REDUCING THETHREA T OF IMPROVISED … Key...Key Recommendations | 1 Bombs are a weapon used by terrorists, violent extremists, and other malicious actors to cause death, injury, and

REDUCING THE THREAT OF

IMPROVISED EXPLOSIVEDEVICE ATTACKSBY RESTRICTINGACCESS TO EXPLOSIVE PRECURSOR CHEMICALS

KEY RECOMMENDATIONS

CONTENTSIntroduction 1

RECOMMENDATIONS

1. Combat Both Small and Large IEDS 2

2. Consider Multiple Chemicals 5

3. Focus on Retail-Level Access 8

4. Explore Opportunities to Harmonize Oversight of Kits for Making Explosive Targets 12

5. Analyze Specifi c Provisions for Strategies 15

6. Provide Additional Support for Voluntary Programs 19

Conclusions 21

References 23

Key Recommendations | 1

Bombs are a weapon used by terrorists, violent extremists, and other malicious actors to

cause death, injury, and fear throughout the world. An improvised explosive device (IED) is an

unconventional, do-it-yourself type of bomb. A malicious actor can construct an IED with common

materials, such as a switch and a battery power source, by following instructions easily found on

the Internet.

The main charge in an IED can be and often is constructed from ready-made products (such as

commercial explosives, military explosives, or pyrotechnics and propellants, including black and

smokeless powders) or from a homemade explosive (HME) (see Figure 1).

FIGURE 1. The components, possible explosive materials, and role of precursor chemicals in an IED.

While both ready-made products and HMEs have been used in IEDs in recent bombings[1–3]

and both are relevant to reducing the threat of IED attacks, this booklet specifi cally looks at

reducing that threat by restricting access to precursor chemicals, namely, chemicals that can

be used, through blending or chemical reaction, to produce HMEs. A 2017 study[4] outlines six

recommendations to help keep precursor chemicals, all of which can be purchased legally for

legitimate use, out of the hands of would-be bombers.

INTRODUCTION

Precursor Chemicals

Main Charge

Explosive Materials Improvised Explosive Device

Military Explosives(e.g., Semtex)

Switch

Initiator

Shrapnel

Container

Booster

PowerSource

Commercial Explosives(e.g., Dynamite)

Pyrotechnics and Propellants(e.g., Fireworks, Black Powder)

Homemade Explosives(e.g., Triacetone Triperoxide)

2 | Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Explosive Precursor Chemicals

RECOMMENDATION 1

Combat Both Small and Large IEDSThe fi rst recommendation is: “Federal, state, local, and private sector entities attempting to reduce

the threat of IED attacks by restricting access to precursor chemicals should focus on both person-

borne and vehicle-borne IEDs.”

Bomb makers construct IEDs in a range of sizes: vehicle-borne IEDs (VBIEDs, such as a truck

bomb) can have a main charge of 40 to tens of thousands of pounds, depending on the carrying

capacity of the vehicle, while person-borne IEDs (PBIEDs, such as a backpack bomb) usually have

a main charge that ranges from 1 to 40 pounds, depending on what the person can carry. The

truck bombs used against the World Trade Center in New York City in 1993 and the Murrah Federal

Building in Oklahoma City in 1995 are examples of VBIEDs. The smaller bombs used in the Boston

Marathon bombing in 2013 and the bomb incidents in New York and New Jersey in 2016 are

examples of PBIEDs. While the Boston bomb used pyrotechnics as its main explosive, the others

used HMEs made from precursor chemicals.

Before 2000, most high-profi le bombing incidents involved large-

scale devices, particularly VBIEDs.[1-3] Thus, U.S. policy makers have

tended to craft policy around concerns for VBIEDs. For example, the

U.S. Department of Homeland Security (DHS) used a 1998 report that

focused on the threat of VBIEDs to help establish a congressionally

mandated program to regulate chemical facilities.[5-7] In 2008, Congress

directed DHS to regulate the sale and transfer of ammonium nitrate by

ammonium nitrate facilities,[8–10] which had been used in several VBIED

attacks,[11–13] including the Oklahoma City bombing.[12] In 2011, DHS

published a notice of proposed rulemaking for an “Ammonium Nitrate

Security Program” and has since drafted a fi nal rule, but the rulemaking

process has not yet moved beyond that stage.

In recent years, however, a number of high-profi le bombing incidents have involved PBIEDs. While a

VBIED can cause more damage, a PBIED can be easier to construct and use. As both types of IED

present a danger, policy makers should consider both in any attempt to reduce the threat of IED

incidents by controlling access to precursor chemicals.


SELECTED ATTACKS INVOLVING EXPLOSIVES from 1970 to 2017 and the Mass of the Main Charge

