Ports are critical gateways for the movement of commerce through the global supply chain. According to CBP data, in fiscal year 2012, about 11.5 million cargo container shipments arrived from more than 650 foreign ports-meaning roughly 31,000 maritime container shipments arrived each day that year. The facilities, vessels, and infrastructure within ports, and the cargo passing through them, all have vulnerabilities that terrorists could exploit. Every time responsibility for cargo in containers changes hands along the supply chain there is the potential for a security breach. While there have been no known incidents of containers being used to transport WMDs, criminals have exploited containers for other illegal purposes, such as smuggling weapons, people, and illicit substances.