Pressure-sensitive adhesive formulations based on acrylic or rubber adhesives are provided in combination with an aluminum phosphorous salt intumescent flame retardant and a nitrogen containing flame retardant which can act as a blowing agent through thermal decomposition. These flame retardant additives can be incorporated into the adhesive in levels of 10 to 30 percent by weight. These formulations are then placed on a polymeric flame retardant substrate in either a single-sided or double-sided form.