1970 Sterling Hall Bombing (Madison, WI): 2,000 lb

1983 Beirut Barracks Bombing (Beirut, Lebanon): 20,000 lb*

U.S. Embassy Bombings (Beirut, Lebanon): 2,000 lb

1992 St. Mary Axe Bombing (London, United Kingdom): 2,000 lb

1993 World Trade Center Bombing (New York, NY): 1,200 lb

Bishopsgate Bombing (London, United Kingdom): 4,000 lb

1995 Oklahoma City Bombing (Oklahoma City, OK): 5,000 lb

1996 Manchester Shopping Mall (Manchester, United Kingdom): 3,000 lb

South Quay Bombing (London, United Kingdom): 3,000 lb

Khobar Towers Bombing (Khobar, Saudi Arabia): 20,000 lb*

1998 U.S. Embassy Bombings (Tanzania, Kenya): 2,000 lb*

1999 Millennial Bomber Interdiction (Port Angeles, WA): 500 lb

2000 USS Cole Bombing (Aden, Yemen): 1,000 lb*

2001 Shoe Bomber (AA Flight 63): 1 lb*

2002 Bali Nightclub Bombing (Bali, Indonesia): 2,000 lb

2003 Marriott Hotel Jakarta Bombing (Jakarta, Indonesia): 100 lb

British Consulate Bombing (Istanbul, Turkey): 2,000 lb

Casablanca Bombings (Casablanca, Morocco: 20 lb

2004 Australian Embassy Attack: 2,000 lb

U.S. Consulate Failed Attack (Karachi, Pakistan): 2,000 lb

2004 Disrupted Jordanian Attack (Amman, Jordan): 10,000 lb

U.S. Embassy Attack (Tashkent, Uzbekistan): 20 lb

Madrid Train Bombings (Madrid, Spain): 20 lb*

2005 7/7 Underground Bombing (London, United Kingdom): 20 lb

7/21 Bombing (London, United Kingdom): 20 lb

2006 Operation Overt (London, United Kingdom): 1 lb

Disrupted Plot (Ontario, Canada): 7,000 lb

2007 Disrupted Bomb (Ramstein, Germany): 1,000 lb

2008 U.S. Embassy Attack (Sana’a, Yemen): 100 lb*

2009 Underwear Bomber (NWA Flight 253): 1 lb*

Operation Highrise Interdiction (Denver, CO; New York, NY): 10 lb

2010 Printer Bombs (United Kingdom; United Arab Emirates): 1 lb*

Failed Times Square Plot (New York, NY): 100 lb

2011 Khalid Ali-M Aldawsari Plot (Lubbock, TX): 20 lb

Oslo Bombing (Oslo, Norway): 2,000 lb

2012 Aurora Theater Shooting (Aurora, CO): 20 lb*

2013 Boston Marathon Bombings (Boston, MA): 20 lb*

2015 Paris Attacks (Paris, France): 20 lb

2016 Brussels Attacks (Brussels, Belgium): 40 lb

Ahmad Khan Rahami (New York; New Jersey): 10 lb

*Incident did not involve homemade explosives.


BEYOND PRECURSOR CHEMICALS Data on bombing incidents in the United States is limited. However, what data is available shows that in the United States, a substantial majority of incidents have used commercial explosives, pyrotechnics, and black powder, smokeless powder, and flash powder, perhaps due to their ease of legal acquisition.[14-16]

This booklet focuses on precursor chemicals that can be blended or reacted to produce HMEs for IED attacks. However, any strategy that focuses only on access to precursor chemicals cannot eliminate the threat of IED attacks as long as these other explosive materials remain accessible to malicious actors.


The second recommendation is: “Federal, state, local, and private sector entities attempting to

reduce the threats from person-borne and vehicle-borne IEDs should consider multi-chemical,

rather than single-chemical, strategies.”

History shows that attempts to block malicious actors from accessing a weapon—or a component

of a weapon—lead them to change tactics. For example, in the 1970s, numerous terrorist groups

staged attacks using dynamite, including the Provisional Irish Republican Army (PIRA) in the United

Kingdom, Fuerzas Armadas de Liberación Nacional in Puerto Rico, the Weather Underground and

United Freedom Front in the United States. Both countries reacted by increasing restrictions on

access to dynamite and malicious actors in each country responded in turn. In the United States,

the bombers began using explosive materials like black and smokeless powders. Such materials

were not accessible in the United Kingdom, but PIRA was able to obtain farm chemicals to replace

the dynamite. PIRA began making HMEs with sodium chlorate from weed killer, but shifted to

ammonium nitrate and later to calcium ammonium nitrate, under pressure from successive rounds

of regulation.[17-18]

While it may be impossible to eliminate the threat of an IED attack, especially when black and

smokeless powders and other ready-made products are available, a strategy for restricting access

to precursor chemicals might help reduce it. However, the strategy is unlikely to help much if it

addresses only one or a few chemicals.

Figure 2 shows many (but not all) of the precursor chemicals that can be used to make HMEs,

each of which can be obtained legally and for legitimate use as industrial or agricultural inputs or as

consumer goods.

RECOMMENDATION 2

Consider Multiple Chemicals


SYNTHESIS CHEMICALSAcetone

Aspirin

Erythitol

Ethylene Glycol

Glycerol

Hexamine

Hydrazine

Hydrogen Peroxide, Dilute

Mannitol

Methanol

MEK

Pentaerythritol

Phenol

Sodium Azide

Urea

UAN Solution

Strong Acids

Sulfuric Acid

Hydrochloric Acid

Nitric Acid

Weak Acids

Citric Acid

Acetic Acid

Ascorbic Acid

OXIDIZERSHypochlorite Salts (Ca2+/ Na+)

Chlorate Salts (Na+/K+)

Hydrogen Peroxide, Concentrated (CHP)

Metal Peroxides (Ba2+/NA+)

Nitrate Salts (Ca2+/ Na+/K+/NH4

+[AN]/Ca2+NH

4+[CAN])

Nitrate Salts (Na+/K+)

Perchloric Acid

Perchlorate Salts (Na+/NH4

+/K+)

Potassium Permanganate

FUELSOrganic Materials

Diesel

Kerosene

Mineral Oil

Motor Oil

Sawdust

Vaseline

Inorganic Materials

Aluminum (Al), Powder/Paste

Antimony Trisulfide

Charcoal

Magnalium Powder

Magnesium Powder

Red Phosphorous

Sulfur

Titanium Powder

Zinc Powder

Food Products

Artificial Creamer

Black Pepper

Black Seed

Cinnamon

Cocoa

Cumin

Flour

Honey

Icing Sugar

Powdered Drink Mix

Energetic Organic Compounds

Nitrobenzene

Nitromethane (NM)

FIGURE 2. Potential precursor chemicals sorted by chemical type and role.

NOTE: Ca2+: calcium; Na+: sodium; K+: potassium; Ba 2+: barium; NH 4+: ammonium; AN: ammonium nitrate; CAN: calcium ammonium nitrate; MEK: methyl ethyl ketone; UAN: urea ammonium nitrate.


It would be impossible to restrict access to all precursor chemicals without disrupting people’s lives

and commerce. For example, many of the chemicals shown in the figure are common household

items, such as foods (e.g., flour and cocoa) or ordinary fuel sources. For this reason, the 2017

study[4] identified a smaller number of key chemicals and then ranked them by priority for policy

makers.

As a first step, the study committee removed the ubiquitous chemicals—such as foods and

common fuels—and those used in very small amounts. With that step, the number of chemicals

dropped to 28.

A second step used three criteria to prioritize the 28 remaining chemicals. Those that pose the

greatest threat (1) can be used to make HMEs for PBIEDs and VBIEDs, satisfying both purposes,

(2) have been used in bombings in the past, and (3) are not dependent on one other chemical,

but can be used with a variety of other chemicals to make an HME. While other precursor

chemicals still pose a threat, these top priority chemicals (shown in the sidebar) are ones that merit

particular concern, with the caveat that any strategy should be flexible enough to allow changes in

priorities as circumstances change. At any point in the future, circumstances can change, causing

other chemicals from the list of 28 to move up to a top priority precursor chemical. Continuous

reevaluation of the precursors is encouraged, as some of the rankings may change over time with

an evolving threat environment.

