Used primarily as a flame retardant in polymers and plastics, especially in polyamides and polyesters. It decomposes upon heating to release phosphorus-containing compounds that promote char formation and suppress flammable gas release, enhancing fire resistance. Also employed in electroless plating baths as a reducing agent to deposit metal coatings, particularly nickel and copper, due to its ability to reduce metal ions in solution. Its thermal stability and low toxicity make it suitable for engineering plastics used in electronics and automotive components where safety and performance are critical.