A fire retardant composition that includes: a polyolefin and an additive package that includes a brominated polystyrene or decabromodiphenyl ether; a nanoclay; and metal oxide fillers in the nanometer particle range. The compositions can have high weight percentages of the additive package because of the compatibilizing effect of the nanoclay. The nanoclay is preferably a quantenary amine treated nanoclay, wherein the quantenary amine causes exfoliation of the nanoclay. The polyolefin is a polyethylene or a polypropylene and the preferred metal oxide is antimony oxide.