TOP PRIORITY PRECURSOR CHEMICALSAluminum (powder, paste, flake)

Ammonium nitrate

Calcium ammonium nitrate

Hydrogen peroxide

Nitric acid

Nitromethane

Potassium chlorate

Potassium perchlorate

Sodium chlorate

Urea ammonium nitrate solution*

* The decision to include urea ammonium nitrate (UAN) solution in the top priority precursor chemicals list represents the only departure from a strict application of the committee’s ranking principles. The ease of

producing various explosives from nitrating urea solutions, as seen elsewhere, supports the notion of UAN as a future threat and justifies its inclusion as a top priority.


RECOMMENDATION 3

Focus on Retail-Level AccessThe third recommendation is: “Federal, state, local, and private-sector entities attempting to reduce

the threats from person-borne and vehicle-borne IEDs should focus on retail-level transactions of

precursor chemicals, especially e-commerce.”

The 2017 study[4] examined the U.S. supply chains of the top priority precursor chemicals, from

their origin in the country (as an import or manufactured product) to their consumption in industry

or retail purchase. As mentioned above, all of these priority chemicals play a part in legitimate

commerce, with users located throughout the economy. Figure 3 shows an overall, stylized supply

chain: Chemicals enter the supply chain at blue nodes, are stored or transported at gray nodes,

and are transformed into something else or consumed at green nodes. Purple indicates the

possibility of e-commerce, directed toward consumers.

Many programs, both mandatory and voluntary, are in place along this supply chain, especially

near the start, but various federal and other agencies administer them differently and for different

purposes, according to their respective organizational goals. At the federal level, for example, the

Department of Transportation regulates hazardous materials during transport for safety reasons,

while the Environmental Protection Agency focuses on public health and environmental protection

and DHS targets security. The Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) directly

regulates chemicals that are defi ned statutorily as explosive materials, but only regulates one of the

identifi ed 28 precursor chemicals (ammonium perchlorate).[19,20] Still, ATF’s regulatory oversight does

apply to nodes where the precursor chemicals are manufactured into explosive materials.

Citing this confi guration of programs, agencies, and goals as a contributing factor, the 2017 report

calls out inconsistencies and possible gaps in coverage relative to concerns about precursor

chemicals and IED attacks, both large and small. Among the latter, DHS identifi es and regulates

high-risk chemical facilities, subject to thresholds for monitoring, such as 400 lb of nitric acid or

2,000 lb of ammonium nitrate, that may not be ideal for preventing access to PBIED-relevant

quantities of precursor chemicals. [7,21-25] Of 60,000 initial assessments submitted for review by

38,000 unique facilities,[24] only 2,570 are currently covered as high risk.[25] The remaining facilities

do not have to implement security plans because they store chemicals below the specifi ed

thresholds. The below-threshold amounts might be more than large enough to produce a PBIED,

even if they are not large enough to construct a VBIED.

In addition, the report suggests opportunities for better coordination among federal, state, and local

programs and with voluntary programs.

Examples of voluntary programs are discussed below under recommendation 6.


FIGURE 3. Generalized supply chain of precursor chemicals in the United States.

Export

Industry Agriculture Consumer

Manufacture

Remanufacture/Repackage

AmatureProduction

Import

PParcelarcelCarrierCarrier

Temporary Storage

Distribution/Wholesaler

AgriculturalRetailer

Point of Sale

Point of Sale

Retailer

TransportationInternational

BorderInternationalBorder

Node where a precursor or formulation containing it enters the supply chain.

Area of supply chain where e-commerce is relevant to consumers.

Node where a precursor or formulation containing it is held temporarily.

Node where a precursor ceases to be that chemical.

Distribution nexus, where precursors can move between all forms of transportation and included nodes.

Includes pipeline, railroad, barge or vessel, trucking, air freight.

May include May include distribution distribution and intake and intake locations.locations.


FIGURE 4. The generalized supply chain overlaid with relevant controls and other measures or activities (black circles).

Export

Industry Agriculture Consumer

Manufacture

Remanufacture/Repackage

AmatureProduction

Import

PParcelarcelCarrierCarrier

Temporary Storage

Distribution/Wholesaler

Agricultural Retailer

Point of Sale

Point of Sale

Retailer

TransportationInternationalBorder

InternationalBorder

A

C

C

E

E

G

R

S

T

T

Ω

T Ω

T Ω

Ω

∏

A C G ∏

T Ω ∏

O

C E ST Ω ∏

O

O

A C E T ∏O

C E T Ω ∏O

E G R T Ω ∏OE G T ΩO A C E T Ω ∏O

Bureau of Alcohol, Tobacco, Firearms and Explosives

Department of Commerce

Department of Transportation

Private-Public Partnership

Trade Group Program

State RegulationsDepartment of Homeland Security (CFATS)

Environmental Protection Agency

United States Coast Guard

Occupational Health and Safety Administration

Node where a precursor or formulation containing it enters the supply chain.

Area of supply chain where e-commerce is relevant to consumers.

Node where a precursor or formulation containing it is held temporarily.

Node where a precursor ceases to be that chemical.

Distribution nexus, where precursors can move between all forms of transportation and included nodes.

Includes pipeline, railroad, barge or vessel, trucking, air freight.

May include May include distribution distribution and intake and intake locations.locations.


Figure 4 shows the same supply chain presented in Figure 3 superimposed with the various

agencies, partnerships, and programs that play a part in oversight, either mandatory or voluntary,

at each node. (Remember that institutional presence at a node does not ensure comprehensive

oversight for all chemicals.) Multiple organizations monitor the chemicals early in the supply chain

(blue nodes), as the chemicals are transported and stored (gray nodes), and when the chemicals

are exported. Fewer or no organizations monitor the chemicals as they are sold to end users (green

nodes) outside of industry and agriculture.[4]

Nevertheless, industry tracks movement of precursor chemicals, especially in bulk quantities,

through much of the supply chain. Documentation includes purchase orders, shipping information,

and proof of delivery. This documentation could draw attention to a product that is misappropriated

for use in HMEs, for example, if a terrorist steals chemicals during transport. But the final step in the

supply chain—the sale of the chemicals to the end user—often lacks equivalent visibility, particularly

if purchasers use cash. In addition, because anyone can legally purchase those chemicals, their

purchase might not send up any red flags that a bomb maker is acquiring chemical ingredients.[26]

Thus, the report concluded that the retail level should be an area of focus. At that level, there

is substantially less oversight and visibility than elsewhere in the supply chain and the risk of

misappropriation appears to be the greatest, both because of the high volume of small transactions

that typically fall below regulatory thresholds and because many more locations are involved (e.g.,

thousands of sales outlets for some products).

