During the Vietnam War, the United States dropped more than 8 million tons of bombs and sprayed 74 million liters of Agent Orange and other herbicides in Vietnam, Cambodia, and Laos. Nearly 50 years after the war’s end, the deadly impacts of these campaigns persist: Unexploded ordnance continues to maim and kill, while hot spots of dioxin, a potent toxin in the herbicides, might still be contributing to cancers and birth defects today.

Now, using declassified military satellite photos, scientists have identified the likely locations of these hidden dangers, which could help direct remediation and cleanup efforts.