Black and smokeless powders. (a) ''perforated disc'' smokeless powder. (b) "tube"  smokeless powder. (c) "cut square" smokeless powder. (d) "disc" smokeless powder.  (e) Grade Fg black powder. (f) Grade FFFG (3Fg) black powder. Photographs  a–d courtesy of the Federal Bureau of Investigation Chemistry Unit's powder  morphology database. Photographs e and f courtesy of Rho Sigma Associates, Inc.



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--> Black and smokeless powders. (a) ''perforated disc'' smokeless powder. (b) "tube"  smokeless powder. (c) "cut square" smokeless powder. (d) "disc" smokeless powder.  (e) Grade Fg black powder. (f) Grade FFFG (3Fg) black powder. Photographs  a–d courtesy of the Federal Bureau of Investigation Chemistry Unit's powder  morphology database. Photographs e and f courtesy of Rho Sigma Associates, Inc.

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--> 1 Background and Overview Introduction Black and smokeless powders are widely available for purchase throughout the United States in sporting stores and gun clubs. Some 3.5 million individuals purchase these powders each year for sport use.1 These individuals include hunters and target shooters who prefer to hand load their own ammunition, as well as those who operate muzzle-loading weapons in reenactments and for hunting. Black powder is also used in the lift charges of fireworks, both for use in large-scale public displays and in fireworks sold for personal use. In the hands of criminals, however, black and smokeless powders can be used to fill a variety of containers (e.g., pipes, tubes, or bottles) to make very effective bombs. Although these powder devices are not well suited for use in large-scale bombings, such as those that occurred at New York City's World Trade Center in 1993 or Oklahoma City's Murrah Federal Building in 1995, they were used in several recent terrorist incidents, including the Centennial Park bombing at the Olympics in Atlanta in 1996 and in several devices mailed by the Unabomber.2 According to the Department of the Treasury's Bureau of Alcohol. 1   Statement of the Sporting Arms and Ammunition Manufacturers' Institute in the H.R. 1710 (The Comprehensive Anti-Terrorism Act of 1995) hearings before the House Committee on the Judiciary, June 13, 1995, distributed to the committee on January 15, 1998. 2   According to information provided to the committee by the FBI, the first seven bombings committed by the Unabomber between 1978 and 1982 involved devices with commercial smokeless powder as the filler. In subsequent devices, the Unabomber used improvised mixtures of chemicals.

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--> Tobacco, and Firearms (ATF) and the Department of Justice's Federal Bureau of Investigation (FBI), black and smokeless powders are the explosive materials most commonly used in improvised explosive devices in the United States; in 1995 these propellants were in roughly one-third of all such devices (ATF, 1997; FBI, 1997). Markers and Taggants Law enforcement agencies at the federal, state, and local levels invest substantial resources to address the bombing problem by detecting and disarming bombs before they go off, as well as by tracing the origins of explosives and other residual material found at a bomb scene. To facilitate these efforts, researchers in the 1970s investigated whether two types of substances added to explosives—markers and taggants—could enhance the capabilities of law enforcement agencies to detect devices before they explode, or to identify and prosecute those responsible (OTA, 1980). In this study, the term "markers" is used to describe any additive to smokeless or black powder designed to increase or assist in detectability. Markers could help in detecting an explosive material before the bomb can be activated and could assist crime scene investigators in determining where to look for evidence after an explosion. The term "taggants" is used to represent any material that can be added to smokeless or black powder in order to assist in identifying the powder or its sources. One type of taggant, a multilayered plastic chip, was tested extensively in explosives, including black and smokeless powders (OTA, 1980; Aerospace Corporation, 1980).3 Support for this research was terminated in the United States in 1981,4 leaving a number of questions unanswered, particularly concerning that taggant's compatibility with some explosive formulations, including smokeless powders. In the interim, however, the same taggant has been used without any reported problems in Switzerland for high explosives and black powder intended for blasting. Although there was no continuing work on taggants for explosive materials in the United States, various taggant concepts have found application in the prevention of counterfeiting and in quality control of commercial products ranging from gasoline to perfumes.5 3   This type of taggant, a multilayered plastic chip, was developed by Richard Livesay in the 1970s and licensed to the Minnesota Mining and Manufacturing (3M) Company. Currently, this technology is used by Microtrace, Inc. 4   The Treasury, Postal Service and General Government Appropriation Bill, 1981 (Committee on Appropriations), Title I, p. 9. 5   Some commercial applications of taggants for prevention of counterfeiting and for product identification are given in Schlesinger (1998). Also see descriptions of individual taggant concepts in Appendix D for more information on nonexplosive applications for taggants.

