isolating the hazard, not by warning people about it, because a warning does not change the consequence of the exposure.

The control hierarchy ranks the options from most to least effective: elimination, substitution, engineering controls, administrative controls, and personal protective equipment. A hazard controlled only by PPE is a hazard the program has chosen to live with at the bottom of the hierarchy, and an incident at that hazard is a predictable outcome rather than an accident. Identifying hazards is the input to a Job Hazard Analysis, and tracking them in a risk register is what makes them auditable. See risk, JHA, and hierarchy of controls.