Cluster Munitions: Background and Issues
for Congress
Andrew Feickert
Specialist in Military Ground Forces
Paul K. Kerr
Analyst in Nonproliferation
January 11, 2011
Congressional Research Service
7-5700
www.crs.gov
RS22907
CRS Report for Congress
P
repared for Members and Committees of Congress
Cluster Munitions: Background and Issues for Congress
Summary
Cluster munitions are air-dropped or ground-launched weapons that release a number of smaller
submunitions intended to kill enemy personnel or destroy vehicles. Cluster munitions were
developed in World War II and are part of many nations’ weapons stockpiles. Cluster munitions
have been used frequently in combat, including the early phases of the current conflicts in Iraq
and Afghanistan. Cluster munitions have been highly criticized internationally for causing a
significant number of civilian deaths, and efforts have been undertaken to ban and regulate their
use. The Department of Defense (DOD) continues to view cluster munitions as a military
necessity but has instituted a policy to reduce the failure rate of cluster munitions to 1% or less by
2018.
There are two major international initiatives to address cluster munitions: the Convention on
Cluster Munitions (CCM) and negotiations under the U.N. Convention on Prohibitions or
Restrictions on the Use of Certain Conventional Weapons (CCW). The Obama Administration
has reiterated U.S. opposition to the CCM, which entered into force August 1, 2010, but is
participating in negotiations regarding cluster munitions under the CCW.
Congressional Research Service
Cluster Munitions: Background and Issues for Congress
Contents
What Are Cluster Munitions? ...................................................................................................... 1
History........................................................................................................................................ 1
Cluster Munitions Criticisms....................................................................................................... 2
Failure Rate .......................................................................................................................... 2
Lack of Self-Destruct Capability ........................................................................................... 2
International Attempts to Regulate Use........................................................................................ 3
U.N. Convention on Prohibitions or Restrictions on the Use of Certain Conventional
Weapons (CCW) ................................................................................................................ 3
Convention on Cluster Munitions (CCM).............................................................................. 3
Current U.S. Policy on Cluster Munitions.................................................................................... 4
Department of Defense (DOD) Policy on Cluster Munitions.................................................. 5
DOD Efforts to Reduce Unexploded Ordnance Rates for Its Cluster Munitions ........................... 5
Potential Issues for Congress....................................................................................................... 6
Cluster Munitions in an Era of Precision Weapons................................................................. 6
Weapons in Lieu of Cluster Munitions................................................................................... 6
Is the CCW a Viable Forum for Regulating Cluster Munitions? ............................................. 6
Legislation in the 111th Congress ........................................................................................... 7
Consolidated Appropriations Act, 2010 ........................................................................... 7
Contacts
Author Contact Information ........................................................................................................ 7
Congressional Research Service
Cluster Munitions: Background and Issues for Congress
What Are Cluster Munitions?1
Cluster munitions are weapons that open in mid-air and disperse smaller submunitions—
anywhere from a few dozen to hundreds—into an area. They can be delivered by aircraft or from
ground systems such as artillery, rockets, and missiles. Cluster munitions are valued militarily
because one munition can kill or destroy many targets within its impact area, and fewer weapons
systems are needed to deliver fewer munitions to attack multiple targets. Cluster munitions also
permit a smaller force to engage a larger adversary and are considered by some an “economy of
force” weapon. Many cluster munitions rely on simple mechanical fuzes that arm the submunition
based on its rate of spin and explode on impact or after a time delay. A newer generation of
sensor-fuzed submunitions is being introduced by a number of nations to improve the munitions’
and submunitions’ accuracy and to reduce the large number of residual unexploded submunitions.
These sensor-fuzed submunitions are designed to sense and destroy vehicles without creating an
extensive hazard area of unexploded submunitions.
History2
Cluster bombs were first used in World War II, and inclusive of their debut, cluster munitions
have been used in at least 21 states by at least 13 different countries. Cluster munitions were used
extensively in Southeast Asia by the United States in the 1960s and 1970s, and the International
Committee of the Red Cross (ICRC) estimates that in Laos alone, 9 million to 27 million
unexploded submunitions remained after the conflict, resulting in over 10,000 civilian casualties
to date. Cluster munitions were used by the Soviets in Afghanistan, by the British in the
Falklands, by the Coalition in the Gulf War, and by the warring factions in Yugoslavia. In Kosovo
and Yugoslavia in 1999, NATO forces dropped 1,765 cluster bombs containing approximately
295,000 submunitions. From 2001 through 2002, the United States dropped 1,228 cluster bombs
containing 248,056 submunitions in Afghanistan, and U.S. and British forces used almost 13,000
cluster munitions containing an estimated 1.8 million to 2 million submunitions during the first
three weeks of combat in Iraq in 2003. Senior U.S. government officials have stated that the
United States has not used cluster munitions since 2003, during the intervention in Iraq.3 It is
widely believed that confusion over U.S. cluster submunitions (BLU-97/B) that were the same
color and size as air-dropped humanitarian food packets played a major role in the U.S. decision
to suspend cluster munitions use in Afghanistan but not before using them in Iraq.
