Unexploded ordnance (UXO, sometimes abbreviated as UO), unexploded bombs (UXBs), or explosive remnants of war (ERW) are explosive weapons (bombs, shells, grenades, land mines, naval mines, cluster munition, etc.) that did not explode when they were employed and still pose a risk of detonation, sometimes many decades after they were used or discarded. UXO does not always originate from wars; areas such as military training grounds can also hold significant numbers, even after the area has been abandoned. UXO from World War I continue to be a hazard, with poisonous gas filled munitions still a problem.[2] When unwanted munitions are found, they are sometimes destroyed in controlled explosions, but accidental detonation of even very old explosives also occurs, sometimes with fatal results.

Regarding land mines, 78 countries are contaminated and they kill 15–20,000 people every year while severely maiming countless more. Approximately 80% of casualties are civilian, with children as the most affected age group. An estimated average of 50% of deaths occurs within hours of the blast. In recent years, mines have been used increasingly as weapons of terror against local civilian populations specifically.[71]

In addition to the obvious danger of explosion, buried UXO entails 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) can enter soil and groundwater.

Risks and problems

Unexploded ordnance, however old, may explode. Even if it does not explode, environmental pollutants are released as it degrades. Recovery, particularly of deeply-buried projectiles, is difficult and hazardous—jarring may detonate the charge. Once recovered, explosives must either be detonated in place—sometimes requiring hundreds of homes to be evacuated—or transported safely to a site where they can be destroyed.

Unexploded ordnance from at least as far back as the American Civil War[5][6][7] still poses a hazard worldwide, both in current and former combat areas and on military firing ranges. A major problem with unexploded ordnance is that over the years the detonator and main charge deteriorate, frequently making them more sensitive to disturbance, and therefore more dangerous to handle. Construction work may disturb unsuspected unexploded bombs, which may then explode. There are countless examples of people tampering with unexploded ordnance that is many years old, often with fatal results.[8][9][10][12][2][2] Believing it to be harmless they handle the device and it explodes, causing deaths, injuries, and damage.[2] For this reason it is universally recommended that unexploded ordnance should not be touched or handled by unqualified persons. Instead, the location should be reported to the local police so that bomb disposal or Explosive Ordnance Disposal (EOD) professionals can render it safe.

Although professional EOD personnel have expert knowledge, skills and equipment, they are not immune to misfortune because of the inherent dangers: in June 2010, construction workers in Göttingen, Germany discovered an Allied 500-kilogram (1,100 lb) bomb dating from World War II buried approximately 7 metres (23 ft) below the ground. German EOD experts were notified and attended the scene. Whilst residents living nearby were being evacuated and the EOD personnel were preparing to disarm the bomb, it detonated, killing three of them and severely injuring 6 others. The dead and injured each had over 20 years of hands-on experience, and had previously rendered safe between 600 and 700 unexploded bombs. The bomb which killed and injured the EOD personnel was of a particularly dangerous type because it was fitted with a delayed-action chemical fuze (with an integral anti-handling device) which had not operated as designed, but had become highly unstable after over 65 years underground.[2][2][2][2] In January 2013 a large undetected World War II bomb was detonated on a building site in Euskirchen by a digger moving debris, killing the operator, wounding eight others, and causing damage across a wide area—windows were shattered several miles away.[2] In November 2013 four US Marines were killed by an explosion whilst clearing unexploded ordnance from a firing range at Camp Pendleton. The exact cause is not known, but the Marines had been handing grenades they were collecting to each other, which is permitted but discouraged, and it is thought that a grenade may have exploded after being kicked or bumped, setting off hundreds of other grenades and shells.[2]

A dramatic example of munitions and explosives of concern (MEC) threat is the wreck of the SS Richard Montgomery, sunk in shallow water about 1.5 miles (2.4 km) from the town of Sheerness and 5 miles (8.0 km) from Southend, which still contains 1,400 tons of explosives. When the deeper World War II wreck of the Kielce, carrying a much smaller load of explosives, exploded in 1967, it produced an earth tremor measuring 4.5 on the Richter scale.

