Abstract: The invention concerns a castable pyrotechnic composition used to produce opaque smoke for impeding the transmission of infrared radiation from a target to a sensor, of the type including a compound generating carbon particles whose dimensions are between 1 and 14 .mu.m.The composition includes a condensed halogenated carbon compound with a melting point between 75.degree. C. and 120.degree. C., with a halogenation ratio greater than 3, such as chloronaphthalene, a fluoro carbon compound such as vinylidene polyfluoride, and a metal powder such as magnesium, reacting together at a temperature of the order of 1500.degree. C.Application is in camouflaging targets emitting infrared radiation.