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--> Origin and Scope of This Study Responding to increased concerns about terrorism, including the bombing of the Murrah Federal Building in Oklahoma City in 1995, Congress passed the Antiterrorism and Effective Death Penalty Act of 1996. In this act, Congress mandated a reexamination of the feasibility and desirability of adding markers and taggants to explosives. The National Research Council (NRC) examined these issues for high explosives in a 1998 report, Containing the Threat from Illegal Bombings (NRC, 1998); however, black and smokeless powders were explicitly excluded from the scope of that report, and the NRC was mandated to conduct a separate study of these powders (see Appendix B). The Committee on Smokeless and Black Powder responded to that mandate. This report of the committee focuses on the detection of devices containing smokeless and black powders and the capability to identify the perpetrator of a bombing from powders recovered at a bomb scene. Two questions are relevant: the first concerns the technical feasibility of adding markers or taggants to a smokeless or black powder; the second and more involved question is whether the economic and social benefits of the addition of markers or taggants outweigh the economic and social costs. The Act stipulates that the study examine the inclusion of markers or taggants in smokeless and black powder in light of several issues: safety, assistance to law enforcement officers' investigative efforts, effect on powder performance in lawful uses, environmental impact, costs to manufacturers and consumers, and susceptibility to countermeasures.6 In the discussion of record keeping that supplements Chapter 3's discussion of taggants for black or smokeless powders, the committee focuses on the retail sale of canister powders to the public for reloading and muzzle loading. Detailed examination of the distribution and tracking systems for the products that use these powders (such as ammunition and fireworks, or pyrotechnics) was not included in this study, because currently the easiest, cheapest, and most common method of obtaining black or smokeless powder for use in a bomb is to purchase the powder that is available in canisters. For several reasons beyond the explicit wording in the charge to the committee (see Appendix B), pyrotechnic compositions are not examined in this study. A broad range of chemical compositions with a large variety of uses can be classified as pyrotechnics, and the systems for manufacturing and distributing them are diverse. Moreover, many pyrotechnic substances can be produced by mixing readily available precursor chemicals.7 6   See Appendix B for a description of the enabling legislation and the statement of task. 7   The issues related to controls on precursor chemicals were discussed in a recent NRC report (NRC, 1998).

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--> Although pyrotechnics are reported as the explosive material in many bombing incidents, most of these have involved devices that used cardboard containers,8 suggesting that fireworks are being purchased and used without alteration for illegal purposes. If legislation mandating the marking or tagging of black powder were to be enacted, the uses of pyrotechnic compositions and of black powder in fireworks as potential countermeasures to the effectiveness of such laws would have to be considered. A brief description of pyrotechnic compositions and devices is given in Box 1.1. Black and Smokeless Powders: Characteristics, Production, and Distribution Any discussion of marking or tagging black or smokeless powders must be informed by an understanding of the variety of legal uses for these powders, the manufacturing processes that produce these powders, and the distribution and sales systems that bring the powders to users. Chemical Composition, Properties, and Legal Uses Literally hundreds of different black and smokeless powder products are produced by a number of processes. The exact compositions of the products are tailored to produce very specific performance characteristics. However, products nominally designed for the same uses but made by different manufacturers may have been formulated quite differently to meet the same performance specifications. This section provides more detail on the nature of black and smokeless powders (including chemical composition and morphology) and some of the common uses for these powders. This background is necessary for the discussion in Chapter 3 on the use of powders as physical evidence in bombing investigations. Black Powders and Black Powder Substitutes The oldest propellant is black powder. Numerous historical works trace the invention of this powder to the Chinese several millennia ago. From China, the technology spread to Central Asia and was brought to Europe by the Arabs about the middle of the 13th century. During their siege of Niebla in Spain in 1257, missiles that probably contained a composition resembling black powder were used. Later accounts show black powder being used as an industrial or mining explosive as early as the 16th century (Urbanski, 1967; Cooper and Kurowski, 1996; Davis, 1943; Ball, 1961; Taylor, 1959). 8   Unpublished data received from the ATF for the years 1992 to 1994 indicate that, of those incident reports listing containers, 61 percent of bombs involving pyrotechnics were in cardboard.

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--> BOX 1.1 Pyrotechnic Compositions and Devices The term "pyrotechnics" is used to describe particular chemical compositions and devices and the effects that they can produce, such as heat, light, smoke, gas, sound, and motion. Pyrotechnic compositions normally consist of one or more oxidizers combined with one or more fuels, binders, or other additives. Pyrotechnic devices are manufactured in many shapes and sizes to meet specific needs and can contain pyrotechnic compositions in amounts ranging from as little as a few milligrams to as much as tens of pounds. Black powder is also employed in many pyrotechnic devices but is not present in all such devices. It is most commonly used in fuses and as a propelling or bursting charge. Pyrotechnic devices can be divided into two classes: civilian and military. Typically it is the intended use of the device that determines its class, not the chemistry of the pyrotechnic composition. Military pyrotechnics include signal and counter-measure flares, signal and obscuration smokes, tracer compositions, incendiaries, and igniters. Civilian pyrotechnics include matches, signaling devices such as highway flares and railroad fusees, automotive air-bag inflators, toy caps, model rocket motors, theatrical special effects, and fireworks. Fireworks often include black powder as well as pyrotechnic compositions.1 The amount of black powder used ranges from a fraction of an ounce in consumer, off-the-shelf fireworks to several pounds in aerial display devices.2 Compared to purchasing a 1- or 2-pound canister of black powder, obtaining an equivalent amount of powder by purchasing fireworks and extracting the black powder would be more difficult, more time consuming, more dangerous, and considerably more expensive. The shelf life of pyrotechnic devices varies, depending on the type of device and the conditions under which it is stored. As is the case for black powder, moisture can cause deterioration. 1   Black powder substitutes are used only occasionally in fireworks, and smokeless powders are not used at all. 2   Access to display fireworks is very restricted. Manufacturers and distributors must be licensed, and display fireworks can be sold legally only to end users who have permits issued by local authorities. Display fireworks are normally stored long term in ATF-inspected magazines, and they are handled administratively as explosives, with the associated record keeping. Black powder consists of a combination of the fuels charcoal and sulfur along with the oxidizing agent potassium nitrate.9 No chemical reactions are involved in the manufacturing process, which depends entirely on the intimate physical mixing of the ingredients in fixed proportions. The physical properties 9   Some blackpowders, designated as "Grade B blasting," use sodium nitrate instead of potassium nitrate. Military grades JAN A, B, and C also use sodium nitrate.

