Article 35 of Protocol I, a 1977 amendment of the Geneva Conventions, prohibits any means or methods of warfare that cause superfluous injuries or unnecessary suffering. Article 35 also prohibits those nations from resorting to means of war that could inflict extensive and long-term damage on human health and the environment.

The observed impacts of DU in Iraq suggest that these weapons fall under Article 35 as being prohibited, by the very nature of their suspected long-lasting effects on human health and the environment.

Article 36 (of Protocol I) also obliges any state studying, developing, or acquiring a new weapon to hold a legal review of that weapon.

Thus far, Belgium (2007) and Costa Rica (2011) have passed domestic laws prohibiting uranium weapons within their territories. In 2008, the European Parliament adopted a resolution that stated that "the use of DU in warfare
runs counter to the basic rules and principles enshrined in written and customary international, humanitarian and environmental law".