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Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Explosive Precursor Chemicals (2018)

Chapter: 6 Potential Approaches to Restricting Malicious Actors' Access to Precursor Chemicals: Conclusions and Recommendations

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Suggested Citation:"6 Potential Approaches to Restricting Malicious Actors' Access to Precursor Chemicals: Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2018. Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Explosive Precursor Chemicals. Washington, DC: The National Academies Press. doi: 10.17226/24862.
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6

Potential Approaches to Restricting Malicious Actors’ Access to Precursor Chemicals: Conclusions and Recommendations

In this report, the committee has presented its assessment of the threats posed by precursor chemicals used to make homemade explosives (HMEs) that can be employed in impovised explosive devices (IEDs), the challenges of restricting malicious actors’ access to precursor chemicals as they move through the supply chain from manufacturers to end users, and the relative merits of different approaches to addressing vulnerabilities without undermining legitimate commerce and use. Responsive to the statement of task, this chapter provides recommendations that draw from the findings and conclusions of previous chapters.

Precursor chemicals have played a significant role in the manufacture of HMEs used in IED terrorist attacks (see Chapter 1), but that role has changed over time and will continue to change in the future. Malicious actors intent on damaging critical infrastructure, inflicting causalities, and eliciting fear have demonstrated the ability to change their tactics in response to the implementation of controls or shifts in the availability of particular precursor chemicals (see Chapter 2). Given the ease of accessing precursor chemicals and the information needed to manufacture HMEs, particularly via the internet, the threat of terrorist attacks using IEDs within the United States has not abated.

While the United States has not experienced a major domestic attack with a vehicle-borne IED (VBIED) since the 1990s, the committee stresses the importance of deliberative thinking before crises, and cautions against intuitive thinking and action bias during and after crises. Even if event-driven policy making is unavoidable, it might be possible to lay a foundation for constructive policy responses. The analyses outlined in this report should serve as the basis for such measured actions.

The committee also stresses the importance of periodically reevaluating priorities among precursor chemicals, in light of changes in the threat environ-

Suggested Citation:"6 Potential Approaches to Restricting Malicious Actors' Access to Precursor Chemicals: Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2018. Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Explosive Precursor Chemicals. Washington, DC: The National Academies Press. doi: 10.17226/24862.
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ment, and of designing control strategies with means of harvesting and leveraging data to learn from experience and strengthen policy over time. The committee assigned chemicals of particular concern to one of three groups, A, B, or C, by priority, but policy makers should treat neither the groups nor any control strategy as static. Policy makers should view policy development and implementation as part of an ongoing process of risk management (see Appendix B) and, for that reason, should consider designing any control strategy with enough flexibility to accommodate environmental change, learning, and amendments.

As described in Chapter 3, the lack of consistency at the federal, state, and local levels appears to have resulted in a domestic policy environment that lacks coherence along the supply chain, leading to confusion for those subject to existing controls and to gaps in visibility and oversight. There have been some efforts to improve coordination and consistency as seen with the Joint Program Office. Further coordination among federal, state, and local agencies, and across independent and overlapping governmental and nongovernmental programs, can strengthen policy implementation.

BEYOND PRECURSOR CHEMICALS

The statement of task for this study clearly focused the efforts of the committee on examining precursor chemicals that can be used to produce HMEs for IED attacks. While precursor chemicals are used to produce HMEs for IEDs, the committee recognizes that, in the United States, a substantial majority of explosives incidents as defined by the U.S. Bomb Data Center (USBDC) used commercial explosives, black powder, smokeless powder, and pyrotechnic filler, perhaps due to their ease of legal acquisition. Thus, 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.

Looking through a wider lens, the committee also recognizes the potential for displacement beyond the realm of explosive materials. Even if policy makers were to eliminate the threat of IED attacks, terrorists could shift strategies and tactics, and choose other lethal means or weapons over explosive materials. Recent attacks targeting pedestrians, shoppers, and others with knives, firearms, and vehicles in the United States, Europe, and elsewhere suggest a range of viable options for inciting terror.

RECOMMENDATIONS

Pursuant to the primary goal of reducing the threat of IED attacks by restricting access to precursor chemicals, and cognizant of the need to preserve legitimate commerce and use, the committee details six recommended courses of action and four research areas meriting future attention.

