EPR can be flame retarded by adding organic halogen flame retardants or inorganic flame retardants, and the common organic halogen flame retardants for EPR are dicyclopentadiene and decabromodiphenyl ether, whose flame retardant mechanism is mainly through the release of non-flammable hydrogen halide, diluting combustible gases, on the one hand, isolating air and heat on the other, and capturing free radicals to inhibit combustion chain reactions, so as to achieve effective flame retardancy.

When the weight ratio of organohalogen flame retardant to antimony trioxide is between 2 and 5, the halogen flame retardant only needs 15 to 40 parts to achieve the flame retardant effect. The disadvantage of organic halogen flame retardants is that once the fire produces strong corrosive hydrogen halide gas, causing secondary disasters, inorganic flame retardants can overcome the above disadvantages.