ABSTRACT
Commonly, the safety engineers use essentially the same criteria used for other risk identication work. Safety hazards are measured in terms of the probability of occurrence and the severity of the occurrence. Criteria are established to numerically assign these factors to particular hazards and all hazards with a numerical gure above a certain value must be mitigated. The mitigation process seeks to nd ways to lower the probability of occurrence and/or severity of impact and may entail design changes, procedural prevention, or safety placarding, for example. Figure 28.1 is a variation on a gure provided MIL-STD-882B on the categorizing of safety hazards. The safety hazard assigned smaller hazard indexes for more serious hazards, which makes it very difcult to combine hazard indexes to form an aggregate program hazard index and track it over time with energy applied to reduce that index by reducing the probability of occurrence and seriousness of occurrence of those hazards.