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--> and performance characteristics of black powder are strongly dependent on the method of manufacture (the equipment used and the process parameters) and the purity of the ingredients. Black powder substitutes are also available commercially as a replacement for black powder in some applications. These powders are formulated using one or more oxidizers, such as potassium nitrate and potassium perchlorate, in combination with fuels such as sulfur, charcoal, ascorbic acid, sodium benzoate, starches, and sugars. Black powder is currently used as a propellant and an explosive in a variety of applications. It is used in muzzle-loading weapons for hunting or in historical reenactments. It is also employed as the propellant for motors in small model rockets and is the powder core in safety fuses. Fireworks manufacturers use black powder extensively, for example in timing fuses and in lift charges for aerial display devices. Mining companies use black powder as an explosive for blasting. The military uses black powder in small rockets, delay trains, and mine projectors, and in gun-propellant primers and igniters. In some of these applications, black powder substitutes can be used in place of genuine black powder. For example, the substitutes now are used often in muzzle-loading weapons, but they have limited applications in fireworks. Black powder and its substitutes can remain viable indefinitely, retaining their properties if the powders are properly packaged and/or stored to exclude moisture. Smokeless Powders In the 20th century, smokeless powders have largely replaced black powder in handguns, rifles, and larger-caliber weapons. Smokeless powders are not truly smokeless but, in comparison to black powder, the "smoke" products produced when smokeless powders are used in ammunition are much cleaner. Smokeless powders are generally grouped in three broad categories, based on their chemical compositions: single-base, double-base, and triple-base. The first two categories are commonly used and commercially available; the last type, like the more chemically complex composite propellants, is for specially applications and is not sold to the general public. Single-base propellants contain nitrocellulose (NC) as the energetic material.10 Various stabilizers are blended with the NC to reduce degradation of the powder over time. Propellant granules may also be coated with burning-rate modifiers, flash suppressants, or deterrents in order to control performance characteristics. The powder is also glazed with graphite to reduce sensitivity to ignition by static electricity and to improve flow characteristics. 10   The nitrocellulose used in single-based smokeless powders has a nitrogen content between 12.6 percent and 13.3 percent.

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--> Double-base propellants are also made with NC but are plasticized with another explosive or energetic material that is often a liquid, usually nitroglycerin (NG). This second component, which may be up to 40 percent of the total by mass, is used to adjust the oxygen balance. This plasticizer, along with other additives, can be used to optimize performance parameters such as burn rate and reaction temperature. As with single-base propellants, stabilizers are added to increase shelf life and granules are coated to control performance. Some double-base powder granules are produced in various colors to help users distinguish between different types of powders, but most powder is glazed with graphite. For both single-and double-base powders, shelf lives of 20 to 30 years can reliably be expected. There have been examples of smokeless powders that have not been exposed to high temperatures proving serviceable even after 40 to 60 years. Surface area per unit mass of the propellant is a key characteristic for determining the overall burn rate and hence performance. To achieve the intended performance, propellant granules are produced in a variety of shapes and sizes including disks, cut squares, tubes, and flattened balls, the dimensions of which are optimized to achieve predictable and repeatable performance. Triple-base propellants add a third reactive material, nitroguanidine (NQ), to the NC and NG. By varying the percentage of each of the reactive ingredients and adding other ingredients, such as oxidizers, plasticizers, and stabilizers, compositions are formulated to achieve specified performance parameters. Triple-base propellants are used mainly by the military, typically in large-caliber guns. Another class of specially formulated propellants is composite propellants in which the oxidizers and fuels are separate materials.11 These propellants are used in a variety of applications, including as rocket fuel and as gas generators.12,13 Triple-base powders and composite propellants are manufactured for specialty uses and not sold to the general public. Single-and double-base smokeless powders are produced mainly for use in ammunition and are sold to both ammunition manufacturers and sporting shooters for this purpose. People who buy smokeless powders in order to assemble and reload their own ammunition do so for a variety of reasons. The two strongest motivations are cost and performance. Purchasing the individual components of ammunition (the bullet, powder, car- 11   Composite propellants typically do not include volatile ingredients, such as the nitrate esters found in conventional double-base smokeless powder, and therefore have very low vapor pressures. This characteristic makes these powders more difficult to detect with certain types of detection equipment; see Chapter 2. 12   See summary of presentation by James Scheld, Indian Head Division, Naval Surface Warfare Center, in Appendix E. 13   As triple-base powders and composite propellants are difficult to obtain currently, they are seldom used in improvised explosive devices. However, if the use of commercial powders in such devices were curtailed through regulations, marking, or tagging, then the specialty propellants might be viewed as a possible alternative explosive material for the makers of illegal devices.

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--> tridge case, and initiator, for example) separately and reusing the cartridge cases can enable the reloader to realize savings of as much as 50 percent over store-bought ammunition. In addition, by hand loading ammunition, the shooter has much more control over the exact specifications of the ammunition and therefore over the performance (National Shooting Sports Foundation, 1996).14 Producers of Black and Smokeless Powders Black and smokeless powders sold in the United States are manufactured by a small number of U.S. companies and imported from foreign companies all over the world. In addition to retail sales to consumers, these powders are sold to U.S. and foreign militaries, companies that manufacture ammunition, and other commercial firms, such as fireworks producers. Black Powders and Black Powder Substitutes Most of the black powder sold in the United States is manufactured domestically; a small amount is imported from Slovenia, Brazil, China, Germany, and Switzerland.15 Commercial customers range from muzzle loaders who buy 1-pound canisters, to companies that manufacture fireworks, model rockets, or safety fuses, to mining concerns buying large quantities for blasting.16 The U.S. military is also a major user. Some quantity of black powder is also imported into this country within premade fireworks, mainly from China. Currently, the only major manufacturer of black powder in the United States is Goex, Inc., located at the Louisiana Army Ammunition Plant. However, black powder is also imported, both in individual canisters for direct sale to consumers and in bulk quantities for repackaging by U.S. companies. A wider variety of black powder substitutes are made in the United States, including Pyrodex from the Hodgdon Powder Company, Clean Shot Powder from Clean Shot Technologies, Inc., and Black Mag from the Arco Powder Company. While no U.S. companies have begun manufacturing black powder in the past half century, the number of black powder substitutes made and available in the United States is growing. 14   Also, personal communication from Robert T. Delfay, president and chief executive officer. Sporting Arms and Ammunition Manufacturers' Institute, and Bill Chevalier, president, National Reloading Manufacturers' Association. See also Appendix F, which includes a report on the committee's site visit to the National Rifle Association headquarters, for more information. 15   Personal communication from Mick Fahringer, Goex, Inc., July 22, 1998. 16   According to Mick Fahringer Goex, Inc., June 9, 1998, roughly 100,000 to 150,000 pounds of black-powder-type propellant are used in blasting applications per year.

