The United States finally began to clean up the defoliant Agent Orange today - 50 years after it was first sprayed by US planes on Vietnam's jungles.
Dioxin, which has been linked to cancer, birth defects and other disabilities, will be removed from the site of a former US air base in Danang in central Vietnam.
"We are both moving earth and taking the first steps to bury the legacies of our past," claimed US ambassador David Shear during the groundbreaking ceremony near the area.
The $43 million (£28m) joint project with Vietnam is expected to be completed in four years on the 47-acre contaminated site.
Washington has been slow to respond, quibbling for years over the need for more scientific research to show that the herbicide caused health problems and birth defects among Vietnamese.
It has given about $60m (£38m) for environmental restoration and social services in Vietnam since 2007, but this is its first direct involvement in cleaning up dioxin, which has seeped into Vietnam's soil and watersheds for generations.
The US military dumped 80m litres of Agent Orange and other herbicides on former South Vietnam and parts of Laos and Cambodia between 1962 and 1971, decimating roughly 5m acres of forest.
Vietnam deputy defence minister Nguyen Chi Vinh said he hopes to receive more support from the international community and the US to help treat dioxin hotspots elsewhere.
It is still unclear how much the US will help in the long term and how much it will allocate for Agent Orange victims.