From 1971-1982, Air Force reservists, who flew in 34 dioxin-contaminated aircraft used to spray Agent Orange and returned to the U.S. following discontinuation of the herbicide spraying operations in the Vietnam War, were exposed to greater levels of dioxin than previously acknowledged, according to a study published in Environmental Research by senior author Dr. Jeanne Mager Stellman, professor emerita at the Columbia University Mailman School of Public Health’s department of health policy and management.