A deflagration occurred during the pelleting of black powder (BP). After a few minutes of pelleting operations, BP dust friction between the hopper and the table (or between the punch and the matrix) caused the deflagration of BP stored in the hopper, whose compression step had already been carried out, accounting for 200 g of product. The movable unit sidewall was jettisoned, the punch and matrix very slightly deteriorated. The operator shortened the interval between cleanings of the various machine control devices in order to mitigate the risks of BP dust accumulation.