He describes himself at the time as "twenty-two years old, dumb, naive to a lot of things." Sentenced for shoplifting, he quickly learned what it would take to survive in this city's toughest lock-up.
"Living conditions was bad and you needed money in Holmesburg to make it," Green explains. "If you didn't have no money in Holmesburg, you was in trouble."
At Holmesburg there was money to be had, Green explains. As a human guinea pig "...that's how I made my money," he says.
Green is just one of hundreds of former inmates who -- for pay -- agreed to participate in medical tests while behind bars. But the tests, they now believe, went too far.
"They cut my back," Green says. "They cut some pieces out -- layers of skin."
Another former inmate told CBS News that there were radiation tests done that burned those who volunteered. Yet another said he was used in an LSD test.
With funding from major pharmaceutical companies -- among others -- Holmesburg had become a testing ground for experimental medical products and procedures.
The prison eventually closed, and what went on there nearly forgotten, until Allen Hornblum, a Temple University professor who worked at the prison in the early seventies told others what he had seen.
"They had bandages on them, on their arms and their backs and their chests," he recalls. "It gave me a chill."
Hornblum has chronicled the wide-ranging series of prison experiments in his book, Acres of Skin.
"Anything as innocuous as hair dyes, skin creams were tested here," Hornblum says, "As well as some very dangerous substances such as dioxin, radioactive isotopes, chemical warfare agents."
The experiments at Holmesburg Prison began in the early 1950's under the direction of Dr. Albert Kligman, a professor at the University of Pennsylvania.
Dr. Kligman saw Holmesburg as a natural laboratory to advance his dermatological research -- a controlled environment with ideal test subjects.
"He didn't see people. He didn't see prisoners. In his own words, he saw 'acres of skin,'" Hornblum says.
Dr. Kligman is now a professor emeritus at the University of Pennsylvania. He declined requests for an interview with CBS News, but issued a statement saying his research:
"Â…was in keeping with this nation's standard protocol for conducting scientific investigations at that time to the best of my knowledgeÂ…no long-term harm was done to any of the volunteers..."
owever, some of the men on the receiving end of the experiments claim harm was done, revealing lumps where medical patches had been, and burn marks.
Most of the records from the prison studies were destroyed, frustrating the inmates' attempts to bring a lawsuit against the university.
"It happened! It happened! We're living proof," one man says.
The evidence is written on their flesh.
Reported By Troy Roberts