brain injury has remained underestimated. Blast lung refers to severe pulmonary contusion, bleeding or swelling with damage to alveoli and blood vessels, or a combination of these. It is the most common cause of death among people who initially survive an explosion. Secondary injuries Secondary injuries are ballistic trauma caused by impacts of flying shrapnels and other objects propelled by the explosion. These injuries may affect any part of the body and sometimes result in penetrating trauma with visible bleeding. At times the propelled object may become embedded in the body, obstructing the loss of blood to the outside. However, there may be extensive blood loss within the body cavities. Secondary blast wounds may be lethal and therefore many anti-personnel explosive devices are designed to generate fast-flying fragments. Most casualties are caused by secondary injuries as shrapnels generally affect a larger area than the primary blast area, because as debris can easily be propelled for hundreds or even thousands of meters. Some explosives, such as nail bombs, are deliberately designed to increase the likelihood of secondary injuries. In other instances, the target provides the raw material for the fragments thrown into surrounding, e.g., shattered glass from a blasted-out window or the glass facade of a building. Tertiary injuries Displacement of air by the explosion creates a blast wind that can throw victims against solid objects. Injuries resulting from this type of traumatic impact are referred to as tertiary blast injuries. Tertiary injuries may present as some combination of blunt and penetrating trauma, including bone fractures and coup contre-coup injuries. Children are at particularly high risk of tertiary injury due to their relatively smaller body weight. Quaternary injuries Quaternary injuries, or other miscellaneous named injuries, are all other injuries not included in the first three classes. These include flash burns, crush injuries, and respiratory injuries. Traumatic amputations quickly result in death, unless there are available skilled medical personnel or others with adequate training nearby who are able to quickly respond, with the ability for rapid ground or air medical evacuation to an appropriate facility in time, and with tourniquets (for compression of bleeding sites) and other needed equipment (standard, or improvised; sterile, or not) also available, to treat the injuries. Because of this, injuries of this type are generally rare, though not unheard of, in survivors. Whether survivable or not, they are often accompanied by significant other injuries. The rate of