It was August 2008 near Taji, Iraq. They had just exploded a stack of old Iraqi artillery shells buried beside a murky lake. The blast, part of an effort to destroy munitions that could be used in makeshift bombs, uncovered more shells.
Two technicians assigned to dispose of munitions stepped into the hole. Lake water seeped in. One of them, Spc. Andrew T. Goldman, noticed a pungent odor, something, he said, he had never smelled before.