The Container Security Initiative (CSI) is a program launched by U.S. Customs and Border Protection after 9/11 to screen cargo containers for nuclear and radiological materials before they are shipped to U.S. ports. CSI places customs officials in foreign ports to target and prescreen high-risk cargo, working with host country officials. The goal is to prevent weapons of mass destruction from being smuggled in cargo containers and protect global trade while facilitating the flow of legitimate commerce. CSI currently operates in over 58 foreign ports.