Evangelina Perez lost count of the number of times her mother, Martha Perez, called her from federal prison, gasping for breath because she had missed dialysis treatments for her kidney failure.
At 59, Martha Perez also had diabetes and congestive heart failure. She had been in various federal prisons since 2005 on money laundering and drug convictions. In 2018, the Bureau of Prisons sent her to the Federal Medical Center Carswell in Fort Worth, the country’s only federal medical prison for women.
The bureau houses some of the sickest women at Carswell, and it’s the only federal women’s prison with in-patient dialysis — a critical, life-sustaining treatment for people with kidney failure.
But in court documents she filed pleading for release, Perez described her worsening health and her fear of dying at Carswell. In May 2022, another incarcerated person had to help her write a final request because of her poor vision. Just over a year later, Perez died in a Fort Worth hospital. No family was with her.
“I understand the circumstances, but initially, like there is a care that they should have been providing,” Evangelina Perez said. “It got to the point where she started retaining fluid on her chest, and she ended up passing away from a heart attack.”
Perez had serious illnesses that required consistent care. But Carswell does not adequately provide the dialysis care that the Bureau of Prisons claims it does, according to lawyers, medical experts, former bureau officials, along with court and medical records. Women at Carswell describe missed treatments, poor education for patients, dialysis machines that break down mid-treatment or that lacked enough clean water, and other routine problems.
A photo of Martha Perez is found in a bin of family photos at the Perez’s home in Prescott Valley, Arizona, on March 9, 2025.
Doctors who reviewed the women’s court filings and allegations say the problems described would put dialysis patients in serious danger. Legal filings by prisoners, medical records and expert court testimony raise flags about preventable — and potentially fatal — conditions arising from substandard care. The Bureau of Prisons, which is supposed to fix those problems, operates with little to no external oversight over its medical care.
A federal judge overseeing a dialysis patient’s compassionate release case said testimony from seven women on dialysis was “concerning,” but said he could not approve the release. Doing so, the judge said, could imply the entire Bureau of Prisons provides ineffective dialysis care.
Michele Deitch, director of the Prison and Jail Innovation Lab at the University of Texas in Austin, said people in prison “have a constitutional right to receive medical care for their serious medical needs. And dialysis is certainly an example of that.”
If the federal government “cannot take care of people and meet their needs as required by the Constitution,” Deitch said, “then we have no business locking them up.”
The Bureau of Prisons declined requests for an interview. In answers to emailed questions, spokespersons wrote that the agency provides adequate dialysis care, including sufficient staffing and education for patients.
“At present, there have been no reports or claims concerning the quality of the dialysis care being provided at FMC Carswell,” wrote spokesman Donald Murphy.
Carswell has been the subject of numerous investigations calling into question its treatment of incarcerated people. In 2020 and 2021, women at the facility described negligent medical care and malicious treatment as COVID spread through the prison. In 2023, a Fort Worth Star-Telegram investigation highlighted a pattern of sexual abuse by staff. In response, a state representative called for a congressional inquiry into the prison, though none were launched.
When she died in June 2023, Perez was one of about 15 women at Carswell receiving dialysis. The treatment uses a surgically-installed port to connect a patient to a machine that filters their blood, removing toxins the kidneys no longer can process, before pumping the cleaned blood back into the patient. The process takes 3 to 5 hours and is usually needed three times a week — or patients may risk serious complications and death.
Kidney failure can be caused by a multitude of issues, most commonly diabetes, high blood pressure and chronic kidney disease. Perez had all three. In June 2021, Perez started dialysis after she had a stroke.
Federal medical prisons, despite their name, are not hospital-like facilities: They keep incarcerated people with medical needs, but in many cases, do not provide all of their care in-house. Carswell, which houses approximately 1,200 people, contracts with the University of North Texas Health Science Center for much of its medical care. The Health Science Center, in turn, subcontracts dialysis services to the private provider U.S. Renal Care of West Fort Worth, according to the Bureau of Prisons. Under Carswell’s contract with the Health Science Center, the bureau is still responsible for providing all dialysis equipment.
