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Why do unexploded shells still remain in the ground around Verdun?

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French soldiers in uniform rest and eat on a grassy field behind the front lines during the Battle of Verdun in World War I, with gear and rifles stacked nearby. — Battle of Verdun French soldiers resting away from the front line at the Battle of Verdun, 1916.

The massive scale of artillery fire during the Battle of Verdun left millions of unexploded shells buried in the landscape, creating a persistent danger that continues to this day.12

Following the conflict, an area of approximately 65 square miles was designated as a Zone Rouge (Red Zone) due to the high concentration of these munitions, and development in the region remains prohibited. While specialized bomb-clearing units, known as les demineurs, remove roughly 40 tons of ordnance annually, the sheer volume of remaining shells—estimated at over 10 million—means that the process of sanitizing the battlefield will likely take several hundred years.12

Among the most hazardous items are chemical rounds, which are difficult to distinguish from standard explosive shells. These munitions have retained their toxicity over time and pose a significant risk of leaking when disturbed or handled. The presence of this unexploded ordnance serves as a somber, enduring legacy of the attrition warfare that defined the battle.12