E-commerce adds additional complexity to the situation. A purchaser can order chemicals without

showing his or her face in a store, and purchases can cross state lines, bypassing local-level

restrictions on access. Although online purchases can be tracked, there is no inherent means to

verify a purchaser’s true identity. One person could purchase multiple quantities of chemicals using

various identities, or from various sellers, to avoid notice.

Still, evidence from other venues and programs suggests the potential for risk reduction. For

example, in the EU, discussed more under recommendation 5, preliminary evidence from retail-

level controls indicates a decrease in the amount of chemicals for sale and an increase in reports of

suspicious retail transactions. Some options to better monitor and control retail-level sales are also

discussed under recommendation 5.


RECOMMENDATION 4

Explore Opportunities to Harmonize Oversight of Kits for Making Explosive Targets

The fourth recommendation is: “Federal, state, local, and private-sector entities should explore

strategies for harmonizing oversight of the sale and use of commercially available kits that contain

precursor chemicals that are specifi cally designed to be combined to produce homemade

explosives.”

These days, it is easy for bomb makers and potential bomb makers to fi nd the chemicals they need

in person or online, along with instructions for how to use them to make an explosive. An extreme

example of this is the exploding target kit.

An exploding target kit contains two precursor chemicals (usually ammonium nitrate and aluminum

powder) that are mixed to make an explosive. The kit’s intended use is as an aid in target practice;

when struck with a bullet, the exploding target explodes, showing the shooter that he or she hit the

mark. As evidenced from online videos and news reports, however, the kits can be and have been

misused with malicious intent. Ahmad Khan Rahami used a chemical from an exploding target kit

in the New York and New Jersey attacks in 2016. These kits are widely available through Internet

retailers and in physical stores.

The kits are especially problematic for a few reasons:

• They are easy to use and include mixing instructions that obviate the need for any technical

know-how

• They contain precursor chemicals in the optimal physical form to make an explosive

• They contain precursor chemicals in a weight ratio for optimized sensitivity to initiation

• They produce a mixture within seconds that either explodes violently or detonates with minimal

energy input

Exploding target kits generally slip through the cracks of oversight because they are not considered

explosives until they are mixed, and their components fall below regulatory thresholds. ATF does

not regulate the distribution and sale of exploding target kits because the individual components,

when unmixed, do not meet the defi nition of explosive materials that establishes ATF’s regulatory

jurisdiction.[27-28] Moreover, consumers do not require an ATF manufacturing license to mix the

components because mixing falls under personal use. DHS monitors relevant precursor chemicals,

but only when present above certain thresholds (2,000 lb for ammonium nitrate and 100 lb for

aluminum powder). Even if a retail store had enough kits to require monitoring, DHS would only

monitor the store’s security and not the transactions.


FIGURE 5. State Controls on Exploding Target Kits and Their Use

The state requires a license or permit to purchase or possess a kit

The state requires a license or permit to mix the components of a kit

The state requires a license or permit to use an exploding target

There is ambiguity in the statute regarding lawful use

The state has only proposed laws

The state has a 5 lb licensing threshold

Currently, the only federal oversight of the kits is from the U.S. Forest Service, which bans their use

on certain federal lands to prevent forest fi res.[29]

Some states attempt to control the kits (see Figure 5). For example, fi ve states regulate purchases

or possession via licensing or permitting,[30-36] while ten states regulate mixing under statutes that

require a license to manufacture and possess explosives.[37-46] States have varying defi nitions of

“explosives” (with some states including kit components in the defi nition) and “lawful purpose” in

relation to explosives. In addition, the FBI provides an advisory for retailers of exploding target kits.[47]


Even with some state-level controls in place, determined bomb makers can easily cross state lines

to acquire kits. Options for harmonizing oversight of the sale and use of exploding target kits could

include the following:

• Congress could expand DHS’s statutory authority to cover exploding target kits;

• Congress could expand ATF’s statutory definition of explosives to include exploding target kits;

• State or local governments could establish new controls for the purchase or use of the kits,

or could redefine terms such as “explosives” and “lawful use” to cover the kits under current

regulations; and

• Manufacturers, distributors, and retailers could develop voluntary measures to reduce threats

of misappropriation, for example, by securing materials, training employees to recognize

suspicious behavior, and reporting suspicious behavior or transactions.


RECOMMENDATION 5

Analyze Specifi c Provisions for StrategiesThe fi fth recommendation is: “U.S. DHS should engage in a more comprehensive, detailed, and

rigorous analysis of specifi c provisions for proposed mandatory and voluntary policy mechanisms to

restrict access to precursor chemicals by malicious actors.”

Precursor chemicals can be used to make bombs, but they also have many legitimate uses. They

are used in industry and agriculture and by the public for both commercial and noncommercial

purposes (e.g., cosmeticians use peroxide-based bleaching products and hobbyists use

nitromethane as a fuel in radio-controlled vehicles, respectively). Any attempt to stop precursor

chemicals from being used to make IEDs by restricting access at the retail level must consider the

effects on commerce and legitimate users.

The 2017 report[4] included an assessment of different strategies to reduce the threat of using

precursor chemicals in IEDs by controlling access at the retail level. Any policy that attempts to do

this would have three goals:

1. Restrict access to precursor chemicals by malicious actors

2. Gather and share information that might aid in responding to or preventing a terrorist incident

3. Minimize the burden on legitimate commerce and use

In general terms, the assessment looked at four possible types of control strategies that could

include a mix of mandatory and voluntary policy mechanisms. Because of the third goal, minimizing

the burden on commerce, commercial users were exempted from new mandatory restrictions if

they were able to provide evidence of commercial status. Noncommercial users, however, could

encounter one of the following:

1. A ban on purchasing

2. A requirement for a license to purchase

3. A requirement to sign a registry and show ID to purchase

4. Existing (but potentially augmented) requirements to purchase

In each of the fi rst three cases, the purchaser, if non-commercial, would face a new mandatory

restriction, that is, a ban, a licensing requirement, or a registry and signature requirement. In the

fourth case, the purchaser would face any existing controls, including state or local, but would not

face any new ones. All four approaches could be supplemented with outreach, training, reporting,

documentation, auditing, and inspections, resulting in the complete strategy package. For example,

retailers might train staff to request and verify evidence of commercial status or a license, or to

properly register people buying certain chemicals. Retailers might report suspicious behavior by

purchasers or the theft or other loss of the chemicals, or might document sales. These additional


policy mechanisms could be voluntary or mandatory. (Use of voluntary measures is discussed

further under recommendation 6.)

