ABSTRACT
In summary, the duty of due diligence as owed between States under customary international law appears to be neither temporal in the sense that it is not limited to the present time but extends into the future, nor is it especially fault-based in terms of requiring some evidence of malice or negligence before it may be deemed to have been breached (cf Higgins (1994) 160-61). These general criteria of the due diligence requirement have been supplemented and arguably strengthened by further treaty obligations of notification and consultation in cases of hazardous activities conducted within States’ territories or under their control. The question remains whether these additional criteria for the fulfilment of the due diligence duty have transcended the treaty instruments in which they are found and become part of general customary international law as well?
