Terror is, by definition, a psychological phenomenon; a state of extreme fear within the psyche of a subject. It is not necessary that an individual be harmed or even be in danger of being harmed. All that is required to create a condition of being “terrified” is that the subject be convinced that he/she is in a precarious situation. In fact, those who would employ terror as a weapon may well prefer that their victims remain uninjured. A panic stricken crowd is much more difficult to control than an equal number of uninjured personnel. By the same token, the dedicated terrorist would prefer to have his activities result in injuries rather than in fatalities. An injured person may tie up a number of badly needed caregivers to provide aid and assistance to the terrorist’s casualty while a fatality can wait until order is restored and an organized body retrieval operation is undertaken. Thus the fundamental objective of the terrorist is to instill fear rather than to kill outright. Fear is contagious. Witness the bombing incident at the Boston Marathon two years ago. Relatively few people were injured but the panic that ensued spread throughout the city, greatly complicating and, perhaps, hampering the work of EMS, fire and law enforcement officers.

The classic, and often cited, example of a terrorist is that of the man who jumps up and yells, “FIRE” in a crowded theater. He touches no one but the fear he engenders could easily lead to multiple injuries and even deaths caused by the panic stricken crowd as it surges toward the exits. Terrified crowds are not likely to be very considerate of fellow citizens.

How does one set about creating a condition of terror in a crowd? Create an atmosphere conducive to fear or terror such as generating a loud noise, a brilliant flash of light, the presence of smoke or an odor that is associated with a harmful substance.

When I taught hazmat courses at Texas A&M, we employed a device to simulate exploding drums. We cut the head out of a 55 gallon drum and covered the opening with a sheet of plastic secured by a rubber band (a section of a tractor inner tube) in the wall of the drum. Near the bottom was a fitting threaded to take an automotive spark plug which was connected to a neon sign transformer. A quarter-inch copper tube brazed into the drum wall completed the outfit.

After injecting oxygen and propane into the drum through the copper tube, we were ready for the simulated explosion. We energized the transformer, which provided a spark that ignited the mixture. The explosion was “awesome.” It rattled the windows and created a tremendous amount of noise that was heard throughout the neighborhood but nothing else. There was no shrapnel or flying debris and any concussion was directed straight upward by the drum. However, it did “get the attention” of those involved in the simulated incident.

What would happen if such a device was set off in a crowded area such as a mall, a theater or a sporting event? Not a pleasant scenario to contemplate.

What was involved in this imaginary incident? Nothing but a 55 gallon drum which could be disguised as an ordinary trash barrel, a little bit of propane, a whiff of oxygen and a few electrical odds and ends. None of the parts are especially lethal and all of them are common articles of commerce found throughout our communities. Simulator parts were found with one sweep through the local hardware store, and no questions were asked.

I once sent a student through Wal-Mart with the assignment to list all the things he found that could be used to make some sort of “terror-genic” device. The list that he came back with surprised even me.

There were of course the usual items that one would expect, the swimming pool chlorine tablets and antifreeze or brake fluid; the bathroom cleaner and “household” ammonia. But what really surprised me was the muriatic (hydrochloric) acid (used to clean masonry) and chopped up coke can along with the used alkaline “D” cells. For some reason, probably the composition of the alloy, an actual Coca-Cola can work better. It can be chopped into approximately ⅛-inch pieces and inserted into a two or three liter soda bottle containing about 500 mls. of muriatic acid. The bottle is then capped. The resulting explosion, actually a pressure rupture, that follows within a few minutes can be quite disquieting to the uninitiated, to say the least (keep your distance!). An exhausted “D” cell tossed in a burning trash barrel can go off with enough force to split the barrel.

This is not, by any means, a complete list of the items that my student came up with but it does serve to illustrate a couple of points. In the first place, the dedicated terrorist can find plenty of material from which to construct his nefarious devices in the local home supply store. In the second place, none of the materials listed would be classed as explosives or, in some instances, even as a hazardous material. However, they serve the terrorist’s purpose.

Time was when one could simply go to the airport, purchase a ticket, stroll to the boarding stairs when the flight was called and get aboard without anyone so much as lifting an eyebrow. Those days are gone forever. Now one must wait in line, remove various articles of clothing, send luggage through the X-Ray and then go through himself. Anything causing the detectors to alarm will immediately get a special “inspection” with an electronic wand and if necessary a “pat down.” Metal detectors have a field day with some types of orthopedic implants and wire sutures, if present. Other detectors are in place to sniff out explosives or incendiary devices and prevent them from being carried on the plane. Yet, those who would do harm still find ways to outwit the detection devices.

