1.12.2020 : 9:47 : +0100

Overview & Observations



Unplanned explosions at munitions sites (UEMS) are a significant safety concern for governments and a major security challenge for the international community. The Small Arms Survey, hereafter referred to as the Survey, has documented more than 500 such incidents over the 35-year period from 1979 to 2013. Explosions of this nature have occurred in 100 countries. They have resulted in thousands of deaths, tens of thousands of injuries, hundreds of thousands of people being displaced, tens of millions of dollars of clean-up costs, and possibly hundreds of millions of dollars spent on replacement stocks. Such resources could have been invested more productively. In some cases, the explosions have even resulted in the arrest and removal of government ministers, civilian officials, and military officers.

The Survey defines UEMS as the accidental explosions of abandoned, damaged, improperly stored, or properly stored stockpiles of ammunition and explosives at munitions sites (see Box 1).

Box 1. UEMS: unpacking the definition

UEMS are accidentsa that result in an explosionb of abandoned,c damaged,d improperly stored,e or properly stored stockpiles of munitionsf at a munitions site.g

a ‘Accident’ is defined as ‘an undesired event that results in harm’ (UNODA , 2011, para. 3.5, p. 2). ‘Harm’ is defined as ‘physical injury or damage to the health of the people’ (UNODA , 2011, para. 3.120, p. 14).
b ‘Explosion’ is defined as ‘a sudden release of energy producing a blast effect with the possible projection of fragments. The term explosion encompasses fast combustion, deflagration and detonation’ (UNODA , 2011, para. 3.95, p. 11).
c ‘Abandoned’ refers to abandoned explosive ordnance (AXO) and is defined as ‘explosive ordnance that has not been used during an armed conflict, that has been left behind or dumped by a party to an armed conflict, and which is no longer under control of the party that left it behind or dumped it. [AXO] may or may not have been primed, fuzed, armed or otherwise prepared for use’ (UNODA , 2011, para. 3.1, p. 1).
d ‘Damaged’ refers to damaged munitions and the physical or chemical deterioration of ammunition and explosives.
e ‘Improperly stored’ refers to munitions stored in a manner which does not generally follow accepted multilateral norms or guidelines, or existing national legislation and controls.
f ‘Munitions’ refers to weapons, ammunition, explosives, and components. (Some armed forces and ammunition specialists, however, use the term ‘munitions’ to refer solely to complete rounds of ammunition (Bevan and Wilkinson, 2008, p. xxvi).)
g ‘Munitions site’ refers to either an explosive storage area (ESA), ‘an area used for the storage of explosives and within which authorized ammunition or missile preparation, inspection and rectification operations may also be carried out’ (UNODA , 2011, para. 3.108, p. 12), or an ammunition-processing site, defined as ‘a building or area that contains or is intended to contain one or more of the following activities: maintenance, preparation, inspection, breakdown, renovation, test or repair of ammunition and explosives’ (UNODA , 2011, para. 3.12, p. 2). A site may be permanent or temporary.

Munitions sites may be temporary or permanent. To qualify for inclusion in the database, an explosion must occur at a static location. Munitions that are in the process of being transported by air, rail, road, and sea are not covered in this Handbook, although they have also caused catastrophic explosions1 and warrant further examination. Similarly, munitions that once were being transported and are now submerged (as a result of either an accident or an attack, see Box 2) are not covered in the UEMS Database. 

Box 2. Submerged munitions: how big a problem are they?

Military conflicts across the globe over the past hundred years have resulted in large quantities of munitions and explosives from thousands of sunken cargo ships and military vessels being strewn across sea beds and ocean floors. Governments, multinational corporations (particularly those active in the telecommunications, oil, and gas sectors), and maritime companies know where most of these wrecks are located. (Some, like the SS Richard Montgomery, a US cargo ship loaded with munitions and explosives on its way from the Delaware to Cherbourg in 1944, are also well known to the general public: see Hamer, 2004.2 The ship sank in the Thames estuary—about 60 km east of central London—and its masts are still visible from land, their fate recently coming into sharper focus due to discussions about a proposed airport project (see BBC, 2013).)
Efforts are made to limit contact with these sites, and when they are engaged it is understood that there is little incentive—and few, if any, requirements—to share information on any explosions or casualties incurred.3
More stringent environmental regulations, counter-terrorism considerations, and emerging new technologies (such as wind energy and the construction of wind farms that require turbines to be cemented and secured off-shore) may require governments to re-examine the manner in which they manage and secure these sites.
Long-established state practices of disposing of munitions at sea and in other bodies of water warrant review, but are not addressed in this Handbook.

