Energetic residues from field disposal of gun propellants

Military training with howitzers and mortars produces excess propellant that is burned on the training range and can result in point sources containing high concentrations of unreacted propellant constituents. Propellants contain energetic compounds such as nitroglycerin (NG) and 2,4-dinitrotoluene (2,4-DNT), both of which are found at firing positions and propellant disposal areas. To quantify the mass of residue remaining from the field-expedient disposal of propellants, two mortar propellants and one howitzer propellant were burned under different field conditions. These conditions included burning on a snow pack, at the bottom of a snow pit, and in a pan surrounded by snow for the mortar propellants and on dry and wet sand for the howitzer propellant. For the mortar propellant, the energetics (NG) remaining after burning in the bowl, on frozen ground, and on snow were 0.21%, 5.2% and 18%, respectively. For the howitzer propellant, the difference in energetics (2,4-DNT) remaining after disposal on wet and dry sand was <0.1%, with the overall residue rate of around 1%, similar to that for the mortar propellant burned in an open container. These tests demonstrate that environmental factors, especially in winter, can play a significant role in the effectiveness of field-expedient disposal of propellants.