BBC NEWS | World | Asia-Pacific | The legacy of Agent Orange: "The US sprayed 80m litres of poisonous chemicals during Operation Ranchhand. There were many Agents used, including Pink, Green and White, but Agent Orange was used the most - 45m litres sprayed over a 10th of Vietnam.
It was also used - mostly in secret - over parts of neighbouring Cambodia.
But Agent Orange in particular was laced with dioxins - extremely toxic to humans. Dioxins accumulate in the body to cause cancers. Anyone eating or drinking in contaminated areas then receives an even higher dose.
Spraying stopped in 1971, after more than 6,000 missions and growing public disquiet."