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In an effort to make bombmaking activity clandestine, explosive mixtures and device components are often manufactured in rented houses, apartments or hotel rooms. We have seen this behavior in past cases, like the December 1999 incident in which the so-called “Millennium Bomber” Ahmed Ressam and an accomplice set up a crude bombmaking factory in a hotel room in Vancouver, British Colombia. More recently, Najibullah Zazi, who was arrested in September 2009, was charged with attempting to manufacture the improvised explosive mixture tri-acetone tri-peroxide (TATP) in a Denver hotel room. In September 2010, a suspected lone wolf assailant in Copenhagen, accidentally detonated an explosive device he was constructing in a hotel. Danish authorities believe the device was intended for an attack on the Jyllands-Posten newspaper, which was targeted because of its involvement in publishing the controversial cartoons featuring the Prophet Mohammed.
Similar to clandestine methamphetamine labs (which are also frequently set up in rental properties or hotel rooms), makeshift bombmaking operations frequently utilize volatile substances that are used in everyday life. Chemicals such as acetone, a common nail polish remover, and peroxide, commonly used in bleaching hair, can be found in most grocery, beauty, drug and convenience stores. Fertilizers, the main component of the bombs used in the 1995 Oklahoma City bombing and the 1993 World Trade Center attack, can be found in large volumes on farms or in farm supply stores in rural communities.
However, the quantities of these chemicals required to manufacture explosives is far in excess of that required to remove nail polish or bleach hair. Because of this, hotel staff, landlords and neighbors can fairly easily notice signs that someone in their midst is operating a makeshift bombmaking laboratory. They should be suspicious, for example, if a new tenant moves several bags of fertilizer into an apartment in the middle of a city, or if a person brings in gallons of acetone, peroxide or sulfuric or nitric acid. Furthermore, in addition to chemicals, bombmakers also utilize laboratory implements such as beakers, scales, protective gloves and masks — things not normally found in a hotel room or residence.
Additionally, although electronic devices such as cell phones or wristwatches may not seem unusual in the context of a hotel room or apartment, signs that such devices have been disassembled or modified should raise a red flag, as these devices are commonly used as initiators for improvised explosive devices. There are also certain items that are less commonly used in household applications but that are frequently used in bombmaking, things like nitric or sulfuric acid, metal powders such as aluminum, magnesium and ferric oxide, and large quantities of sodium carbonate — commonly purchased in 25-pound bags. Large containers of methyl alcohol, used to stabilize nitroglycerine, is another item that is unusual in a residential or hotel setting and that is a likely signal that a bombmaker is present.
Fumes from the chemical reactions are another telltale sign of bombmaking activity. Depending on the size of the batch being concocted, the noxious fumes from an improvised explosive mixture can bleach walls and curtains and, as was the case for the July 2005 London attackers, even the bombmakers’ hair. The fumes can even waft outside of the lab and be detected by neighbors in the vicinity. Spatter from the mixing of ingredients like nitric acid leaves distinctive marks, which are another way for hotel staff or landlords to recognize that something is amiss. Additionally, rented properties used for such activity rarely look as if they are lived in. They frequently lack furniture and have makeshift window coverings instead of drapes. Properties where bomb laboratories are found also usually have no mail delivery, sit for long periods without being occupied and are occupied by people who come and go erratically at odd hours and are often seen carrying strange things such as containers of chemicals.