Exclusive: X-ray is the answer, says Todd Research

December 15, 2022


Jason Wakefield, Sales Director at Todd Research Ltd, charts the evolution of postal threats and concludes safety lies with technology

In a world so heavily reliant on email and mobile phones, it can sometimes be easy to forget how profoundly the postal service has transformed society as a whole, opening up new channels of communication and trade for centuries.
Unfortunately, much like online networks being susceptible to hacking, the postal system is also vulnerable to misuse by individuals and organizations with ill intent.
One of the first high profile mail incidents dates back to 1712, when the Earl of Oxford was sent a package containing a number of cocked pistols rigged to fire as soon as the lid was opened.
Luckily, this plan was foiled, and the device was disarmed before reaching its intended target, but it certainly served to highlight the postal service’s potential for harm if abused.
It goes without saying that boxes of guns are not the modus operandi of most terrorist organizations these days, and modern mail threats are much more likely to contain explosive devices or harmful substances, such as anthrax or ricin.
As threats continue to evolve, so too do the methods of detection, and the postal system is safer than ever thanks to experienced personnel working with state-of-the-art X-ray scanners and sophisticated software packages.
This article looks at the evolution of mail threats, and the development of innovative detection technologies to keep the public safe.

Mail threats
The IRA and the Unabomber may be among the first names that spring to mind for many at the mention of mail bombings, with such high-profile incidents of the late 20th century seared into the public’s collective consciousness. However, widespread incidents occurred much earlier than this.
Perhaps the first coordinated use of mail bombs can be attributed to the Suffragettes in the early 1900s, with a bombing campaign instigated by the Women’s Social and Political Union to target infrastructure, churches, the government and the general public as part of its crusade for women’s suffrage.
Although varying bomb construction methods were used during this time, a number of these devices contained nitro-glycerine, a potent but highly volatile explosive.
In fact, some of these bombs were so unstable that they ended up exploding in mailboxes before reaching the intended target. Early parcel bombs like these were often improvised devices, comprised of whatever materials were available to hand.
This changed in the 1970s, when the IRA developed a somewhat standardised approach, disseminating ingredient lists and detailed ‘recipes’ to its various factions.
This not only simplified the build process – opening up the manufacture of parcel bombs to a wide array of less skilled individuals – it also solved the volatility issues, increasing the chances of a package reaching its desired target.
As time went on, and the postal service became more competent at spotting suspicious packages, it forced terrorists to think of innovative ways to conceal their devices, exemplified in the case of the Unabomber. Theodore Kaczynski – who remained at large in the US from 1978 until 1996 – disguised his 16 bombs as a range of objects, including presents and books, to increase his chances of outwitting law enforcement and the postal service.

Mail bombs
The mail bombs described so far have generally been ‘victim activated’, meaning the physical act of opening the package is what triggers the explosion. However, the advent of mobile phones has given terrorists easy access to remote control of bomb triggering, allowing devices to be detonated at any point during transit or delivery.
The powdered spores of Bacillus anthracis – the cause of the infectious disease anthrax – is particularly well known to the public, in part due to several high-profile attacks covered by the media.
In one such incident, just a week after the 9/11 terror attack, letters containing powdered spores were mailed via the US postal system, resulting in 22 people contracting anthrax – including 12 mail handlers – five of which died.
These substances are particularly hard to detect, as only a tiny amount is needed to kill many people once airborne, allowing such quantities to be easily concealed in letters and packages.
Powder attacks are becoming increasingly common – making up most modern-day postal threats – but thankfully most turn out to be hoaxes. However, even these can be an effective scare tactic and, in 2018, a package containing a suspicious (later found to be harmless) powder was mailed to Prince Harry and Megan Markle, sparking concerns of a potentially deadly attack.


Manual detection
Mail threats come in many shapes and sizes, and until the widespread deployment of postal screening equipment, physical inspection by experienced individuals was the only way to gain any insight into a parcel’s contents.

The tell-tale signs of suspicious packages are:
• Shape: Explosive devices tend to contain irregularly shaped items – such as power supplies, detonators and trigger switches – giving the package an unbalanced look, feel and weight.
• Smell: Certain explosives can give off distinctive sweet aromas, like the smell of almonds or bananas.
• Stains: Some explosives can ‘sweat’ when exposed to temperature variations, leaving greasy or oily marks on the packaging.
• Seal: Packages containing toxic powders – such as anthrax, ricin and caustic soda – are generally heavily sealed with tape to prevent the contents escaping during transit.

Detection equipment
The postal service had to rely on manual detection alone until 1972, when the first X-ray mail scanner was introduced. Early iterations of these systems were extremely power hungry, and could only provide low resolution images, viewable to the operator via a series of mirrors.
They were also relatively unsafe compared to modern systems, due to minimal containment of the hazardous radiation used to generate the images.
Fortunately, modern X-ray cabinet scanners are far safer and much more efficient than their ancestors and are now a common sight in mailrooms around the world. These instruments can produce extremely high-resolution images and are capable of pinpointing even the smallest and most well concealed threats.
In fact, they can often produce clearer images than most airport baggage scanners – and at a lower power – since X-rays can more easily penetrate postal items than suitcases. State-of-the-art systems are often equipped with smart software and added functionality that make it even easier to spot suspect packages, including the ability to detect tiny amounts of hazardous powders.
This is especially useful to identify substances like ricin and anthrax – which are harmful even in minute quantities – before they can be released into the environment.
There are now systems available that are able to spot as little as three grams of a substance, a feat made even more remarkable by the fact that they can do this while scanning bundles of more than 50 letters simultaneously.

Continued protection
It can be intimidating to think about the ways that the postal service can be used to deliver harm. However, it is prudent to remember that, even as terrorist organizations and nefarious individuals find new ways of disguising harmful packages to thwart the postal service and law enforcement, innovative companies are constantly developing state-of-the-art detection solutions in response to these threats. The combination of skilled personnel, high resolution X-ray imaging equipment and the continuing development of powerful machine learning algorithms means it that it is harder than ever for mail threats to evade detection. With such cutting-edge technologies installed in mailrooms around the world, it may be a comfort to know that the postal system is only getting safer with every passing day.

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