International humanitarian law (IHL) does not address business entities, except in situations where they directly participate in hostilities, and there is no reference to business actors in the International Committee of the Red Cross's recent Guidelines on the Protection of the Natural Environment in Armed Conflict. Yet, there has been an increasing reaffirmation of specific “duties”, “obligations” or “responsibilities” imposed on private companies operating in conflict zones. For instance, the UN Guiding Principles on Business and Human Rights suggest that business entities should respect IHL rules in addition to human rights during armed conflicts, and the third revised draft of the international legally binding instrument on transnational corporations and other business enterprises refers to IHL as an interpretative framework of human rights obligations of States and businesses. The International Law Commission's 2022 Draft Principles on the Protection of the Environment during Armed Conflicts are even more specific, providing that corporations should exercise due diligence concerning the protection of the environment when acting in conflict-affected areas. However, these references to IHL as applicable to business activities remain vague and lack elaboration. This paper intends to close this gap by clarifying whether and, if so, the extent to which IHL imposes environmental obligations upon private companies in conflict situations. It submits that business entities bear environmental duties during armed conflicts deriving from IHL rules and other complementary sources of international law. The paper further discusses the content of the obligation of business entities not to harm the environment as well as their due diligence obligation.