U.S. Renal Care confirmed it provides dialysis at Caswell, but did not respond to several interview requests and other emailed questions about its services there.
Dialysis is only part of the treatment for people with kidney failure. They also need a strict diet and water intake monitoring, and blood work to closely check various chemical levels. A patient’s port must be kept extremely clean to avoid sepsis, a life-threatening infection.
According to Bureau of Prisons mortality reviews from 2015 to April 2020, at least three women undergoing dialysis at Carswell died in that time period. All three women had been transferred to Carswell specifically to receive medical treatment, and all three developed sepsis prior to their death, according to the mortality reviews. Reason Magazine obtained the documents through a records request and provided them to The Marshall Project.
Sepsis is far less common if staff follow the proper contamination protocols for dialysis machines, said Dr. Charles Howard, who has served as medical director at two federal prisons for over two decades.
There are no publicly available records of deaths in federal prisons. The Bureau of Prisons has yet to fulfill records requests for mortality reviews or the number of dialysis patients who have died at Carswell.
When asked how many Carswell dialysis patients have died since 2020, a bureau spokesman initially said “zero.” When asked specifically about Perez, who died in 2023, spokesman Scott Taylor said that no one “had passed away as a result of their condition that required dialysis.” Regarding Perez’s death, Taylor said “there was no correlation between the need for dialysis and the cause of death.”
Five current or former dialysis patients at Carswell spoke with The Marshall Project and also detailed in court records the dialysis conditions there. Four others described dialysis treatments in compassionate release pleas or other court records. The women said their treatment included severe cramping during dialysis, treatment sessions cut short or missed, and poor machine maintenance, such as broken parts, discolored tubing, and machine settings that were set incorrectly. Four women said pipes in the water room would break frequently, and the machines would sit in puddles of water.
“The truth lies in the consistency of the women’s statements,” said Amber Rabon, a lawyer in one of the women’s cases, who has been a federal criminal defense attorney since 2008.
Evangelina Perez, Martha Perez’s daughter, said her mother told her she frequently missed dialysis treatments prior to her death in 2023.
“I can’t even keep track of how many times that occurred where they wouldn’t complete the dialysis on them. And that was an issue, and she would call me, she would call me panicking because she knows how she would get if she skipped one,” Evangelina Perez said. “She would be so short of breath that her stomach would be tight from all the fluid she was retaining.”
She said her mother would tell staff that something was wrong, but they “said ‘She was fine, she’s fine,’ until there was fluid literally coming out of her belly button,” Perez said.
Missing a dialysis session is dangerous for patients, said Dr. Rebecca Ahdoot, a kidney specialist at the University of California Irvine. Without rigorous dialysis, toxins can build up, and the person can die.
Alicia Elliott, who was on dialysis at Carswell for 15 months while incarcerated on drug charges, said in court records and interviews that she was forced to miss appointments or had her treatment cut short multiple times. In late 2022 and twice in early 2023, Elliot emailed Carswell’s associate warden for medical to complain about being taken off dialysis early. In one case, she said staff wanted to leave early because of ice on the roads.
Sanjuana Garcia-Ramirez started dialysis at Carswell in November 2023. She said she had been on dialysis for two years before incarceration; comparatively, she said treatments at Carswell are less consistent and the machines are poorly managed.
“I have four kids I have to get back home to, and it frightens me that I might not make it out of here because of the way they run dialysis,” said Garcia-Ramirez, who is serving a 6-year sentence on a drug conviction.
Successful dialysis goes hand-in-hand with proper nutrition plans, said Howard, the former bureau medical director.
“A patient has to be their own advocate, and they have to be very, very, very much aware of what they need and what they have to do to manage their condition,” Howard said. If they’re not able to do it or they’re not properly educated, he said, “they will not do well on dialysis.”
But Stephanie Williams, who said she was on dialysis at Carswell for 11 months, said women would start dialysis and get no education on nutrition. Some women did not know that people with kidney problems have to monitor their potassium, sodium, fluid and phosphorus levels, for example, or they risk possibly fatal complications.
