"They picked some of the oldest guys and asked us if we wanted to be in this club," Dyer, 72, said in an interview from his home in Watertown, Mass. "We all got together and decided, why not? We'll get time off the grounds."
The boys were promised presents, outings to the seashore, trips to Fenway Park and extra helpings of oatmeal.
"It was like Christmas," Dyer recalled. "Red Sox games, parties. I got a Mickey Mouse watch that I still have."
It took decades before Dyer learned that he and the boys he still considers brothers were little more than guinea pigs. A state task force in 1994 found Massachusetts Institute of Technology scientists fed the unwitting boys radioactive oatmeal and milk for a Quaker Oats nutrition study.
His story is one of many told in a new book, "Against Their Will," the result of five years of gathering data from medical and university libraries and archives, medical journals and records from many of the now-shuttered state hospitals and orphanages where experiments were conducted.
"We thought something wasn't right, but we didn't know," Dyer said. "They were using the kids who they were supposed to be helping."
The authors interviewed nearly a dozen former test subjects, along with relatives of test subjects, medical researchers and historians.
"These are throwaway, unwanted, damaged people," said Allen Hornblum, one of the book's authors. "You had the best and the brightest minds doing this stuff, doing it very cavalierly and doing it exclusively to the most vulnerable."
While researching his 1998 book "Acres of Skin" about medical experiments on inmates in Holmesburg Prison in Philadelphia, Hornblum came across documentation about similar experiments conducted on children and even infants.
Thousands of children warehoused in overcrowded orphanages and facilities for "feebleminded" children underwent spinal taps, lobotomies and electric shock. They were also exposed to viruses, radioactive and hazardous chemicals and were administered psychotropic drugs.
Often lacking legal or family advocates, they were treated in the decades after World War II as cheap and abundant raw material for trials that proved lucrative for scientists who conducted the tests and for the institutions housing the kids.
"I think people are going to be shocked," he said. "These aren't inmates ... these are children who are having these things done to them."
While disenfranchised children were used as human guinea pigs during the American eugenics fervor of the late 19th and early 20th centuries, Hornblum said, the practice rose along with Cold War fears of nuclear and biological threats from the Soviet Union and a booming pharmaceutical industry.
In one of the most egregious cases in the book, more than 90 children as young as 6 were given large twice-daily doses of LSD — some for a year or more — as an experimental treatment for schizophrenia and autism at Creedmoor State Hospital in the New York City borough of Queens in the 1960s.
On New York's Staten Island from the 1950s to the early 1970s, mentally disabled children at the Willowbrook State School — famously called a "snake pit" by Sen. Robert Kennedy after a 1965 visit — were intentionally infected with viral hepatitis by feeding them an extract made from the feces of infected patients.
In dozens of orphanages and sanitariums, children were exposed to hepatitis, meningitis, ringworm, influenza, measles, mumps and polio in the name of medical advancement. Dietary experiments induced severe vitamin and mineral deficiencies to observe the effect on the children's health.
"All of this information was out there. It was just a matter of someone pulling it together and giving it context," said co-author Judith Newman, a psychologist and Penn State associate professor who teaches a course on medical ethics.
Attitudes about medical research were different then, and many prominent researchers of the era felt it was legitimate to experiment on people who did not have full rights in society — prisoners, mental patients, poor blacks, orphans — in the quest for finding cures of deadly infectious diseases.
Ethical guideposts from the Hippocratic oath to the Nuremberg code were also trumped by misguided patriotism, veneration of doctors, eugenics ideologies and the financial and career benefits for people and places that conducted and published such large clinical studies, Newman said. It wasn't until the late 1970s that the federal government issued a report outlining principles and guidelines strictly limiting the use of children in medical research.
"The last few years working on this book have been very sad," she said. "The hope is that it gives voice to those thousands of children — how many thousand we don't even know."
Dyer, a retired truck driver, makes ends meet with yard sales and odd jobs. He and about 30 former "Fernald Science Club" boys filed a class-action lawsuit that settled out of court in 1998; Dyer says they ended up with around $30,000 apiece.
What bothers him most is that the "feebleminded" diagnosis from his childhood remains part of his medical records.
"We went to court to try to get it changed," he said. "We just didn't have any schooling; they didn't teach us to read. I learned a lot of things on my own when I got out of there."