The CBU-24, a key cluster bomb during the Vietnam War era, was an unguided dispenser releasing up to 665 BLU-24/B bomblets—small, roughly baseball-sized explosives filled with steel fragments.

In February 1968, American forces in Vietnam were still reeling from the sudden onslaught of the Tet Offensive. The January surprise attack by the North Vietnamese and the Viet Cong saw strategic but ...