Even this week, in Belgium someone died due to a shell (although he had stockpiled it instead of having it sent to disposal as he should have done.)

A second problem which you do not touch in your post, but is equally problematic, though lesser known are the sea dumps.

Loads of ordnance have been dumped in the Northsea, where those shells lie rusting for almost a century now. Many of those shells contain poisonous gasses, and no-noe has any idea what the result will be when they start to release those gasses into the North sea (and also the regular shells will cause great environmental harm when they are released into the sea).