Risk assessment from potential exposure to tetrabromobisphenol A (TBBPA) from its use in electronics

Tetrabromobisphenol A (TBBPA) is the most extensively used brominated flame retardant worldwide, primarily employed reactively in printed circuit boards and additively in plastic housings of electronic equipment. This study systematically evaluates human exposure to TBBPA from electronic devices and characterizes associated risks. A targeted literature review of 55 peer-reviewed studies published over the past 25 years was conducted, focusing on global TBBPA occurrence in environmental media, occupational and residential settings, and biological matrices. Exposure pathways assessed include dermal contact dust ingestion, and inhalation. Quantitative exposure estimates were generated or extracted where available and compared against established toxicological reference values, including the European Food Safety Authority (EFSA) tolerable daily intake (TDI) of 0.7 μg/kg body weight/day and a derived oral Reference Dose (RfD) of 0.26 mg/kg/day for cancer. Hazard Quotients (HQs) calculated across all exposure scenarios, including high-exposure e-waste settings, remained well below 1 indicating a low likelihood of adverse health effects. Likewise, a basic deterministic aggregate exposure assessment shows that upper bound exposure estimates for both an office worker and a worker in an electronics dismantling facility result in the Hazard Index (HI) < 1. Despite methodological variability and inherent uncertainties in exposure attribution, this risk assessment demonstrates that current exposures to TBBPA likely originating from electronic equipment are not of toxicological concern.