The assessment, which was just qualitative, looked at the benefits, costs, and uncertainties of each

of the first three strategy packages and ranked them accordingly. The assessment did not indicate

a clear “winner” among those strategies, but it did highlight various tradeoffs. For example, a ban

would be more restrictive than licensing or a registry; would possibly be cheaper to implement,

administer, and enforce; and could result in faster transaction times, but it might also result in the

most lost sales and use and entail the greatest additional social cost in terms of lost personal

freedom. Although a ban might be the most difficult option for terrorists to circumvent and could

make people feel safest, it might also be most likely to disrupt commerce or to “displace” terrorists,

prompting them to switch to different tactics.

The assessment also considered the benefits, costs, and uncertainties of the supplemental

measures and activities, some of which could result in gains in security and information gathering

but would still entail costs and uncertainties. For example, training and reporting on suspicious

behavior, fraud, theft, and loss could create better awareness of chemicals and concerns, and

could reduce purchases by malicious actors and lead to better tracking and visibility at the retail

level. However, these measures would cost money to administer and implement.

Nationwide control strategies for precursor chemicals are already in use in some countries. The EU,

which has had to grapple with the diverse circumstances of 28 member states much as the United

States must consider the circumstances of its own constituents, passed a regulation in 2013 on

the sale and use of certain precursor chemicals that defaults to a ban on sales to noncommercial

users, referred to as “members of the general public,” but allows member states to instead use

licensing or a registry.[48] Figure 6 shows how various EU member states have chosen to restrict

access.[49]

Since the regulation passed, the EU reports that the amount of precursor chemicals for sale has

decreased and that authorities’ capacity to investigate suspicious incidents involving the chemicals

has increased, but with some cost to commerce and legitimate users.[50] However, the EU has

also noted challenges: for example, authorities face difficulties reaching retailers and enforcing

restrictions on Internet sales, imports, and intra-EU product flows; differences among member

states’ programs can obstruct legitimate commerce; and retailers have had difficulty identifying

which products fall under the regulation and which purchasers are legitimate commercial users.[51]

The United States could face similar challenges; already, differing state laws concerning ammonium

nitrate might cause confusion that inhibits commerce and undermines state’s efforts to mitigate

risk.

The results of the assessment of the strategy packages, noted above, are illustrative, but for a

policy change to occur, policy makers need more detail. Benefits and costs of specific provisions

should be studied comprehensively, preferably with numbers attached. The different effects of

voluntary measures and mandatory measures should be considered, as well as the effect of

applying the controls to commercial purchases or to certain quantities of chemicals. U.S. policy


makers should consider the results of existing U.S. programs that restrict access to precursor

chemicals, including those intended to curb illicit drug production, and of existing programs

worldwide. This more rigorous analysis would help policy makers objectively consider the tradeoffs

and build consensus about the benefits and costs of different options. Therefore, DHS should

conduct a more detailed and comprehensive analysis of possible strategies for restricting access to

precursor chemicals to reduce the threat of IED attacks.

Supplementary to this recommendation, the 2017 report urged policy makers to identify and

overcome impediments to further analysis, including time constraints and lack of funds, expertise,

or suitable analytical tools and methods.

FIGURE 6. Implementation of the EU’s 2013 regulation by country.

License

Registration

Ban

S The country licenses or registers a subset of the list of precursor chemicals

S

SS

S

S


DYNAMIC POLICIESPolicy regarding precursor chemicals should not be static. For one, use of some chemicals might wane and others take precedence as situations and technology change; no list of priority precursors can be immutable. For another, experience—good or bad—can inform policy making and implementation. If a control strategy can be reduced, expanded, or reoriented to meet changing needs or improve functionality, it can better serve policy, but the strategy can only do so if it is alterable.

Evaluation is needed to help policy makers leverage experience. Although it can be difficult to separate out the effects of a control strategy, it is still possible to examine participation rates, inspection results, data on terrorist episodes, and evidence from elsewhere. If, as suggested above, the policy community can identify and overcome impediments to analyzing the benefits and costs of strategy proposals, it would likely help in this effort.


The sixth and fi nal recommendation is: “The federal government should provide additional support

for voluntary measures, activities, and programs that can contribute to restricting access by

malicious actors to precursor chemicals used to manufacture IEDs.”

Voluntary measures, activities, and programs can help to restrict potential bomb makers’ access

to precursor chemicals. They can—and in some instances already do—include the supplemental

efforts listed in recommendation 5:

• Outreach and training seek to raise awareness and to educate retailers about precursor

chemicals, including their oversight and safety, to help them to recognize suspicious behavior,

and to encourage them to adopt best practices

• Reporting on suspicious behavior, fraud, theft, and loss aims to prevent terrorist incidents or

facilitate better responses to them, for example, by providing details on the circumstances of

suspicious purchases of precursor chemicals

• Documentation can preserve information that might be useful to investigators seeking to

prevent or follow up on a bombing incident

• Audits and inspections can be used to evaluate retailers’ practices as tools for education or

enforcement; random audits catch them off guard, while planned inspections allow them to

prepare

• Mystery shopping, which is used as an educational tool in the EU, is a type of audit in which an

“actor” attempts to purchase a precursor chemical and then provides feedback to the retailer

or responsible authorities on the transaction, if it was done properly, and what, if anything,

could be done better in the future

These types of efforts could be made mandatory or voluntary, as noted under recommendation

5, but businesses might choose to participate in voluntary programs and act voluntarily for many

reasons: for example, they do not want to enable terrorism or harm to others; they do not want to

be seen as a business that enables terrorism or harm to others and risk losing sales from a bad

reputation; or they do not want to risk being fi nancially liable for a terrorist incident. In addition,

trade associations can take steps, as described below, to encourage their members to participate

and act, for example, through education and outreach, by highlighting members’ performance, and

by conditioning membership on compliance.

