The decomposition of polyethylene and ethylene-vinyl acetate copolymers in composites with Al(OH)3 and Mg(OH)2 (60% by wt.) has been estimated from the aspect of the extent of synchronization of the two fundamental processes, the release
of water and flammable volatiles from a polymer and the effect of this on the resulting polymer flammability. An attempt has
been made to implement the peculiarities of decomposition observed for each system to the fire behaviour of these materials.