The moment Border Patrol agents swooped in on Claudia and her husband, Marvin, as they tried to sneak across the Rio Grande, the 31-year-old mother of two almost felt relief.

It had been an arduous 18-day journey from their native of El Salvador, which they had fled for fear of their lives at the hands—and machetes—of a vicious gang, she said in a recent interview.

But she soon faced a new, unexpected ordeal as she quickly was separated from her husband and locked away with her preteen son and infant girl in cold cells with an ominous name.

“Then they took us,” Claudia said, “to the famous hieleras.”

Las hieleras, or “the freezers,” is how immigrants and some Border Patrol agents refer to the chilly holding cells at many stations along the U.S.-Mexico border. The facilities are used to house recently captured border crossers until they can be transferred to a long-term Immigration and Customs Enforcement detention facility, returned to their native country or released until their immigration hearing.

According to interviews and court documents, many immigrants have been held for days in rooms kept at temperatures so low that men, women and children have developed illnesses associated with the cold, lack of sleep, overcrowding, and inadequate food, water and toilet facilities.

These complaints are backed up by anonymous surveys of recent migrants. A 2011 report (PDF) from the advocacy group No More Deaths, for example, found that about 7,000 of nearly 13,000 immigrants interviewed reported inhumane conditions in Border Patrol cells—with about 3,000 of them saying they suffered extreme cold.

The treatment of migrants in these facilities has been muted in the roiling debate in Congress over expanding the Border Patrol and overhauling the nation’s immigration system. But for thousands of men and women, the facilities have provided a harsh official greeting after what they thought would be the hardest part of their journey, crossing the border.

Since their experience, Marvin and Claudia have filed administrative complaints against the Border Patrol, which can result in agents facing disciplinary action. The couple’s baby still has a persistent cough, Claudia said.

“It’s that they make you feel like you’re worthless,” she said. “They make you feel like you’ve committed a horrible crime.”

Apprehended immigrants are staying longer in short-term detention because ICE facilities are too crowded to accept new detainees, and there are not enough Border Patrol agents in some stations to process immigrants in a timely manner.

A few lawmakers have taken an interest in the problem. In June, Sen. Barbara Boxer, D-Calif., added an amendment to the immigration overhaul package, calling for limits on the number of people held in a cell, adequate climate control, potable water, hygiene items and access to medical care, among other stipulations.

It ultimately was stripped from the Senate version, but Rep. Lucille Roybal-Allard, D-Calif., has included similar stipulations in a bill she proposed in September, called the Protect Family Values at the Border Act. It is currently in committee.

U.S. Customs and Border Protection first approved, then declined, to give The Center for Investigative Reporting a tour of one of the Border Patrol stations in question, citing unspecified pending litigation.

Luis Megid, a reporter with CIR partner Univision, was allowed in. He said the cells looked as immigrants have described, but cleaner—concrete cells, aluminum toilets, doors with glass windows. He was not allowed into a holding cell with detainees to judge the temperature. Border Patrol agent Daniel Tirado told Megid that agents are supposed to provide blankets upon request.

Christopher Cabrera, a local vice president of the National Border Patrol Council, the union that represents the agency’s 21,000 agents, said that when a tour or special investigative inspection is scheduled, the station typically brings in a cleaning crew ahead of time.

It’s clear the stations are overcrowded. Border Patrol agent Juan Ayala said he recently made 732 bologna sandwiches for a single lunch at the Border Patrol station in McAllen, Texas. It took him almost five hours, he said. He loaded the sandwiches and juices into a shopping cart and delivered them to the 732 adult immigrant detainees in the station that day.

The station, Cabrera and Ayala said, was built to hold between 200 and 250 people at any one time.

Out of everything, former detained immigrants said it was the cold that was the worst. Several border crossers who have contacted attorneys and immigrant rights groups agreed to speak to CIR about conditions in the facilities, but on condition of anonymity to protect their pending asylum cases.

Adonys, 15, who came from Honduras in July to join his mother, said the Border Patrol apprehended him crossing the border near McAllen, in a group of 28 men, women and children. Agents put him in a van and took him to their station to process him.

He said the agents made him take off all his layers except for a T-shirt and made him remove his belt and shoelaces.

“I bent over to untie my shoelaces, and I felt an agent pouring cold water on me,” said Adonys, who has filed an asylum request. “He was laughing.”

Five other agents stood by, saying nothing, Adonys said.

They then moved him to a cold cell, wet shirt and all.

“I asked for something to cover myself with, and he said, ‘No, you’re just going to be in there like that,’ ” Adonys said. “It was very, very cold. It was unbearable. We couldn’t stand it.”

Sofía, a 25-year-old woman who has applied for asylum and also requested anonymity, was held for two weeks. She said it was so cold in one cell that she could see her breath.

“It’s so cold, you’re trembling,” she said. “Your lips split.”

Few complain, but problems appear widespread

Despite the conditions in the detention rooms, legal complaints about short-term detention are few. Generally, lawyers and immigrants alike are more concerned with the immediate issue of how to stay in the United States, attorneys said.

