My personal experience - living in Munich, Germany - is that approx. one or two times per year I am late because of traffic problems caused by bomb disposal activities.
Another source of explosives in the forests here are blanks that were left by NATO troops during maneuvers.
It‘s a bit of a local media spectacle, with the local newspaper running stories welcoming back the defusing team by name.
http://www.messynessychic.com/2015/05/26/the-real-no-go-zone...
I've heard different estimates from it will take 300 years to clear the UXO from the Zone Route to it will never be truly free of UXO.
The Wehrmacht also laid millions of mines but thanks to German obsession with administration those were all removed in a few years (with the "assistance" of German POWs)
Note in various places it's WW1 munitions as well (and some of those being chemical and biological weapons).
There was just so much used in both wars that it's practically inevitable, because much is now below the surface and exposed through ploughing.
Just 2 months ago another defusion, in Dresden, also partly went wrong but luckily nobody was injured [2]
[0] https://de.wikipedia.org/wiki/Tennenloher_Forst#/media/File:...
[1] http://www.spiegel.de/international/germany/routine-disposal...
[2] https://www.br.de/nachrichten/bombe-in-dresden-bei-entschaer...
Blanks? As in blank small-arms ammunition and artillery rounds? I've never heard of them being a fire-risk before, or being dumped like that. They don't contain much explosive do they? How is this happening?
> Firefighters there have found their work hampered by explosions from munitions dating back to World War II, which were buried and had been undisturbed until the heat of the flames set them off.
My point was more that the explosions (blanks are loud) could have been caused by ammunition dropped long after WWII.
Not on large exercise ranges like those common in Germany. Do you really think every single soldier collects every blank he ejected, that didn't initially fire/jammed, during the maneuver?
No, these are simply left behind, in all sizes and calibers, and for all purpose and effect are still "small lumps of explosives with detonator", just with some kind of malfunction preventing the regular way of triggering the donation, but they are still very capable of detonating.
We found the ammo not at designated exercise ranges like those around Grafenwöhr or Hohenfels but ordinary forests, fields and meadows where we children used to play.
We often found small batches and the ones I had in my hands were new and without scratches. My theory is that they were thrown away after the mission because the guys were too lazy to carry them back to the camp, but I don't know for sure.