(CNN) The 40-year-old mother found herself in solitary confinement, locked in a cell behind a steel door for 23 hours a day, according to her legal filing and attorney.

The woman, identified in court documents only by the initials R.M., was taken into custody in May while crossing the border illegally to seek asylum. She was separated from her teenage daughter. Now, she's being held at a privately run immigrant detention facility -- effectively, a prison -- known as the Northwest Detention Center in Tacoma, Washington.

The facility, which US Immigration and Customs Enforcement said held 1,495 detainees as of June 30, sits within a toxic sludge field and EPA Superfund site where residential construction has been barred. It has been the target of more than a dozen hunger strikes in recent years, each involving from a dozen to hundreds of detainees, over complaints of inadequate food and medical care, among other issues.

Its operator, Florida-based The GEO Group, is fighting two lawsuits in Washington over alleged labor-law violations for a dollar-a-day migrant detainee work program it calls voluntary. And the center has in recent years faced one of the highest number of complaints about alleged physical and sexual assaults against detainees of any facility of its kind in the nation, according to US Immigration and Customs Enforcement data obtained through public records requests by the advocacy group Freedom for Immigrants.

GEO Group declined CNN's requests for an interview. In emailed responses, spokesman Pablo Paez defended the company's record in detaining immigrants and said it complies with "performance-based standards set by the Federal government" and accreditation guidelines.

"Our employees are proud of our record in managing the Tacoma ICE Processing Center with high-quality, culturally responsive services in a safe, secure, and humane environment," Paez said. "Members of our team strive to treat all of those entrusted to our care with compassion, dignity, and respect."

JUST WATCHED Dad reunited with 4-year-old son after 43 days Replay More Videos ... MUST WATCH Dad reunited with 4-year-old son after 43 days 01:21

The Trump administration's aggressive immigration enforcement strategy has been a financial boon for GEO Group, which along with its affiliates contributed more than half a million dollars to then-candidate Donald Trump's 2016 campaign and his inaugural committee, according to Federal Election Commission data.

And GEO Group is not alone.

The private-prison industry as a whole is benefiting from Trump's border policies. But those lucrative business opportunities are also drawing increased public and legal scrutiny to a system that, advocates say, treats detainees cruelly. And, thanks to the hunger strikes and a grass-roots protest campaign, the public spotlight is now falling on the Northwest Detention Center.

An asylum-seeker in quarantine

R.M. is one in a wave of new detainees sent thousands of miles to the facility over the last few weeks. Many of these recent arrivals were, like her, separated from their children at the border, according to Jorge Baron, executive director of the Northwest Immigrant Rights Project, which provides legal services to detainees.

The mother arrived at the detention center in the midst of a chickenpox outbreak there, according to her attorney, Luis Cortes Romero. When she was tested for the disease, the result was inconclusive. So, though she showed no symptoms, the center's staff quarantined her -- not by sending her to the medical unit but by putting her in what GEO Group calls "segregation," meaning she has been confined alone in her cell for all but one hour a day and given almost no access to telephones or other communication, Cortes Romero said.

GEO Group said that medical care at the center is provided by ICE's Health Services Corps and that GEO Group "has no involvement in provision of these services."

R.M. crossed the Rio Grande south of McAllen, Texas, with her 15-year-old daughter on May 18, flagging down the first Border Patrol agents they saw, Cortes Romero said. She told them they were seeking asylum because of threats against their lives in El Salvador.

Agents quickly separated the two. She said one agent mocked her over her fears that she would not see her 15-year-old again, Cortes Romero said in a declaration. A Border Patrol spokesman declined comment on the allegation, citing pending litigation.

As of July 5, Cortes Romero said, his client "has been able to talk to her daughter one time, for one minute, and both of them were crying, so they didn't get a lot of words out."

