For every square meter of land along the Western front from the Channel coast to the Swiss border it is estimated that a ton of explosives fell during WW1 (the “Iron Harvest“)
Belgian UXO (unexploded ordnance) experts estimate there are 450 million pieces of UXO in Belgium alone. At Verdun in France the estimate is that 12 million pieces of UXO remain.
630 French UXO personnel have been killed since WWII working on this stuff. Currently in France the UXO specialists recover about 900 tons per year, with 30 tons of that being chemical munitions (mustard gas shells, phosgene shells, etc.), and they estimate there's enough work there to keep them busy for another 900 years.
900 tons per year (repeated on many, many sites):
In 1991 alone 36 French farmers were killed by UXO while plowing their fields.
That's just one small area of the world. In many, many places huge swaths of land are covered by UXO which continue to maim and kill.