1. Health Risk = Consequences X Probability (Likelihood)
Acute - Estimated on the basis of experience and or evidence that a certain outcome has previously occurred
Chronic - Estimated based on the historical evidence that excess exposure has occurred
In order to determine the health risk to the business (high, medium or low) the hazard rating will be plotted against the probability (likelihood) of the effect in industry. This assessment is based on historical evidence, and will assess the business risks. It does not assess the individual’s risk of exposure to the agent.
For the purposes of using the RAM for Health Risk Assessment, the RAM principle, as explained in the Yellow Guide works for Acute Health Hazards. However, for Chronic Health Hazards, because of the latency period that may occur before an actual endpoint is noticed (e.g. cancer, chronic respiratory disease etc.) it is more useful to describe likelihood in terms of whether an overexposure to the health hazard has occurred, e.g. carcinogen, rather than whether the ill health effect has occurred, e.g. cancer.
Experience has shown that health, and environmental, hazards are not always assigned a RAM risk rating which reflects the full extent of their potential consequences. This is particularly true of hazards with chronic effects. To allow for this, the estimate of ‘Likelihood’ for chronic health risks should be based on the historical exposure evidence. It is also recommended that decisions on Likelihood should tend towards the higher category. This is because the RAM assessment is only a screening mechanism to identify priorities. Where there are uncertainties, it is prudent to move to the next stage to begin more detailed assessment
Consequence
Estimate of what could happen (acute and chronic)

2. Risk Assessment Matrix
Manage for continuous improvement
Incorporate risk reduction measures
If a consequence has been heard of in the world, then by default you are immediately within the B Likelihood Category.
You need to be pragmatic in applying Likelihood categories. Don’t forget that a detailed review of controls to reduce employee exposure is only carried out if the risk is medium or high. Low risks are managed for continuous improvement via standard procedures and staff competences. Remember that hazards which are assessed as Low risk may have a legal exposure limit which requires confirmation of compliance.
Intolerable – investigate alternatives