In 1962, the United States started spraying Vietnam with a powerful defoliant known as 'Agent Orange.'
Fighting in the Vietnam War ended in 1975, but even today, many veterans of that war are still battling health problems they believe were caused by the chemicals.
"If you was in Vietnam, out in the field, you were exposed to Agent Orange, or to the chemical," Irby said.
"This big old plane would come over and this sticky stuff like on you. You didn't think nothing about it. All we know a couple of days the leaves was gone," Carruthers said.
These men returned home thinking they had escaped the war. "I thought that was the end of it. You know, come back to the states and just pick up where I left off. But it didn't turn out that way," Lastinger, an Army Vietnam Veteran from 1967, said.
No one is sure how many Vietnam War vets are still alive, but some veteran group studies have estimated less than half. The Veteran's Administration says all the disease problems these men face are presumptive to exposure to the dioxin in Agent Orange.