Namely: (1) the possibility of occurrence of accidents or dangerous events; (2) conditions exposed to such dangerous environment; (3) consequences may occur in the event of accidents. The formula is expressed as:
D＝L×E×C
式中D－风险性；
In the formula, D represents risks
L－风险发生的可能性；
L represents the possibility of occurrence of risks
E－风险发生的频率；
E represents the frequency of occurrence of risks
C－发生事故或危险事件的可能结果。
C represents the possible consequences of occurrence of accidents or dangerous events
表1 风险发生可能性分值（L）
Table 1 Value of possibility of occurrence of risks (L)
|
分值 Value |
风险发生的可能性 Possibility of occurrence of risks |
分值 Value |
风险发生的可能性 Possibility of occurrence of risks |
|
10 6 3 1 |
完全可以预料 Entirely predictable 相当可能 Quite likely 可能，但不经常 Possible, but not frequent 可能性小，完全意外 The possibility is small, completely unexpected |
0.5 0.2 0.1 |
很不可能，可以设想 Quite impossible, can imagine 极不可能 Highly unlikely 实际不可能 Actually impossible |
表2 风险发生的频率分值（E）
Table 2 Value of frequency of occurrence of risks (E)