“Them girls, when I said phosphorus, they said, ‘What is phosphorus?’ And [I was] like, ‘What are you doing?’” Williams said.
She also said in interviews and court records that women were not told how to keep their port clean — or the importance of doing so. Women would shower without covering up their ports and get them wet, which increases the risk for infection, she said.
“It’s a lack of education. It’s not the girls’ fault. But it’s killing them.”
While U.S. Renal Care oversees dialysis treatments and a nephrologist — a kidney specialist — visits once a month, patients rely on Carswell staff at all other times for medical needs. Doctors, lawyers and the Bureau of Prisons’ own budget proposal this year questioned whether Carswell has the ability and resources to provide that care.
Understaffing and a depleted budget have sapped federal prisons of resources over the last few years. In a 2024 report, the Office of the Inspector General identified providing adequate medical care as one of the primary challenges the bureau faces.
In the bureau’s 2025 budget submission to Congress, the agency lamented its difficulties in hiring and maintaining medical staff. The budget cited a 2016 Office of Inspector General report, which declared recruitment of medical professionals to be “one of the Bureau’s greatest challenges.”
Carswell is no exception. In 2022, Carswell then-staff union leader Jennifer Howard filed a whistleblower complaint about COVID-19 guidance and staff shortages at the facility. At the time, Howard told the Fort Worth Star-Telegram that staffing levels were “unacceptable for a medical facility.”
The entrance to the Federal Medical Center Carswell in Fort Worth, Texas.
Despite understaffing, the bureau may face further cuts. In February, the agency announced it would reduce or eliminate retention pay for correctional officers, a decision that American Federation of Government Employees said would “exacerbate staffing shortages and make working conditions less safe.”
A former bureau warden and administrator, Jason Terris, questioned Carswell’s ability to care for dialysis patients as part of his declaration cited in a compassionate release case for Feliza Renteria, a 45-year-old dialysis patient at the facility.
Renteria arrived at Carswell in 2021. But the dialysis treatments have made her sicker, she argued in court records. In an interview, she described excruciating pain during treatment. “I did not experience what a cramp was before I was incarcerated —- I did dialysis a year before this and never had cramps,” she said.
Dialysis patients should not have constant cramping, Ahdoot said. Cramps can be a sign that too much fluid is being pulled out of the body too quickly, she said, and treatment should be adjusted.
Patients “certainly shouldn’t be on dialysis and suffering,” said Ahdoot, who has been a nephrologist for 12 years. “If you are having crazy cramps all the time, then there is certainly a problem.”
Carswell’s contract with the Health Science Center says a kidney doctor will be available to patients once a month for up to four hours. Ideally, Ahdoot said, a nephrologist should see patients once a week to ensure the right amount of fluid is being pulled off during dialysis.
In his declaration for Renteria’s suit, Terris wrote that he did not know if the staff at Carswell could handle the “logistical and care-related challenges” Renteria’s condition presented due to staffing shortages and a lack of resources.
But those statements are part of the reason U.S. District Judge Anthony Battaglia, in California’s Southern District, denied Renteria’s compassionate release. When he denied the request in a September 2023 hearing, Battaglia said granting her motion could have implications beyond Renteria’s case because of the message it would send about the bureau’s care.
“I mean, granting relief here, does that mean that every dialysis patient in the Bureau of Prisons should be similarly accommodated because the quality of care is, perhaps, ineffective?” Battaglia said, according to a court transcript. “I’m looking at sort of the greater picture here. Because some of the accounts, from some of the people, is concerning.”
Last year, the Ninth Court of Appeals denied Renteria’s appeal for compassionate release.
There is no third-party agency currently monitoring dialysis treatments at Carswell. Multiple outside agencies that used to evaluate the Bureau of Prisons’ medical care no longer do so.
Carswell’s contract with the Joint Commission, which provided the facility’s accreditation as a healthcare organization, expired in October 2020 and was not renewed, according to the Bureau of Prisons spokesperson. The American Correctional Association ended its audits of the agency in 2023, after the Office of Inspector General found the Bureau of Prisons was “in effect, paying ACA to affirm [the bureau’s] own findings,” and as a result, there was “no real certification or action for improvement.”
