31. Research has shown a link between spina bifida and exposure to the chemical defoliant Agent Orange during service in Vietnam. 32. In 1969, studies linked the herbicide to birth defects, and use of all defoliants was stopped by 1971. 33. About half of the Ranch Hand group, he said, had average levels of the defoliant in their blood. 34. He is also expected to talk privately with leaders about research on the effects of the toxic defoliant Agent Orange. 35. American planners say they intend to cover as much acreage with defoliant as possible to stop the replanting of coca. 36. In Vietnam, U . S . aircraft sprayed 20 million gallons of defoliants to deny cover to Communist forces. 37. During the Malayan Emergency, in 1952, he was instrumental in the use of sodium trichloroacetate as a defoliant . 38. Where bombs and defoliants parted the triple-canopy jungle, the camouflage of tree branches could not mask the convoys. 39. In many places, the Vietnamese countryside has not rebounded from the defoliant , but the environmental damage is not uniform. 40. He once argued in a study that dioxin, a component of the defoliant Agent Orange, is not a carcinogen.
