READING, Pa. — There were a lot of young veterans with missing limbs at the 1982 national gathering of the Vietnam Veterans of America in Washington.
At first, Ken Wunder figured they were all casualties of enemy fire.
He was wrong. Some were casualties of Agent Orange.
"A lot of them that were there had limbs missing from cancer caused by Agent Orange," said Wunder, an Army veteran who attended as a representative of the then-new Berks County Vietnam Veterans of America Chapter 131.
The U.S. sprayed millions of gallons of chemical herbicides in Vietnam and other combat-related areas during the war to remove foliage that might hide enemy soldiers.
According to the Department of Veterans Affairs, Agent Orange -- named for the orange identifying stripe on its 55-gallon storage drums -- was the most widely used substance.
It was sprayed from 1962 to 1971 during "Operation Ranch Hand." Ever since then, it has been a major health issue for veterans, their spouses and even their children.
Tumors, rashes, miscarriages and birth defects were reported in the years after the war. In 1979, a group of veterans sued the U.S. government and chemical companies, claiming they had been injured by Agent Orange.
Gradually, over a period of decades, the government gave official recognition to the human damage caused by Agent Orange.
"They denied it for years and years," said Andy Lewandowski of Lower Alsace Township, who fought in Vietnam with the Marines. "Now, it is almost automatic."
The Veterans Administration maintains a long list of "presumptive diseases" that, if diagnosed in a Vietnam-era veteran who served in certain places, are presumed to have been caused by Agent Orange exposure. They include many types of cancer, Parkinson's disease and Type 2 diabetes.
Dale Derr, Berks County director of veterans affairs, said courts have ordered the VA to take various actions related to Agent Orange and its victims.
"In the fall of 2010, the floodgates really opened up," he said. "The VA really gave priority to the Vietnam vets for these presumptive conditions, to move these claims through quicker."
Ken Marks Jr. of Bern Township, an Air Force veteran who served two tours of duty in Vietnam, said a percentage of his government disability payments are based on exposure to Agent Orange.
He is diabetic. At the VA, he said, he saw evidence that made him think about the link.
"They had a map of the areas where it was sprayed, and I was in those areas," he said.
Agent Orange, Derr said, has had lasting effects on veterans who endured other trauma on the battlefield.
But Vietnam veterans are helped by the fact that they are a close-knit group.
"Most of them now are at the end of their careers," he said. "They really are very supportive of each other."