Hometown Security: Reduction of the Explosion Potential of Ammonium Nitrate by Coating with Low-Cost, Coal Combustion By-Products

Ammonium nitrate (AN) mixed with fuel oil creates a powerful explosive, ANFO, whose destructive power has been graphically demonstrated in a number of malicious attacks from the Alfred P. Murrah Federal building in Oklahoma City to the Marriott Hotel in Jakarta. ANFO is too often a weapon of choice for acts of terrorism due to its relatively low cost, ready availability, ease of assembly, and magnitude of destructive force unleashed upon detonation. Despite its beneficial and critical role in agriculture, AN has become a vehicle for disseminating chaos and an ominous threat to society. Prior attempts to lessen the threat posed by AN have included the proposed addition of desensitizing agents, such as polymeric coatings or diluents. However, such measures have not been mandated at the federal level due to a combination of ineffectiveness, cost, and undesirable side effects. That is, while such agents may reduce the destructive capacity of ANFO, they are relatively ineffective when applied at low concentrations and are too costly or detrimental to agricultural use to be added in higher amounts, where their effectiveness is more pronounced. We propose to demonstrate a more practical approach for desensitizing agricultural-grade AN with respect to detonation. Our approach entails coating the AN with an ash-like, coal-combustion by-product (CCB). CCBs are inexpensive and are produced in large quantities during the generation of electricity from coal. In 2003, over 121 million tons of CCBs were produced in the US compared to an annual US production of approximately three million tons of AN. Currently, the majority of these CCBs are simply discarded by the producer at a significant expense. In addition to the advantages of supply and cost, CCBs can have a significant agricultural value as many contain lime or other pH adjustment components, can serve as a soil ameliorant, and can supply valuable plant nutrients (e.g., sodium, potassium, trace elements). We contend that the addition of an ultra-low-cost blast suppressant that is also has agricultural benefits can address the obstacles that have thus far prevented the mandated addition of an effective blast-mitigation agent to AN.