low heat release properties while simultaneously maintaining favorable electrical insulation properties are desired the polyolefin blends employable in the present compositions are selected from the group consisting of vldpe ldpe lldpe hdpe pp epr eva eea ema eba copolymers containing ethylene monomeric units and terpolymers containing ethylene monomeric units the preferred polyolefin blend is selected from the group consisting of vldpe and hdpe the polyolefin blend is preferably employed at a level of 100 parts by weight the filler in the present compositions contains one or more from the group consisting of metal hydrates oxides carbonates talcs clays molybdates borates stannates carbon black silicates and phosphates the preferred compositions contain approximately 200 parts per hundred by weight of filler in relation to the weight of the base polymer the additive package contains but is not limited to antioxidants organosilanes pigments and lubricants the preferred compositions also contain antioxidant stabilizers and lubricants in the preferred compositions the additive package is approximately 5 parts by weight in relation to the weight of the base polymer the compositions contain unsaturated dicarboxylic anhydrides such as maleic itaconic aconitic or citraconic anhydride or unsaturated dicarboxylic anhydrides modified thermoplastic polymers where the anhydrides may be replaced in whole or in part by carboxyl or carboxylate functionality the preferred compositions contain maleic anhydride modified polyolefins at a level of 5 parts by weight in relation to the weight of the base polymer the present compositions contain suitable nanoclay fillers which are synthetic and or natural layered silicate montmorillonites.