A favourite weapon of the American military
, not so popular with citizen
s of the countries they are used against. Cluster bombs are controversial not just for their ability to cause such intense devastation
over such a wide area (650ft x 1,300 feet or more, the size of about eight football pitches
) but also because at least 5% of the hundreds of bomblet
s dropped by the average cluster bomb don't go off straight away*; instead, they litter the ground very much like land mine
s, potentially for years to come - for this reason many have argued that they should be banned under conventions banning land mines. About thirty-five thousand of these are said to be scattered around Kosovo
, where they have killed around two hundred people since the conflict ended in spite of relatively extensive cleanup operations after the war. In Laos
, which the USA carpet bomb
ed with these munitions during the Viet Nam War
, cluster bombs still make many areas unsuitable for cultivation or habitation some thirty years on. After the Gulf War
of the early 1990s had ended, more than 1600 civilians were killed by left-over bomblets.
The tail-fins of the cluster bomb are designed so that the whole canister spins rapidly (at as much as 2,500 rpm), in order to scatter the bombs over a wider area; the rate of spin and the height of the canister when it releases its bomblets provide some control over the size of the area affected by the attack.
The CBU-87/B "combined effects munition" is the air-delivered cluster bomb usually used by the US. Each CBU weighs 950 lbs, and carries 202 BLU-97/B bomblets - with a 5% dud rate, that's about ten unexploded bomblets per cluster. Each BLU-97/B is about the size of a drinks can. Every one is capable of penetrating about seven inches of armour, and has a blast radius of as much as 250 feet. The bomblets are scored so that they fragment predictably, each one creating about 300 shards of shrapnel. They also carry incendiary zirconium rings to start fires.
* 5% is a conservative estimate. The UN Mine Action Coordinating Centre in Kosovo suggests a failure rate of 11-12% for the British-made RBL755, a cluster bomb available on the open market. Human Rights Watch says: "Estimates of overall dud rates vary from the conservative 2-5 percent claimed by manufacturers, to up to 23 percent observed in acceptance and operational testing, to some 10-30 percent observed on the ground in areas of Iraq after the Gulf War."