2,4,6-tribromophenol (TBP) is implied in the production of brominated flame retardants but is also a major chlorination by-product in seawater. A growing number of studies indicate that TBP is highly toxic to the marine biota, but the contribution of anthropogenic sources among natural production is still under question concerning its bioaccumulation in marine organisms. Here, several water sampling campaigns were carried out in the industrialized Gulf of Fos and clearly showed the predominant incidence of industrial chlorination discharges on the TBP levels in water, at the 1-10 ng L-1 level in average and reaching up to 580 ng L-1 near the outlets. The bioaccumulation of TBP was measured in 90 biota samples of the Gulf of Fos. The concentrations found in European conger muscle tissues (140 to 1000 ng g-1 lipid weight, in average), purple sea urchin gonads (830 to 880 ng g-1 lipid weight, in average), and Mediterranean mussel body (1500 to 2000 ng g-1 lipid weight, in average) were above all published references. Significant correlations with fish length (European conger) and gonad somatic index (purple sea urchin) were also identified. Comparatively, fish, urchins and mussels from other Mediterranean sites analyzed within this study showed a lower bioaccumulation level of TBP, consistently with what found elsewhere. Industrial outflows were thus identified as hotspots for TBP in seawater and marine organisms. The environmental risk assessment indicated a high potential toxicity in the industrial Gulf of Fos, in particular near the outlets, and a limited threat to human but toxicological references are lacking.