Around the world

Top ten countries with
most number of mines deployed on their territory[2][71]
1 Egypt236 Iraq10
2 Iran167 Cambodia7
3 Afghanistan108 Bosnia and Herzegovina6
4 Angola109 Kuwait5
5 China1010 Vietnam3.5
World Total = 110 million Mines


North Africa, and in particular the desert areas of The Sahara, is heavily mined and with serious consequences for the local population. Egypt is the most heavily mined country in the world (by number) with as much as 19.7 million mines as of 2000.

Land mines and other explosive remnants of war are not limited to North Africa however; they poses a persistent threat to local people all over the continent, including the countries of Ethiopia, Somalia, Nigeria, Senegal, Angola, Kenya, Uganda and South Africa to mention just a few. In the Tropics, typhoons and floodings often displace and spreads landmines, further aggravating the problems. In Mozambique, as much as 70% of the country is now contaminated with mines.[71][71]

The Americas


During the long Colombian conflict that began around 1964, a very large number of landmines were deployed in rural areas across Colombia. The landmines are homemade and were placed primarily during the last 25 years of the conflict, hindering rural development significantly. The rebel groups of FARC and the smaller ELN are usually blamed for having placed the mines. All departments of Colombia are affected, but Antioquia, where the city of Medellin is located, holds the largest amounts.[71] After Afghanistan, Colombia has the second-highest number of landmine casualties, with more than 11,500 people killed or injured by landmines since 1990, according to Colombian government figures.[76]

In September 2012, the Colombian peace process began officially in Havana and in August 2016, the US and Norway initiated an international five-year demining program, now supported by another 24 countries. Both the Colombian military and FARC are taking part in the demining efforts. The program intends to rid Colombia of landmines and other UXO by 2021 and it has been funded with nearly US$112 million, including US$30 million from the US (as part of the larger US foreign policy Plan Colombia) and US$9.4 million from the EU.[71] Experts however, have estimated that it will take at least a decade due to the difficult terrain.[76]

United States

While, unlike many countries in Europe and Asia, the United States has not been subjected to aerial bombardment, according to the Department of Defense, "millions of acres" may contain UXO, Discarded Military Munitions (DMM) and Munitions Constituents (e.g., explosive compounds).[45]

According to US Environmental Protection Agency documents released in late 2002, UXO at 16,000 domestic inactive military ranges within the United States pose an "imminent and substantial" public health risk and could require the largest environmental cleanup ever, at a cost of at least US$14 billion. Some individual ranges cover 500 square miles (1,300 km2), and, taken together, the ranges comprise an area the size of Florida.

On Joint Base Cape Cod (JBCC) on Cape Cod, Massachusetts, decades of artillery training have contaminated the only drinking water for thousands of surrounding residents.[71] A costly UXO recovery effort is under way.[71]

UXO on US military bases has caused problems for transferring and restoring Base Realignment and Closure (BRAC) land. The Environmental Protection Agency's efforts to commercialize former munitions testing grounds are complicated by UXO, making investments and development risky.

UXO cleanup in the US involves over 10 million acres (40,000 km2) of land and 1,400 different sites. Estimated cleanup costs are tens of billions of dollars. It costs roughly $1,000 to demolish a UXO on site. Other costs include surveying and mapping, removing vegetation from the site, transportation, and personnel to manually detect UXOs with metal detectors. Searching for UXOs is tedious work and often 100 holes are dug to every 1 UXO found. Other methods of finding UXOs include digital geophysics detection with land and airborne systems.[46]


In December 2007 UXO was discovered in new development areas outside Orlando, Florida, and construction had to be halted.[5] Other areas nearby are also affected; for example boaters avoid the Indian River Lagoon, which contains UXO[5] thought to be left from live bombing runs performed during World War II by pilots from nearby DeLand Naval Air Station.