Earlier this year, Americans for Immigrant Justice, based in Florida, filed tort claims on behalf of seven women and one man detained in las hieleras in the spring. Like Claudia and Marvin, these people were held in stations in South Texas. The problem, however, stretches along the U.S.-Mexico border, according to lawyers and activists.

“I don’t see how it could be any more widespread,” said James Duff Lyall, a border litigation attorney for the ACLU in Arizona.

Lawyers for detained immigrants raise concerns that migrants are placed in these cold rooms for punitive reasons. Immigration detention is intended, however, to ensure that people seeking asylum or fighting deportation appear in court. It is not because they have been convicted of a crime.

International and North American human rights standards are stricter for this type of detention than for criminal lockups because no one has been convicted of anything.

Immigration detention is held to a Fifth Amendment standard, said Lyall of the ACLU. The Fifth Amendment prohibits conditions that amount to punishment without due process of the law, including freedom from risk of harm and the right to adequate food, clothing, shelter and medical care.

Further potentially violating immigrants’ right to due process, according to Lyall, is the denial of access to an attorney and to their consulate, as well as coercing detainees to sign voluntary removal orders.

While many of these standards are laid out in internal Customs and Border Protection policies and procedures, the agency is not subject to regular inspections to ensure compliance.

The agency’s policy dictates that “whenever possible,” detainees should not be held in short-term detention for more than 12 hours. At 24 hours, agents need to file a report to the station’s patrol agent in charge if a detainee hasn’t been transferred yet. At 72 hours, the chief of the sector should get a report.

For human rights attorneys, the conditions in las hieleras likely violate international standards. Michele Garnett McKenzie, advocacy director at The Advocates for Human Rights, said that if the temperature is turned down for humiliation or to degrade the detainees, that would be evidence of a more serious kind of violation.

“There’s a point where [the temperature] is deliberately turned down to harass people and make them unable to sleep,” McKenzie said, “and that’s where the allegation is here.”

Journey from El Salvador to a holding cell

For Claudia and her family, the cold holding cells were a shock.

They had left San Salvador, El Salvador’s capital city, in a hurry. They stuffed some clothes, diapers and cash in two small backpacks, got on a bus and went north. Marvin had gotten his paycheck from his bus-driving job the day before, and Claudia had a bit of cash from helping an aunt sell food on the street.

The couple had just gotten word that their family had been “denounced”—marked for death—by MS-13, the gang that ran their neighborhood. Marvin saw gang members torturing Claudia’s brother-in-law, who had a rival gang tattoo on his chest. The family was able to lay low for a while, but once the threat came, they fled.

For 18 days, the family rode crowded, broken-down buses to Cancun, Mexico, and then on to the town of Reynosa, bordering South Texas. The baby developed a cold. The parents didn’t have the money to pay coyotes controlled by a cartel to smuggle them across the river. As a result, the cartel held them in a house for eight days until a family member in Canada wired the money.

They were caught not long after crossing the river.

Once inside the Border Patrol detention facility, Claudia was given a heat-reflective “space” blanket—which she likened to a potato chip bag—to keep her and the baby warm. Her son was separated into a cell with other teens, no one would tell her where her husband was, and the baby was coughing. The small cell was packed.

Miles away, at another Border Patrol station, Marvin was in a similar cold, crowded cell. There was barely room to crouch, let alone lie down and sleep.

Even if the agents did turn off the overhead lights, which they never did, and even if they didn’t make a ruckus every time someone closed their eyes, which they always did, there were no mattresses. Just the cold, hard concrete floor, directly underneath large ceiling vents blowing cold air, according to Marvin.

In both cells, the toilet was in plain sight. In Claudia’s cell, a security camera pointed at it, and she could see the agents watching the screens in the control room whenever a woman got desperate enough to use the toilet. In Marvin’s cell, the area around the toilet was covered with dried spit laced with blood.

There were no showers, no soap, no toothbrushes.

Claudia got two sandwiches a day—bologna on white bread. The water was muddy-tasting, so she was afraid to drink it, even though she was breastfeeding. Her son got a few frozen mini-burritos and punch.

The baby coughed more.

After they were taken to the hospital, a doctor scribbled a prescription while a nurse allowed Claudia to bathe the baby and dress her in clean clothes. Then the agents took them back to the cell. They did not fill the prescription, she said.

They lived like this for six days, until one day, the agents told Claudia and her two children they could go. With no friends or family, Claudia and the kids found help at La Posada Providencia, an immigrants’ shelter in San Benito, Texas, where the program director, Sister Zita Telkamp, contacted the pro bono legal organization ProBAR to help find Marvin. The lawyer, Meredith Linsky, found him at an ICE facility.

In total, Claudia and her children spent 144 hours, or six days, in short-term detention, transferred among three different stations. Marvin spent 120 hours split between two Border Patrol locations.

The baby is still sick, and Claudia has nightmares about the Border Patrol coming back. The family’s plan, according to Marvin: “Continue struggling on so they don’t return us.”

Reporter Andrew Becker contributed to this report. This story was edited by Robert Salladay and copy edited by Nikki Frick and Christine Lee.

The independent, nonprofit Center for Investigative Reporting is the country’s largest investigative reporting team. For more, visit cironline.org. Bale can be reached at rbale@cironline.org.