To determine the risk, you have to look at 3 factors.
- Consequence – The most likely outcome if control measures failed and an incident occurred. (It is not the worst case scenario.)
- Exposure – How often the process takes place. This is not how often, for example, “you spill a chemical on yourself”, but how often you “undertake the process using that chemical”.
- Probability – The likelihood that the consequence you have chosen will occur while undertaking the process.
Consequence – the most likely outcome from an incident event. Consequences can be personal injury, environmental or economic damage. They range from Minor (e.g. first aid, small bruises) to Catastrophe (e.g. many fatalities, extensive environmental/financial cost) with several categories in-between.
|Category||Human injury||Financial cost||Work||Environment|
||Numerous fatalities||Extensive financial loss (greater than $5m)||Major disruption to operations||Extensive environmental damage|
|Disaster||Multiple fatalities||Significant financial loss ($1-5m)||Major disruption to operations||Major environmental damage|
|Very Serious||Single fatality||Significant financial loss ($500,000 to $1m)||Significant production disruption||Significant environmental damage|
|Serious||Serious injury (permanent disability, amputation)||Substantial financial loss ($50,000 to $500,000)||Notable production disruption||Serious environmental damage|
|Substantial||Disabling injury requires medical treatment||Notable financial loss ($5000 to $50,000)||Slight production disruption||Minor environmental damage|
|Minor||First aid treatment – minor cuts, bruises or bumps||Negligible financial loss (up to $5000)||No effect on work||Negligible environmental damage|
Exposure – how often an individual undertakes the process. Your exposure to a process may range from Very Rare (has never happened yet) to Continuous (occurs many times per day).
- Very Rare
- Not known to have occurred
- Occurs rarely, but has been known to occur
- Infrequent/ Unusual
- Occurs between once per month and once per year
- Occurs between once per week and once per month
- Occurs approximately once per day
- Occurs many times per day
Probability – how likely the consequence will occur when an individual interacts with hazard. Probability ranges from Practically Impossible to Almost Certain.
- Almost certain
- The most likely and expected result if the hazard-event takes place
- Quite possible
- Quite possible, not unusual, even 50:50 chance
- Unusual but possible
- Unusual but possible sequence or coincidence
- Remotely possible
- Remotely possible coincidence
- Conceivable but unlikely
- Has never happened after many years of exposure, but is conceivably possible
- Practically impossible
- Practically impossible, has never happened before