Plum Tree Island National Wildlife Refuge in Poquoson, Virginia was heavily used as a bombing range by pilots from nearby Langley Air Force Base from 1917 through the 1950s. The 3,276-acre former bombing range was transferred to the US Fish and Wildlife Service in 1972. Air Force records show that 300,000 pounds—150 tons—of various-sized bombs were dropped in just one exercise in December 1938. Because the area is alternately marshy or sandy, many of the bombs didn't explode and instead were partly or completely buried in the mud and sand or lie in the surf just offshore. In 1958 three teenage boys who landed their boat on the island were seriously injured when a 25-pound practice bomb exploded. As of 2007 the US military had not removed a single bomb from the Island. The island is adjacent to the Poquoson Flats, a popular destination for fishermen and recreational boaters. Some signs that have been placed offshore to warn boaters of the hidden danger posed by the UXO in the surf or buried beneath the idyllic-looking sand beach and salt marsh have been blown down by storms and have not been replaced.[5] According to the US Army Corps of Engineers, the cleanup of the UXO on Plumtree Island could take years and cost tens of millions of dollars.[5]

During World War I, the US Chemical Corps was established at American University, based in the University's McKinley Building. After the war, many toxic chemicals and weaponry were buried in or around the Northwest DC community where the university is located. Excavations in the area were carried out after significant discoveries were made in 2010.[50]

Although comparatively rare, unexploded ordnance from the American Civil War is still occasionally found and is still deadly 150 years later. Union and Confederate troops fired an estimated 1.5 million artillery shells and explosive cannonballs at each other from 1861 to 1865. As many as one in five did not explode.[83] In 1973, during the restoration of Weston Manor, an 18th-century plantation house in Hopewell, Virginia that was shelled by Union gunboats during the Civil War, a live cannonball was found embedded in the dining room ceiling. The ball was disarmed and is shown to visitors to the plantation. In 1999 a Civil War cannonball fell from a large tree in the yard of country music singer Jimmy Dean's home overlooking the James River where it had been lodged since the battle of Chaffin's Bluff.[5]

In late March 2008 a 44-pound, 8-inch mortar shell was uncovered at the Petersburg National Battlefield, the site of a 292-day siege. The shell was taken to the city landfill where it was safely detonated by ordnance disposal experts.[83] Also in 2008, Civil War enthusiast Sam White was killed when a 9-inch, 75-pound naval cannonball he was attempting to disarm in the driveway of his home in a Richmond, Virginia suburb exploded. The explosion sent a chunk of shrapnel crashing into a house a quarter-mile away.[51]



Thousands of tons of UXOs remain buried across Japan, particularly in Okinawa, where over 200,000 tons of ordnance were dropped during the final year of the Second World War. From 1945 until the end of the U.S. occupation of the island in 1972, the JSDF and US military disposed of 5,500 tons of UXO. Over 30,000 UXO disposal operations have been conducted on Okinawa by the JSDF since 1972, and it is estimated it could take close to a century to dispose of the remaining UXOs on the islands. No injuries or deaths have been reported as a result of UXO disposal, however.[5] Tokyo and other major cities, including Kobe, Yokohama and Fukuoka, were targeted by several massive air raids during the Second World War, which left behind numerous UXOs. Shells from Imperial Army and Navy guns also continue to be discovered.

On 29 October 2012, an unexploded 250-kilo US bomb with a functioning detonator was discovered near a runway at Sendai Airport during reconstruction following the 2011 Tōhoku earthquake and tsunami, resulting in the airport being closed and all flights cancelled.[5] The airport reopened the next day after the bomb was safely contained, but closed again on 14 November while the bomb was defused and safely removed.[6]

In March 2013, an unexploded Imperial Army anti-aircraft shell measuring 40 cm long was discovered at a construction site in Tokyo's North Ward, close to the Kaminakazato Station on the JR Keihin Tohoku Line. The shell was detonated in place by a JSDGF UXO disposal squad in June, causing 150 scheduled rail and Shinkansen services to be halted for three hours and affecting 90,000 commuters.[6] In July, an unexploded 1000-kilo US bomb from an air raid was discovered near the Akabane Station in the North Ward and defused on site by the JSDGF in November, resulting in the evacuation of 3,000 households nearby and causing several trains to be halted for an hour while the UXO was being defused.[6]