Suggested Citation:"6 Potential Approaches to Restricting Malicious Actors' Access to Precursor Chemicals: Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2018. Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Explosive Precursor Chemicals. Washington, DC: The National Academies Press. doi: 10.17226/24862.
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Priority Precursor Chemicals

Recommendation 1: 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.

Precursor chemicals can be and have been used in the explosive charges applied in VBIEDs, person-borne IEDs (PBIEDs), aircraft bombings, and detonators. Prior research efforts, such as the 1998 Academies report,14 and much of current U.S. policy (see Chapters 1 and 3) have tended to emphasize the threat posed by VBIEDs requiring the use of large charges over the threat posed by PBIEDs requiring the use of smaller main charges. However, as shown in Chapter 2, PBIEDs represent a substantial proportion of IED attacks, both domestically and internationally, and can inflict substantial casualties when deployed near crowds of people. The committee concluded that any effort seeking ultimately to reduce the threat of IED attacks should account for precursor chemicals used in PBIEDs along with those used in VBIEDs. Taking a more comprehensive approach to threat reduction would require consideration of the wider range of precursor chemicals that can be used to construct a PBIED, the overlap of those chemicals with VBIED-relevant precursor chemicals, and the masses and properties of the precursor chemicals required to construct a main charge for each attack mode.

Recommendation 2: 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.

Data from domestic and international terrorist incidents involving explosives demonstrates that a multitude of precursor chemicals can be used to manufacture HMEs for VBIEDs or PBIEDs. A strategy that focuses on merely one chemical, such as ammonium nitrate (AN) as proposed by the ANSP, cannot adequately reduce the threat of IED attacks due to the availability of alternatives and the historically demonstrated capacity of terrorists to modify their tactics in response to single-chemical controls. This behavioral response has been observed in Northern Ireland, where a strategy that responded narrowly to particular circumstances focused on individual chemicals allowed the Provisional Irish Republican Army (PIRA) the opportunity to change its tactics while maintaining the amount of damage caused (see Chapter 2).

The committee developed a prioritized list of precursor chemicals according to three equally weighted criteria: (1) whether the precursor chemical can be used to make HMEs suitable for a VBIED, a PBIED, or both; (2) the precursor chemical’s history of use in manufacturing HMEs; and (3) whether the precursor chemical can be used independently, or is dependent on other specific chemicals, for creating a main charge. On that basis, the committee established three groups of chemicals,

Suggested Citation:"6 Potential Approaches to Restricting Malicious Actors' Access to Precursor Chemicals: Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2018. Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Explosive Precursor Chemicals. Washington, DC: The National Academies Press. doi: 10.17226/24862.
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Groups A, B, and C, by order of priority. Chemicals that met all three criteria—that is, they could be used for both VBIEDs and PBIEDs, had a history of use, and could be used independently—were placed into Group A. Chemicals that satisfied two criteria were placed in Group B, with one exception, and chemicals that satisfied one criterion were placed in Group C.

Twenty-eight precursor chemicals are distributed among the three groups. Group A consists of aluminum (powder, paste, and flake), AN, calcium ammonium nitrate (CAN), hydrogen peroxide, nitric acid, nitromethane, potassium chlorate, potassium perchlorate, sodium chlorate, and urea ammonium nitrate (UAN) solution; Group B consists of calcium nitrate, hydrochloric acid, potassium nitrate, potassium permanganate, sodium nitrate, sodium nitrite, sulfur, sulfuric acid, urea, and zinc (powder); and Group C consists of ammonium perchlorate, antimony trisulfide, hexamine, magnalium (powder), magnesium (powder), pentaerythritol, phenol, and potassium nitrite.

The committee made only one exception to the application of the three criteria. While UAN, as a commercially available product, does not meet the historical usage criterion, and thus would otherwise belong in Group B, the committee observed a well-documented history of explosive production in Iraq from analogous solutions of urea and nitrate salts. The history of nitrating urea solutions, the ease of producing various explosives from this precursor, and the strong belief that UAN solution may potentially constitute a significant future threat justified its inclusion in Group A.

The chemicals in Groups B and C could become higher priority chemicals at any time because of their suitability for making HMEs used in IEDs. A change in the threat environment could also cause an increase in amateur production of the precursor chemicals that appear in Groups A, B, and C. As a result, continuing evaluation and, potentially, re-prioritization of chemicals will be required to meet changes in the threat environment.

