Carles Ibanez, ICL discussed the challenge for flame retardants and for all plastics additives of persistence versus durability. Flame retardants must be chemically stable, that is “durable”, both in processing (e.g. melting of plastic compounds and injection molding or extrusion), and throughout the whole product lifetime and to enable recycling. For flame retardants in building materials, this means ensuring fire safety over decades. But this means that flame retardants must be “persistent” chemicals. To ensure safety, flame retardants must therefore show no health or environmental impact and should not leach out of products during lifetime. Also, appropriate handling is necessary in processing and during product end-of-life management, to avoid exposure or losses.