It proved to be an extremely complicated and difficult problem. This is basically due to the unknown nature of the background within which contraband materials are hidden. There are several approaches to developing detection systems that can offer some solutions. The design and development of such systems depend on the specific application and the local environment. For example, devices that are designed to inspect cargo will differ from those designed to inspect small parcels or passengers' luggage.
Some applications demand mobility while others require fixed inspection stations.
In other words, while the underlying scientific principles are the same, the engineering development will be markedly different for different applications. It is experiencing a renaissance and many resources are being dedicated to it. The worldwide market for explosives detection systems is presently very large. Nov 1999 in Tores Brazil.