Strategies at the Retail Level

Recommendation 3: 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 precursor chemicals, regardless of their association with Group A, B, or C, flow through complex supply chains and have legitimate uses for both commercial and personal use. Most of these precursor chemicals are readily available through physical retailers, online retailers, or both, and all Group A chemicals are available online. Notwithstanding considerable differences in the paths that each precursor chemical follows, the committee found sufficient commonality to create a generalized supply chain; to overlay existing mandatory and voluntary

Suggested Citation:"6 Potential Approaches to Restricting Malicious Actors' Access to Precursor Chemicals: Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2018. Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Explosive Precursor Chemicals. Washington, DC: The National Academies Press. doi: 10.17226/24862.
×

policy mechanisms that touch the chain; and to identify potential vulnerabilities, as evidenced in a lack of either visibility or oversight.

Federal controls on precursor chemicals focus on their import, manufacturing, and storage and on bulk distribution and transportation, with authorities spread piecemeal across multiple federal agencies. Similarly, trade associations work primarily with bulk quantities of precursor chemicals or just with specific retail groups (e.g., in the agricultural sector).

The committee found a pronounced lack of visibility and oversight in retail-level transactions, especially those involving e-commerce, suggesting ample opportunity for malicious actors to acquire precursor chemicals for making HMEs. Challenges posed by e-commerce, in particular, include the reach of internet sales across national, state, and local borders, the anonymity of the purchaser, the absence of information on the intended use of the chemical, and the lack of opportunity to engage directly with purchasers, as a means of identifying suspicious activity. What could be suspicious behavior, for example, might only manifest through face-to-face engagement. The European Union (EU) and some of its member states (MS) have expressed similar concerns about the challenges of e-commerce. Another challenge is the difficulty of tracking multiple purchases from different sources, both brick and mortar and online. While the committee cannot provide guidance on how to detect the acquisition of combinations of chemicals that can be used in HMEs, the committee acknowledges that having this information could play an important role in the prevention of bombing events.

In addition to concerns about the anonymity of the purchaser using e-commerce, many representatives of industries and trade groups reported that they do not know how precursor chemicals flow to online retailers. For example, none of the AN producers sells its product to exploding target kit manufacturers, yet those finished products are available for purchase, which indicates a gap in the visibility of the overall AN supply chain that the committee could not illuminate. While manufacturers are able to provide some fundamental information on the distributors with which they have direct contact, the practices of smaller distributers or wholesalers are more opaque.

Many options are available for improving visibility and oversight of precursor chemicals at the retail level; some would require changes to law and corresponding regulatory action while others would not. The committee considered opportunities for new mandatory restrictions regarding access to precursor chemicals (i.e., controls) and addressed the possibility of other, potentially supplemental measures and activities—such as outreach, training, and reporting—which can be implemented with or without legal mandates. Further details about other measures and activities are discussed under the rubric of voluntary measures and programs (see Recommendation 6) because these programs have precedent and established records of participation in the private sector, not because they

Suggested Citation:"6 Potential Approaches to Restricting Malicious Actors' Access to Precursor Chemicals: Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2018. Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Explosive Precursor Chemicals. Washington, DC: The National Academies Press. doi: 10.17226/24862.
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must be voluntary. As stated above, these other measures and activities could be mandatory.

The committee’s review of the domestic and international policy landscapes (see Chapters 3 and 4) suggests the possibility of at least four general types of control strategy for retail-level transactions; three of them would add a new mandatory restriction or control and one would not. In particular, the three strategies with new controls would implement either a ban, licensing, or a registry, and the fourth strategy, which the committee refers to as “business as usual plus” (BAU+) would augment existing federal, state, or local controls with other measures and activities. Indeed, any of the four approaches, not just BAU+, could include other measures and activities, established as mandatory or voluntary policy mechanisms, with varying degrees of government and industry involvement.

However, all the strategies would entail costs, including potential adverse effects and or impacts on legitimate commerce and use; benefits, primarily relating to security; and various uncertainties. Overall, the strategies might or might not yield a positive balance. Preliminary evidence suggests that retail-level controls in the EU, which have included bans, licensing, and registries, have decreased the amount of precursor chemicals available on the market and increased the capacity of authorities to investigate suspicious incidents, but that industry and users have experienced some adverse effects. The committee believes that these options would require a thorough evaluation, involving a more rigorous and more detailed analysis (see Recommendation 5) to support any regulatory decisions.

