he former Holmesburg Prison in Northeast Philadelphia has been inactive since 1995, concealing its dark legacy of inmate exploitation from a time when the United States was ethically permissive – and often aggressive – about medical experimentation using people behind bars.

Medical testing programs at Holmesburg Prison ran from 1951-1974, led by University of Pennsylvania dermatology professor Albert Kligman, who viewed the predominantly Black prison population as a low-risk and plentiful pool of test subjects for more than 250 different chemical compounds.

On Thursday, 20 years after a federal court dismissed a lawsuit filed by more than 300 inmates involved in these experiments, Philadelphia Mayor Jim Kenney issued an apology for the city's role in preying on prisoners:

While this happened many decades ago, we know that the historical impact and trauma of this practice of medical racism has extended for generations – all the way through to the present day. One of our Administration’s priorities is to rectify historic wrongs while we work to build a more equitable future, and to do that, we must reckon with past atrocities. That is why our Administration today, on behalf of the City of Philadelphia, is addressing this shameful time in Holmesburg’s history.

Without excuse, we formally and officially extend a sincere apology to those who were subjected to this inhumane and horrific abuse. We are also sorry it took far too long to hear these words. To the families and loved ones across generations who have been impacted by this deplorable chapter in our city’s history, we are hopeful this formal apology brings you at least a small measure of closure. Recognizing the deep distrust experiments like this have created in our communities of color, we vow to continue to fight the inequities and disparities that continue to this day.

Built in 1896, Holmesburg Prison was modeled after Eastern State Penitentiary and intended to relieve overcrowding at the former Moyamensing Prison in South Philly. The massive, radial structure along Torresdale Avenue, nicknamed "The Terrordome" for the violence that occurred within its walls, has 10 cell blocks that accommodated approximately 1,500 inmates.

As recounted by staff at the Mütter Museum, Kligman visited the prison in 1951 to treat an outbreak of athlete's foot among the inmates, and he saw an opportunity.

"All I saw before me were acres of skin," Kligman said in an interview in 1966. "It was like a farmer seeing a field for the first time."

Kligman's experiments used hundreds of inmates to test products like facial creams, skin moisturizers, anti-rash treatments, toothpastes, shampoos, perfumes and detergents. He hoped his research would change the way dermatologists treated common conditions, such as ringworm, staph infections, herpes and acne.