UEMS may be associated with various activities, including production, demilitarization, and explosive-ordnance disposal (EOD ). The common qualifying factor is the storage of munitions at fixed locations. (See Box 3 for examples of what does, and does not, meet these criteria.) 

Box 3. Is it a UEMS incident or not? Some examples

  • Accidental explosions during manufacturing are not included. But accidental explosions at manufacturing sites for post-production stored munitions are.
  • Unplanned explosions occurring during industrial dismantling or demilitarization (i.e. during processing) are not included. Explosive events that occur within the storage facilities of these sites are.
  • Explosions that occur during transportation within the storage or processing site are included. Explosions that occur in transit outside storage or processing sites are not.
  • Incidents of unexploded ordnance (UXO) that detonates during mishandling during scavenging or clearance operations (by civilians or EOD experts) are not included; explosions of UXO held in storage or being processed are included.
  • Munitions that misfire and explode during military or training operations are not included. But explosions of munitions used for military or training operations that occur during storage are.
  • Acts of sabotage that proper standard operating procedures should have prevented are included. Explosions that occur due to aerial attack or artillery bombardment by hostile forces are not (as physical security and stockpile management (PSSM) best practices are not intended to address these threats).
  • Explosions that occur at underwater munitions sites formed by disposal programmes are not included, nor are those that occur at underwater sites of shipwrecks or downed aircraft.
  • Explosives, including fireworks and commercial-grade explosives, which are not affiliated with munitions, are not included.

UEMS result from improper storage and handling as well as inadequate record keeping, reporting, investigation, and oversight. A dearth of expertise and resources is also a contributing factor. Explosives may deteriorate over time and can become unstable.4 Explosives storehouses (ESHs) designed in keeping with international best practices allow for safer storage by including proper physical properties (ventilation, temperature control, construction, and sufficient space between structures) in their design, as well as routine and effective surveillance and monitoring (King and Diaz, 2011, pp. 20–22).

UEMS speak to a larger problem than the damage generated by a single conflagration. The incidents indicate a troubling mindset of many policy-makers concerning appropriate levels of stocks and dangerous quantities of surplus. These events occur in large part because too many states view their stockpiles of munitions as assets rather than liabilities, regardless of the materiel’s age or its storage conditions. Identifying and destroying surplus stock should be a planned and integral stage of the life cycle of munitions management (see Figure 1).

Figure 1. Munitions life-cycle management

When munitions are stored with no regard for their quantities, quality, or safe-keeping, oversight suffers. Such conditions lend themselves to possibly questionable transfers and unintentional or unauthorized diversion (see Bevan, 2008, pp. 145–53). Governments will determine their requirements and therefore their surpluses differently (see Bevan and Karp, 2008, pp. 103–10; Karp, 2010). Generally speaking, while some improperly stored and managed materiel may meet the needs of a government, much does not.

This Handbook has been published to serve three primary purposes. First, it strives to support best practice by explaining the scale and scope of the challenge that policy-makers face, and it aims to encourage states to manage their stockpiles effectively (see Part I). To this end, it is designed to help generate better data capturing and record keeping (see Part II; Annexe A). Second, the study is intended to serve as a reference tool. Detailed profiles review more than 30 actors undertaking UEMS-related activities (see Part III). An annotated bibliography lists and summarizes useful guides and studies, as well as reviews of web-based materials such as tools with which to calculate quantity–distance principles to promote safety (see Part IV). Annexes B and C document UEMS incidents (by date and country within regions, respectively) and summarize data that the Survey continues to collate. And third, the book serves as a training tool. The UEMS Incident Reporting Template (IRT) presented in Annexe A is provided to promote accurate record keeping and the sharing of systematized data (see Part II). Short explanations indicate why the information sought is of value. Annexe D provides the content of the Survey’s best practice on PSSM (for ‘physical security and stockpile management’) in the form of playing cards containing useful guidance and photographs. Both the IRT and the Best-practice Cards are available in languages other than English from the Survey’s website:



The effects of unplanned explosions are numerous and often long-lasting. The media tend to focus on the immediate direct effects of such an incident, namely casualties incurred from the initial explosion. This focus on casualties is both understandable and a valuable indicator of the human costs of UEMS, and why it is important to work towards preventing them. Only if we look at their longer-term socio-economic and politico-military effects, however, is it possible to understand the full costs of UEMS and to appreciate why countering them should be prioritized on national, regional, and international agendas.