There are currently many voluntary programs in use in the United States.

RECOMMENDATION 6

Provide Additional Support for Voluntary Programs


Some voluntary programs result from public-private partnerships. For example, the Federal

Aviation Administration created the Known Shipper Program to allow air carriers to follow different

procedures for shippers that have previously been vetted.[52,53] Customs and Border Patrol works

with shippers through the Customs-Trade Partnership Against Terrorism to develop security plans in

exchange for reduced inspections and faster processing.[54,55]

Other voluntary programs are sponsored by trade associations. For example, the Institute of

Makers of Explosives provides members with best practices training materials and tools, and

requires members to comply with safety guidelines.[56] The American Chemistry Council requires

members to participate in its Responsible Care program, which promotes security and safety[57, 58]

and makes public the performance of companies to motivate them to comply. ResponsibleAg Inc.

is a nonprofit that certifies agribusinesses that comply with federal regulations regarding the safe

handling and storage of fertilizer products, and assists them in doing so.[59-61] While these programs

might be required of association members, they are considered voluntary because membership in

the association is voluntary.

Both industry and the government engage in voluntary outreach activities. For example, ATF

runs programs like Be Aware for America to educate the fertilizer industry on illegitimate use of

precursor chemicals, encourage voluntary reporting of suspicious activity involving the precursors,

and increase awareness of security vulnerabilities.[62] The FBI performs similar outreach targeted at

retailers.[63] In addition, both government[64,65] and private groups[66] have written and made available

literature on best security practices, which industry can choose to implement.

While a mandatory program, measure, or activity might have more force than a voluntary one, due

to the threat of fines or imprisonment, voluntary approaches can and have gained acceptance, with

some effect. For example, within a few years, 2,282 facilities participated in the ResponsibleAg

program, with 452 reaching full compliance,[60] and Responsible Care has reduced health and safety

incidents at member companies by 53–78 percent (depending on the measure).[57, 58]

Voluntary programs, such as those designed to educate retailers on how to identify suspicious

activity, might be most effective if designed with input from businesses’ leadership so that the

programs can become part of the prevailing corporate culture.


CONCLUSIONSPrecursor chemicals have been used to make HMEs for IEDs used in terrorist attacks. Such an

attack in the United States might someday prompt policy makers to make a rapid and narrow

decision about controlling the chemicals, as has sometimes happened in the past. However, a

decision made rapidly and under the duress of a recent attack will probably not lead to the best

long-term strategy for reducing further attacks. Instead, engaging in deliberative thinking before an

attack occurs can help to avoid the pitfalls of intuitive thinking and a bias toward action during and

after crises.[67,68]

Congress has an essential role in developing and implementing appropriate risk-reducing control

strategies. They are poised to defi ne the responsibilities of federal agencies, gather information via

fact-fi nding hearings, and adequately fund collaborative public-private work, among other things.

In particular, Congress can help to ensure that crisis-driven interests do not unduly infl uence new

laws or regulations. The six recommendations in this booklet are fi rst steps that policy makers can

take to reduce the threat posed by the availability of precursor chemicals and ensure the safety of

our nation.


FURTHER RESEARCH NEEDEDIn addition to the six recommendations given in this booklet, at least four areas merit additional research.

1. Data collection from incidents involving explosivesData from incidents is needed to track the changing use of precursor chemicals in IEDs and to provide an analytical perspective. The U.S. Bomb Data Center, which collects and stores relevant domestic data, and other federal agencies should focus on collecting detailed and verified data on incidents involving explosives. Focus areas include the following: improving data collection on the chemical composition of the explosives used in IEDs and the precursor chemicals recovered during incidents and investigations; verifying data when final laboratory results become available; aggregating and presenting data; improving data entry compliance for robustness and timeliness; and conveying policy makers’ information requirements to the U.S. Bomb Data Center.

2. Substitute chemicalsWhile many products require the particular precursor chemicals listed on page 7 as ingredients, other products might be able to use less risky alternatives. In some instances, the changes might be straightforward, for example, replacing the ammonium nitrate in cold packs with a different salt, but in other instances the changes, including identification, might require substantial effort. Given the costs of research, development, and implementation in those cases, clear incentives would be needed from the market or elsewhere to initiate the process.

3. Standardized thresholdsCurrent regulations use a variety of mass and concentration thresholds to control chemicals. The different thresholds may create unnecessary confusion for legitimate commerce and still not prevent malicious actors from purchasing the precursor chemical at the quantity or quality needed to manufacture HMEs. For example, 35 percent concentration is DHS’s threshold for monitoring hydrogen peroxide, which exempts most products from oversight, but lower concentrations can be used to make the explosive triacetone triperoxide.[69] A systematic study to identify the thresholds based on sound scientific principles would contribute toward the goal of preventing the use of precursor chemicals in HMEs.

4. Behavioral responsesThe 2017 report suggests further research into the behavioral responses of (a) malicious actors, businesses, and end users to policy, and (b) the public and policy makers to the threat of a terrorist act or an actual terrorist act, both of which can affect the benefits and costs of policy efforts. Research could delve into questions in each dimension. For example, how much knowledge is needed for a terrorist to circumvent a control, or what perception of difficulty will cause a shift in tactics? How much inconvenience will businesses or consumers tolerate? Are there ways to ingrain and encourage deliberative thinking in policy making processes, especially in the midst of crises, without forestalling decision making?


1 Kirk Yeager, FBI, Washington, DC, personal communication, April 19, 2017.

2 Corderoy, J. 2014. Material Harm. London: Action on Armed Violence. https://aoav.org.uk/wp-content/uploads/2015/03/ied_material_lr.pdf (accessed 09/25/2017).

3 Rostberg, J.I. 2005. Common Chemicals as Precursors of Improvised Explosive Devices: The Challenges of Defeating Domestic Terrorism. M.A. Thesis, Naval Postgraduate School, Monterey, CA.

4 National Academies of Sciences, Engineering, and Medicine. 2017. Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Explosive Precursor Chemicals. Washington, DC: The National Academies Press. https://doi.org/10.17226/24862.

5 NRC. 1998. Containing the Threat from Illegal Bombings: An Integrated National Strategy for Marking, Tagging, Rendering Inert, and Licensing Explosives and Their Precursors. Washington, DC: National Academy Press.

