Review of Brominated and Halogen-free Flame Retardant Levels in Indoor Dust

Flame retardants (FRs) are chemicals that are added to combustible materials to delay or prevent the ignition or spread of a fire, thereby saving lives and property. Indoor dust is thought to be a major source of human exposure to FRs as a result of their release from commercial products. We conducted a comprehensive review and analysis of studies of FRs in indoor dust, focusing on three brominated compounds (BDE-209, TBBPA, and DeBDethane) and three phosphorus-based non- halogenated compounds (RDP, BDP, and DOPO). For those compounds for which data were available, we observed a wide range of concentrations. The geometric mean bulk dust concentrations in residences, (non-source) workplaces, automobiles, and a hotel from studies providing individual sample results were 2,777 ng/g for BDE-209 (n=337); 11 ng/g for TBBPA (n=115); and 18 ng/g for DeBDethane (n=50). No dust data were available for RDP, BDP, or DOPO. BDE- 209 concentrations in bulk dust, excluding those from automobiles, were highest in the United Kingdom (UK), followed by concentrations in North America and the rest of Europe. As with the bulk dust samples, limited data from surface loading samples were highly variable - BDE-209 concentrations varied from an arithmetic mean of 6 in one study to a maximum of 82,100 ng/m 2 , and TBBPA concentrations ranged from < 0.06 to 24 ng/m 2 . Overall, we found a high variability in dust levels of FRs from different indoor sources around the world, although it is unclear how much differences in sample collection and analytical methodology contributed to this.