Complaints of mistreatment

In recent weeks, amid intense public debate over the Trump administration's now-reversed policy of separating all children from parents at the border, the protests outside the Northwest Detention Center have escalated. On June 23, one group of protesters set up a camp in front of the center, their tents lining the public space outside the center's fence.

Three days later, Tacoma police arrested 10 people there after one youth allegedly blocked the road in front of a police car with a shopping cart. The next day, the city ordered protesters to clear out their tents within 24 hours. But another protest -- with mariachis -- is planned for Saturday, July 14, organizers said.

The detention center sits on the Tacoma Tideflats, in an industrial area where residential construction is otherwise barred because it sits within a toxic sludge field and Superfund site deemed by the EPA to have "widespread contamination" of water and soil. The center's neighbors include a methanol plant and a liquified natural gas facility.

As the Tacoma Tribune reported , despite environmental concerns, Tacoma city officials supported locating the center on this 16-acre site when it was built in the early 2000s.

The EPA and Washington Department of Ecology permitted construction as long as the center did not use groundwater from the site or disturb an engineered cap sealing hazardous substances underground.

In 2009, the EPA looked into community concerns that excavation during GEO Group's expansion of the center to house 553 more people might have exposed workers and detainees to contamination from mercury and naphthalene vapors.

The EPA said that GEO Group improperly dug into the ground without notifying the state Department of Ecology but hadn't broken through the engineered cap. It didn't substantiate any health risks from the expansion.

But community groups continued to raise concerns.

In March, the city council passed an ordinance to prevent the Northwest Detention Center from expanding, along with interim measures to determine whether, long term, the facility is compatible with zoning policies for the area. GEO Group has filed a federal suit contesting the city's decision to, in effect, re-zone an existing operation.

The detention center opened in 2004. In 2008, a report by the Seattle University School of Law and human rights group OneAmerica, based on dozens of interviews with detainees, alleged frequent misconduct by guards, including physical and verbal abuse and sexual harassment.

It described outbreaks of food poisoning, including one in 2007 that sickened more than 300 people; it said detainees often had to wait as long as two weeks to receive medical care; it detailed servings of food so paltry that 80% of detainees said they were hungry after every meal. It also described the food as sometimes rotten or bug-infested. One man who weighed 190 pounds when he entered the center lost 50 pounds over two years in detention, the report said.

ICE, at the time, disputed the report. A spokeswoman told the Seattle Times it was "filled with inaccuracies and vague allegations."

The center has been subject to more complaints alleging sexual and physical assaults against detainees than all but three of the more than 200 Immigration and Customs Enforcement facilities around the country, according to a review of ICE data from 2012 through 2016, by nonprofit Freedom for Immigrants.

And for four years, detainees there have engaged in one hunger strike after another, despite what they describe as ongoing retaliation by GEO Group and ICE.

'Psychological torture'

Manuel Abrego, who was released from the Northwest Detention Center in April after being put in solitary for taking part in a hunger strike, sees such treatment at the center as "psychological torture."

Abrego, who is from El Salvador, was 15 when he came to Seattle with his parents in 1999, under Temporary Protected Status. That's a status that can be granted to foreigners who are unable to return to their countries because of ongoing armed conflict, environmental disasters or other special circumstances.

He had lived in Seattle since then, working as a cook in recent years. He's married to a US citizen and has two daughters, also US citizens, from an earlier marriage. But a conviction on an attempted assault charge resulting from a dispute with an acquaintance led to his being turned over to ICE in late 2016.

He said he and many detainees think they have been treated poorly and given little information as a way to get them to give up and agree to deportation.

Abrego, 34, was released from the center this spring after the ACLU intervened in his case. He is under ICE supervision and still faces deportation, but he is seeking a work permit and permission to stay. He described the conditions in a recent interview with CNN

"The food they gave us was not enough to keep the hunger away," he said. Vegetables and fruit were rarely available. "We'd get sandwiches for lunch; the meat would still be frozen. Food that was supposed to be hot wasn't." Because there was never enough to eat, Abrego said, detainees would ask their families for money to buy overpriced food at the commissary.

