The present invention is a flame-retardant composition comprising a polyolefin polymer, a nano-silicate, a metal hydroxide, and calcium carbonate. The invention also includes a coating prepared from the flame-retardant composition as well as a wire-and-cable construction made by applying the coating over a wire or a cable. The invention also includes articles prepared from the flame-retardant composition, such as extruded sheets, thermoformed sheets, injection-molded articles, coated fabrics, roofing membranes, and wall coverings.