Recycling of flame retarded waste polystyrene foams (EPS and XPS) to PS granules free of hexabromocyclododecane (HBCDD) Martin Schlummer a* , Andreas Mäurer a , Swetlana Wagner a , Arthur Berrang a , Tanja Siebert a , Fabian Knappich a a Fraunhofer Institute IVV, Recycling Plastics, 85354 Freising, Germany *: corresponding author Keywords: PS foam, EPS, XPS, waste, recycling, HBCDD Highlights:  Hexabromocyclododecane (HBCDD ) is removed from waste EPS and XPS by solvent based recycling to PS granules  HBCDD levels in recycled PS are below the low POP content (100 ppm) defined by the EU POP regulation  The solvent circle is closed and ppm range solvent residues in recycled PS do not alter product properties  Mechanical properties of recycled PS compare well to virgin PS Abstract Expanded and extruded polystyrene (EPS and XPS) belong to the most often used insulation materials and - with respect to this application- both materials have been equipped with the brominated flame retardant hexabromocyclododecane (HBCDD) for more than 50 years. After HBCDD had been identified as a substance of very high concern, it was set under control of the Stockholm Convention and the European REACh legislation. In consequence, the use of HBCDD in insulation materials is