Chia Poh Ling*, Lim Chin Chin, Michael Tay Ming Kiong
Joint 9th ISADE/4th Finex International Symposium on the Analysis and Detection of Explosives,
Paris, France, July 2007 (poster presentation)
Objective: To present case studies of incidents in Singapore where common chemicals were used to make improvised explosives devices (IEDs). The ingredients used, effects of the explosions and reconstruction of the IEDs would be discussed.
Case 1: A passenger boarded a public bus with two shopping bags at around 8.30 a.m. He moved to the rear of the bus and left one of the bags there. Before the bus reached the stop, white smoke began to pour out of the abandoned bag. Remnants of a badly deformed and burnt bottle with a green plastic screw cap and 660 g of dark powdery material were recovered from the scene. The base of the bottle contained a colourless, acidic liquid which was found to be concentrated (37%) formalin. The powder was found to contain potassium permanganate and its products of reaction. Potassium permanganate and formalin react exothermically to produce formaldehyde, an irritant and lachrymatory gas.
Case 2: At about 1.40 a.m, a man saw someone walk past his house and threw a 500 ml plastic bottle containing coloured sand-like material into his living room. He picked up the bottle and threw it out just as it exploded. A partially burnt, distorted bottle, a bottle cap, some yellow powder and the victim’s clothing were recovered at the scene. The damages in the bottle suggested that it had undergone burning and exploded. The moist brownish black material inside the bottle was found to contain aluminium, glycerol and the reaction products of potassium permanganate. The yellow powder was found to be sulphur. Potassium permanganate reacts violently with glycerin when mixed and produces a dazzling flash with smoke and high temperatures.
Cases involving the use of sparkler materials
Numerous cases involving the use of sparkler and/or sparkler materials have been encountered in Singapore. The different modes in which these materials were used to construct IEDs include: bundling of wire sparklers with confinement, packing the finely ground sparkler material into glass bottles and metal pipes, attaching a tube of powder to a spray can. The effects of the explosions related to these incidents will be discussed.