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--> Smokeless Powders Approximately 10 million pounds of commercial smokeless powders are sold in the United States each year. Roughly 70 percent of this amount is sold to original equipment manufacturers (OEMS) to be put directly into ammunition. The remaining quantity is sold in individual canisters (ranging from 1/2-pound cans to 12- or 20-pound kegs) to reloaders for personal use. These purchases can occur in gun stores, retail outlets (such as Wal-Mart or K-Mart), or through hunting and shooting clubs. A large quantity of smokeless powder is also manufactured for sale to domestic and foreign militaries. In North America, the major producers of smokeless powders are Alliant Techsystems (previously Hercules, Inc.) in Radford, Virginia; PRIMEX Technologies (previously Olin Corporation) in St. Marks, Florida; and Expro Chemical Products, Inc. (improved military rifle propellants previously manufactured by E.I. DuPont) in Valleyfield, Quebec, Canada. Numerous other companies import smokeless powders into the United States. These companies include Australia Defense Industries, Lovex (Czech Republic), Bofors (Sweden), Vihtavouri (Finland), and SNPE (France). Often these companies' products are repackaged by U.S. companies, such as Hodgdon Powder Company and Accurate Arms, for commercial sales within the United States. Distribution Systems Both black and smokeless powders are sold to individuals at a variety of retail outlets. The powder manufacturers and repackagers disburse their products to these businesses through a system of approximately 20 master distributors in North America. These companies buy large quantities of canister powders, which are then resold in smaller quantities to smaller distributors and wholesalers, who in turn supply cans to dealers, gun shops, shooting clubs, hardware stores, and other retailers. Consumers can purchase a 1-pound canister of black or smokeless powder for $15 to $20 at a standard retail outlet. The cost per pound can be lower if the quantity purchased is large (e.g., a 20-pound keg) or if the purchase is made through a gun club. Currently, the powder manufacturers' systems are not designed to ensure that one blended lot of a particular type of powder goes to a single master distributor. In some cases, powders are packaged for retail sale at the manufacturing site and are sold by the manufacturers directly to the master distributors; at other times powder is sold in bulk by the manufacturers to other powder sellers and to original equipment manufacturers, who repackage the powders and sell under their own labels. Powders produced for military use can be distributed in several ways. They can be sold directly to the U.S. military for various uses. They can be loaded into

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--> ammunition by the powder manufacturer, and the ammunition then sold to military users. The powders can be shipped to military subcontractors for loading into ammunition. Finally, they can be exported for sale to friendly foreign governments and foreign loading companies. Military surplus powders are sometimes sold back to powder manufacturers for reuse as raw materials or to repackagers for sale in the commercial market.17 Figure 1.1 outlines the various paths smokeless and black powders take from manufacturers to users. Manufacturing Processes In gathering information for this study, the committee heard presentations from industry organizations and individual companies (see Appendix E). In addition, subgroups of the committee made several site visits to various plants to observe the manufacturing process and equipment used in producing and packaging smokeless and black powders (see Appendix F). The following descriptions are brief summaries of the manufacturing practices in use in the industry today. This background is necessary for the discussion in Chapters 2 and 3 on the feasibility and desirability of adding markers or taggants to these powders. Black Powders and Black Powder Substitutes The performance of black powder depends in large part on the process by which it is manufactured. Over the decades, certain equipment and procedures have been found to yield powder with desirable characteristics, and these methods have become the standard for black powder manufacture. Today, black powder is produced by combining the three main ingredients (sulfur, charcoal, and potassium nitrate) in heavy wheel mills that mix and crush the powder.18 the tremendous pressures in the mill cause the sulfur to plasticize and flow, thereby binding the charcoal and nitrate. The mixture is then pressed into blocks and passed through a series of rollers to break the chunks into granules of various sizes. Vibrating screens are then used to separate the granules into consistently sized batches. This screening produces the various grades of black powder, as the bulk burning rate is a function of particle size. Finally, the granules are coated with graphite before being sifted, weighed, and packaged. While the composition and morphologies of black powder substitutes differ from those of genuine black powder, the manufacturing process is fairly similar. 17   If a powder marking or tagging program were to be instituted, the contributions of these surplus military powders to the commercial market would have to be considered and accounted for. 18   The typical composition is approximately 75 percent potassium nitrate, 15 percent charcoal, and 10 percent sulfur.

