[Updated: 9 March 2014]
Next month, on the 22nd, it will be the 99th anniversary of the start of modern chemical warfare. The salient around the Flemish town of Ieper offered the perfect location: its northern edge was the only place along the Western front where German troops did not face the prevailing south-westerly winds that could have blown back the chlorine cloud. Later, of course, shells replaced gas cloud attacks.
Shells imply depots, including ones close to the trenches. In Flanders it is not uncommon to still uncover duds—shells that failed to detonate because of malfunction or simply because they got buried in very soft mud. Each year, some hundred metric tonnes (give or take a few tonnes) of unexploded ordnance is recovered and taken to a demolition site near the village of Poelkapelle. About five percent of that volume is filled with a chemical warfare agent. However, statistics usually shoot up when a former underground storage bunker still full with munition is discovered. Such was the case earlier this week, when a farmer in Moorslede, next to the infamous town of Passendale (Passchendale), was transforming a meadow to grow crops. Since then the bomb disposal unit of the Belgian Armed Forces have already recovered over 300 German shells, a large portion of which are chemical (mostly mustard agent). They expect to unearth plenty more. Some press accounts suggest thousands of shells. That figure may not be exaggerated: almost ten years ago to the day, the bomb disposal unit unearthed 3,242 British and German artillery shells in another part of the same municipality. Presumably they had been buried in the field after the war.