Unexploded ordnance

Unexploded ordnance (UXO, sometimes abbreviated as UO) and unexploded bombs (UXBs) are explosive weapons (bombs, shells, grenades, land mines, naval mines, cluster munition, and other munitions) that did not explode when they were deployed and remain at risk for detonation, sometimes many decades after they were used or discarded. When unwanted munitions are found, they are sometimes destroyed in controlled explosions, but accidental detonation of even very old explosives might also occur, sometimes with fatal consequences. For example, UXO from World War I continues to be a hazard, with poisonous gas filled munitions still a problem. UXO does not always originate from conflict; areas such as military training bases can also hold significant numbers, even after the area has been abandoned. Seventy-eight countries are contaminated by land mines, which kill or maim 15,000–20,000 people every year. Approximately 80% of casualties are civilian, with children being the most affected age group. An average estimate of 50% of deaths occur within hours of the blast. In recent years, mines have been used increasingly as weapons of terror; especially against local populations, such as in the Syrian civil war. In addition to the obvious danger of explosion, buried UXO can cause environmental contamination. In some heavily used military training areas, munitions-related chemicals such as explosives and perchlorate (a component of pyrotechnics and rocket fuel) may enter soil and groundwater, thereby contaminating the water supply, preventing agrarian uses such as farming.