The options for controls are outlined here for the specific case of retail-level transactions and, while potentially providing a means of categorizing options at other levels of the supply chain, may or may not apply to those levels in their current forms. The potential for application elsewhere in the supply chain would require additional and separate consideration given the different nature of the commerce and actors at those locations. In addition, each strategy will require unique caveats and structures to address the challenges posed by e-commerce. In Chapter 5, the committee assessed tradeoffs among control strategies and, for the sake of minimizing disruptions to commerce, focused on applications of any new controls to noncommercial purchases. A summary of the four options is as follows:

  • Banning sales of specific precursor chemicals. This option could ban the sales of certain precursor chemicals in specific quantities, concentrations, or formulations. The option might also include a right to refuse sales under suspicious circumstances.
  • Requiring a license to purchase. This option could require a valid license to purchase certain precursor chemicals in specific quantities, concentrations, or formulations. Licensing could involve vetting of the purchaser, such as a background check and verification of need. This option might also include a right to refuse sales under suspicious circumstances. To imple-
Suggested Citation:"6 Potential Approaches to Restricting Malicious Actors' Access to Precursor Chemicals: Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2018. Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Explosive Precursor Chemicals. Washington, DC: The National Academies Press. doi: 10.17226/24862.
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  • ment a licensing scheme for online purchasing, e-retailers could ask purchasers to enter a verifiable license number prior to proceeding to checkout.
  • Maintaining a registry of purchases. This option could require a signature for purchases of certain precursor chemicals in specific quantities, concentrations, or formulations, and showing proof of identity, such as a government-issued photo ID. This option, like the others, might also include a right to refuse sales under suspicious circumstances. To implement a registry scheme for online purchasing, e-retailers could ask purchasers to enter an electronic signature and a verifiable government-issued ID number prior to proceeding to checkout.
  • Supplementing current controls with other measures and activities. This option would augment current federal, state, and local controls with various measures and activities, such as outreach, training, and reporting, as discussed below.

In each case, if a control pertains only to noncommercial sales, as in the assessments in Chapter 5, commercial purchasers might be required to provide evidence of commercial status. Separating commercial and noncommercial users could be challenging, as evidenced by the EU’s experience, and would require additional analysis to determine whether it would require any new credentialing and to assess the associated benefits, costs, and uncertainties.

Recommendation 4: 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 specifically designed to be combined to produce homemade explosives.

Commercially available exploding target (ET) kits are pre-packaged consumer products consisting of precursor chemicals in the proper forms and ratio to make an HME, which are packaged with explicit instructions for how to make an HME that can be detonated in the absence of either a commercial detonator or any other primary explosives. ET kits contain either ammonium nitrate or potassium perchlorate as the oxidizer and powdered aluminum as the fuel, all three of which are Group A chemicals. Moreover, like other precursor chemicals under consideration in this report, ET kits are readily available at retail locations and online. ET kits were designed for target shooting; however, as the recent attacks in New York and New Jersey (see Chapter 2) demonstrate, ET kits can be used to construct IEDs.

Currently, no federal entity has explicit authority from Congress to oversee the sale of ET kits. As discussed in Chapter 3, the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) regulates neither the distribution and sale nor the use of ET kits because the individual components, when unmixed, do not meet the definition of explosive materials, and when mixed after purchase, fall

Suggested Citation:"6 Potential Approaches to Restricting Malicious Actors' Access to Precursor Chemicals: Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2018. Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Explosive Precursor Chemicals. Washington, DC: The National Academies Press. doi: 10.17226/24862.
×

outside the scope of commerce in explosives that ATF enforces. The Department of Homeland Security (DHS) does not regulate the distribution and sale of ET kits, unless in limited circumstances where quantities exceed the Chemical Facilities Anti-Terrorism Standards (CFATS) thresholds at facilities where ET kits are manufactured, stored, or sold. A subset of states has implemented controls on the sale and use of ET kits. Some private entities have issued disclaimers about the use of their ET products.

