Worried retailers, including Wal-Mart and Target, fear proposed regulations by the US Customs Service will inflict heavy costs on their supply operations and make them targets for theft and terrorist activities. If it gets the go-ahead, the ruling will require retailers to collect and make public information on their cargo 24 hours before it leaves foreign ports for the United States. The data would have to be more detailed than at present, and customs agents would be able to examine the data and order searches of suspicious shipments before the containers are loaded.