Process of HIRARC requires 4 simple steps :
a. classify work activities;
b. identify hazard;
c. conduct risk assessment (analyze and estimate risk from each hazard), by calculating or estimating;
- likelihood of occurrence, and
- severity of hazard;
d. decide if risk is tolerable and apply control measures (if necessary).
Likelihood is an event likely to occur within the specific period or in specified circumstances.
This value is based on the likelihood of an event occurring. You may ask the question “How many times has this event happened in the past?” Assessing likelihood is based worker experience, analysis or measurement. Likelihood levels range from “most likely” to “inconceivable.”
For example, a small spill of bleach from a container when filling a spray bottle is most likely to occur during every shift. Alternatively, a leak of diesel fuel from a secure holding tank may be less probable.
Table A indicates likelihood using the following values
