Arab states’ accusation that Israel used depleted uranium weapons in its recent attacks against Gaza, and Israel’s denial of this, raise an interesting question: is a customary norm against the use of depleted munitions* emerging? As scholars studying norm emergence, how would we know?

As far as I can ascertain it would not be illegal for Israel to have used such weapons, since there is no ban on DPU in international law, and since the suspected qualities of the weapons that would render them illegal if proven (widespread environmental damage and uncontrollable negative effects on civilians) have not been shown conclusively. Indeed, neither most governments nor leading human rights and humanitarian law organizations have concluded the DPU is a violation of humanitarian law. The ICRC has not commented on the issue since 2001, when a press release stated:

“Currently available scientific information provides evidence that the increase in levels of uranium is marginal in areas where depleted uranium munitions have been used, except at the points of impact of depleted uranium penetrators.”

So this is not an issue around which mainstream human rights organizations are actively mobilizing.

A growing opposition to the use of DPU is clearly emerging in public opinion, however. A widespread transnational network of activists has emerged promoting a global ban on depleted uranium munitions, drawing members from the anti-war community, veterans groups, feminist peace groups, environmental movement, the anti-nuclear movement, and local NGOs in war-torn countries where DPU weapons have been deployed. This network of groups has lobbied the UN, EU and various member states to ban the use of such weapons. Some meager results so far: Belgium initiated a moratorium; and the UN First Committee has issued a resolution expressing concern over the possible health effects of DPU and encouraging the Secretary General and several specialized agencies to look into it.

None of this renders DPU illegal, and without a clear position on the issue by organizations such as the ICRC and Human Rights Watch, it is hard to imagine that momentum will develop to formally codify a ban against these munitions. If I read the tea leaves correctly there is not widespread support among humanitarian law mainstream for taking such a position in favor of a ban along the lines of landmines or cluster munitions.

This makes it that much more interesting, in my mind, that the use DPU is now being routinely cited by governments eager to accuse one another of misconduct, despite its current legality. Even more interesting is the compulsion to deny their use. Does this mean a norm against the weapons is emerging even in the absence of a formal treaty process? Or are there other ways to interpret this discourse?

*Depleted uranium is a by-product of nuclear enrichment processes increasingly used in armor-piercing incendiary projectiles to penetrate tanks, bunkers and personnel carriers; and by corollary, to harden tank armour against anti-material weapons. Its military utility is said to come from its particular density: depleted uranium munitions are both cheaper and more effective at penetrating armor than tungsten, the alternative. DPU has been used by the United States and Britain since approximately 1960 and is increasingly sought after by other militaries: China, France, Russia and Pakistan are among the countries now known to include DPU rounds in their arsenals. Whether Israel does or not is uncertain.