Triethyl phosphate is use as a flame retardant in the manufacture of polyisocyanurate (PIR) and polyurethane (PUR) foam insulation and thermoset plastic products. The chemical compound is also used as a viscosity reducer in plastic resins, and as a catalyst, solvent or intermediate in the production of pesticides, pharmaceuticals, lacquers and other products.As ethylating agent; formation of polyesters which are used as insecticides.