Brominated Flame Retardants Toward Sustainable Fire Safety: Mechanisms, Environmental Challenges, Recycling, and Future Perspectives

Brominated flame retardants (BFRs) remain indispensable for polymer fire safety owing to their efficient radical-quenching capability and excellent compatibility, yet their environmental persistence, bioaccumulation, and toxicity pose a fundamental tension between fire performance and life-cycle sustainability. This review addresses this tension through a central “structure–performance–exposure/hazard–circularity” framework, which links the molecular features governing flame-retardant efficiency to migration and release behavior, environmental fate, and toxicological outcomes. The review proposes an integrated Safe and Sustainable by Design (SSbD) strategy spanning scenario-specific authorization, low-release molecular design, bromine reduction via synergistic formulations, and life-cycle risk management. For the end-of-life stage, it further assesses the technical boundaries of precise identification, separation, targeted debromination, bromine resource regeneration, and safety evaluation of recycled products. A key contribution is an evidence-based, tiered decision rule: applications characterized by high exposure, high release potential, and inadequate safe-treatment pathways should be prioritized for substitution, whereas applications with severe fire-failure consequences and immature alternatives should be managed through low-release design, traceable management, and controlled recycling. This framework offers a coherent basis for coordinated decision-making among flame-retardant performance, environmental safety, and resource circularity.