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The fatal blast was unusual for a Civil War relic — especially in the hands ofsomeone like White, who had previously disarmed an estimated 1,600 shells for collectors and museums, according to the Associated Press. Explosives aren’t often still potent a century and a half after they were made.

But the Union and Confederate troops lobbed an estimated 1.5 million artillery shells and cannonballs at one another during the war, according to the AP, and as many as 20 percent were duds (explosives that failed to detonate on time). Some inevitably end up still posing a threat.

Left:  A live Civil War-era artillery round was discovered and then destroyed in Ilwaco, Wash., in April. Right: U.S. Army bomb squad soldiers disposed of a Civil War cannonball that was found in a Georgetown townhouse’s chimney in Washington, D.C. (Photos courtesy of CBRNE)

In the small farming towns of France and Belgium, undetonated World War I explosives that turn up during each year’s spring planting and autumn plowing are known as the “iron harvest.”

More than a billion shells were fired during the conflict, according to the BBC, and as many as a third never exploded. In 1996, the French Interior Ministry estimated that 12 million shells still slumber in the soil near Verdun alone. So many explosives linger from century-old battles that residents often see their discovery as utterly banal.