In 2006, Israeli use of cluster munitions against Hezbollah forces in Lebanon resulted in
widespread international criticism. Israel was said to have fired significant quantities of cluster
munitions—primarily during the last three days of the 34-day war after a U.N. cease fire deal had
been agreed to4—resulting in almost 1 million unexploded cluster bomblets to which the U.N.
1 Information in this section unless otherwise noted is from Mark Hiznay, “Operational and Technical Aspects of
Cluster Munitions,” United Nations Institute for Disarmament Research Disarmament Forum,” 2006, pp. 15-25.
2 Ibid.
3 Stephen D. Mull, Acting Assistant Secretary of State for Political-Military Affairs, U.S. Cluster Munitions Policy,
On-the-Record Briefing, Washington, D.C, May 21, 2008.
4 Scott Peterson, “Cluster Bombs: A War’s Perilous Aftermath,” Christian Science Monitor, February 7, 2007, and
“Israel Criticized for Cluster Bombs,” Los Angeles Times, February 1, 2008.
Congressional Research Service
1
Cluster Munitions: Background and Issues for Congress
attributed 14 deaths during the conflict.5 Reports maintain that Hezbollah fired about 113 “cluster
rockets” at northern Israel and, in turn, Israel’s use of cluster munitions supposedly affected 26%
of southern Lebanon’s arable land and contaminated about 13 square miles with unexploded
submunitions.6 One report states that there was a failure rate of upwards of 70% of Israel’s cluster
weapons.7
Cluster Munitions Criticisms
The fundamental criticisms of cluster munitions are that they disperse large numbers of
submunitions imprecisely over an extended area, that they frequently fail to detonate and are
difficult to detect, and that submunitions can remain explosive hazards for decades. Civilian
casualties are primarily caused by munitions being fired into areas where soldiers and civilians
are intermixed, inaccurate cluster munitions landing in populated areas, or civilians traversing
areas where cluster munitions have been employed but failed to explode. Two technical
characteristics of submunitions—failure rate and lack of a self-destruct capability—have received
a great deal of attention.
Failure Rate8
There appear to be significant discrepancies among failure rate estimates. Some manufacturers
claim a submunition failure rate of 2% to 5%, whereas mine clearance specialists have frequently
reported failure rates of 10% to 30%. A number of factors influence submunition reliability. These
include delivery technique, age of the submunition, air temperature, landing in soft or muddy
ground, getting caught in trees and vegetation, and submunitions being damaged after dispersal,
or landing in such a manner that their impact fuzes fail to initiate.
Lack of Self-Destruct Capability
Submunitions lacking a self-destruct capability—referred to as “dumb” munitions—are of
particular concern because they can remain a hazard for decades, thereby increasing the potential
for civilian casualties. Some nations are developing “smart” or sensor-fuzed weapons with greater
reliability and a variety of self-destruct mechanisms intended to address the residual hazard of
submuntions.9 Experts maintain that self-destruct features reduce—but do not eliminate—the
unexploded ordnance problem caused by cluster munitions and that the advantage gained by
using “smart” cluster munitions is negated when high-failure rate and/or “dumb” cluster
munitions are used in the same area.10 For some nations, replacing “dumb” and high-failure rate
5 “Major Violations on Both Sides in Israel-Lebanon Conflict, Say UN Experts,” United Nations Office at Geneva
News & Media, October 4, 2006.
6 Scott Peterson.
7 Ibid. Failure rate as described here is either a failure to detonate on impact or a failure to detonate after a
predetermined time delay.
8 Unless otherwise noted, information in this section is from Mark Hiznay. p. 22.
9 Gayle S. Putrich, “Cluster-Bomb Ban Exempts Some Smart Munitions,” Defense News, June 2, 2008, p. 4.
10 Hiznay, p. 23.
Congressional Research Service
2
Cluster Munitions: Background and Issues for Congress
cluster munitions may not be an option—China, Russia, and the Republic of Korea maintain that
they cannot afford to replace all current submunitions with “smart” submunitions.11
International Attempts to Regulate Use
The use of cluster munitions is currently not prohibited under international law or governed by
international treaty. There are however, two major ongoing international initiatives to regulate
cluster munitions.
