Container Security Initiative

The Container Security Initiative (CSI) a.k.a. the 24-Hour Rule was launched in 2002 by the U.S. Bureau of Customs and Border Protection (CBP), an agency of the Department of Homeland Security. Its purpose was to increase security for container cargo shipped to the United States. As the CBP puts it, the intent is to "extend [the] zone of security outward so that American borders are the last line of defense, not the first."