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--> General Comments on the Manufacturing Processes All the processes described above have some characteristics in common that are relevant to issues related to marking or tagging of black or smokeless powders. While some elements of these processes may be continuous, propellants, on the whole, are manufactured in batches or lots.19 In general, a good deal of recycling of materials occurs; unsatisfactory material may be removed from a given batch and returned to the beginning or near the beginning of the process for use in another lot. Such material may be rejected owing to a variety of factors, such as granules that are too small or too large, or poor performance in quality control tests. Not only can partially processed powder be recycled, but the manufacturers also reuse finished products. Such material may come from returns by the distributors or from surplus or obsolete military powders purchased cheaply to be used as a low-cost source of raw materials. All of this reworking and recycling in the manufacturing process serves three purposes: (1) to assure good quality control of the final product, (2) to reduce costs by reusing material that fails to meet performance specifications, and (3) to reduce pollution by avoiding destruction of such material by burning (the only legal way to destroy a discarded propellant). The issue of reworked powders, with the attendant mixing of powders with varying origins, would be an important consideration in the possible implementation of a marker or taggant scheme. Black and Smokeless Powders in Improvised Explosive Devices The construction of an effective bomb using black or smokeless powder requires several components, including, at a minimum, a robust container, the propellant powder, and an initiation system (for a rough sketch, see Figure 3.1 in Chapter 3). Other common potential elements include a power source, a timing device, and nails or tacks. As discussed in Chapters 2 and 3, the nonpowder components in the device may play an important role in detecting the bomb or identifying the perpetrator. The typical black or smokeless powder pipe bomb contains approximately 1/2 pound of powder and is roughly 10 inches long and 1 inch wide.20 This is a relatively small device when compared to the truck bombs used at the Murrah Federal Building and the World Trade Center. In general, bombs that use black and smokeless powders tend to be ''package size'' rather than "car size" for two reasons: cost and containment. Using approximate values, powders are $15 per pound, while dynamite is $1.50 per pound, and the explosive mixture of ammo- 19   The typical lot is between 10,000 and 20,000 pounds, with a range of 5,000 pounds (for specialty powders) to 50,000 pounds (for military ammunition), according to written materials received from the Sporting Arms and Ammunition Manufacturers' Institute by the committee on January 15, 1998. 20   Presentation to the committee by Roger Broadbent, Virginia State Police, January 15, 1998.

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--> nium nitrate and fuel oil (ANFO) is $0.15 per pound. Therefore, for very large explosive devices, use of powder is not cost-effective. In addition, powders require containment to produce an explosion, and it is difficult to buy, construct, or safely transport a container sufficiently robust to be used in a very large powder bomb. These two factors explain why large-scale powder bombs are not used. However, the issues related to cost and containment are less problematic on a small scale, and are compensated for by the fact that small quantities of powder currently are much easier to obtain than dynamite or ANFO and that, unlike these explosives, powders can be initiated by flame. Metal pipes are the most common containers used for effective black and smokeless powder bombs, while cardboard tubes are the most common containers used for bombs filled with pyrotechnic powders.21 However, many other types of containers have been used, including plastic pipe, cans, glass and plastic bottles, grenade hulls, and even tennis balls. The primary purpose of the containers is to confine the gases produced during the burning of the explosive powder. The resulting pressure then explodes the container. The fragments of the container are propelled outward at high speeds to cause deaths, injuries, and property damage. Nails or tacks taped to the outside of the container are designed to increase the number of dangerous fragments produced in the explosion. Often, the bomb itself is placed within a larger package, such as a box, a suitcase, or a knapsack (as in Centennial Park). The primary purposes of the packaging are usually ease of transport and concealment. An initiation system is designed to start the black or smokeless powder burning within a pipe bomb. Simple examples of such systems include a cigarette with one end imbedded in the powder (Scott, 1994) or a match, a length of safety fuse, and a charge of black powder (Stoffel, 1972). More elaborate systems may include a complex timing apparatus or triggering devices that operate remotely or are designed to be set off by the intended victim (as in car bombs). The use of any particular mode of initiation will result in potentially useful physical evidence being recovered at the crime scene: lengths of safety fuse, wires, springs, percussion caps, fragments of batteries, fragments of clocks, and the like. Statistics on the Use of Improvised Explosive Devices Containing Black and Smokeless Powders Two federal agencies gather statistics on bombing incidents in the United States: the ATF and the FBI.22 This study relied on bombing statistics supplied by 21   Cardboard containers were used in 61 percent of pyrotechnic bombing incidents in which the container was reported, and metal pipes were used for 62 percent of smokeless and black powder bombing incidents in which the container was reported, according to ATF data for 1992-1994. 22   The U.S. Postal Inspection Service investigates and tracks bombs sent through the mail. The total number of such devices has averaged about 16 per year between 1983 and 1997. Unpublished materials received from the U.S. Postal Inspection Service.

