Scale | Severity | Detection | Frequency | Frequency/Indicator | |
10 | Highly hazardous | Non-detectable | 1 in 2 | Very high | 0.5 |
9 | Hazardous | Very improvable | 1 in 3 | Very high | 0.33 |
8 | Very high | Improvable | 1 in 8 | High | 0.125 |
7 | High | Very low | 1 in 20 | High | 0.05 |
6 | Moderate | Low | 1 in 80 | Moderate | 0.0125 |
5 | Low | Moderate | 1 in 400 | Moderate | 0.0025 |
4 | Very low | Moderately high | 1 in 2000 | Low | 0.0005 |
3 | Minor | High | 1 in 15,000 | Low | 6 × 10−5 |
2 | Very minor | Very high | 1 in 150,000 | Very low | 6 × 10−6 |
1 | None | Highly detectable | 1 in 1,500,000 | Remote | 6 × 10−7 |