On 13 April 2014, the JSGDF defused an unexploded 250-kilo US oil incendiary bomb discovered at a construction site in Kurume, Fukuoka Prefecture, which required the evacuation of 740 people living nearby.[6]

On 16 March 2015, a 1-ton bomb was found in central Osaka.[6]

South Asia

Sri Lanka

Southeast Asia

Most countries of Southeast Asia – and all countries of Indochina specifically – are contaminated with unexploded ordnance. Most of the UXOs of today are remnants from the Vietnam War, which apart from Vietnam also included neighbouring Cambodia and Laos, but other conflicts and civil wars has also contributed.


Laos is considered the world's most heavily bombed nation. During the period of the Vietnam War, over half a million American bombing missions dropped more than 2 million tons[6] of ordnance on Laos, most of it anti-personnel cluster bombs.[6] Each cluster bomb shell contained hundreds of individual bomblets, "bombies", about the size of a tennis ball. An estimated 30% of these munitions did not detonate. Ten of the 18 Laotian provinces have been described as "severely contaminated" with artillery and mortar shells, mines, rockets, grenades, and other devices from various countries of origin. These munitions pose a continuing obstacle to agriculture and a special threat to children, who are attracted by the toylike devices.

Some 288 million cluster munitions and about 75 million unexploded bombs were left across Laos after the war ended. From 1996–2009, more than 1 million items of UXO were destroyed, freeing up 23,000 hectares of land. Between 1999 and 2008, there were 2,184 casualties (including 834 deaths) from UXO incidents.[6][6]


Western Asia

Western Asia, including the Middle East and border states towards Russia, is severely affected by UXO, in particular land mines. Not only are civilians killed and maimed regularly, it also impedes economic growth and development by restricting the use of natural resources and farmland.


Iraq is widely contaminated with unexploded remnants of war from the Iran–Iraq War (1980–88), the Gulf War (1990–91), the Iraq War (2003–11) and lately the ongoing Iraq Civil War. The UXO in Iraq poses a particularly serious threat to civilians as millions of cluster bomb munitions were dropped in towns and densely populated areas by the US and British air forces, mostly in the first few weeks of the invasion in 2003. An estimated 30% of the munitions failed to detonate on impact and small unexploded bombs are regularly found in and around homes in Iraq, frequently maiming or killing civilians and restricting land use.[6] From 1991 to 2009, an estimated 8,000 people were killed by cluster bomblets alone, 2,000 of which were children. Land mines are another part of the UXO problem in Iraq as they litter large areas of farmland and many oil fields, severely affecting economic recovery and development.[86]

Reporting and monitoring is lacking in Iraq and no completely reliable survey and overview of the local threat levels exists. Useful statistics on injuries and deaths caused by UXO is also missing, only singular local reports exist. UNDP and UNICEF however, issued a partial survey report in 2009, concluding that the entire country is contaminated and more than 1.6 million Iraqis are affected by UXO. More than 1,730 km2 (670 square miles) in total are contaminated with unexploded ordnance (including land mines). The south-east region and Baghdad are the most heavily contaminated areas and UNDP has designated around 4,000 communities as "hazard areas".[7][7][86]


In the aftermath of the 2006 war between Israel and Lebanon, it is estimated that southern Lebanon is littered with one million undetonated cluster bombs[7] – approximately 1.5 bombs per Lebanese inhabitant of the region, dropped by Israeli Defense Forces in the last days of the war.[7]



Video of the 2012 detonation in Munich
Discarded RGD-5 hand grenade (live but unfuzed) in Northern Kuwait dating from 1991.