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--> both the ATF and the FBI. Each agency maintains a separate statistics database on bombing incidents, and each has its own form for use by local investigators who are reporting incidents.23 No law requires local investigators to report a bombing incident to either the ATF or the FBI; both the initial reporting of an incident and any subsequent updating as the investigation proceeds are done on a voluntary basis. Although these agencies exchange information on bombing cases reported to them, and although they go through an annual data-reconciliation process intended to result in a common set of numbers, discrepancies nevertheless remain that complicated the committee's analysis of the bombing threat.24 Previous attempts to analyze bombing statistics have met with similar problems (OTA, 1980; White House Commission, 1997; and NRC, 1998). Total Number of Reported Bombings Involving Black and Smokeless Powders Table 1.1 shows the number of actual and attempted bombings reported in the United States involving black and smokeless powders25 in the 5-year period from 1992 to 1996. Over this period, the number of reported bombings using 23   Public Law 104–208 specified that "the Secretary (of the Treasury) is authorized to establish a national repository of information on incidents involving arson and the suspected criminal misuse of explosives. All Federal agencies having information concerning such incidents shall report the information to the Secretary pursuant to such regulations as deemed necessary to carry out the provisions of this subsection. . . ." The Uniform Federal Crime Reporting Act of 1988 states that the "Attorney General may designate the Federal Bureau of Investigation as the lead agency" to "acquire, collect, classify, and preserve national data on Federal criminal offenses as part of the Uniform Crime Reports.'' 24   For instance, the number of actual and attempted bombings involving black and smokeless powders in 1995 as reported by the ATF was 286 (ATF, 1997), while the FBI reported 624 (written materials from Gregory Carl, FBI). This difference was apparently caused by a change in the FBI reporting forms from 1994 to 1995, in which black and smokeless powder bombs, which were reported in separate categories in 1994, were combined in the same category in 1995. When the FBI reported the cases to the ATF using the new combined category, the ATF (which continues to keep the categories separate in its statistics database) could not definitively put the cases in either the black or smokeless powder category and chose not to enter those cases in any category. Another example of discrepancies was apparent as a result of the committee's attempt to extract data on "significant" bombings—those actual bombings that caused at least one death, one injury, or $1,000 in property damage. Staff analysis of data provided by the ATF indicated that there were 160 such incidents in 1993 and 122 in 1994, while a computer search conducted by the FBI of its own statistics database found 80 such incidents in 1993 and 41 such incidents in 1994. The FBI suggested that one reason for the difference might be different estimates of property damage in the two statistics databases. 25   To obtain a consistent data set over the 5-year period from 1992 through 1996, it was necessary combine black and smokeless powder incidents into one category and to use data from different sources. Incidents involving black and smokeless powders were reported separately on FBI reports prior to 1995. For 1995, 1996, and 1997, incidents involving black and smokeless powders were combined on FBI reports. Starting in 1998, these categories will again be reported separately. Data from 1992 to 1994 are from the ATF. Data from 1995 and 1996 are from the FBI.

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--> TABLE 1.1 All Reported Actual and Attempted Bombings Using Propellants, Pyrotechnics, and High Explosives Between 1992 and 1996 Type of Explosive Used 1992 1993a 1994 1995b 1996 Bomb containing smokeless powder/black powder/black powder substitutes Total incidents 667 637 696 624 643 Actual 524 498 447 454 405 Attempted 143 139 249 170 238 Deaths 9 12 6 8 13 Injuries 82 68 49 53 162 Property damage $780K $856K $1.8M $243K $896K Pyrotechnics/fireworks Total incidents 365 310 439 308 332 Actual 313 268 381 245 251 Attempted 52 42 58 63 81 Deaths 2 6 3 2 1 Injuries 126 54 87 33 36 Property damage $171K $253K $237K $122K $95K High explosives Total incidents 38 43 29 57 46 Actual 22 26 16 39 33 Attempted 16 17 13 18 13 Deaths 2 18 4 177 2 Injuries 3 1054 2 538 12 Property damage $129K $511M $317K $100M $141K NOTE: Actual or attempted bombings include incidents in which a device either exploded or was delivered to a target but did not explode. It does not include unexploded devices that were recovered by law enforcement personnel but not associated with a target. a High-explosives data for 1993 include the figures from the World Trade Center bombing on February 26, 1993, in which 6 people were killed, 1,042 were injured, and $510 million of property damage was sustained. b High-explosives data for 1995 include the anomalous carnage in the bombing of the Murrah Federal Building in Oklahoma City, in which 168 people were killed, 518 were injured, and roughly $100 million worth of property was damaged. SOURCE: Adapted from unpublished data for 1992–1994 received from the ATF and for 1995–1996 from the FBI, and reports from the ATF (1997) and the FBI (1997). black and smokeless powders remained relatively constant, averaging 653 per year. However, between 1979 and 1992, the number of bombings involving these powders approximately doubled (reflecting the general trend in bombings involving all types of explosives) (Hoover, 1995). Therefore, although the frequency of smokeless and black powder bombings does not appear to have increased significantly in recent years, it remains at a historically high level.26 26   Because the statistics gathered by national agencies depend on state and local officials reporting bombing incidents to these agencies, it is not clear what percentage of the increase in bombings is due to a growth in the number of incidents and how much reflects improved reporting.

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--> Table 1.1 also lists the deaths, injuries, and property damage attributable to the various types of devices from 1992 to 1996. The data show that bombs with black or smokeless powder fillers caused on the order of 10 deaths, 100 injuries, and $1 million in property damage in each of the 5 years.27 For purposes of comparison, bombing incidents involving pyrotechnics and high explosives are also shown. Analysis of the data for the years 1992–1994 shows that black and smokeless powders were used with roughly equal frequency.28 During this period, there was an average of 364 incidents per year involving black powder and 302 per year involving smokeless powder. "Significant" Reported Bombings The data in Table 1.1 represent a mix of serious incidents that caused death and injury, as well as less serious incidents involving juvenile experimentation and simple vandalism (e.g., blowing up mailboxes). While these latter, "nuisance" incidents do have negative consequences, the committee's primary concern is those "significant" incidents that cause—or have the potential to cause—deaths, injuries, or significant property damage. Accordingly, the data in Table 1.1 were examined in order to select the actual bombings that caused at least one death, one injury, or a minimum of $1,000 in property damage. In addition, attempted bombings aimed at significant29 targets were included.30 These significant actual and attempted bombing incidents involving black and smokeless powders are presented in Table 1.2. For comparison, significant actual and attempted bombing incidents involving pyrotechnics during the period 1992–1994 are shown in Table 1.3. The filtering process eliminated 59 percent of the bombings in which black powder, smokeless powder, or black powder substitutes were used, and 67 percent of the bombings in which pyrotechnics or fireworks were used. To make an effective bomb, black powder, smokeless powder, and pyrotechnic powders must be enclosed in a container. Tables 1.2 and 1.3 also provide a breakdown of the containers used in the significant incidents involving these fillers. The type of container used in these bombs bears importantly on the ease with which these devices can be detected by various detection technologies. The data indicate that significant black and smokeless powder bombs most commonly use metal pipes, and significant pyrotechnics bombs most commonly use cardboard containers. 27   Approximately 6 out of the 10 deaths and 24 out of the 100 injuries for each of the 5 years were suffered by those believed to be involved in constructing or delivering the explosive device. 28   Committee analysis of data received from the ATF. 29   In this context, significant targets included all targets listed in Table 1.4 except open areas and mailboxes, which were judged to have a low potential for death, injury, or significant property damage. 30   The data made available to the committee made it possible to do this analysis only for the years 1992–1994.

