For-profit prisons are a lucrative industry in the United States. After falling out of favor in the Obama years, they’ve found a new purpose—and extensive profits—in the Trump administration by incarcerating undocumented immigrants.

These prisons have come under scrutiny from advocates alleging extensive human rights abuses, but as The New York Times explained in October, the biggest companies in the industry defend themselves by touting their efficiency, claiming they “build and operate prisons more cheaply than governments can, what with the public sector’s many mandates.”

A new investigation by The Daily Beast, however, found that rather than saving public money, private prison companies are actually costing taxpayers $807 million, while inmates work for $3 a day or less. In 2018, The Daily Beast writes, “For-profit immigration detention was a nearly $1 billion industry underwritten by taxpayers and beset by problems that include suicide, minimal oversight, and what immigration advocates say uncomfortably resembles slave labor.”

A New York Times video on conditions in immigration detention centers revealed “barely edible food, indifferent health care, guard brutality and assorted corner-cutting measures.”

In November, NPR reported that Douglas Menjivar, a former inmate in the Joe Corley Detention Facility in Texas, said “he was raped by gang members in his cell, and when he reported it to the medical staff they mocked him.” Menjivar told NPR that he was forced to work for less than $1 per day at Corley.

Yesica, a current inmate at Corley, told The Daily Beast she earns slightly more at $3 a day for her graveyard shift in the prison kitchen. And that’s at the high end of what inmates are paid.

While inmates are earning $3 or less a day, their jailers are reaping huge profits. GEO Group, which owns the Corley facility, reported in November that it was on track to earn $2.3 billion by the end of 2018.

In compiling its report, The Daily Beast read and analyzed multiple ICE budget submissions and other public records. “For 19 privately owned or operated detention centers for which The Daily Beast could find recent pricing data, ICE paid an estimated $807 million in fiscal year 2018,” the article explains.

Those prisons hold about 18,000 people, or 41 percent of the approximately 44,000 migrants currently detained by ICE. The Daily Beast, however, cautions that this might not be a comprehensive picture; the article notes that “The true figures are likely significantly higher. The National Immigrant Justice Center estimated that for November 2017, roughly 71 percent of immigrant detainees , then a smaller total figure, were held in 33 privately operated jails.”

Advocates are concerned about the low wages and potential for abuse in these facilities. As Emily Ryo, an associate professor at the University of California’s Gould School of Law, told The Daily Beast:

To the extent that the industry is in the business of expanding the system so they can make more money off holding more immigrants that can be confined, and doing everything possible to profit off of it by labor processes like getting detainees to work and paying them a dollar a day, there is very little distinction you can draw between slave labor and what they’re doing.