U.N. Convention on Prohibitions or Restrictions on the Use of
Certain Conventional Weapons (CCW)
In an effort to restrict or ban specific types of weapons used in armed conflicts, 51 states
negotiated the CCW in 1980.12 When the treaty entered into force in December 1983, it applied
only to incendiary weapons, mines and booby-traps, and weapons intended to cause casualties
through very small fragments. Since then, some states parties have added provisions through
additional protocols to address other types of weapons. Negotiations on cluster munitions are
carried out under Protocol V on Explosive Remnants of War. Some have characterized the CCW
as “slow-moving,” “ponderous,” and “lacking life.”13
Acting in accordance with the recommendation of a group of experts established during the 2006
CCW review conference, states-parties to the convention decided in 2007 to “negotiate a proposal
to address urgently the humanitarian impact of cluster munitions.”14 Negotiations took place in
2008 and 2009, but the parties have not reached agreement on a new proposal. The experts group
is to continue negotiations in 2011 “informed by” a Draft Protocol on Cluster Munitions.15
Convention on Cluster Munitions (CCM)16
Described as “frustrated with the CCW process,” a number of CCW members—led by Norway—
initiated negotiations in 2007 outside of the CCW to ban cluster munitions.17 On May 30, 2008,
11 Ibid.
12 Information in this section is from an Arms Control Association Fact Sheet. “Convention on Certain Conventional
Weapons Convention (CCW) at a Glance,” Washington, D.C., October 2007.
13 “A Change of Heart, or of Tactic?, Cluster Munitions,” The Economist, June 23, 2007.
14 Report from the November 2007 meeting of states-parties to the CCW, December 3, 2007. Available at
http://www.unog.ch/80256EDD006B8954/(httpAssets)/029247C7A309EAC2C12573CF005B93B6/
$file/CCW+MSP+2007+5+E.pdf.
15 “Cluster Munitions Remain the Focus of CCW Ahead of the 2011 Review Conference,” December 3, 2010.
Available at http://www.onug.ch/80256EDD006B9C2E/%28httpNewsByYear_en%29/
33009AD680B169BDC12577EE003F9762?OpenDocument. A copy of the Draft Protocol is available at http://daccess-
ods.un.org/TMP/834449.529647827.html.
16 For detailed information on the Convention on Cluster Munitions, see http://www.clustermunitionsdublin.ie/
documents.asp.
17 Arms Control Association Fact Sheet. “Convention on Certain Conventional Weapons Convention (CCW) at a
Glance,” Washington, D.C., October 2007.
Congressional Research Service
3
Cluster Munitions: Background and Issues for Congress
they reached an agreement to ban cluster munitions.18 The United States, Russia, China, Israel,
Egypt, India, and Pakistan did not participate in the talks or sign the agreement. During the
Signing Conference in Oslo from December 3-4, 2008, 94 states signed the convention and four
of the signatories ratified the convention at the same time.19 China, Russia, and the United States
abstained, but France, Germany, and the United Kingdom were among the 18 NATO members to
sign the convention.20 The convention was to enter into force six months after the deposit of the
30th ratification. The United Nations received the 30th ratification February 16, 2010, and the
convention entered into force August 1, 2010. As of January 10, 2011, 108 states had signed the
convention and 49 had ratified it.
The Convention on Cluster Munitions (CCM), inter alia, bans the use of cluster munitions, as
well as their development, production, acquisition, transfer, and stockpiling.21 The convention
does not prohibit cluster munitions that can detect and engage a single target or explosive
submunitions equipped with an electronic self-destruction or self-deactivating feature22—an
exemption that seemingly permits sensor-fuzed or “smart” cluster submunitions. U.S. officials
were concerned that early versions of the CCM would prevent military forces from non-states
parties from providing humanitarian and peacekeeping support and significantly affect NATO
military operations, but the version signed May 30, 2008, does permit states parties to engage in
military cooperation and operations with non-states parties (Article 21, Paragraph 3).
