Globalization may have severe negative side impacts on the environment, especially as a consequence of the growing opportunities for businesses to avoid strict national environmental laws by moving operations (or waste) to places in the world where environmental legislation tends to be less well developed and/or enforced. As international law is primarily directed at states and not at transnational corporations, it has serious weaknesses to counteract such severe environmental impacts. Moreover, the few national legislative attempts to specifically regulate the environmental performance of companies that operate abroad, did not pass through parliament. The limitations of law have led to the rise of non-state environmental law in which national authorities play no or only a very limited role. Still, the role of national law has not been played yet: as from the mid-nineties of the past century there is a steadily growing body of court cases from the home state of the parent company. Although, mainly for tax reasons, a relatively large numbers of transnational corporations have chosen the Netherlands as their elected domicile, only recently we saw the first two court cases – one of them still pending – regarding the alleged liability of (partly) Dutch-based corporations for serious environmental impacts caused while operating in Africa. The first one, the Trafigura case, concerned the dumping of hazardous waste in the African state of Ivory Coast. The second one, the Shell-Nigeria case, relates to environmental damages from oil leakage in Nigeria. This paper discuss both cases. Although both the Trafigura case and the Shell-Nigeria case concern overseas environmental impacts, the cases differ considerably. For one, the Trafigura case followed a criminal law track, whereas the Shell-Nigeria case follows a tort proceeding. Secondly, unlike the (Dutch) national law approach used in the Trafigura case, in the Shell-Nigeria case the actual consequences of the oil leakages in Nigeria, and the way RDS and SPDC responded to these are central. Also, in the Shell-Nigeria case, soft law such as codes of conduct might be relevant to support constructing the violation of the duty of care. Given contemporary calls for corporate sustainability, many companies have either volunteered to adhere to codes of conduct and/or have their own ones in place. Independent monitoring mechanisms are, however, seldom incorporated. Through interpretation of a rule of unwritten duty of care with reference to such codes of conduct, they might be uplifted from a merely public relations effort to a useful purpose in transnational tort law.