U.K. terror plot exposes vulnerability of current detection systems

Published 10 August 2006

Governments have invested billions of dollars in explosive detection devices (EDs) and radiation detectors; the unfolding terrorist drama in London show that the current detection system has gaping holes which clever terrorists might exploit

The U.S. and other governments have spent billions of dollars on explosive detection devices (EDs), but the plot discovered today in London — allegedly, a group of would-be suicide terrorists were to smuggle liquid explosive on board several planes — shows that terrorist groups try to keep one step ahead of law enforcement forces. Liquid explosives could be tricky for terrorists to handle, but equally difficult for security checks to detect. The raw materials to make liquid bombs which require no detonator are readily available, but there is a need of some expertise in the effort to mix them in order to create a potent bomb.

Security experts say that for would-be suicide bombers the advantage of being able to buy the components of a liquid bomb may outweigh the problem that even a small shock could detonate the device prematurely. Explosive experts said further that many of the liquids used in bomb-making were hard to detect because they were colorless or could easily be treated and masked so as to pass off as, for example, milk in a baby’s bottle. Such liquids will likely be missed by a superficial search. These experts said that such a bomb could either be pre-prepared before the terrorist boarded the plane, and then detonated by a shock, or mixed on board and set off the same way. The prevent discovery, three or four terrorist could board the plane separately, each carrying another component, and the components could then be mixed on board.

A shock-triggered bomb is easier to conceal from ground security checkers, but it may go off prematurely (also, in the process of mixing the components on board, noxious gases such as nitric acid give off smelly fumes, so security personnel on board my intervene to halt the attack); a detonator-triggered bomb is more predictable, but can be discovered more easily by security scanners.

Experts point out that one example of a liquid bomb which could be made from readily available materials is dithekite, a mixture of nitric acid, water, and nitrobenzene. Other possibilities include bombs based on nitroglycerine or nitromethane, which is used in the oil industry to clear debris from wells.

-read more in Michael Peel’s FT report