But they were wrong. For two decades, they faced a succession of new lawsuits, all of which were dismissed because, in the eyes of a U.S. Federal Court, the 1984 case had settled the matter.
Then, in 2003, the U.S. Supreme Court affirmed an appeals-court decision that allowed Vietnam veterans who had opted out of the original settlement, or were diagnosed afterward, to sue the manufacturers.
The door was opened to a new wave of lawsuits, and American veterans weren't the only ones paying attention. Around the world, people injured by Agent Orange were inspired to take action.
In May, 2005, Mr. Cadger, who had worked at Gagetown as a communications technician, saw a CBC television report revealing that the U.S. military had tested Agent Orange at the base.
"I remember thinking, 'This is going to be another government cover-up.' And I got involved."
He joined other veterans and former Gagetown residents seeking redress, a group that included Mr. Connolly, who had spent part of his childhood at the base when his father worked in the army.
A year later, Mr. Connolly flew to Hanoi for a conference on illness and pollution related to Agent Orange that was also attended by delegates from South Korea and the United States.
It was a depressing trip - he toured an orphanage for children with ghastly deformities - but inspiring too, he says. A few months earlier, veterans from South Korea - the United States' biggest ally during the Vietnam War - had won their $63-million settlement from Dow Chemical and Monsanto. And then, on Sept. 12, the government of Prime Minister Stephen Harper announced that it would compensate the Gagetown residents.
Mr. Cadger, who had developed diabetes, received his $20,000 in December, paid a few bills and banked the rest. "I took it because I had it coming," he said of the money, "but it angered me more than anything."
Despite his anger, he conceded that he was better off than his Vietnamese counterparts. But last month, at the age of 64, he suffered a heart attack and died.
'WE KEPT HOPING WE WOULD HAVE A HEALTHY CHILD'
With his health problems and those of his children and grandchildren, Tong Van Vinh, the former truck driver, tells a sad tale. But it is no less heartbreaking than those of his roommates at Friendship Village, a huddle of buildings on the outskirts of Hanoi where Agent Orange survivors receive temporary respite and health assistance from their government and foreign charities.
Quang Van Tuoi, a 65-year-old veteran of the Viet Cong, shows a small photo of his youngest daughter, born with deformed limbs and mental handicaps. Her eyes are glassy and unfocused, and her body is partly paralyzed.
All five of his children, born from 1975 to 1994, have similar mental problems. "We kept hoping we would have a healthy child," he says. "But they all suffered the same illness."
Although the Vietnamese government tries to discourage Agent Orange victims from trying again if their first child is born disabled, most are impoverished farmers who rely on children for help. Persuading them to give up their dreams of having a large family isn't easy.
Some can't have children at all. Ha Van Mang, 64, was digging a bunker when the Agent Orange fell on him in 1968. Ever since, he has endured numbness and migraine headaches, and after the war, his wife gave birth to a son with no legs or hands.
The baby died two months later, he says, and "no matter how sorrowful we were, we were never able to have any more children."
Mr. Mang's body twitches uncontrollably, day and night, and he is tormented by rashes that feel like ants crawling on his skin. He feels guilty that he has been unable to work on his rice farm since 1978.
"I get headaches so strong that it brings tears to my eyes, and sometimes I just cry and can't do anything else."
Like Jim Cadger, he gets angry when he thinks of how the U.S. courts have rejected appeals from the only victims of Agent Orange yet to receive assistance.
"It's an injustice," he says. "An unfairness."
Geoffrey York is The Globe and Mail's correspondent in Beijing. Hayley Mick is a Toronto-based reporter with Globe Life.