Despite massive demining efforts, Europe is still affected to some extent by UXO from World War I and World War II, some countries more than others. However, newer and present military conflicts are also affecting some areas severely, in particular the countries of former Yugoslavia in western Balkans and Ukraine.

The Balkans

As a legacy of the Civil war in Yugoslavia (1991–2001), Albania,[7][7] Bosnia-Herzegovina, Croatia and Kosovo are all affected badly by UXO, mostly land mines.

France and Belgium

In the Ardennes region of France, large-scale citizen evacuations were necessary during MEC removal operations in 2001. In the forests of Verdun French government "démineurs" working for the Département du Déminage still hunt for poisonous, volatile, and/or explosive munitions and recover about 900 tons every year. The most feared are corroded artillery shells containing chemical warfare agents such as mustard gas. French and Flemish farmers still find many UXOs when ploughing their fields, the so-called "iron harvest".

In Belgium, Dovo, the country's bomb disposal unit recovers between 150 and 200 tons of unexploded bombs each year. Over 20 members of the unit have been killed since it was formed in 1919.[7]


Germany has is a specialized unit for defusing bombs called (German: Kampfmittelbeseitigungsdienst (KMBD), Explosive Ordnance Disposal Service). It is considered one of the busiest worldwide as it deactivates a bomb every two weeks.[91]

Thousands of UXOs from the Second World War are still uncovered each year in Germany. The daily average is 15, most of them aerial bombs.[7] Concentration is especially high in Berlin, where many artillery shells and smaller munitions from the Battle of Berlin are uncovered each year. While most cases only make local news, one of the more spectacular finds in recent history was an American 500-pound aerial bomb discovered in Munich on 28 August 2012.[8] As it was deemed too unsafe for transport, it had to be exploded in situ, shattering windows over a wide area of Schwabing and causing structural damage to several homes despite precautions to minimize damage.

One of the largest individual pieces ever found was an unexploded 'Tallboy' bomb uncovered in the Sorpe Dam in 1958.[8] In 2011, a 1.8-tonne RAF bomb from the Second World War was uncovered in Koblenz on the bottom of the Rhine River after a prolonged drought. It caused the evacuation of 45,000 people from the city and was then called "the biggest bomb-related evacuation in Germany's post-war history".[8] In May 2015, Some 20,000 people had to leave their homes in Cologne in order to defuse a one-tonne bomb.[8]

On December 20, 2016 another 1.8-tonne RAF bomb was found in the city centre of Augsburg and prompted the evacuation of 54,000 people on December 25.[8] In May 2017, 50,000 people in Hanover had to be evacuated in order to defuse three British unexploded bombs.[8]

On 29 August 2017, a British HC 4000 bomb was discovered during construction work near the Goethe University in Frankfurt, requiring the evacuation of approximately 65,000 people within a radius of 1.5 km. This was the largest evacuation in Germany since the Second World War.[8][8][8] Later, it was successfully defused on 3 September.[91]


Ukraine is contaminated with UXO from WW I, WW II, former Soviet military training and the current Ukraine Crisis, including the War in Donbass. Most of the UXO from the world wars has presumably been removed by demining efforts in the mid 1970s, but sporadic remnants may remain in unknown locations. The UXO from the recent military conflicts includes both landmines and cluster bomblets dropped and set by both Ukrainian, anti-government and Russian forces. Reports of booby traps harming civilians also exists.[8] Ukraine reports that Donetsk and Luhansk Oblast are the regions mostly affected by unexploded submunitions. Proper, reliable statistics are currently unavailable, and information from the involved combatants are possibly politically biased and partly speculative.[9] However, 600 deaths and 2,000 injured due to UXO in 2014 and 2015 alone have been accounted for.[9]

United Kingdom

UXO is standard terminology in the United Kingdom, although in artillery, especially on practice ranges, an unexploded shell is referred to as a blind, and during the Blitz in World War II an unexploded bomb was referred to as a UXB.

