"I find hope in the work of long-established groups such as the Arms Control Association...[and] I find hope in younger anti-nuclear activists and the movement around the world to formally ban the bomb."

– Vincent Intondi
Professor of History, Montgomery College
July 1, 2020
Cluster Munitions at a Glance

Last Reviewed: 
December 2017

Contact: Daryl Kimball, Executive Director, (202) 463-8270 x10

Cluster munitions, also called cluster bombs or CBUs, are gravity bombs, artillery shells, and rockets that fragment into small bomblets or grenades. Some cluster munitions disperse only two bomblets while others can spread up to hundreds of submunitions over a large area. These weapons are designed for use against massed formations of troops and armor or broad targets, such as airfields. Cluster submunitions, however, sometimes fail to explode on impact and can kill or maim civilians who later come into contact with them. These unexploded submunitions may remain dangerous for decades. According to Cluster Munition Monitor 2017, at least 21,200 cluster munition casualties have been confirmed globally since the 1990s. About 17,291 came from unexploded submunitions, and about 3,983 from strikes. Estimated totals, however, are considered much higher, and according to the Monitor, “are likely a better indicator of the true numbers.” Estimates for a global total range from 58,000 to 85,000. Almost all reported cluster munition casualties have been civilians, in large part because of the unwillingness of militaries to provide information.

Cluster munitions have been used during armed conflict in 40 countries and four disputed territories since the end of World War II. Almost every part of the world has experienced cluster munition use at some point over the past 70 years, including Southeast Asia, Southeast Europe, the Caucasus, the Middle East and North Africa, Sub-Saharan Africa, and Latin America. Although cluster munitions first saw use in World War II and more than 50 countries have since acquired stockpiles of such arms, efforts to regulate or ban the use of cluster munitions gained greater attention and momentum after the summer 2006 war between Israel and Hezbollah, a Shiite organization that the United States identifies as a terrorist group. Israel’s extensive cluster munitions use in the last 72 hours of that conflict resulted in an estimated one million unexploded bomblets scattered across southern Lebanon, arousing some strong condemnation. Jan Egeland, then-UN Undersecretary General for Humanitarian Affairs, blasted Israel’s use of cluster munitions as “shocking and completely immoral.”

Convention on Cluster Munitions

The Convention on Certain Conventional Munitions (CCW) did not restrict the use of cluster munitions. Although a group of states initially sought to establish a new protocol banning cluster munitions in the CCW, years of negotiations in the consensus-based forum failed to produce such a protocol. Frustrated with the slow-moving CCW approach, Norway at the November 2006 review conference announced an alternative effort to negotiate a treaty on cluster munitions. The inaugural meeting of that effort convened February 2007 in Oslo. Of the 49 governments attending the conference, 46 ultimately signed the “Oslo Declaration” to “conclude, by 2008, a legally binding instrument that will…prohibit the use, production, transfer, and stockpiling of cluster munitions that cause unacceptable harm to civilians.”

Much of the debate among participating governments over the treaty centered on two issues. The first was whether future use restrictions would take effect immediately or, as Germany argued, be phased in to allow time for the development of alternative weapons. The second was whether the treaty should outlaw all cluster munitions or permit some exemptions for certain types or for their use in certain circumstances. Sweden called for a treaty balancing “legitimate humanitarian and military interests,” while the United Kingdom sought exemptions for systems equipped with self-destruct or self-deactivation devices that are supposed to render unexploded munitions harmless after a short period of time. Other countries, such as Norway, Ireland, and Mexico, favored a total ban.

On May 30, 2008 the Dublin Diplomatic Conference on Cluster Munitions adopted a comprehensive new treaty banning cluster munitions. The 107 states adopted the treaty. The Convention on Cluster Munitions (CCM) is a legally binding international treaty that prohibits the use, production, stockpiling and transfer of cluster munitions and requires clearance of remnants and destruction of stocks. It requires states to provide assistance to survivors and their communities and builds on existing international human rights and humanitarian law. The treaty requires states to destroy existing stockpiles within eight years and to clear contaminated land within 10 years. The obligations relating to victim assistance were groundbreaking; they demanded the full realization of the rights of people affected by cluster munitions and require states to implement effective victim assistance measures. 