Those who couldn't get funds from their families had to try to earn money by volunteering for the center's work program.

"They said it's voluntary, ... but you're in a position where you have no choice," he said. "You might clean all night and get a dollar or a bag of chips."

That's why, he said, "we organized ourselves. We said, they can't keep treating us this way."

The hunger strikes, he said, led to only the briefest of changes. "They'd make the food better to make us stop, give us chicken," Abrego said. "But if you stop, then the food gets worse. It's like a retaliation."

Paez, Geo Group's spokesman, said the company "strongly refutes these baseless allegations" and that the center "provides culturally responsive, nutritious meals three times daily." He also said that commissary services are provided by a vendor whose prices are reviewed and approved by ICE.

ICE spokeswoman Carissa Cutrell did not address the allegations specifically but said "ICE takes very seriously the health, safety and welfare of those in our care. The agency is committed to ensuring that those in our custody reside in safe, secure, and humane environments and under appropriate conditions of confinement."

Abrego's account matches complaints by other inmates dating back more than a decade.

He said while he was at the center, four detainees were beaten after refusing to eat a meal, with no repercussions for the guards. "They can hit us and nothing happens," he said.

One of those allegedly beaten, Jesus Chavez Flores, is pursuing a federal lawsuit with the help of the ACLU against ICE and GEO Group. He alleges he was punched in the eye by a guard and placed into solitary confinement for participating in a hunger strike in February.

Chavez, a married father of five from Mexico, was arrested by police in Toppenish, Washington, in December for walking in public with an open beer and was then turned over to ICE, according to Amy Roe, an ACLU spokeswoman. He is still being held at the Northwest Detention Center.

GEO Group denied Chavez's allegations. In a motion to dismiss the suit, the company's attorneys called his complaint false.

"(He) appears to have been accidentally clipped, possibly by a detention officer," attorneys for GEO Group stated. They also denied that Chavez was disciplined for taking part in a hunger strike.

Business opportunities

Just two years ago, GEO Group and other private-prison companies saw grim prospects ahead. Several lawsuits over wrongful deaths and many other issues had led to growing public and political concerns over conditions in private prisons.

These concerns came to a head in the waning months of the Obama administration. In August of 2016, the Department of Justice's Office of the Inspector General released a report concluding that, compared with federal facilities, private prisons had higher rates of assault, contraband and lockdowns. The report also identified problems with overuse of solitary confinement and poor medical care.

A few weeks later, Deputy Attorney General Sally Yates issued a memo directing the federal Bureau of Prisons to phase out the use of private prisons as existing contracts expired.

GEO Group's stock price fell 40% in one day.

The top private-prison companies have long been active politically. In the 2016 election cycle, GEO Group alone donated more than $1.2 million to candidates, parties and outside interest groups, with other operators, such as CoreCivic (then named Corrections Corp. of America) and Management & Training Corp. donating about $317,000, according to Federal Election Commission records analyzed by the Center for Responsive Politics, a nonpartisan nonprofit that tracks spending in US politics.

GEO Group donated $275,000 to a Trump-aligned super PAC and $250,000 to Trump's inaugural committee, according to FEC data. It also spent $1.7 million in lobbying last year, including $550,000 through Ballard Partners, a firm run by former Trump campaign Florida finance chair Brian Ballard.

GEO Group's spokesman, Paez, said in an email response that "we do not take a position on, or advocate for or against, criminal justice, sentencing, immigration enforcement or detention policies."

Within weeks of Trump's inauguration, a White House memo to Homeland Security leaked, describing plans to nearly double immigration detention housing to handle more than 80,000 people a night, as first reported by the Los Angeles Times.