Although this Handbook documents the longer-term costs related to UEMS in considerable detail, information on individual events is often sparse. Governments can better share their findings in the wake of explosions. The UEMS IRT—which the Survey developed in consultation with national verification centres, EOD experts, United Nations officials, and stockpile-management and surplus-destruction practitioners—serves to facilitate the collection and collation of data and to improve on current practices. If used as intended, the IRT can collate substantially better information and analysis, which can then assist the international community to stop UEMS from occurring in the first place.

Preventing UEMS incidents calls for strategies that can be expensive to implement and may require external assistance; the international community is starting to address these challenges. Some sites will certainly need to be closed and their ordnance transported to another location, at significant expense. New facilities, incorporating quantity–distance principles and security features, may need to be constructed from scratch.

Many measures, however, can be undertaken unilaterally and with modest investment. As depicted in the Survey’s PSSM Bestpractice Cards (Annexe D), states can achieve positive results without investing in major infrastructure projects. They can do so by installing proper doors and locks, using adequate fences and barriers, posting warning signs and labels, organizing the stockpile into stacks or aisles free of obstruction, cutting the grass, and sorting, storing, and working on munitions appropriately. (For concrete examples of ‘phased programming’ which differentiates among activities that are short-term/low-cost, mediumterm/medium-cost, and long-term/high-cost, see King and Diaz, 2011, pp. 26–30.) The adage that 28 grams of forestalling are equivalent to 0.454 kg of remedy—‘an ounce of prevention is worth a pound of cure’—was never more apt than for stockpile management.

Besides investment in physical infrastructure and equipment, more expenditure is required to develop human capital. Governments must invest in education, training, management, and oversight of the personnel responsible for storing, securing, and disposing of munitions. Training currently provided is often of insufficient duration and of limited value, as it focuses on best practice and not on how to improve safety from first principles using a riskbased approach. Moreover, too often training, when it is provided, is not given to the people who need it. And when those who do need it are properly trained, they sometimes get reassigned to other duties in which they do not apply their new skills.

There is still much to do. Given the significant investments made in peace operations and disarmament, demobilization, and reintegration (DD R) programmes, stockpile management and surplus destruction of munitions (and firearms) warrant more attention. The fact that RENA MO (Resistência Nacional Moçambicana), a former rebel group which participated in a DD R process brokered by the United Nations (UN), is still in control of stocks of arms and munitions 20 years after a UN peacekeeping operation, largely deemed successful5—and the fact that one of its sites subsequently suffered an explosion—suggests that current practice is wanting.

And solutions themselves can generate new challenges. For example, several explosions at demilitarization plants have called into question the efficacy of existing national controls, oversight, and related coordination with commercial contractors. The Biennial Meetings of States (BMS) and Meetings of Governmental Experts (MGEs) within the framework of the UN Programme of Action on Small Arms (PoA) will give the international community important opportunities to take stock of progress and to consider ways to improve current practice. Those regional organizations that long ago developed best-practice guidelines are encouraged to review them in light of new international measures, such as the International Ammunition Technical Guidelines (IATG). Other organizations may wish to draw on their considerable hard work and expertise.

It is hoped that this Handbook will support these institutions and processes.




  1. The largest such incident occurred off the coast of Canada in December 1917, when a cargo ship carrying explosives on its way from the United States to Europe collided with another boat in Halifax harbour. The shockwave damaged homes over a 25 km-radius, with windows broken as far as 80 km from the epicentre. The blast and subsequent tsunami resulted in more than 1,900 deaths, the largest loss of life recorded from a single man-made conflagration until 6 August 1945. The event is still commemorated annually in Nova Scotia (Walker, 2011, pp. 48–52, 102–103).
  2. After the ship ran aground, the UK government was able to unload much of the SS Richard Montgomery’s dangerous cargo before it broke apart. Submerged munitions include 13,700 explosive devices amounting to 1,400 tonnes of TNT (Hamer, 2004).
  3. Author interview with David Hewitson, director, Fenix Insight, 19 September 2013, Geneva.
  4. By contrast, the chemical compound trinitrotoluene (TNT), for example, is an explosive material that is extremely stable.
  5. Disarmament, which at first had been the prerequisite to holding elections (which were held peacefully in October 1994), eventually became a secondary consideration. Former combatants surrendered relatively few of their weapons and small amounts of munitions; and of the material surrendered, less still was destroyed (see Berman, 1996).

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