The Convention on Cluster Munitions was signed by 94 countries at the Oslo Signing Conference in December 2008, and entered into force on August 1, 2010, after 30 states ratified it by February 16, 2010. In November 2010, the First Meeting of States Parties to the Convention on Cluster Munitions (1MSP) took place in Vientiane, Lao PDR. After holding their First Meeting of States Parties in Lao PDR in November 2010, states parties convened in Lebanon, another highly contaminated country, for the convention’s Second Meeting of States Parties on September 12–16, 2011. At the meeting, states parties adopted the Beirut Progress Report, charting implementation of the Vientiane Action Plan, which guides the work of the convention through to its First Review Conference in 2015.

Status of the 2008 Convention on Cluster Munitions

A total of 102 states have ratified or acceded to the Convention on Cluster Munitions to become full states-parties as of 1 August 2017, and 17 states that have signed have yet to ratify. States-parties include former producers and users of cluster munitions such as France, Germany, the Netherlands, and the United Kingdom (UK). Since the convention entered into force on August 1, 2010, becoming binding international law, states can no longer sign, but must instead accede.

A total of 53 signatories have ratified the convention since August 2010, including countries where cluster munitions have been used (Afghanistan and Mauritania), former cluster munition producers (Italy, Sweden, and Switzerland), and countries that have stockpiled cluster munitions (Afghanistan, Côte d’Ivoire, Czech Republic, Honduras, Hungary, Italy, Mauritania, Sweden, and Switzerland). 

Unilateral restrictions on use

Several states that have not joined the Convention on Cluster Munitions have imposed restrictions on the possible future use of cluster munitions. Romania has said it restricts the use of cluster munitions to use exclusively on its own territory. Poland has said it would use cluster munitions for defensive purposes only, and does not intend to use them outside its own territory. Estonia and Finland have made similar declarations. During the CCW negotiations on cluster munitions, several states that have not signed or ratified the Convention on Cluster Munitions publicly stated that they were prepared to accept a ban on the use of cluster munitions produced before 1980 as part of the proposed CCW protocol, including Russia, China, India, and South Korea. The CMC urges that as an interim measure toward joining the Convention on Cluster Munitions, these states should institute the commitment made at CCW as national policy. 

U.S. Cluster Munitions Policy

In June 2008, the U.S. Department of Defense released a directive requiring that any U.S. use of cluster munitions before 2018 that results in a one percent or higher unexploded ordnance (UXO) rate—which includes all but a tiny fraction of the US arsenal—must be approved by a “Combatant Commander,” a very high-ranking military official and that after 2018, the United States would no longer use cluster munitions that result in more than one percent UXO.

However, in a Defense Department memorandum circulated on November 30, 2017, the Trump administration eliminated the 2019 deadline to stop using cluster munitions resulting in more than one percent UXO but retained the requirement for Combatant Commander authorization for their use.

The United States is a producer and exporter of cluster bombs. In 2011, the United States reported that it possessed more than 6 million cluster munitions. In 2001, the United States adopted a policy that all cluster munitions produced domestically after late 2004 must have submunitions with failure rates of less than one percent. As with all U.S. arms exports, transfers of cluster munitions are governed by conditions restricting their re-transfer and use by importers.

One such agreement applies to U.S. cluster munitions shipped to Israel. Although secret, the agreement is generally understood to prohibit the use of cluster munitions in populated areas and against targets that are not clearly military. Following the 2006 conflict in Lebanon, the Department of State’s Office of Defense Trade Controls opened an investigation into whether Israel had violated the agreement. State Department spokesperson Sean McCormack said that the preliminary report, delivered to the president and Congress in January 2007, found that “there likely could have been some violations.” The United States sanctioned Israel for misusing cluster munitions in the past. The Ronald Reagan administration suspended cluster munitions sales to Israel between 1982 and 1988 following Israel’s widespread use of such arms during an earlier invasion of Lebanon.

While as recently as 2006, the United States opposed negotiating a protocol on cluster munitions at CCW review conferences, in 2007, it changed its position. Ronald Bettauer, head of the U.S. delegation, attributed the reversal “to the importance of this issue, concerns raised by other countries, and our own concerns about the humanitarian implications of these weapons.” Department of State Legal Adviser Harold Koh stated November 9, 2009, that the United States has determined that it’s “national security interests cannot be fully ensured consistent with the terms” of the CCM but that “the United States remains committed to negotiate a legally binding Protocol on Cluster Munitions in the CCW.”

Research Assistance by Daria Medvedeva