In recent decades, HBCDD has been widely used in many different products, and the implementation of this new regulation affects the production, consumption and removal of such products. As an important action towards implementing the new regulation, the Dutch Ministry of Infrastructure and the Environment has decided to make an inventory of the size and value of HBCDD-containing products and waste streams. For that purpose, the Ministry has developed a project plan, which is the basis of this study. The inventory focuses on expanded polystyrene (EPS) and extruded polystyrene (XPS) products and