In a pyrotechnics plant, an explosion occurred during the destruction by burning of 250 kg of pentrite in large rust-stained crystals. Destruction of this product represented an unusual occurrence (1st time in 10 years), and the associated combustion would typically last 20 minutes. The explosion was triggered 4 minutes after ignition. The critical product height would have exceeded the threshold in many places due to warping and overall deformation of the destruction platform floor. As per operational guidelines, the technician was in a sheltered locale 150 m from the ignition zone and was not injured. The metal burning floor was destroyed and a crater carved into the concrete slab. The operator reinforced the barricades in place around the ignition control room and replaced the window panes with an impact-resistant material.