Current U.S. Policy on Cluster Munitions
Then-Acting Assistant Secretary for Political-Military Affairs Stephen Mull stated in May 2008
that the United States relies on cluster munitions “as an important part of our own defense
strategy,” and that Washington’s preferred alternative to a ban is “to pursue technological fixes
that will make sure that these weapons are no longer viable once the conflict is over.”23 U.S.
officials note that:
Cluster munitions are available for use by every combat aircraft in the U.S. inventory, they
are integral to every Army or Marine maneuver element and in some cases constitute up to
50 percent of tactical indirect fire support. U.S. forces simply can not fight by design or by
doctrine without holding out at least the possibility of using cluster munitions.24
The United States also maintains that using cluster munitions reduces the number of aircraft and
artillery systems needed to support military operations, and that if cluster munitions were
eliminated, significantly more money would need to be spent on new weapons systems,
18 Kevin Sullivan and Josh White, “111 Nations, Minus the U.S., Agree to Cluster-Bomb Ban,” Washington Post, May
29, 2008.
19 Convention on Cluster Munitions Homepage http://www.clusterconvention.org/ accessed January 28, 2009.
20 Marina Malenic, “Dozens of Nations Sign Cluster Bomb Treaty, U.S. Begins Upgrading Related Technology,”
Defense Daily, December 5, 2008.
21 Diplomatic Conference for the Adoption of a Convention on Cluster Munitions, Convention on Cluster Munitions,
Dublin, Ireland, May 30, 2008 http://www.clustermunitionsdublin.ie/documents.asp.
22 Ibid.
23 Mull, 2008.
24 Richard Kidd, Director of the Office of Weapons Removal and Abatement, U.S. Department of State, “Is There a
Strategy for Responsible U.S. Engagement on Cluster Munitions ?” April 28, 2008.
Congressional Research Service
4
Cluster Munitions: Background and Issues for Congress
ammunition, and logistical resources. Officials further suggest that if cluster munitions were
eliminated, most militaries would increase their use of massed artillery and rocket barrages,
which would likely increase destruction of key infrastructure.
Department of State Legal Adviser Harold Koh stated November 9, 2009, that the United States
has determined that its “national security interests cannot be fully ensured consistent with the
terms” of the CCM.25 However, the United States has agreed to address the humanitarian aspects
of cluster munitions use in the CCW.26 Koh stated that “the United States remains committed to
negotiate a legally binding Protocol on Cluster Munitions in the CCW.” The United States was
originally against any CCW negotiations on cluster munitions, but dropped its opposition in June
2007.
Department of Defense (DOD) Policy on Cluster Munitions27
Koh stated November 9, 2009, that the “United States continues to implement” the DOD policy
on cluster munitions issued June 19, 2008, which recognizes the need to minimize harm to
civilians and infrastructure but also reaffirms the contention that “cluster munitions are legitimate
weapons with clear military utility.” The central directive in the Pentagon’s new policy is the
unwaiverable requirement that cluster munitions used after 2018 must leave less than 1% of
unexploded submunitions on the battlefield. Prior to 2018, U.S. use of cluster munitions with a
greater than 1% unexploded ordnance rate must be approved by Combatant Commanders. This
policy will permit the development of a new generation of cluster munitions less dangerous to
civilians. While such a high level of performance might be achievable under controlled laboratory
conditions, previously mentioned factors such as delivery technique, landing in soft or muddy
ground, getting caught in trees and vegetation, and submunitions being damaged after dispersal or
landing could result in an appreciable number of dud submunitions, even if they have a self-
deactivation feature.
DOD Efforts to Reduce Unexploded Ordnance Rates
for Its Cluster Munitions
DOD and the services have been and are currently involved in efforts to reduce cluster munitions
failure rates. The Army’s Alternative Warhead Program (AWP) is intended to assess and
recommend new technologies to reduce or eliminate cluster munitions failure rates.28 The AWP
program is viewed as particularly relevant, as the Pentagon estimates that “upward of 80 percent
of U.S. cluster munitions reside in the Army artillery stockpile.”29 In December 2008, the Army
decided to cease procurement of a Guided Multiple Launch Rocket System (GMLRS) warhead—
25 “Opening Statement for the United States Delegation by Harold Hongju Koh, Legal Adviser, United States
Department of State, at the Third Conference of the High Contracting Parties to Protocol V on Explosive Remnants of
War.” November 9, 2009.
26 Kidd, 2008.
27 Information in this section is from DOD Policy on Cluster Munitions and Unintended Harm to Civilians, June 19,
2008.
28 Daniel Wasserbly, “Army Warhead Program to Reduce Dud Rate for Cluster Munitions,” InsideDefense.com, July
21, 2008.
