American U. in NW Dc.................

Across the street, Miller knocks on the door of another stone house. A gray-haired man in running gear greets her. 

The Corps has dug up more than 1,000 munitions, such as this projectile found on the AU campus. Photograph by Brad Howell.

“I know about the trenches at the bottom of the hill,” he says. “That’s where they tied up the goats and set off bombs.”

The “Sedgwick trenches” ran behind his house. The Army dug the circular pits in 1918 and field-tested chemical-warfare agents, such as mustard gas and other lethal compounds. Soldiers tied animals to stakes in the circles, set off bombs in the center, and saw how quickly the animals died.