Luong Hoai Thuong does her homework. She was born without her left hand, a birth defect caused by Agent Orange remaining from the U.S. war against Vietnam. Agent Orange was a herbicide that the U.S. military used to defoliate vast stretches of Vietnam and Laos during the 1960s and early 1970s, so the Communist forces would have no place to hide. The defoliant is known to cause a myriad of birth defects in the children of those exposed. As much as 18 million gallons of Agent Orange were sprayed around Vietnam, according to a study by the Government Accountability Office, an investigative arm of the U.S. Congress. The Vietnamese government estimates that as many as 400,000 Vietnamese have died from illnesses related to exposure to dioxin, such as cancer. It also claims that up to 500,000 children have birth defects, such as spina bifida, because their parents were exposed.