A few years ago there was quite a commotion over an attempt to use a compound known as acetone peroxide to create an IED (Improvised Explosive Device) on an in-flight airliner. The operative managed to get the material on board the airplane and very nearly succeeded in his plan to blow it up or at least create panic. The reason that the material could be clandestinely taken aboard the airplane was to be found in the detectors in use at the airport at the time.

All of the compounds commonly used as explosives contain, in their molecular formulations, nitrogen bonded to one or more oxygen atoms in the “nitro” linkage. The presence of this structure is obvious from the names of the agents i.e. nitroglycerin (glyceryl trinitrate), TNT (trinitrotoluene), Picric acid (trinitrophenol), dynamite (nitroglycerin adsorbed on diatomaceous earth), nitromethane and so on. The commonality is the nitro group and the instrument designers developed a detector sensitive to these compounds by using the nitro-oxygen bond as an identifier. These are also sensitive to the nitrate group as found in black powder (as potassium nitrate or saltpeter) and ammonium nitrate (nitrogenoxygen bonding, again). There is at least one case on record where one of these “sniffers” zeroed in on an elderly heart patient who was carrying nitroglycerin pills for use in case of an angina attack. Now it must be admitted that these pills can make a substantial “pop” if struck sharply on a hard surface so the “sniffer” did what it was supposed to do, but one does wonder about the mental state of the patient when the commotion finally calmed down.

Now if the terrorists can come up with an explosive that contains no nitrogen-oxygen bonds, these detectors will not “see” it. Acetone peroxide filled this bill and so would my exploding drum at Texas A&M as well as potassium chlorate and elemental phosphorus dissolved in carbon disulfide or swimming pool chlorine tablets (HTH) and antifreeze or brake fluid since none of these contain the nitro linkage. When this situation became known the designers went to work to produce a screening instrument for non-nitrogen explosives. But since there is no commonality detected in the chemical formula of the materials, the results have been somewhat less than optimal and research continues. So far the instrumentation that could detect non-nitrogen explosives is too expensive for widespread use and so complicated that it requires a graduate chemist to operate it. There are, however, instruments that would detect specific agents such as those containing chlorine in its higher oxidation states or hydrocarbons at or near their lower explosive limits. This equipment is of great value in investigating incident scenes, but their usefulness for mass screenings is questionable on the basis of practical considerations.

Thus, the chemists find themselves in a contest with the operative terrorists. As fast as the terrorists devise an explosive or other nefarious device, the chemists and electronics wizards try to develop a way to detect it while the general public has to put up with an increasingly bothersome protocol at the airport boarding gate.

Of course, the easiest way to prevent the use of industrial materials by terrorists for nefarious purposes is to simply eliminate them. However, the chemical industry makes its living producing compounds that, while in the wrong hands, can be dangerous. Yet, at the same time, make possible the lifestyle that we all embrace. These materials move down the highway and through the air, warm and light our homes, cook our food, heal our illnesses and fertilize our fields. Without these entities, our lives would deteriorate to a point of bare subsistence. Elimination is not a viable option.

 Since we cannot, as a practical matter, eliminate potentially dangerous substances from our environment, we must initiate measures to prevent their inappropriate use and safeguard our citizenry. The best place to control any commodity is at its source, and this puts the chemical manufacturers on the “front lines” in the war on terror. These parties do a good job of monitoring the destination and ultimate use of their products and we should better utilize this ability. This can be accomplished but at some cost in time, treasure and convenience for the legitimate user.

Those who actually make chemical commodities are the ones who are most knowledgeable about their properties and the best way to deal with them in the event on an incident. These people are accustomed to thinking of their products in terms of their normal utilization in industrial processes and they prefer not to think about them as “weapons of mass destruction” or agents of terror. Unfortunately, there are those who do think about industrial chemicals as means of inciting terror and disrupting the functioning of society, and they have been all too successful in adapting these materials to their nefarious purposes.

For example, consider the case of chlorine. This element is produced in tremendous amounts and transported throughout the U.S. in tank car quantities. Chlorine is used at some point in almost any commercial chemical operation or process either as a primary ingredient or as a disinfectant in the treatment of potable water and sanitary sewage. Few other elements touch our lives in as many ways as does chlorine. Continuous chlorination of drinking water was first introduced in Belgium in 1910 after Louis Pasteur validated the germ theory of disease transmission. When one reads the mortality figures for the various epidemics that ravaged the cities of Europe and America during the 18th, 19th and early 20th centuries, it seems that chlorination of drinking water could well be ranked as one of the greatest public health innovations of all time. Chlorine, as a constituent of Dakin’s solution, made possible for the first time the wide scale antiseptic treatment of wounds during World War I and was responsible for saving many lives through the prevention of gangrene.

Unfortunately, on April 22, 1915, during the second battle of Ypres, the darker side of chlorine was revealed.