For nearly twenty years, travelers have had to limit the contents of their liquids to 100 ml when passing through security checks at airports. A constraint so familiar that it now seems inseparable from air travel. Yet a security expert argues that this rule is not truly based on safety logic. And the advent of new scanners at several major airports could well render this rule obsolete.
A measure born after a foiled attack plot
To understand the origin of this limit, one must go back to the summer of 2006. In the United Kingdom, authorities uncovered a planned attack involving liquid explosives that those behind it allegedly intended to conceal in beverage bottles and transport in carry-on luggage. The operation was fortunately thwarted before it could be carried out.
Following this discovery, British authorities initially prohibited passengers from carrying liquids beyond security checks. A few months later, in November 2006, the ban was eased: travelers were allowed to carry liquids, but only in containers with a maximum capacity of 100 ml.
This rule, later adopted at many airports worldwide, has since required passengers to remove their bottles from their luggage or present them according to the applicable procedures. Shampoo, cream, perfume or toothpaste must thus comply with this limit, or they will be discarded at security.
But for Bruce Schneier, a security technology expert and member of the Harvard Kennedy School, this logic is problematic. Interviewed on The Telegraph’s The Travel Expert podcast, he argues that the measure is primarily what he calls a “security theatre”.
“It is 100% security theatre. They do not do this with safety in mind; they do it as a compromise, which would make no sense if it were a real security issue”, he stated
New scanners are gradually making the limit obsolete
The expert points to a notable difference between how dangerous items are treated and how liquids are handled. In his view, a passenger who tries to pass through security with a weapon and is detected clearly cannot continue their journey as if nothing had happened. Meanwhile, for an illegal liquid, the situation is entirely different.
“If I go through airport security with a weapon and they find it… they ruin my day. If I go through security with a bottle of liquid and they find it, they throw it away and let me pass”, he explains.
Bruce Schneier also notes that this difference in handling makes the restriction peculiar: the liquid is deemed problematic enough to be banned on the plane, yet eliminating it at the checkpoint is sufficient to resolve the issue. “Here is something so dangerous that you cannot take it on a plane, but so harmless that security officers will throw it into a trash can next to them”, the expert states in the same podcast.
In practice, technology is starting to shift the balance. Next-generation scanners allow officers to analyze the contents of luggage more precisely, without passengers necessarily having to remove their liquids or electronic devices.
In the United Kingdom, several airports have already scrapped the 100 ml limit. In January, Heathrow became the largest airport in the world to abandon it completely after completing the deployment of the new scanners, as part of a £1 billion investment (approximately €1.17 billion). Birmingham, Bristol, Gatwick, and Edinburgh have also completed the installation of these devices.
