For the second time since 2011 there was a major accident at a Russian ammo depot in the Ural Mountains (near the town of Pugachyovo). The recent one took place in mid-May and was much smaller than the one in 2011. The 2018 incident did not kill anyone and only about 2,000 civilians had to be evacuated while nearly 500 firefighters put out the fires and prevented more damage. In mid-2011 this ammo depot, used for the destruction of elderly ammo, contained over 150,000 shells and about half of them blew up after someone apparently tossed a lit cigarette into the dry vegetation and it started a large bushfire. The 2018 accident began when someone was illegally clearing dry grass with a fire that got out of control and spread to the ammo depot.
The 2011 accident caused about 30,000 civilians to be evacuated and nearly a hundred were injured by shell fragments or fire. After the 2011 accident the base was repaired and destruction of the remaining elderly (and dangerous to move) ammo continued, often via controlled explosions that the local civilians heard regularly. But when they hear (or see) this stuff going off at night they know it is an uncontrolled explosion and depending on how close they are to the explosions, or intact ammo warehouses, time to run.
While two accidents like this on one place are rare, these ammo storage site fires and massive explosions continue despite the fact that the Russian armed forces are a fifth the size they were when the Soviet Union collapsed in 1991. For example, in mid-2013 there was an ammo explosion in Central Russia (near the city of Chapayevsk). A fire began in an ammo storage base, forcing the evacuation of over 7,000 people. Two people died and 48 were wounded. It took over a week to deal with the aftereffects. Five warehouses were destroyed and over 20,000 shells, thrown (some for over a kilometer) clear were collected for disposal. The damage cost the military over $5 million.
Disasters like this still occur in Russia, largely because as recently as 2012 there was still over six million tons of ammunition in storage, much of it obsolete and in need of disposal. Getting rid of this stuff is expensive and the government has not allocated enough money to get it done quickly. Russia does not like to publicize this problem and is seeking to get the ancient ammo disposed of as quickly and quietly as possible.
These explosions are also a common problem in countries that have long used ammunition bought from Russia or China. During the communist period, as per the Soviet custom, old ammunition was not destroyed but kept around. Communist countries were poor. It made sense to keep those old mortar and artillery shells (plus bombs and military explosives) for the inevitable war with the enemies of socialism. But the chemical reactions taking place in propellants and explosives, after these items are manufactured, eventually cause dangerous side effects. Over time the compounds that make the propellants and explosives deteriorate and change. This renders the propellants and explosives useless or, in many cases, unstable and very dangerous.
Elderly and unstable ammunition has resulted in many spontaneous explosions on Russian ships as well as ammunition depots. There was another one similar to the Chapayevsk incident in 2012. That one was traced to human error. Because not enough money was spent to properly take care of what is held in storage the workforce was often untrained and careless. Part of this problem arises from the army use of conscripts or minimum-wage civilians to take care of these ammo storage sites. The 2012 accident was traced to a soldier who carelessly tossed aside a lit cigarette, which led to the disastrous fire and explosions.
The danger is not over once the explosions have died down. Many shells and rockets are thrown, unexploded, hundreds of meters from the storage area. These will have to be carefully removed before someone, or an animal disturbs the munition and sets it off. Some of these munitions are buried in the wreckage of damaged or destroyed structures.
Russia has long had problems with elderly, and cranky, munitions. One saving grace was that Russia tended to put these depots in isolated areas, so the casualties were low. However, the Russians took the hint during the 1990s and set about disposing of huge quantities of Cold War surplus munitions.
After the 1990s ammunition explosions like this became increasingly common because of the ammo getting older and not enough trained ammo disposal personnel available. Until about 2010 there was usually one big explosion somewhere, and 10-20 smaller ones, each year. There are still some small ones, but far fewer of the big ones. The aging munitions not only became unstable but also very dangerous just move. Russia had more of a problem with this than China, which could afford to dispose of older munitions and had much less older stuff stored away. This sort of thing has been the cause of many spontaneous explosions on Russian ships and in ammunition depots, even before the Cold War ended in 1991. These accidents also happen while efforts to safely dispose of it are underway.
In 2008 an Albanian ammunition processing facility north of the capital exploded. There were over 200 casualties, including at least nine dead (largely among the 4,000 civilians living nearby). Over 300 buildings were destroyed, and over 2,000 damaged. The facility was used to destroy old ammo, which was a condition for Albania to join NATO. There were about 100,000 tons of old ammunition in Albania, and the destroyed facility dismantled 500-600 tons of the stuff each month. The explosion in Albania probably occurred during the process of extracting explosives from the old ammo. This can be tricky, as the least little spark, can set this stuff off. Worse, older ammo in an unstable state can go off without a spark. This sort of thing is what makes the crudely made Islamic terrorist explosives so dangerous.
Since the 1990s there were more explosions worldwide that involved elderly Russian or Chinese made ammo that was stored improperly. After 2000 the Russians, embarrassed by this as they sought to sell new weapons and munitions to old customers made an effort to help nations, especially in Africa and the Middle East, who still had a lot of that old stuff in storage, on how to inspect and detect ammo that was dangerous. The Russians also provided help in safely disposing of the older, unstable munitions.
Despite that effort, embarrassing accidents still took place, although not as frequently. In early 2014 an explosion in a military ammunition warehouse in southern Congo killed at least twenty and more than fifty were wounded. The cause was a lightning strike that started a fire that reached some of the ammo before firefighting efforts could deal with it. This took place near Congo’s third-largest city, Mbuji-Mayi. Like many African countries, Congo received ammo supplies from Western and Russian sources after colonial rulers left in the 1960s. A lot of this ammo was never used and has simply grown old and unstable. Heeding advice from Russian and Chinese arms experts the African nations were making an effort to improve the security of these ammo dumps, to make theft (which means moving this dangerous stuff) or spontaneous detonation (from age and heat) less likely.
Russia could speak from recent experience in such matters. From 2008-12 Russia suffered 17 of these ammo depot explosions, all of which included some fatalities. While there were five of these incidents in 2012, there were only two in 2013 and even fewer since 2014. The new safety measures were less enthusiastically embraced outside Russia, especially in parts of Africa where fighting was still going on and chaos was the rule. For example, the Congo had planned to upgrade ammo depots to better handle lightning problems, but the Mbuji-Mayi ammo storage site had not yet been upgraded to deal with that. By 2017 Congo was drifting towards another civil war and ammo warehouse safety was no longer a top priority.
Africa has been the scene of many of these explosions, largely because of the climate (often hot and damp) and the laxest safety standards. Another problem in Africa is that ammo storage facilities are often in urban areas. Thus there tend to be hundreds of civilian deaths. As is common in Africa, military units are often based inside major cities, the better to deal with any attempts to overthrow the government. Large quantities of ammunition are often stored on these urban bases, so the troops can quickly handle any contingency. African armies tend to be poorly trained and led, which often expresses itself in sloppy safety procedures and hazardous handling of munitions.
Even recently manufactured ammo can accidentally detonate if not stored or handled properly. You cannot be too careful how you store, and handle this stuff. For example, in 2010 four Ukrainian sailors were seriously injured when two 30mm cannon shells spontaneously exploded. Actually, those shells didn't go off entirely without warning. The Navy reported that the shells were old, beyond their “use by” date, and were probably set off by vibrations ships generate during training exercises.