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--> TABLE 1.2 Significant Actual and Attempted Bombings Involving Devices Using Smokeless Powder, Black Powder, or Black Powder Substitutes   Number of Incidents Deaths Injuries   1992 1993 1994 1992–1994 1992–1994 Total incidents: 260 258 294 27 199 Actual 166 160 122 27 199 Attempted 94 98 172 — — Container: Pipe/metal 158 169 158 19 122 Pipe/plastic 28 34 43 0 16 Cardboard/paper 7 3 4 0 2 Other 60 42 72 8 53 Unknown 7 10 17 0 6 NOTE: Significant bombings represent actual bombings that caused at least one death, one injury, or a minimum of $1,000 in property damage, or attempted bombings aimed at specified targets. SOURCE: Adapted from data received from the ATF. TABLE 1.3 Significant Actual and Attempted Bombings Involving Devices Using Pyrotechnics or Fireworks   Number of Incidents Deaths Injuries   1992 1993 1994 1992–1994 1992–1994 Total incidents: 130 100 142 11 267 Actual 88 72 103 11 267 Attempted 42 28 39 — — Container: Pipe/metal 17 6 14 2 13 Pipe/plastic 5 7 2 0 2 Cardboard/paper 28 35 26 3 88 Other 12 10 14 1 11 Unknown 68 42 86 5 153 NOTE: Significant bombings represent actual bombings that caused at least one death, one injury, or a minimum of $1,000 in property damage, or attempted bombings aimed at specified targets. SOURCE: Adapted from data received from the ATF.

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--> TABLE 1.4 Sites of Casualties Caused by Bombs Using Propellants and Pyrotechnics Between 1992–1994 Type of Facilitya Deaths Injuries Detector installation likely Utilities 0 0 Government (federal) 1 2 Government (local/state) 0 0 Military 0 1 Energy facilities 0 0 Airport/aircraft 0 0 Detector installation possible Commercial 0 10 Educational 0 18 Police facilities 0 1 Banks 0 0 Church/synagogue 0 0 Medical facilities 0 0 Detector installation unlikely Residential 16 85 Apartments 3 6 Mailboxes 0 5 Vehicles 6 24 Open area 1 45 Parks 0 0 Other 0 2 aFacilities listed are those that are tracked by the ATF SOURCE: Adapted from data received from the ATF. Targets of Bombings The feasibility of detecting bombs prior to their explosion depends on the targets against which the bombs are directed and the method of delivery to the target. If it is not feasible to deploy a detector system at a target for routine screening, by definition a bomb will not be detected unless a detection system is directed to the scene for a specific reason—e.g., discovery of a suspicious package or receipt of a bomb threat. Table 1.4 shows the sites at which bombs involving black powder, smokeless powder, or pyrotechnic fillers were targeted in the years 1992–1994 and the deaths and injuries caused at those sites. The targets can be grouped into three categories, depending on the feasibility of deploying bomb detection systems for routine screening at those locations. High-profile targets such as airports, utilities, or government facilities would likely be protected by such detection equip-

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--> ment. In the second category are establishments, such as commercial buildings, schools, and medical clinics, in which detection systems could be deployed, but only if the systems were relatively inexpensive.31 In the third category are apartments, vehicles, and open areas where the deployment of bomb detection systems for routine screening is unlikely. Table 1.4 shows that for the period 1992–1994, 26 out of 27 deaths and 167 out of 199 injuries caused by bombs filled with black powder, smokeless powder, or pyrotechnic compositions occurred at locations at which the deployment of detection systems for routine screening is unlikely. Thus, if these bombing pattern continue, wider deployment of routine screening technologies is unlikely to significantly affect the number of victims of black and smokeless powder bombings. Note, however, that improving the capability of law enforcement to deploy bomb detection technologies in response to an identified threat at a given site may still help to prevent casualties to bystanders and bomb squad personnel. This point is discussed further in Chapter 2. Another factor that affects the ability to detect explosive devices using black and smokeless powders is the method by which the bombers deliver the devices to their targets. According to ATF data, the predominant method of delivery for black and smokeless powder bombs is hand placement, which was used in at least 66 percent of the 812 significant incidents that occurred in 1992–1994 (for 22 percent of the incidents, no delivery mechanism was reported).32 It is not clear from this classification if these devices were carried into buildings (in which case a detection system at the entrance might have detected them) or were placed on the property or against an external wall. Mailed bombs that use black and smokeless powders were quite rare; the ATF data reported 19 such incidents in 1992–1994. When a bombing incident is an act of terrorism, more people are affected than those actually injured or killed. A terrorist bombing can be defined as a premeditated act designed to cause public fear through carefully chosen acts on random and symbolic targets, including people. It is used to influence political behavior, provoke a reaction, catalyze a more general conflict or publicize a political or ideological cause (Cannistraro and Bresett, 1998).33 In the early 1990s, the pattern of bombing casualties and targets shown in Table 1.4 indicates that 31   Detection systems that routinely screen people and packages entering a building through a controlled portal protect the people and property in the interior of the building but do not prevent the placement of a bomb on the grounds or against an exterior wall. 32   The possible methods of delivery listed on the ATF reporting form are "placed," "mailed," "thrown,'' and "launched." 33   Alternative definitions for terrorism exist. For example, 18 USC, Sec. 2332b (g)(5), states that "the term 'federal crime of terrorism' means an offense that is calculated to influence or affect the conduct of government by intimidation or coercion, or to retaliate against government conduct . . . ." Another definition of terrorism is "the unlawful use of force or violence against persons or property to intimidate or coerce a Government, the civilian population, or any segment thereof, in furtherance of political or social objectives" (FBI, 1995).

