Cluster bombs are large weapons that contain dozens and often hundreds of smaller submunitions.4 They come in at least 208 models and can be delivered from the air or the ground, releasing "bomblets" or "grenades" respectively. At least fifty-six nations stockpile these weapons and at least thirty-three produce them. At least nine states have used them in combat in thirteen different countries.5 This report, which covers the U.S. air campaign in Afghanistan, discusses only airdropped cluster munitions. The basic mechanics and effects of cluster bombs are the same, however, so many of the report's conclusions and recommendations can be applied to other models.
The United States used primarily two types of cluster bombs in Afghanistan-the CBU-87 and the CBU-103.6 Each model consists of a three-part green metal casing about five-and-a-half feet (1.7 meters) long with a set of four fins attached at the rear. Formally known as a tactical munitions dispenser (TMD), the casing contains 202 submunitions, or bomblets, packed in yellow foam. The casing opens at a pre-set altitude or time and releases the bomblets, which spread over an oval area that ranges from 120 by 200 feet to 400 by 800 feet (from thirty-seven by sixty-one meters to 123 by 244 meters). The military can change the dispersal pattern by adjusting the spin of the bomb as it falls and the altitude at which it opens. The faster the spin and the higher the altitude, the wider the dispersal pattern is. The CBU-87, whose initial production dates to 1984, was one of the first designs to provide some control over the footprint through its spin mechanism.
The newer CBU-103 adds a wind corrected munitions dispenser (WCMD) to the rear of its unguided predecessor and is designed to improve accuracy by compensating for wind encountered during its fall.7 According to the Air Force, the WCMD helps the bomb hit its intended target especially when dropped from medium to high altitudes.8 The United States introduced this model in 1999 and first used it in combat in Afghanistan.9 Air Force Chief of Staff Gen. John Jumper described the high-altitude WCMD strikes as "highly successful."10 The WCMD also narrowed the bomblets' dispersal pattern, leading the United States to estimate footprints with a 1,500-foot (458-meter) radius for CBU-87s and a 600-foot (183-meter) radius for CBU-103s.11 During its mission to Afghanistan, Human Rights Watch did not find sufficient evidence to judge the effectiveness of the WCMD.
The bomblets, known as BLU-97s, are six-and-a-half-inch (16.5 centimeters) tall cylinders that are often described as resembling soda cans.12 When stowed, a bomblet consists of a yellow canister with a silver six-legged or black four-legged cap called a "spider." The legs of the spiders hook into square holes at the top of the canister and then flare out so that they will catch wind. When the casing opens and the bomblets fall towards the ground, the wind pops the spiders off. The newer four-legged version is designed to pop off more easily. The loss of the cap allows a spring inside to push up a flat, triangular decelerator, or parachute, and a plastic collar that arms the BLU. The nylon parachute stabilizes the bomblet so that it lands perpendicular to the ground and explodes on impact.
Each bomblet represents a triple threat. The steel fragmentation core targets people. This scored yellow cylinder inside the canister breaks into three hundred jagged pieces of metal, which can injure people five hundred feet (152 meters) away. They can also damage light armor and trucks at fifty feet (fifteen meters). The shaped charge, a concave copper cone located at the bottom of the BLU, serves as an anti-armor weapon. When the bomblet explodes, it turns into a molten slug than can penetrate five inches (thirteen centimeters) into tanks and other armored vehicles. Finally, an incendiary zirconium wafer, located above the shaped charge, spreads incendiary fragments that can burn nearby vehicles. This three-part effect makes the BLU a "combined effects munition."
In addition to having multiple effects, the cluster bomb has military value as an area weapon. Because of the dispersal of its bomblets, it can destroy broad, relatively "soft" targets, like airfields and surface-to-air missile sites. It is also effective against targets that move or do not have a precise location, such as enemy troops or vehicles.13 In Afghanistan, the United States primarily used the cluster bomb as an antipersonnel and area weapon.
4 For the purposes of this report, Human Rights Watch is using "cluster bomb" as a shorthand, catchall term for air- and surface-delivered dispensers containing unguided explosive submunitions.
5 Human Rights Watch, A Global Overview of Explosive Submunitions, p. 1. This document represents the best information available at the time and will be updated as Human Rights Watch obtains and confirms new data.
6 CBU stands for "cluster bomb unit." Although there are other munitions that use this designation, CBU in this report refers to CBU-87s and CBU-103s. For more information on these weapons, see Human Rights Watch, "Cluster Bombs in Afghanistan," pp. 5-7; Human Rights Watch, "Ticking Time Bombs," pp. 7-8. A small number of Navy CBU-99s, CBU-100s, and JSOW-As were also used in Afghanistan. NAVAIR Weapons Division, China Lake-Influenced Weapons and Aircraft Deployed/Used During Times of Military Conflict, at http://www.nawcwpns.navy.mil/r2/wc/WpnsAir.htm (last visited November 25, 2002).
7 The accuracy of air-launched munitions is measured by "circular error probable" (CEP), which is "the radius of a circle within which half of a missile's projectiles are expected to fall." U.S. Department of Defense (DoD), Dictionary of Military Terms, available at http://www.dtic.mil/doctrine/jel/doddict/ (last visited October 10, 2002). The WCMD is designed to have a CEP of eighty-five feet (twenty-six meters), according to manufacturer specifications. Lockheed Martin, Wind Corrected Munitions Dispenser Fact Sheet, available at
8 The WCMD is designed for use at 30,000 feet (9,200 meters), but the Air Force claims it "has proven effective around 40,000 feet" (12,000 meters). Frank Wolfe, "Air Force Outfitting Sensor Fused Weapons with WCMD Tail Kits," Defense Daily, December 3, 2001. For more information on the WCMD, see Jane's Air Launched Weapons, ed. Duncan Lennox (Surrey, U.K.: Jane's Information Group, 1999).
9 Jake Swinson, "Eglin's WCMD Goes to War," Air Force Materiel Command (AFMC) Public Affairs Link, December 2001, at http://www.afmc.wpafb.af.mil/HQ-AFMC/PA/news/archive/2001/dec/Eglin_WCMDtowar.htm (last visited November 25, 2002).
10 Frank Wolfe, "Air Force Employing WCMD, Flex Targeting on B-52s, Linking Predator and AC-130s," Defense Daily, November 28, 2001.
11 U.S. DoD, Probable UXO [Unexploded Ordnance] Locations, January 2002 [hereinafter U.S. Cluster Bomb List-January].
12 BLU stands for "bomb live unit." Although there are other munitions that use this designation, BLU in this report refers to BLU-97s.
13 CBUs "are area weapons that you drop in an area where you don't know the exact coordinates or exact location," said U.S. Air Force Maj. Gen. Don Shepperd (ret.). "U.S. Military Begins Use of Cluster Bombs in Afghanistan," CNN: Live This Morning transcript, October 26, 2001.