The following month, newly appointed Attorney General Jeff Sessions rescinded the Yates memo. GEO Group's share price, which had fallen to as low as $13 the day the Yates memo was released, soared, climbing by late April to $34.12 a share. That month, GEO Group was awarded the first new immigration detention contract under the Trump administration, a 10-year agreement for a 1,000-bed facility in Conroe, Texas, expected to generate $44 million a year in revenues. In May 2017, the Bureau of Prisons awarded GEO Group a pair of 10-year contracts, expected to generate $66.4 million a year in revenues, to house immigrants convicted of crimes.

Today, GEO Group operates 141 prisons, detention centers and community re-entry facilities. In October, the company moved its annual leadership conference from Boca Raton, Florida, where it is headquartered, to the Trump National Doral, a Miami golf resort owned by the President.

'Voluntary work program'

One of the biggest points of conflict between GEO Group and the immigrants at Northwest Detention Center is over the "Voluntary Work Program," mandated by ICE, under which detainees do cleaning, laundry, kitchen and other jobs.

GEO Group is fighting two lawsuits in federal court -- one filed by the state of Washington -- that accuse it of violating labor laws by paying a dollar a day or less, regardless of how many hours they work, to detained migrants whose labor is essential to keep the Northwest Detention Center running.

According to the Washington attorney general's office, at the Northwest Detention Center, "Detainees described working through the night buffing floors and painting walls in exchange for chips and candy."

Similar suits target four other detention centers run by GEO Group or another private-prison operator.

One suit, against a GEO Group facility in Colorado, noted that the company employed only one janitor on staff there, relying on its captive migrant workers to do almost all the work.

Based on court filings and its 2015 ICE contract, GEO Group appears to save at least $10 million a year at its Tacoma facility through the work program, compared to paying standard wages. Currently, it is reimbursed by ICE for the dollar a day it pays each immigrant detainee worker.

GEO Group's emailed response to an interview request stated that the wage rates for the "Voluntary Work Program" are stipulated under guidelines set by Congress and detention standards for all ICE detention facilities and that, as a federal contractor, GEO is required to abide by those standards.

The company argued in court papers that the work opportunities were strictly voluntary and that GEO "incurred costs and expenses" for caring for the detainees in the program.

In practice, ICE detention facilities operate with little oversight or accountability, according to Homeland Security's Office of Inspector General. In a June 26 report , it concluded that inspections and on-site monitoring by ICE and its contractors don't ensure that facilities actually comply with federal detention standards or correct problems.

"Moreover, ICE does not adequately follow up on identified deficiencies or consistently hold facilities accountable for correcting them," the OIG report said. "Even well documented deficiencies that facilities commit to fixing routinely remain uncorrected for years."

It cited examples of inspectors contracted by ICE submitting false information that made detention facilities look like they were following regulations when they weren't.

The inspector general found a slew of other problems that "include facilities failing to notify ICE about alleged or proven sexual assaults" and conducting strip searches with no reasonable suspicion.

In a letter responding to the report, ICE agreed with the findings and said it would take steps to improve inspections and oversight.

'A lot of the mothers are really confused'

At the Northwest Detention Center, R.M. had to wear a surgical mask on Monday to speak with her attorney as a precaution against spreading chickenpox, which she still had showed no signs of having contracted.

She and many other mothers anxiously await promised reunification with their children. "A lot of the mothers are really confused," about what is going on, Cortes Romero, the attorney, said.

Baron, the Northwest Immigrants Right Project executive director, said many parents have been held for weeks without getting asylum interviews or receiving any information about whether or when they'll see their children again.

R.M. got her interview with an asylum officer last week at the detention center, said Cortes Romero. She is scheduled for a court hearing on Wednesday to determine whether she should be released from custody.

She remains in solitary confinement.

This story was updated to reflect more explicitly that the federal government mandates the Voluntary Work Program at immigrant detention centers and determines the parameters under which it is run by contractors.

The article was previously updated to reflect additional comments from GEO Group received after publication and a statement from an ICE spokeswoman.