In other industries, particularly metals recycling, plants can be incapacitated for years, a blow from which they may never recover, if radiation sources are allowed to creep into the process.

America’s Homeland Security Department wants to spend, over the next five years, more than $1bn on radiation detection equipment to scan containers and cargoes entering the country. Although the scale of the spend was challenged earlier this year, it nevertheless points out the perception of risk on that side of the Atlantic.

The challenge to the spend is a response to the belief that currently-available detection equipment can’t tell the difference between illicit radiation sources with the capability to become part of a dirty bomb, and innocuous substances with naturally-occurring levels of radiation.

But that’s when they’re hidden inside a container; the dilemma is removed entirely for grab crane operations because the cargoes they unload will never be those items – such as ceramics, bananas, or even cat litter.

However, visibility of the cargo isn’t enough, since radiation sources aren’t necessarily visible to the naked eye. Detection devices can be fitted to grabs, which can be extremely useful, because they can identify sources in individual ‘bites’ of the cargo, which can then be isolated before any harm is done.

Companies such as Thermo Scientific (America) and Radcomm (America and Europe) market them, and claim they’re effective and easy to operate, continuously comparing the level of background radiation with the load, and sounding an alarm in the crane cab to alert the driver if one dramatically exceeds the other.

But another manufacturer, Corus Northern Engineering Services, part of Indian-owned steelmaker Corus, isn’t so certain. The company markets fixed and hand-held detection radiation detection systems under the name Redeem, and believes the harshness of the environment for such equipment, with the constant pounding of the grab driving into the cargo, can prevent the detection unit from functioning. The company claims greater ‘security of security’ is available from units a discreet distance from the sharp end of materials handling, mounted on conveyors or vehicle portals instead.