The committee observes the following opportunities for federal, state, local, and private sector entities to take actions to address threats associated with ET kits:

  • U.S. DHS. Congress could expand DHS’s statutory authority to cover ET kits to enable DHS to explore strategies to reduce IED threats by overseeing the transactions of these kits to consumers.
  • U.S. ATF. Congress could expand ATF’s statutory definition of explosives to include ET kits, as several states have done, to create a common approach to security controls for explosives and ET kits.
  • State or Local Governments. States or localities seeking to reduce threats associated with ETs may ban sales or institute licensing or permitting programs for the purchase or use of ET kits. They might also redefine terms such as explosives and lawful use so that they are covered under existing regulations.
  • Private Sector Entities. Companies involved in the manufacture, distribution, and sale of ET kits could develop voluntary measures that reduce threats of misappropriation, for example, by securing materials, training employees to recognize suspicious behavior, and reporting suspicious behavior or transactions.

Analysis of Control Strategies

Recommendation 5: U.S. DHS should engage in a more comprehensive, detailed, and rigorous analysis of specific provisions for proposed mandatory and voluntary policy mechanisms to restrict access to precursor chemicals by malicious actors.

Consideration of potential control strategies should not end with this report. The committee began a process of assessment in Chapter 5 that can serve as a starting point for a closer examination of retail-level restrictions and other policy options. The committee conducted a qualitative assessment of retail-level control strategies that included a ban, licensing, a registry, existing controls, and various other measures and activities and could not identify a dominant option. Each type of control strategy would incur costs, benefits, and uncertainties that can only be weighed comprehensively with a more rigorous and more detailed analysis of

Suggested Citation:"6 Potential Approaches to Restricting Malicious Actors' Access to Precursor Chemicals: Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2018. Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Explosive Precursor Chemicals. Washington, DC: The National Academies Press. doi: 10.17226/24862.
×

specific policy mechanisms and a final evaluation of options. A relatively stringent option might, for example, do more to restrict malicious actors’ access to precursor chemicals, yet entail more forgone sales and use and increased risks of displacement and commercial disruption, but the details will matter greatly to the analysis.

A full analysis, as would be necessary to support a policy decision, would require more time, data, industry participation, and specificity, including a clear articulation of the structure and content of proposed actions. Any such analysis should also consider the results of existing domestic programs that restrict access to precursor chemicals, including those intended to curb illicit drug production, and programs adopted in other countries. For example, the EU’s experience with bans, licensing, and registries might provide valuable data for further analysis of those types of controls. As the EU’s efforts mature, it might be possible to learn more about what is and is not working in the EU, the associated costs, and the applicability to the United States.

Similarly, DHS should use the available data on precursor chemical trends overseas to analyze new control systems, reevaluate priorities among precursor chemicals based on the threat level, and respond to new threats proactively.

The analysis recommended here should work to expand beyond the kind of breakeven analysis of benefits and costs that frequently informs executive branch decisions on security regulations (see Appendix G). Supplementary to the recommendation for further analysis, the committee urges the executive and legislative branches to identify and overcome impediments to such work, including time constraints and lack of funds, expertise, or suitable analytical tools and methods. Ideally, a more rigorous and more detailed analysis of options would enable executive and legislative branch officials to more deliberately consider a wide range of tradeoffs and would help build consensus about the benefits and costs of different control strategies.

Voluntary Measures, Activities, and Programs

Recommendation 6: 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.

Efforts to strengthen outreach, better educate retailers, and partner with commercial enterprises, including trade associations, in voluntary programs are likely to increase compliance with current security programs and can contribute positively in their own right. Anecdotal evidence suggests that commercial enterprises are willing to engage in voluntary programs tied to their memberships in trade groups, sponsored by trade groups, or sponsored by government agencies

Suggested Citation:"6 Potential Approaches to Restricting Malicious Actors' Access to Precursor Chemicals: Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2018. Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Explosive Precursor Chemicals. Washington, DC: The National Academies Press. doi: 10.17226/24862.
×

as private-public partnerships, or as outreach between the government and commercial enterprises.

ATF and FBI are actively trying to increase awareness and reporting of suspicious behavior. More specifically, ATF has focused on educating and developing relationships with the agribusiness industry to limit illegitimate access to precursor chemicals such as AN by increasing voluntary reporting of suspicious activity. FBI has engaged in efforts targeting retailers (e.g., pool and spa and beautician suppliers carrying hydrogen peroxide). To incentivize participation by commercial entities, government agencies might need to persuade them of the importance of the problem and necessity of voluntary action, or provide direct benefits or cost offsets, as might occur in a public-private partnership.

