The Department of Homeland Security (DHS) has issued an analytical "note" to U.S. law-enforcement officials cautioning that al-Qaeda terrorists have in the past expressed interest in attacking public buildings using a dozen suicide bombers each carrying 20 kilograms of explosives. The intelligence is based on recently discovered information about Al Qaeda training sessions conducted some year ago, so there is no reason to assume the threat is specific to this time.
ARC Analytical Comment: The London bombings of 2005 demonstrated how suitably radicalized individuals, with limited technical skills, can manufacture home-made TATP high explosive devices using readily available ingredients. And there is no shortage of vulnerable “public” targets which can be attacked in this way. A reasonably strong person should be able to carry a load of 20kg in a backpack without raising suspicion, and would blend in very well in a tourist environment, such as a major European city.
The effect of detonation of such a charge in a confined space, such as the ground floor lobby of a building, would be significant. Although unlikely to cause building collapse, there would be major loss of life, damage and injury beyond the immediate area of detonation, and significant damage to building management systems. Building security services, which are often located in or near a lobby, would also be paralyzed. It is likely that the lobby would be unusable as an emergency escape route for surviving building occupants.
In addition to considering proactive antiterrorism measures, those responsible for building safety and security should consider the following reactive components of a facility terrorism emergency response plan:
1. Evacuation via non-planned routes
2. First aid and rescue capacity in the event of security staff being killed or injured
3. Dispersal upon evacuation, rather than assembly (assembly presents a target for a secondary suicide attacker)
4. Floor wardens trained and exercised in the above
5. Road and transportation (fire and ambulance) gridlock if several coordinated attacks are concentrated in one locality
