13) Tell participants to move onto to estimating the likelihood of each of the identified
accident situations actually taking place. At this step of the exercise, participants will
estimate the probability of occurrence of each identified accident situation taking into
account the following scale:
1. Practically impossible (not expected to happen during the lifespan of the operation)
2. Unlikely (never happened, but could occur, perhaps during the lifespan of the
operation)
3. Rarely (expected to occur at least once every 10 years)
4. Regularly (expected to occur at least once per year)
5. Frequently (occurring more than once per year)