"Agent orange (aka orange crush) was a herbicide used during the Vietnam war and the Malayan emergency as a defoliant and crop killer to reduce the food and cover for guerrilla fighters. The batches were contaminated however because of the high-heat method of making it, which resulted in a highly toxic chemical mixture which caused numerous defects in Vietnam vets and their children. The former us airbases are still contaminated nearly 3 times the lethal limit for exposure."