The expansion of global supply chains has meant an exponential growth of the risk of disruptions to those networks. Catastrophic events, such as the Japanese earthquake and Hurricane Katrina, have highlighted the need for analysis of disruption risk and development of mitigation plans to cope with them. In addition, trends such as globalization, heavy reliance on transportation and communication infrastructures, and lean manufacturing have led to an increase in the vulnerability of supply networks. Furthermore, nodes on supply chains are very often interrelated, causing these vulnerabilities to propagate rapidly.