
300 ◾ Risk Assessment and Security
Table 7. 27 Risk Rates Based on Engineering Judgment of the Event Tree
Analysis for Oil and Gas Pipelines
Symbol Event Tree List of Events Risk Rate
PP1 Terrorists situated themselves near oil and gas
“gathering lines” (8 in. diameter pipelines)
0.25
PP2 Terrorists situated themselves near oil and gas “trunk
lines” adjacent to shorelines
0.25
Pa Lack of intelligent devices for immediate defensive
actions against terrorists
1.0
Pb No sophisticated security measures and surveillance for
the oil and gas pipelines
0.20
Pc Lack of stringent policy and technology for security and
safety
0.40
Pd Agencies in charge of developing ...