6 Gares, K.L., K.T. Hufziger, S.V. Bykov, and S.A. Asher. 2016. Review of explosive detection methodologies and the emergence of standoff deep UV resonance Raman. J. Raman Spectrosc. 47(1):124-141.

7 6 CFR (Code of Federal Regulation) § 27. Chemical Facility Anti-Terrorism Standards (2017).

8 DHS (U.S. Department of Homeland Security). 2011. Ammonium nitrate security program; Proposed rule. Fed. Reg. 76(149):46908-46957.

9 Consolidated Appropriations Act of 2007, Pub. L. No. 110-161, 121 Stat. 1844.

10 6 U.S.C. (U.S. Code) § 488. Defi nitions (2016).

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13 CBS. 2013. A look back at the Norway massacre. News: February 18, 2013. http://www.cbsnews.com/news/a-look-back-at-the-norway-massacre (accessed 06/08/2017).

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15 27 CFR § 555.26. Prohibited Shipment, Transportation, Receipt, Possession, and Distribution of Explosive Materials (2017).

16 27 CFR § 555.41. General (2017).

17 Hayes, B.C., and I. McAllister. 2005. Public support for political violence and paramilitarism in Northern Ireland and the Republic of Ireland. Terror. Polit. Violence 17(4):599-617.

18 Foulger, B., and P. Hubbard. 1996. A review of techniques examined by UK authorities to prevent or inhibit the illegal use of fertiliser in terrorist devices. Pp. 129-133 in Compendium of Papers of the International Explosives Symposium, September 18-22, 1995, Fairfax, VA. Washington, DC: Bureau of Alcohol, Tobacco, Firearms and Explosives.

19 27 CFR § 555.23. List of Explosive Materials (2017).

20 ATF (Bureau of Alcohol, Tobacco, Firearms, and Explosives). 2016. Commerce in explosive: Annual list of explosive materials. Fed. Reg. 81(221):80684-80686.

21 6 U.S.C. § 627. SFATs Regulations (2016).

22 Klessman, T., and K. Murray. 2017. Chemical Facility Anti-Terrorism Standards (CFATS) and Secure Handling of Ammonium Nitrate Overview. Presentation at the Third Meeting on Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Chemical Explosive Precursors, February 7, 2017, Washington, DC.

23 IP (The Offi ce of Infrastructure Protection). 2017. Chemical Facility Anti-Terrorism Standards (CFATS) Tiering Results Update. Webinar on CFATS Tiering Update - April 2017, April 24, 2017.

24 DHS. 2017. Tiering update. CFATS Quarterly 3(4).

25 DHS. 2017. Chemical Facility Anti-Terrorism Standards: Monthly Update. Fact Sheet: May 2017. https://www.dhs.gov/sites/default/fi les/publications/cfats-fact-sheet-05-17-508.pdf (accessed 07/06/2017).

26 Sheffi , Y. 2005. The Resilient Enterprise: Overcoming Vulnerability for Competative Advantage. Cambridge, MA: The MIT Press.

REFERENCES


27 ATF. 2017. Binary Explosives. https://www.atf.gov/explosives/binary-explosives (accessed 07/26/2017).

28 27 CFR § 555.11. Meaning of Terms (2017).

29 DOJ (U.S. Department of Justice). 2013. U.S. Forest Service Implements Closure Order to Prohibit Use of Exploding Targets on National Forest and Grasslands in Rocky Mountain Region, August 5, 2013. U.S. Attorney’s Office District of Colorado. https://www.justice.gov/usao-co/pr/us-forest-service-implements-closure-order-prohibit-use-exploding-targets-national-forest (accessed 07/28/2017).

30 Washington Revised Code § 70-74-022. License Required to Manufacture, Purchase, Sell, Use, Possess, Transport, or Store Explosive-Penalty (2017).

31 California Penal Code § 18720. Destructive Devices and Explosives Generally; Prohibited Acts (2016).

32 Massachusetts General Laws, Ch. 266 § 102. Possession or Control of Incendiary Device or Material; Possession of Hoax Device or Material Penalty (2016).

33 Maryland. Code Public Safety § 11-101. Definitions (2016).

34 Lousiana Laws Revised Statutes § 40:1472.2. Public Health and Safety Definitions (2016).

35 Code of Virginia § 18.2-85. Manufacture, Possession, Use, etc, of Fire Bombs or Explosive Materials or Devices; Penalties (2016).

36 Herring, M.R. 2014. Tannerite Advisory Opinion. Commonwealth of Viriginia, Office of the Attorney General, Richmond, VA. https://www.vafire.com/content/uploads/2016/10/Enclosure-1-Attorney-General-Opinion-Tannerite-October-2014.pdf (accessed 09/29/17).

37 Oregon Revised Statutes § 480.210. Certificate, License or Permit Required (2015).

38 New Mexico Statutes § 30-7-19.1. Possession of Explosive Device or Incendiary Device (2016).

39 Colorado Revised Statutes § 18-12-109. Possession, Use, or Removal of Explosives or Incendiary Devices-Possession of Components Thereof-Chemical, Biological, and Nuclear Weapons-Persoms Exempt-Hoaxes (2016).

40 Tennessee Code § 39-17-1301. Weapons; Part Definitions (2016).

41 Ohio Revised Code § 2923.17. Unlawful Possession of Dangerous Ordnance-Illegally Manufacturing or Processing Explosives (2016).

42 West Virginia Code § 61-3E-1. Offenses Involving Explosives; Definitions (2016).

43 New Jersey Revised Statutes § 21:1A-133. Permits for Manufacture, Sale, Storage, Transportation or Use of Explosives (2016).

44 Connecticut General Statutes § 29-349. Storage, Trasportation and Use of Explosives and Blasting Agents. Licenses, Permits: Fees, Suspension or Revocations (2015).

45 Hawaii Revised Statutes § 134-28. Explosive Devices; Prohibitions; Penalty (2016).

46 25 Maine Revised Statutes § 2472. Explosives; Rules (2016).

47 Tannerite. 2016. Legal Advisory. https://tannerite.com/legal-advisory (accessed 08/01/2017).

48 EU (European Union). 2013. Regulation (EU) No. 98/2013 of the European Parliament and of the Council of January 15, 2013, on the marketing and use of explosives precursors. O.J. (L 39):1-11.

