For twenty years, the inmates at Holmesburg rented out their skin.

1951.

Holmesburg Prison opened in the 1890s on the northeast side of Philadelphia, and it looked like a fortress. Stone walls, a central hub, and long cellblocks spreading out from the middle like the spokes of a wheel. The city sent men there who were waiting for trial and men who were serving their sentences. Many of the men waiting for trial could not afford bail. They sat in Holmesburg for months at a time without having been convicted of anything.

Prisons pay almost nothing for work. At Holmesburg, a man who wanted money for cigarettes, toothpaste, food from the commissary, or bail had very few ways to get it. Jobs inside paid pennies a day. Family on the outside, if he had any, could send something. Most of the men came from poor neighborhoods, and a large share of them were Black.

Across town, the University of Pennsylvania had one of the best-known medical schools in the country. One of its dermatologists was Albert Kligman. He was ambitious, inventive, and in his thirties. He studied fungal infections of the skin and hair.

In 1951 Holmesburg had an outbreak of athlete’s foot among the inmates, and Kligman was called in to deal with it. What he saw inside the walls was more than an outbreak. Hundreds of men were confined in one place. They ate the same food, slept on the same schedule, and could not leave. They could be watched every day for as long as a study ran. They needed money. To a researcher who tested things on skin, it was an ideal setting.

Kligman later described his first impression to a Philadelphia newspaper. “All I saw before me were acres of skin,” he said. “It was like a farmer seeing a fertile field for the first time.”

He came back with studies. At first they were about skin diseases, the subject he knew. The work grew quickly. Holmesburg became a testing ground, and the university, Kligman, and the companies that paid for the research built an operation inside the prison that ran for more than twenty years.

The arrangement was simple. Companies that wanted to know what a product or chemical did to human skin paid for the work. Kligman’s team designed the tests and ran them inside Holmesburg. Inmates signed up and got paid. The pay was more than any prison job offered, sometimes by a wide margin. For a man trying to raise bail, a few weeks of testing could be the difference between waiting for trial at home and waiting for it in a cell.

The research moved into a section of the prison set aside for it. Trailers and lab rooms were brought in. Over the years the list of what was tested got longer: shampoos, deodorants, detergents, skin creams, and cosmetics. The program also tested chemicals whose effects nobody fully understood, along with infectious organisms and radioactive substances. Patches of skin were blistered, scraped, or stripped with tape so researchers could measure how fast they healed. Some men had fungal infections placed on their skin on purpose. Some had their fingernails removed.

Men came back to the cellblocks with gauze and tape on their backs, their arms, their legs. Squares of skin were marked off where something had been applied. The tests were part of the routine at Holmesburg. Inmates talked about which studies paid best and which ones hurt.

The consent forms were short. Many inmates had little schooling, and some could not read well. They were told little about what was being put on their bodies or what it might do to them in the long run, and often nothing at all. There was no independent review. In the 1950s and most of the 1960s, the rules that would later govern human research did not yet exist in any form that applied to a place like Holmesburg.

The United States Army became a sponsor. Its chemical warfare laboratories at Edgewood Arsenal in Maryland wanted to know how chemical agents acted on people. Some of the Army’s work at Holmesburg involved agents designed to affect the mind and incapacitate soldiers. Inmates were given substances, observed, and paid.

The Dow Chemical Company also paid for testing at Holmesburg. Dow made herbicides and other chemicals, and some of its products contained dioxin, a compound that was suspected of causing a severe skin condition in workers who handled it. In the mid-1960s, Dow arranged for Kligman to test dioxin on inmates’ skin. Men had it applied directly. Some developed the skin lesions the company had been worried about. Dioxin would later be identified as one of the most toxic substances ever made by industry and would become central to the long fight over Agent Orange.

Kligman’s reputation outside the prison kept growing. He published widely. In the late 1960s he helped develop Retin-A, a cream based on tretinoin, as an acne treatment. It became one of the most successful dermatology products ever sold, and later a best-seller as an anti-wrinkle cream. Patent income made Kligman wealthy and brought money to the university.

The men from the testing program were released, or transferred, or went back to their old neighborhoods. Some had scars. Some reported rashes, discoloration, and other problems that stayed with them for years. Nobody followed up on most of them. There were no long-term health checks and no records given to them. Many could not say what had been tested on them because nobody had told them.

The country’s view of human experiments began to change in the early 1970s. In July 1972 the Associated Press reported on the Tuskegee syphilis study, in which the U.S. Public Health Service had watched hundreds of Black men go untreated for syphilis for forty years. The public reaction was immediate. Congress held hearings on human experimentation. Prison research came under the spotlight with it.

In 1971, before most of that broke, a young man named Allen Hornblum started working at Holmesburg in an adult literacy program. He noticed inmates walking around with patches of gauze and tape on their backs and arms. He asked what they were. The answers stayed with him for decades.

In 1974 the testing program at Holmesburg was shut down. The national rules that followed in the 1970s made research on prisoners much harder to conduct. The federal commission set up after Tuskegee looked at prisoners in particular and concluded that men in confinement could not freely agree to be experimented on in the same way as people on the outside.

Kligman continued his career at Penn. Retin-A remained a commercial success. He kept publishing and teaching for decades and was honored by professional groups in his field.

Hornblum spent years tracking down former inmates and digging through records. In 1998 he published Acres of Skin: Human Experiments at Holmesburg Prison, taking its title from Kligman’s own words. It was the first detailed public account of what had gone on inside the walls.

Holmesburg Prison closed in the mid-1990s. The building stayed standing behind its walls in Northeast Philadelphia.

In 2000, a large group of former inmates sued the University of Pennsylvania, Kligman, and several companies that had paid for testing. The case was dismissed because the statute of limitations had run out. The court did not reach the question of what had been done to the men.

No criminal charges were ever filed in connection with the Holmesburg experiments.

Albert Kligman died in 2010. His obituaries led with Retin-A.

In 2021, the University of Pennsylvania’s medical school issued a formal apology for the experiments at Holmesburg and for the harm done to the men who took part. It removed Kligman’s name from an endowed professorship and a lecture that had been named in his honor.

The apology came forty-seven years after the program ended. Many of the men it was addressed to were dead.

The stone walls of Holmesburg are still there.