European farms still yield tons of live shells and soldiers’ remains annually (VIDEO)

France 24 reports on the annual “Iron harvest” which produces an average of 50 tons of aging WWI artillery shells– some filled with poison gas– and unmapped graves in Northern France.

“The biggest one we’ve found is an English 15-incher,” says Michel Collings, an EOD specialist, after his team unearths a live German field artillery shell. “That was 800 kilos.”

Gas shells, of which millions were fired and as many as a third did not explode, can be tricky, with techs watching out for the tell-tale smell they give off.

Collings estimates that it could take as long as 500 years to remove all of the unexploded ordnance.

Besides the shells, there are still an estimated misplaced 700,000 war graves across Northern France dating from the Great War.