Existing program initiatives include Be Aware for America (1995), Be Secure for America (1998), and America’s Security Begins with You (2004).

Trade group programs were reported to include a majority of businesses in certain industries (>90% in some cases), which encompasses thousands of individual locations related to manufacturing, chemical distribution, and agriculture.

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 they can become part of the prevailing corporate culture. Some examples of programs that could be implemented either voluntarily or under mandates are listed below. Some trade groups, government agencies, or private-public partnerships already implement some of these options.

  • Developing outreach programs that target retailers. Many retailers, either brick and mortar or online, that sell products that contain precursor chemicals may not be aware that these commercial products can be converted into explosive materials or contribute to the threat of IED attacks, as evidenced by the EU’s experiences (see Chapter 4). To increase retailers’ awareness of concerns and, hence, their ability to detect and report suspicious behavior and questionable sales transactions, trade associations or government agencies could create new outreach programs or strengthen existing ones. An outreach program could make use of a variety of educational tools, including online interactive programs, videos, pamphlets, in-person seminars, and other forms of information dissemination.
  • Training on programs and reporting of suspicious behavior, fraud, theft, and loss. Whether policy makers choose to invoke a ban, licensing, a registry, or other mandatory or voluntary measures, retailers must have the knowledge and skills to implement the measures and report on suspicious behavior, fraud, theft, and loss. Trade associations, as some do currently, could develop tools, as listed above, and provide online or in-person training to support these goals, or government agencies could take the lead in development and implementation (see Chapters 3 and 4).
Suggested Citation:"6 Potential Approaches to Restricting Malicious Actors' Access to Precursor Chemicals: Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2018. Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Explosive Precursor Chemicals. Washington, DC: The National Academies Press. doi: 10.17226/24862.
×
  • Training could cover techniques on requesting and verifying purchasing credentials, ascertaining the intended customer use, recognizing suspicious behavior, and reporting activity, such as purchasing a combination of precursor chemicals, to the designated authorities.
  • Maintaining documentation of transactions. Documentation could include an electronic or written record of purchases that occur in a brick-and-mortar retail outlet or online, and data analytics that could, for example, correlate precursor chemicals, quantities sold, dates and times of purchases, and the purchaser’s identity. This record of relevant information on sales transactions could assist authorities by providing actionable information to thwart an IED attack or to investigate one that has occurred.
  • Verifying training and program implementation. Auditing, inspections, and other feedback mechanisms could be used to determine whether workers have been trained properly or if retailer outlets are adequately implementing program requirements. Trade associations and some federal agencies already conduct inspections, either announced or unannounced, on facilities that store precursor chemicals, and in the EU mystery shopping has been used to provide feedback to retailers and regulatory agencies on program implementation.

PRIORITY RESEARCH AREAS

In addition to the aforementioned recommendations, the committee identified several areas of research that could provide additional pathways for limiting access to precursor chemicals or designing appropriate policy mechanisms.

Data Collection from Incidents Involving Explosives

Detailed, verified, and comprehensive data on the precursor chemicals used in HMEs is required to track the evolution of the IED threat and to provide perspective for the analysis of effective measures to consider for regulatory action. The Department of Defense (DOD) has developed the Level 1 Explosive Ordnance Disposal Reporting Guidelines, providing an example of how an agency has collected tactical and technical information for its purposes related to explosives.238 The committee suggests that the USBDC and other federal agencies focus on collecting detailed and verified data on incidents involving explosives. Focus areas include the following:

  • how to improve the collection of relevant data on the chemical composition of the explosives used in IEDs and the precursor chemicals recovered during incidents and investigations;
Suggested Citation:"6 Potential Approaches to Restricting Malicious Actors' Access to Precursor Chemicals: Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2018. Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Explosive Precursor Chemicals. Washington, DC: The National Academies Press. doi: 10.17226/24862.
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  • how the collected data may be verified when final laboratory results become available during the investigation;
  • how to aggregate and present the data;
  • how policy-making bodies can improve data entry compliance across bomb squads to ensure robust and timely collection; and
  • how policy-making bodies can inform USBDC of their information requirements.

