From 1961 to 1971, the United States dropped seventy-nine-plus million litres of defoliants over large swaths of Vietnam, of which forty-five million were Agent Orange. The herbicide was manufactured for the US Department of Defence primarily by Monsanto Corporation and Dow Chemical. The name derives from the colour of the orange-striped barrels in which it was shipped. There were other colours in the “rainbow herbicides,” but Agent Orange was by far the most widely used. This was an experimental form of chemical and biological warfare, designed to strip foliage and deny the enemy jungle cover — and to deprive enemy forces of their food supply (directly spraying rice fields, for instance).