Grew up with that
The same is going on in Belgium's western corner. The annual "harvest" is about 250 ton. After a century of collecting, it is estimated that the upper 16" of soil has been cleared in most locations. But the stuff lower down is getting more unstable as time goes on...
As in France, recovered ammo was detonated in place except for the chemical shells. Those were collected and stored in open air on the terrains of the (military) bomb disposal unit. It wasn't until the later '80s (or maybe even early '90s) that an incinerator was built capable of disposing the chemical agents. (A replacement was commissioned in 2006. That new one suffered a premature detonation in 2012 and processing was down for 5 years.)
But no all no-go zones are even on land. In the aftermath of WWI and II, left over ammo was dumped in the sea; in some cases, just offshore. There are more than 80 identified dumps. One of the more notorious sites is the Paardenmarkt (Horse Market) sand bar next to Zeebrugge.
http://www.wereldoorlog1418.nl/gasoorlog/paardenmarkt.html
The area enclosed by T markers on the included map holds a minimum of 35,000 ton of ammo, mainly mustard gas shells, at a depth of only 15'. (The three little black dots on the pier, about 1.5 miles away, are LNG storage tanks... Interestingly, expansion of the harbor starting in 1972 altered the currents and caused an additional 5' of silt deposits on the ammo dump. It has significantly slowed down the deterioration of the shells. That's not bad for long term safety, but the extra weight may also end up crushing weakened shells.)
(Same area in real life. Not exactly deserted.)
As in France, recovered ammo was detonated in place except for the chemical shells. Those were collected and stored in open air on the terrains of the (military) bomb disposal unit. It wasn't until the later '80s (or maybe even early '90s) that an incinerator was built capable of disposing the chemical agents. (A replacement was commissioned in 2006. That new one suffered a premature detonation in 2012 and processing was down for 5 years.)
But no all no-go zones are even on land. In the aftermath of WWI and II, left over ammo was dumped in the sea; in some cases, just offshore. There are more than 80 identified dumps. One of the more notorious sites is the Paardenmarkt (Horse Market) sand bar next to Zeebrugge.
http://www.wereldoorlog1418.nl/gasoorlog/paardenmarkt.html
The area enclosed by T markers on the included map holds a minimum of 35,000 ton of ammo, mainly mustard gas shells, at a depth of only 15'. (The three little black dots on the pier, about 1.5 miles away, are LNG storage tanks... Interestingly, expansion of the harbor starting in 1972 altered the currents and caused an additional 5' of silt deposits on the ammo dump. It has significantly slowed down the deterioration of the shells. That's not bad for long term safety, but the extra weight may also end up crushing weakened shells.)
(Same area in real life. Not exactly deserted.)