The state of Texas does not monitor Carswell either. Oversight rules are built into Carswell’s contract with the Health Science Center, but neither the Sciences Center nor Carswell have responded to requests for monitoring records.
According to its contract with the bureau, the Health Science Center is supposed to send quarterly reports about dialysis treatment at Carswell to a bureau administrator. But Health Science Center spokeswoman Paula Cobler said the hospital does not have those records; she said U.S. Renal Care is responsible for them and provides Carswell with copies. Another Health Science Center spokesman, Andy North, said the dialysis reports include “patient-care specific problems experienced during the quarter,” but declined to answer questions about what those problems entailed.
U.S. Renal Care did not provide those records to The Marshall Project. The bureau has not fulfilled a records request for those quarterly reports.
The Office of the Inspector General found evidence that the bureau’s contracts are not always monitored adequately. A 2023 audit found the bureau’s contract evaluations were often untimely, incomplete, or for the wrong time period. This may result in the agency not getting the best services, the report noted.
In 2024, then-President Joe Biden signed the Federal Prison Oversight Act to increase independent inspections of prisons, but Congress has not approved money for the inspections. Deitch, of the Prison and Jail Innovation Lab, said the priority now is for the act to be fully funded “to provide the critical oversight role that is needed.”
As her fears of dying inside prison grew, Perez filed requests for a reduced sentence or compassionate release five times between 2012 and 2022. A judge had not ruled on her final release request when she died in July 2023.
Compassionate release is a way to address deficiencies in care for some incarcerated people, but it is seldom granted. Judges look for evidence that a prison can’t provide the necessary treatment, said Marc Stern, the court-appointed monitor for the State of Arizona Department of Corrections. Without that proof, most motions will be denied. Out of the nine dialysis patients at Carswell that The Marshall Project identified, eight filed for sentence reduction or compassionate release since 2022. Seven were denied. In the remaining case, a judge initially denied the request, but reversed the decision and released the woman in 2020, citing “the abominable COVID-19 statistics at FMC Carswell.” The judge said the facility’s inaccurate data suggested the bureau could not be trusted to care for someone with complicated health conditions.
A photo of Martha Perez is found in a bin of family photos at the Perez’s home in Prescott Valley, Arizona, on March 9, 2025.
In a compassionate release request for one woman, who asked not to be named due to fear of retaliation, her lawyer wrote that Carswell frequently missed her dialysis treatments, forcing her to go five to six days without. The woman’s former physician wrote a letter in November 2023 in support of her release request, saying that “continued incarceration would be severely detrimental” to her health due to her complex medical issues.
Williams, the former Carswell patient, described Perez’s deteriorating condition as “the scariest thing I’ve seen.”
“She was bad off,” said Williams, who was released in November 2023. “The week she died, she said, ‘I need to see a doctor right now.’”
In the days before Perez’s death, her family said, the bureau did not tell them that her condition had worsened or that she was in the hospital. She was admitted to John Peter Smith Hospital in Fort Worth on July 2, 2023, for low blood pressure after a dialysis treatment, medical records show. Her admission records at the hospital indicated she had had a serious heart attack and, on July 6, she was transferred to Medical City Fort Worth Hospital for surgery.
Medical staff tried to reverse the damage and stabilize Perez, but on July 7, she lost her pulse. For one hour, staff tried to bring Perez back. A prison guard finally called the family to ask if they wanted them to continue to try to resuscitate Perez. Her daughter said the decision fell to her father as Perez’s next of kin. He told them to stop.
In a letter to the family, the Bureau of Prisons said Perez died from cardiac arrest; she also had coronary artery disease. Seven months later, Evangelina Perez got her mother’s death certificate from the state of Texas. The cause of death is listed as “pending investigation.”
Kaley Johnson is a reporter based in Texas. She can be reached at kaleyalyssajohnson@gmail.com.