Liquid Explosives – The Threat to Civil Aviation and the European Response

Abstract

This paper deals with the specific group of homemade liquid high explosives in relation to aviation security. The sudden and irrefutable focus on homemade explosives and liquid explosives in particular after the 2006 defeated attacks in London, made the aviation security community realize that the security system and equipment were not optimized for this particular kind of substances. It is now generally accepted that hydrogen peroxide based liquid explosives (HPOM) pose a terrorist threat to civil aviation. It is easy, cheap and relatively safe to make effective HPOM IEDs. It is a high explosive of increasing and serious interest to terrorists and has been used recently. In comparison to the well-know 'old fashioned' military and commercial explosives, liquid explosives and in particular HPOM are more difficult to detect because they are less well-defined by their chemical properties (poorly controlled manufacturing), they contain no nitrogen and their physical appearance (like shape, color) is poorly defined an hardly unique, in part because they need a container like a bottle or can or plastic bag etc. Both Europe and USA introduced late 2006 the so-called liquids-regulations at checkpoints to counter this threat, but this may become harder to sustain in the future. Several countries contribute to the search for and development of existing and new technological solutions with the aim to relieve the measures and increase the effectiveness of the overall security process. The final solution would be to be able to detect liquid explosives inside a carry-on bag at operational speed. This is not yet possible with current technology. A second best option for the time being would be to be able to detect liquid explosives inside the 11 plastic bag. Even now existing technologies (like X-ray transmission, trace and chemical) can help in detection, sometimes after tuning to the specific problem. Inspection of single bottles or the 11 plastic bag offers the best options today, but detection inside the carry-on bag in operation (speed requirements, false alarm behavior) offers prospects too. Further development in combination with ongoing research into the characteristics of homemade explosives, specifically liquid explosives, will probably make the balance shift towards technological solutions in the near future. © 2008 Springer Science + Business Media B.V.