A lead-free composition comprising: (A) Polyvinyl chloride (PVC); (B) Bioplasticizer; (C) Calcium Carbonate; and (D) Calcined clay; with the combined weight of the calcium carbonate and calcined clay in the composition in the range of 1 to 15 weight percent, and the weight ratio of calcium carbonate to calcined clay in the range of 15:85 to 85:15. In one embodiment the invention is an insulation sheath for a wire or cable made from the lead-free composition described in the preceding embodiment. In one embodiment the invention is a wire or cable comprising the insulation sheath of the preceding embodiment.