The latest uprising at the Willacy County Correctional Center began quietly on Friday morning, when prisoners refused to go to their work assignments or to breakfast. Then, inmates broke out of the massive Kevlar tents that serve as dorms. Willacy County Sheriff Larry Spence told reporters some had kitchen knives, sharpened mops and brooms. Prison officials sprayed tear gas; a SWAT team, the Texas Rangers, the FBI and the US Border Patrol all showed up. It took two days to quell the demonstration. Now administrators are beginning to transfer the 2,800 prisoners—undocumented immigrants, most serving time for low-level offenses—to other facilities, because the protest made the center “uninhabitable.”

But reports suggest that Willacy has been uninhabitable for years. This is the third disturbance at the center since the summer of 2013, when inmates protested after their complaints of broken, overflowing toilets were ignored. “I feel suffocated and trapped,” a prisoner named Dante told the American Civil Liberties Union, which released a report on conditions at the facility last year. Dante and others described the 200-man tents they were housed in as “dirty and crawling with insects…. the toilets often overflow and always smell foul.” The ACLU also found that “basic medical concerns are often ignored or inadequately addressed.” Reportedly, inadequate medical care is what sparked the weekend’s demonstrations.

The events at Willacy put a spotlight on a shadowed corner of overlap between the federal prison system, private prison companies and the nation’s immigration enforcement machinery. Willacy is one of thirteen facilities in a network of Criminal Alien Requirement (CAR) prisons under the jurisdiction of the federal Bureau of Prisons. These “second-class” prisons, run by notorious contractors like the GEO Group and Corrections Corporation of America, hold some 25,000 immigrants whose crimes largely fall into two categories: minor drug offenses and immigration infractions such as re-entering the country illegally. A decade ago the latter was rarely treated as a criminal case; as I explain in more detail here, increased prosecution of unlawful entry and re-entry has become a hallmark of President Obama’s enforcement policies. In 2013, nearly a third of all federal criminal cases related to border crossings. In Arizona, New Mexico and Texas, they represent 80 percent of the federal criminal docket.

CAR prisons are distinct from the detention facilities maintained by the Immigration and Customs Enforcement agency, but they aren’t run like most BOP facilities either. Most CAR prisoners don’t have access to attorneys, and because the BOP assumes they will be deported after serving their time, they are denied some services and considerations afforded to others in the corrections system, such as work training or drug treatment programs. Bob Libal, the executive director of a Texas prison reform group called Grassroots Leadership, explained the BOP’s reasoning: “In a system with scarce resources, why should we be giving them to immigrants who are just going to get deported?”

“These uprisings are a predictable consequence of the Bureau of Prisons turning a blind eye to the abuse and mistreatment that happens at these private prisons,” said ACLU senior staff attorney Carl Takei. Successive riots broke out at the Reeves Detention Center Complex in Pecos, Texas, late in 2008 and early 2009, after a year in which four inmates died. One was Jesus Manuel Galindo, who’d been convicted of re-entering the United States illegally, and died of a grand mal seizure while locked in solitary confinement. Several CAR prisons use isolation excessively and capriciously, the ACLU discovered. It’s essentially written into their contracts: because of quotas, Texas CAR prisons house twice the percentage of their population in solitary as the average BOP facility, even though CAR inmates are considered low-security.

Takei interviewed inmates at Willacy in 2013. The facility, he said, “is a physical example of everything that’s wrong with the criminalization of immigration, and the relationship of the private prison industry to both ICE and the Bureau of Prisons.” Willacy was built as an ICE detention facility in 2006, but after a series of reports of sexual and other forms of abuse, the agency transferred the detainees and ended its contract with Management & Training Corporation, the company running the center. Just one month later MTC announced it would again be responsible for detaining immigrants at Willacy, this time with a new partner: the Bureau of Prisons. The ten-year contract was worth more than half a billion dollars.

Although the BOP monitors conditions at CAR prisons, the ACLU says that the agency has failed to enforce oversight and accountability, “leaving the private prison companies in a position of dangerous impunity.” When the BOP re-evaluated its contract with the GEO group for the Reeves facility in 2010, the agency noted, among other problems, that “lack of healthcare has greatly impacted inmate health and wellbeing” and that the “contractor shows little sign of improvement.” The BOP renewed the contract anyway—in part because officials were worried the BOP would lose “credibility as a solid customer” with prison corporations.

At this point it’s hard to know exactly what happened at Willacy beyond official statements, or what awaits the detainees being transferred. Takei and Libal said that prison officials had cut off all access to the facility and communication channels to prisoners. But nothing that happened is particularly surprising in light of the ACLU’s findings—not even the reports that three of the ten housing tents were set on fire.

“A lot of people get very upset and angry,” Dante, the Willacy prisoner, told ACLU staffers in 2013. “Sometimes they become so frustrated that they even speak of burning down the tents. But what’s the point? They’d build them back up.”