Halogen-free polymer composite materials, which are commonly for use in sheathing and insulation applications for wire and cable, are provided. The composite materials include a polymeric blend, which includes ethylene/α-olefin copolymer and polyolefin, a hydrated metal oxide flame-retardant, such as hydrated magnesium oxide, and an antimony compound. In some instances, the polymeric blend may include an olefin/unsaturated ester copolymer.