29 Ibid.
Congressional Research Service
5
Cluster Munitions: Background and Issues for Congress
the Dual-Purpose Improved Conventional Munition (DPICM) warhead—because its
submunitions had a dud rate up to 5%.30 The Air Force is also acquiring cluster munitions that
comply with the less than 1% failure rate—the CBU-97 Sensor Fuzed Weapon (SFW) and the
CBU-105 WCMD/SFW.31
Potential Issues for Congress
Cluster Munitions in an Era of Precision Weapons
It may be argued that even with advances in “sensor-fuzed” type submunitions that seek out and
destroy certain targets, cluster munitions are still essentially an indiscriminate area weapon in an
era where precision weapons are increasingly becoming the military norm. In Operation Desert
Storm in 1991, only about 10% of ordnance used were precision-guided, but by the time of the
Iraq invasion in 2003, “the ratio of ‘smart’ to dumb weapons was nearly reversed.”32 Since then,
this trend towards greater precision has continued, if not accelerated with the development of
precision rocket, artillery, mortar munitions, and smaller precision aerial bombs designed to
reduce collateral damage.33 Given current and predicted future precision weaponry trends, cluster
munitions might be losing their military relevance—much as chemical weapons did between
World War I and World War II.
Weapons in Lieu of Cluster Munitions
According to the State Department, the U.S. military suspended its use of cluster munitions in
Iraq and Afghanistan in 2003. For subsequent military operations, where cluster munitions would
otherwise have been the weapon of choice, Congress might review what types of weapons were
substituted in place of cluster munitions and how effective they were in achieving the desired
tactical results. Also worth considering are effects-based weapons systems and operations, which
seek to achieve the same or similar effect against a potential target without applying a “kinetic
solution” such as a cluster munition. Such insights could prove valuable in analyzing U.S. policy
options on the future of cluster munitions.
Is the CCW a Viable Forum for Regulating Cluster Munitions?
Given the failure of CCW delegates to reach an agreed protocol in November 2008 and the
signature of CCM by prominent U.S. NATO allies Great Britain, France, and Germany, it has
been suggested by some that it might be worth reevaluating the CCW as a means to regulate
cluster munitions. There are doubts that CCW efforts to develop a cluster munitions protocol will
be viable, as some nations that are part of the CCW who have also signed the Convention on
30 Kate Brannen, “Army Will Stop Procurement of GMLRS-DPICM After Final Deliveries,” InsideDefense.com,
December 1, 2008.
31 Marina Malenic, “Dozens of Nations Sign Cluster Bomb Treaty, U.S. Begins Upgrading Related Technology,”
Defense Daily, December 5, 2008.
32 J.R. Wilson, “Pinpoint Accuracy: Bombs, Rockets, and Mortars Get New Brains,” Armed Forces Journal, January
2005, pp. 32-34.
33 Jeffrey Kofman, “Introducing the Small Diameter Bomb,” ABC News, February 16, 2008.
Congressional Research Service
6
Cluster Munitions: Background and Issues for Congress
Cluster Munitions stand in opposition of a CCW protocol on cluster munitions. If the United
States were to become an active participant in the CCM, along with allies such as Great Britain,
France, and Germany, it might have a greater role in shaping the future of this convention. One
potential drawback, should the United States support the CCM, is that it could be seen as
undermining the entire CCW, which encompasses more than just cluster munitions. Such a policy
shift to support the CCM could also have a detrimental impact on any future CCW initiatives
dealing with other conventional weapons.
Legislation in the 111th Congress
Consolidated Appropriations Act, 2010
The Consolidated Appropriations Act, 2010 (P.L. 111-117), which the President signed into law
December 16, 2009, prohibits the provision of military assistance for cluster munitions, the
issuing of defense export licenses for cluster munitions, or the sale or transfer of cluster munitions
or cluster munitions technology unless “the submunitions of the cluster munitions, after arming,
do not result in more than 1 percent unexploded ordnance across the range of intended
operational environments.” Moreover, any agreement “applicable to the assistance, transfer, or
sale of such cluster munitions or cluster munitions technology” must specify that the munitions
“will only be used against clearly defined military targets and will not be used where civilians are
known to be present or in areas normally inhabited by civilians.”
These restrictions were also contained in the 2009 Omnibus Appropriations Act (P.L. 111-8). The
Consolidated Appropriations Act, 2008 (P.L. 110-161) contained similar restrictions, but they
applied only for that fiscal year.
Author Contact Information
Andrew Feickert
Paul K. Kerr
Specialist in Military Ground Forces
Analyst in Nonproliferation
pkerr@crs.loc.gov, 7-8693
Congressional Research Service
7