Tran Duc Nghia, 39, sits in a wheelchair in his family's home in Da Nang, Vietnam. Nghia and his younger sister are second-generation victims of dioxin exposure, the result of the U.S. military's use of Agent Orange and other herbicides during the Vietnam War more than 40 years ago. According to his mother, Nghia was born normally, but began developing problems by the time he was 12. He is now completely physically and mentally disabled, and his sister is beginning to exhibit many of the same conditions. The family gets no government support, and Hoang Thi Te, 75, the mother, worries who will take care of her children when she is gone. She is bitter at the U.S. government for using toxic herbicides during the war, and says she wishes the U.S. military would have killed her children right away, instead of leaving to suffer decades later. ?I am very angry. They are heartless people,? she says of U.S. policymakers. ?They are the cause of this illness for my children. I've had to care for him for almost 40 years. I feel like I've been in prison.? The Vietnam Red Cross estimates that at least 3 million Vietnamese suffer from illnesses related to dioxin exposure, including at least 150,000 people born with severe birth defects since the end of the war. The U.S. government is paying to clean up dioxin-contaminated soil at the Da Nang airport, which served as a major U.S. base during the conflict. But the U.S. government still denies that dioxin is to blame for widespread health problems in Vietnam and has never provided any money specifically to help the country's Agent Orange victims. March 18, 2013.