At a former American air base in southern Vietnam, work abruptly stopped last month on efforts to clean up tons of soil contaminated with deadly dioxin from the military’s Agent Orange defoliant.

Vietnam’s main museum on the war, which is currently focused on documenting American atrocities such as the My Lai massacre and the devastating effect of Agent Orange. The exhibit, which was to ...

FILE- Attendants sit next to a field contaminated with dioxin before a ceremony marking the start of a project to clean up dioxin left over from the Vietnam War, at a former U.S. military base in ...