Most current UXO risk is limited to areas in cities, mainly London, Sheffield and Portsmouth, that were heavily bombed during the Blitz, and to land used by the military to store ammunition and for training.[9] According to the Construction Industry Research and Information Association (CIRIA), from 2006 to 2009 over 15,000 items of ordnance were found in construction sites in the UK.[9] It is not uncommon for many homes to be evacuated temporarily when a bomb is found.[9] 1,000 residents were evacuated in Plymouth in April 2007 when a Second World War bomb was discovered,[9] and in June 2008 a 1,000 kg bomb was found in Bow in East London. In 2009 CIRIA published Unexploded Ordnance (UXO) – a guide for the construction industry[9] to provide advice on assessing the risk posed by UXO.

The burden of Explosive Ordnance Disposal in the UK is split between Royal Engineers Bomb Disposal Officers, Royal Logistic Corps Ammunition Technicians in the Army, Clearance Divers of the Royal Navy and the Armourers of the Royal Air Force. The Metropolitan Police of London is the only force not to rely on the Ministry of Defence, although they generally focus on contemporary terrorist devices rather than unexploded ordnance and will often call military teams in to deal with larger and historical bombs.

The Pacific

Demining of UXO in Palau

Buried and abandoned aerial and mortar bombs, artillery shells, and other unexploded ordnance from World War II have threatened communities across the islands of the South Pacific. As of 2014 the Office of Weapons Removal and Abatement in the U.S. Department of State's Bureau of Political-Military Affairs invested more than $5.6 million in support of conventional weapons destruction programs in the Pacific Islands.

On the battlefield of Peleliu Island in the Republic of Palau UXO removal made the island safe for tourism. At Hell's Point Guadalcanal Province in the Solomon Islands an explosive ordnance disposal training program was established which safely disposed of hundreds of items of UXO. It trained police personnel to respond to EOD call-outs in the island's highly populated areas. On Mili Atoll and Maloelap Atoll in the Marshall Islands removal of UXO has allowed for population expansion into formerly inaccessible areas.

In the Marianas, World War II-era unexploded ordnance is still often found and detonated under controlled conditions.[108][109][110][111]

In international law

Protocol V of the Convention on Certain Conventional Weapons requires that when active hostilities have ended the parties must clear the areas under their control from "explosive remnants of war". Land mines are covered similarly by Protocol II.

Detection technology

Many weapons, including aerial bombs in particular, are discovered during construction work, after lying undetected for decades. Having failed to explode while resting undiscovered is no guarantee that a bomb will not explode when disturbed. Such discoveries are common in heavily bombed cities, without a serious enough threat to warrant systematic searching.

Where there is known to be much unexploded ordnance, in cases of unexploded subsoil ordnance a remote investigation is done by visual interpretation of available historical aerial photographs. Modern techniques can combine geophysical and survey methods with modern electromagnetic and magnetic detectors. This provides digital mapping of UXO contamination with the aim to better target subsequent excavations, reducing the cost of digging on every metallic contact and speeding the clearance process. Magnetometer probes can detect UXO and provide geotechnical data before drilling or piling is carried out.[10]

In the U.S., the Strategic Environmental Research and Development Program (SERDP) and Environmental Security Technology Certification Program (ESTCP)[10] Department of Defense programs fund research into the detection and discrimination of UXO from scrap metal. Much of the cost of UXO removal comes from removing non-explosive items that the metal detectors have identified, so improved discrimination is critical. New techniques such as shape reconstruction from magnetic data and better de-noising techniques will reduce cleanup costs and enhancing recovery.[10] The Interstate Technology & Regulatory Council published a Geophysical Classification for Munitions Response guidance document in August 2015.[56] UXO or UXBs (as they are called in some countries – unexploded bombs) are broadly classified into buried and unburied. The disposal team carries out reconnaissance of the area and determines the location of the ordnance. If is not buried it may be dug up carefully and disposed of. But if the bomb is buried it becomes a huge task. A team is formed to find the location of the bomb using metal detectors and then the earth is dug carefully.

See also