Substitute Chemicals

The likelihood of precursor chemicals being obtained from retail locations could be reduced if these chemicals were replaced by other chemicals that lack the utility to manufacture HMEs while providing the same legitimate service. For example, the AN in cold packs could be replaced by another nonprecursor salt that is sufficiently endothermic upon dissociation. While that example is relatively straightforward, other substitutions are not so obvious and would require additional research to identify, and may not be possible for chemicals such as oxidizers, which fulfill the same chemical role in HMEs and legitimate applications. Given the costs of research, development, and implementation, there would need to be clear incentives from the market or elsewhere to initiate the process.

Standardized Thresholds

As detailed in Chapters 3 and 4, a wide range of precursor chemical concentration and mass regulatory thresholds are used by various agencies, both domestic and international. The cited thresholds listed by the various agencies may create unnecessary confusion for legitimate commerce and may still not prevent malicious actors from purchasing the precursor chemical at the quantity or quality needed to manufacture HMEs. For example, while CFATS cites a hydrogen peroxide threshold concentration of 35%, lower compositions can be used to synthesize triacetone triperoxide (TATP), but the threshold exempts most retail-level products from oversight. A systematic study to identify the thresholds based on sound scientific principles will contribute toward the goal of preventing the use of precursor chemicals in HMEs.

Behavioral Responses

The committee suggests further research into behavioral responses of: (1) malicious actors, businesses, and end users to any proposed or implemented policy, and (2) the public and policy makers to the threat of a terrorist act or an actual terrorist act. As explored throughout the report (see Chapters 1, 2, 3, and 5, and Appendixes B and G), such behavioral responses can affect the efficacy

Suggested Citation:"6 Potential Approaches to Restricting Malicious Actors' Access to Precursor Chemicals: Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2018. Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Explosive Precursor Chemicals. Washington, DC: The National Academies Press. doi: 10.17226/24862.
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of any strategy and the tradeoffs among strategies. Questions deserving attention include the following:

  • What levels of knowledge, expertise, or ability would be required to circumvent a control that limits access to specific precursors?
  • What level of real or perceived difficulty of obtaining a desired precursor will cause a terrorist to shift to a less desirable material or tactic, and will those tactics yield a greater or lesser overall risk?
  • What levels of real and perceived risk and inconvenience are tolerated by business and the general public, and how would they respond to a new policy mechanism?
  • How do we ingrain deliberative thinking processes into regulatory frameworks in such a way as to encourage appropriate consideration without forestalling decision making?

FINAL THOUGHTS

Precursor chemicals have played a major role and evolving role in the manufacture of HMEs in prior IED terrorist attacks. Given the ease of accessing precursor chemicals and the information required to manufacture HMEs, particularly via the internet, the threat of terrorist attacks using IEDs within the United States remains. While the United States has not experienced a major VBIED attack since the 1990s, the committee stresses the importance of engaging in deliberative thinking before crises to avoid the pitfalls of intuitive thinking and action bias during and after crises. In addition, the committee stresses the importance of periodically reevaluating and reprioritizing the precursor chemicals that it considered in this report and of building in means of harvesting and leveraging experience and data to strengthen policy over time. Restricting access to precursor chemicals may help to reduce the threat of IED attacks as terrorist tactics change, but only if policy can change, too.

The committee emphasizes the essential role of Congress in developing and implementing appropriate risk-reducing control strategies. Whether by addressing questions of federalism, defining the responsibilities of federal agencies, holding fact-finding hearings to articulate welfare interests and policy objectives, or adequately funding collaborative public-private work, Congress provides foundational opportunities for the executive branch to implement effective and efficient control strategies across administrations. Congress can be particularly instrumental in ensuring that crisis-driven interests do not unduly influence new laws or regulations, and can play a role in each of the six recommendations to enhance the nation’s domestic and international risk-reduction programs.

