Health hazards

Exposure to the coplanar stereoisomer 3,3',4,4',5,5'-hexabromobiphenyl (but not the non-coplanar stereoisomer) in genetically susceptible mice is known to cause immunotoxicity and disorders related to the central nervous system, and even at doses as low as 2.5 mg/kg, excess neonatal fatalities are observed (LD₅₀ is from 5-10 mg/kg). The mechanism of toxicity is thought to be related to aryl hydrocarbon receptor