Ayaka Katsuki, Adeka underlined the need to find substitutes to brominated flame retardants because these generate dense black smoke and carbon monoxide in fires. Tests with PIN FRs, acting by intumescence (solid phase) in polypropylene show burning with nearly no smoke. Using the ISO 5659-2, as required by European railway regulations EN 45545-2, polypropylene shows only one sixth of smoke emissions when treated with phosphorus flame retardants than neat polymer, whereas brominated flame retardants with antimony result in higher smoke density. Adeka has achieved the first ever “UL Verified” label for functional polypropylene, for samples with PIN FR propylene UL94-V0 classification (1.6 mm) “99% less smoke density and 89% less carbon monoxide” compared to brominated flame retardant with antimony. In combination with appropriate antioxidant additives, the material also shows durability of flame retardancy and mechanical properties under heat and ageing treatments.