BELGIUM. Poelkapelle. Every year, an estimated 150 tons of unexploded ordnance is recovered from the old World War I battlefields of southwestern Belgium. Of this, an estimated 5% or some 7 to 8 tons consists of live chemical weapons, mostly phosphorus artillery shells. With the technical assistance and oversight of the OPCW, the Belgian military employs a special unit to collect and destroy these volatile and highlytoxic munitions that have lain in the ground for nearly a century. 2013.