49 EC. 2017. List of Measures to Implement Regulation (EU) 98/2013 on Explosives Precursors in the EU/EEA. European Commission, Brussels, Belgium. https://ec.europa.eu/home-affairs/sites/homeaffairs/files/what-we-do/policies/crisis-and-terrorism/explosives/explosives-precursors/docs/list_of_measures_en.pdf (accessed 10/4/2017).

50 Nagesh, A. 2017. Five terror plots thwarted since Westminster attack in March. Metro News: May 25, 2017. http://metro.co.uk/2017/05/25/five-terror-plots-thwarted-since-westminster-attack-in-march-6661876 (accessed 07/12/2017).

51 EC. 2017. Report from the Commission to the European Parliament and the Council on the Application of, and Delegation of Power under Regulation (EU) 98/2013 of the European Parliament and of the Council on the Marketing and Use of Explosives Precursors. European Commission, Brussels, Belgium.

52 49 CFR § 1548.17. Known Shipper Program (2016).

53 OIG. 2009. Transportation Security Administration’s Known Shipper Program (OIG-09-35). U.S. Department of Homeland Security Office of the Inspector General: Washington, DC. https://www.oig.dhs.gov/assets/Mgmt/OIGr_09-35_Mar09.pdf (accessed 09/26/2017).

54 6 U.S.C. §§ 96 -973. Customs -Trade Partnership Against Terrorism (2016).


55 Krupinsky, S. 2017. C-TPAT. Presentation at the Third Meeting on Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Chemical Explosive Precursors, February 8, 2017, Washington, DC.

56 Hilton, C. 2016. Institute of Makers of Explosives. Presentation at the Second Meeting on Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Chemical Explosive Precursors, December 13, 2016, Washington, DC.

57 Roczniak, D. 2017. American Chemistry Council Responsible Care & Security Code. Presentation at the Third Meeting on Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Chemical Explosive Precursors, February 8, 2017, Washington, DC.

58 ACC (American Chemistry Council). 2017. Responsible Care. https://responsiblecare.americanchemistry.com (accessed 06/13/2017).

59 Liske, K. 2017. Agricultural Retailers and Chemical Explosive Precursors. Presentation at the Third Meeting on Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Chemical Explosive Precursors, February 7, 2017, Washington, DC.

60 O’Hare, A. 2016. Improvised Explosives and the Fertilizer Industry. Presentation at the Second Meeting on Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Chemical Explosive Precursors, December 12, 2016, Washington, DC.

61 ResponsibleAg. 2017. News. https://www.responsibleag.org (accessed 06/13/2017).

62 McCrary, W. 2017. Bureau of Alcohol, Tobacco, Firearms, and Explosives. Presentation at the Third Meeting on Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Chemical Explosive Precursors, February 8, 2017, Washington, DC.

63 Sheehan, K., and M. Hendley. 2017. How We View the Threat. Presentation at the Third Meeting on Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Chemical Explosive Precursors, February 8, 2017, Washington, DC.

64 DHS. 2012. Chemical Sector Security Awareness Guide: A Guide for Owners, Operators, and Chemical Supply-Chain Professionals. https://www.dhs.gov/sites/default/files/publications/DHS-Chemical-Sector-Security-Guide-Sept-2012-508.pdf (accessed 09/28/2017).

65 DHS. 2015. Chemical Sector-Specific Plan: An Annex to the NIPP 2013. https://www.dhs.gov/sites/default/files/publications/nipp-ssp-chemical-2015-508.pdf (accessed 09/28/2017).

66 Adams, J., P. Kurzer, A. Allen, P. Aubrey, E. Auner, R.G. Baird, C. Beecroft, N. Donohue, K.A. Grant, A. Kattan, and J.E. Nolan. 2013. Remaking American Security: Supply Chain Vulnerabilities & National Security Risks Across the U.S. Defense Industrial Base. Washington, DC: Alliance for American Manufacturing. http://docs.house.gov/meetings/FA/FA14/20130725/101216/HHRG-113-FA14-Wstate-AdamsB-20130725.pdf (accessed 09/28/2017).

67 Kunreuther, H. 2017. Conceptual Frameworks for Dealing with Risk. Presentation at the Third Meeting on Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Chemical Explosive Precursors, February 7, 2017, Washington, DC.

68 Kahneman, D. 2011. Thinking, Fast and Slow. New York: Farrar, Straus, and Giroux.

69 Anderson, R. 2016. Hydrogen Peroxide and Sodium Chlorate. Presentation at the Second Meeting on Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Chemical Explosive Precursors, December 13, 2016, Washington, DC.

DISCLAIMER

This Key Recommendations product has been prepared by Emily Buehler as a factual summary of what is presented in the final

report Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Explosive Precursor Chemicals. The

statements made are those of the authors or individual meeting participants and do not necessarily represent the views of all

meeting participants, the committee, the Board on Chemical Sciences and Technology, or the National Academies.

COMMITTEE MEMBERS

Victoria A. Greenfield (Chair), George Mason University; Robert G. Best, Defense Threat Reduction Agency – JIDO; Leo E.

Bradley, LE Bradley Consulting LLC; John C. Brulia, Austin Powder Company (Retired); Carrie L. Castille, Independent Consultant;

David G. Delaney, University of Maryland; Arthur G. Fraas, Resources for the Future; William J. Hurley, Institute for Defense

Analysis; Karmen N Lappo, Sandia National Laboratory; Becky D. Olinger, Los Alamos National Laboratory; Jimmie C. Oxley,

University of Rhode Island; Kevin F. Smith, Sustainable Supply Chain Consulting; Kirk Yeager, Federal Bureau of Investigation.

STAFF MEMBERS

Camly Tran, Study Director; Samuel M. Goodman, Postdoctoral Fellow; Jarrett Nguyen, Senior Program Assistant.

The National Academies’ Board on Chemical Sciences and Technology (BCST) exists as the oversight group that ensures the

highest quality scientific and technical advice is being provided to our Nation’s decision makers from experts in chemistry and

chemical engineering. BCST is a forum through which the chemistry and chemical engineering communities can give back to

society, demonstrate the broader impact of their expertise, and help address critical societal problems.

This activity and summary were supported by the U.S. Department of Homeland Security Grant No. HHSP233201400020B/

HHSP23337050. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors

and do not necessarily reflect the views of the organization or agency that provided support for the project.

LEARN MORE ABOUT OUR WORK

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REDUCING THETHREA T OF IMPROVISED … Key...Key Recommendations | 1 Bombs are a weapon used by terrorists, violent extremists, and other malicious actors to cause death, injury, and