Suggested Citation:"6 Potential Approaches to Restricting Malicious Actors' Access to Precursor Chemicals: Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2018. Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Explosive Precursor Chemicals. Washington, DC: The National Academies Press. doi: 10.17226/24862.
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Suggested Citation:"6 Potential Approaches to Restricting Malicious Actors' Access to Precursor Chemicals: Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2018. Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Explosive Precursor Chemicals. Washington, DC: The National Academies Press. doi: 10.17226/24862.
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Suggested Citation:"6 Potential Approaches to Restricting Malicious Actors' Access to Precursor Chemicals: Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2018. Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Explosive Precursor Chemicals. Washington, DC: The National Academies Press. doi: 10.17226/24862.
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Suggested Citation:"6 Potential Approaches to Restricting Malicious Actors' Access to Precursor Chemicals: Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2018. Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Explosive Precursor Chemicals. Washington, DC: The National Academies Press. doi: 10.17226/24862.
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Suggested Citation:"6 Potential Approaches to Restricting Malicious Actors' Access to Precursor Chemicals: Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2018. Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Explosive Precursor Chemicals. Washington, DC: The National Academies Press. doi: 10.17226/24862.
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Suggested Citation:"6 Potential Approaches to Restricting Malicious Actors' Access to Precursor Chemicals: Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2018. Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Explosive Precursor Chemicals. Washington, DC: The National Academies Press. doi: 10.17226/24862.
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Suggested Citation:"6 Potential Approaches to Restricting Malicious Actors' Access to Precursor Chemicals: Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2018. Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Explosive Precursor Chemicals. Washington, DC: The National Academies Press. doi: 10.17226/24862.
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Suggested Citation:"6 Potential Approaches to Restricting Malicious Actors' Access to Precursor Chemicals: Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2018. Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Explosive Precursor Chemicals. Washington, DC: The National Academies Press. doi: 10.17226/24862.
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Suggested Citation:"6 Potential Approaches to Restricting Malicious Actors' Access to Precursor Chemicals: Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2018. Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Explosive Precursor Chemicals. Washington, DC: The National Academies Press. doi: 10.17226/24862.
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Suggested Citation:"6 Potential Approaches to Restricting Malicious Actors' Access to Precursor Chemicals: Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2018. Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Explosive Precursor Chemicals. Washington, DC: The National Academies Press. doi: 10.17226/24862.
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Suggested Citation:"6 Potential Approaches to Restricting Malicious Actors' Access to Precursor Chemicals: Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2018. Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Explosive Precursor Chemicals. Washington, DC: The National Academies Press. doi: 10.17226/24862.
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Suggested Citation:"6 Potential Approaches to Restricting Malicious Actors' Access to Precursor Chemicals: Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2018. Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Explosive Precursor Chemicals. Washington, DC: The National Academies Press. doi: 10.17226/24862.
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Suggested Citation:"6 Potential Approaches to Restricting Malicious Actors' Access to Precursor Chemicals: Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2018. Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Explosive Precursor Chemicals. Washington, DC: The National Academies Press. doi: 10.17226/24862.
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Suggested Citation:"6 Potential Approaches to Restricting Malicious Actors' Access to Precursor Chemicals: Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2018. Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Explosive Precursor Chemicals. Washington, DC: The National Academies Press. doi: 10.17226/24862.
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Suggested Citation:"6 Potential Approaches to Restricting Malicious Actors' Access to Precursor Chemicals: Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2018. Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Explosive Precursor Chemicals. Washington, DC: The National Academies Press. doi: 10.17226/24862.
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Improvised explosive devices (IEDs) are a type of unconventional explosive weapon that can be deployed in a variety of ways, and can cause loss of life, injury, and property damage in both military and civilian environments. Terrorists, violent extremists, and criminals often choose IEDs because the ingredients, components, and instructions required to make IEDs are highly accessible. In many cases, precursor chemicals enable this criminal use of IEDs because they are used in the manufacture of homemade explosives (HMEs), which are often used as a component of IEDs.

Many precursor chemicals are frequently used in industrial manufacturing and may be available as commercial products for personal use. Guides for making HMEs and instructions for constructing IEDs are widely available and can be easily found on the internet. Other countries restrict access to precursor chemicals in an effort to reduce the opportunity for HMEs to be used in IEDs. Although IED attacks have been less frequent in the United States than in other countries, IEDs remain a persistent domestic threat. Restricting access to precursor chemicals might contribute to reducing the threat of IED attacks and in turn prevent potentially devastating bombings, save lives, and reduce financial impacts.

Reducing the Threat of Improvised Explosive Device Attacks by Restricting Access to Explosive Precursor Chemicals prioritizes precursor chemicals that can be used to make HMEs and analyzes the movement of those chemicals through United States commercial supply chains and identifies potential vulnerabilities. This report examines current United States and international regulation of the chemicals, and compares the economic, security, and other tradeoffs among potential control strategies.

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