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--> relatively few casualties occurred at locations that might be expected to be targets of terrorist attacks, e.g., aircraft, utilities, government institutions, and the like. Instead, most of the casualties occurred in private residences, vehicles, and open areas, suggesting that personal attacks on individuals, or accidents, were responsible.34 Findings and Recommended Action Finding: Bombs that use black or smokeless powder cause a relatively small number of deaths and injuries, but their potential for use in terrorist activity is important. Typically over the past 5 years, about 300 "significant" bombing incidents have involved black or smokeless powder, and these bombings caused on the order of 10 deaths, 100 injuries, and $1 million in property damage annually.35 Although the number of incidents attributed to terrorism is currently very low—in the range of one or two incidents per year—the committee notes that when bombing incidents are acts of terrorism, the target is larger than the physical location of the explosion, since a goal is to induce panic or fear among the general population. Recent examples of terrorist acts that used black and smokeless powders include the bombings of the Unabomber and the knapsack bombing in Centennial Park, Atlanta, during the 1996 Olympics. Finding: The databases on bombing statistics as currently compiled by two federal agencies contain serious discrepancies and are not sufficiently comprehensive. To reach informed, appropriate decisions about legislation involving marking or tagging of explosives, policymakers need access to accurate and detailed information about the use and effects of improvised explosive devices in the United States. Currently, data are collected about the materials used in such devices, the type of target, the delivery mechanism, the number of deaths and injuries, who was killed or hurt, and the property damage. This information is valuable, and it would be useful to have, in addition, details about the final disposition of the bombing incidents (i.e., whether a suspect was identified and convicted). The data should be filed in such a way that interpretive correlations and trends in criminal activity can be readily extracted—especially for bombings judged to be "significant" according to specified criteria. RECOMMENDED ACTION: A single, national database on bombing statistics that is comprehensive, searchable, and up-to-date should be established. 34   A review of the data given in Tables 1.2 and 1.3 showed that only one incident was officially attributed to terrorism in the 3-year period. However, information on motives was not available for all of the incidents. 35   Approximately 6 of those killed and 24 of those injured each year are perpetrators, people who are believed to have been involved in constructing or delivering the explosive device.

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--> Both the ATF and the FBI provided the National Research Council with their data on the use of improvised explosive devices in the United States to assist the committee in understanding the extent of the problems caused by bombs involving smokeless and black powders. While this information was helpful, there were several areas in which the committee believed that more detailed and accurate statistics should be available to policymakers to allow them to make informed decisions about legislation involving the regulation, marking, or tagging of smokeless and black powders. Although both the ATF and the FBI are currently improving their systems for handling the reporting, updating, and storage of bombing data in ways that should make the data more accessible and searchable for analysts, discrepancies are likely to continue due to the agencies' different incident-reporting mechanisms and differences in the way that data exchanged between the two agencies are handled. A single form submitted36 to a single statistics database would reduce the delays in publishing data caused by the need for reconciling data between two agencies.37 Much of the information needed for this statistics database must come from state and local law enforcement agencies. Therefore, a single form by which to report incidents, and incentives designed to encourage these agencies to report bombing incidents, would be useful in establishing a more accurate and complete statistics database.38 In addition, entries should be updated as more information about an incident becomes available (such as the source of the powder used); this follow-up is particularly important for the data on suspects' identification, motivations, and convictions. In the absence of information on the resolution of bombing cases without taggants, it is difficult to assess the incremental utility that taggants would provide to law enforcement. 36   Ideally, incident reports would be filed and updated online by law enforcement officers in the field and be available for online searching by analysts nationwide. The FBI Bomb Data Center is already organizing its database along these lines. Michael Fanning, FBI, personal communication, August 10, 1998. 37   In June 1998, the most recent published bombing statistics from both the ATF and the FBI were for 1995. 38   In 1997, the White House Commission on Aviation Safety and Security recommended that a central clearinghouse be established to compile and distribute important information relating to previously encountered explosive devices, both foreign and domestic. However, the ATF and FBI continue to maintain separate statistics databases. Public Law 104-208 specified in 1996 that the "Secretary (of the Treasury) is authorized to establish a national repository of information on incidents involving arson and the suspected criminal misuse of explosives. All Federal agencies having information concerning such incidents shall report the information to the Secretary pursuant to such regulations as deemed necessary to carry out the provisions of this subsection. . . ." The Uniform Federal Crime Reporting Act of 1988 states that the "Attorney General may designate the Federal Bureau of Investigation as the lead agency" to "acquire, collect, classify, and preserve national data on Federal criminal offenses as part of the Uniform Crime Reports."

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