Many nation's armed forces are undertaking efforts to minimize the environmental impacts of live-fire military training. Based on this, the Canadian Department of National Defence has undertaken a project to examine potential alternatives to the use of Composition C4, an RDX-based plastic explosive. Plastic explosives are widely used by all armed forces for both military engineering tasks and explosive ordnance disposal and their use may lead to the deposition of explosives in the environment, namely RDX, in the case of C4. RDX is very stable in the environment, water soluble, and moves relatively rapidly towards surface and groundwater bodies. One option identified as a potential RDX-free formulation is a pentaerythritol tetranitrate (PETN) based plastic explosive, commercially available in Germany and referred to as Seismoplast. In order to measure the environmental impacts of this formulation, a deposition rate study was conducted. These tests consist of evaluating the detonation efficiencies of munitions during detonation scenarios representative of military training. Data generated from these tests are the deposition masses of the energetic components in the explosive filler, which in this case is PETN. To achieve this objective, seven blocks of Seismoplast were open detonated over a surface of pristine snow, and post-detonation surface samples were collected to measure residual PETN. The trial demonstrated that less than 1 x 10(-7)% of PETN is deposited upon detonation of Seismoplast. The energetic material deposition rates obtained in this trial are much lower than rates obtained for the RDX-based C4 currently in-service within Canada. Switching from a RDX-based plastic explosive to one based on PETN may be an interesting option through which the Department of National Defence can reduce the environmental impact of its activities.