This paper focuses on two classes of chemical pollutants that raise thorny regulatory issues for regulators on both sides of the Atlantic: persistent organic pollutants (POPs) and endocrine disrupting chemicals (EDCs). POPs are chemical pollutants with at least four key characteristics: they are toxic; they are persistent; they bioaccumulate; and they can be transported long distances (Adeola 2004). EDCs are chemical pollutants that disrupt the normal functioning of hormone systems. The dose response effects of EDCs are poorly understood, but they may have consequential effects at low doses as well as interactive effects with other environmental pollutants. What is therefore of special concern is that POPs may be EDCs and vice versa (Yoder 2003). When the persistent, bioaccumulating quality of POPs intersect with the potentially low dose effects of EDCs, the biosafety and biodiversity consequences may be grave.