They hope to detect illegal or dangerous shipments by spotting something unusual about the package or the shipper. Some security experts give the companies good marks while pointing out the limitations of their approach. FedEx and UPS say only that they have security measures in place and co-operate with law enforcement. Cargo on passenger planes must be screened, usually by computed-tomography scanners although explosive-trace detection and dogs are also used, said Jeffrey Price, an aviation-security expert at Metropolitan State University in Denver. The U.S. then banned large toner and ink cartridges from passenger planes and ordered new inspections of high-risk shipments on cargo planes coming into the country.

Source: National Post March 20, 2018 19:41 UTC