At Federal Plaza in Lower Manhattan, the nation's busiest immigration court reopened Monday morning after the unprecedented 35-day government shutdown. Judges put on their black robes again, government attorneys wheeled shopping carts full of paperwork to courtrooms, and lawyers and clients attended their previously scheduled trials and procedural hearings.

But beneath the calm surface of a court getting back to business, many immigration attorneys said they were deeply concerned about the impact on clients whose hearings couldn't take place during the shutdown.

Attorney Sofia Dee said she had four clients whose trials were cancelled. "I have no idea what's going to happen with those," she said. When hearings are cancelled, judges reschedule them for their next available opening — which could mean another year or more, depending on the judge's calendar. New York's immigration court has a backlog of more than 105,000 cases and many judges aren't scheduling new hearings until 2022.

Dee described one client as a single dad from Ecuador who is trying to prevent the government from deporting him because of the impact it would have on his U.S.-citizen daughter. Dee said the 11-year-old girl has special needs and chronic asthma. "She's in the hospital at least once a year," she said. "So she would certainly suffer extreme hardship if she were to return to Ecuador."

Undocumented immigrants who have been in the U.S. for at least ten years and don't have a serious criminal record can request what's called "cancellation of removal" if their deportation would cause exceptional and extremely unusual hardship on a U.S.-citizen spouse or child. Dee said this client lives in Putnam County, has no criminal record and has been paying taxes for over a decade. He was counting on getting a green card after the court hearing that was scheduled for January 17th. Now he can’t until the case is resolved.

"He could've traveled, he could've not been looking over his shoulder all the time," she said.

On Long Island, Aaron Rivera Julka said he has a client from El Salvador with a similar situation whose hearing was canceled this month. He said the man has a 20-year-old U.S. citizen son with diabetes who depends on the father's financial support. "We're concerned that we're not going to be able to get the case heard before the child turns 21 and is no longer a qualifying relative," he said.

The research group TRAC at Syracuse University estimates more than 86,000 immigration hearings nationally may have been cancelled during the shutdown — as many as 10,000 cases in New York alone. California, New York and New Jersey were among the five states most affected. One New York judge who came back to work on Monday, called it "a disaster" for the court’s backlog. The individual asked not to be quoted because judges are not allowed to speak to the press.

The Executive Office for Immigration Review, which runs the courts, said trials that did not go forward due to the shutdown “will be rescheduled for the soonest date available.”

New York’s immigration judges have extremely busy calendars. On Monday, some had 70 or more cases scheduled for “master calendars,” procedural sessions when immigrants and their lawyers file motions before they get to the trial stage. This is normal. Support staff worked over the weekend with overtime to get the cases ready, according to New York immigration judge Amiena Khan, executive vice president of the National Association of Immigration Judges, speaking in her capacity as a union representative.

But things weren’t as calm in Los Angeles. Union president Ashley Tabaddor, who is based in L.A., said all hearings except for trials there had to be cancelled when the court reopened on Monday. "Our clerks could not be expected to pull the files for hundreds of cases in time for court," she explained. She said she also heard some cases were adjourned because no interpreters had been requested in advance.

Because of the shutdown, the union wants the Department of Justice to halt a quota system it began in October for immigration judges, who work for the agency. Each must complete 700 cases a year to get a satisfactory performance rating. "They want the agency to suspend the application of the quotas and deadlines in light of the great disruption of the shutdown on our dockets and ability to work properly," Tabaddor said, of her fellow judges.

For asylum-seekers whose trials were canceled during the shutdown, the situation could be especially perilous. Attorney Inessa Spevakova described a client from Uzbekistan who is seeking political asylum. She said he's eager to win his case as soon as possible so he can bring his children to the U.S. They're in a "dangerous situation" she said because their family is known to the Uzbek authorities. But she doesn't know if the judge will be able to schedule a new hearing for him before 2020.

Some attorneys acknowledge there could be a bright side to these cancellations. A decision by former Attorney General Jeff Sessions made it harder for immigration judges to grant asylum to women fleeing domestic violence and victims of gangs, because he said these cases involved private criminals and not government actors. As employees of the Department of Justice, immigration judges are obliged to follow any precedent-setting rulings by the attorney general.

Dee said she had three clients from Central America with gang and domestic violence claims whose trials were cancelled by the shutdown. She said she hopes it takes a couple of years for them to be rescheduled because there might be a new president by then, with different immigration policies.

"It can't hurt," she said. "It can't be any worse than it is today."

Other immigrants whose lawyers considered their cases to be weak might also benefit from shutdown cancellations, if it allows them to collect more evidence or save money. Immigrants waiting for asylum hearings are allowed to work legally — one reason the Trump administration has criticized what it calls a “catch and release” policy at the border for migrants. The administration has noted that most migrants pass a credible fear test at the border, allowing them to spend years waiting for court hearings, even if their cases ultimately fail.

For more on this story, listen to Beth Fertig's WNYC segment.

Hearings for detained immigrants were not affected by the shutdown because they're considered the top priority. Those immigrants, who are held in jails in New Jersey and upstate New York, continued seeing judges at another federal court on Varick Street. Those hearings are usually done by video, unless there’s a technical glitch, because in-person hearings were canceled last June.

But two judges at Federal Plaza also saw detained immigrants on Monday, and they did it by person instead of by video. DocumentedNY reported that the move happened shortly before the shutdown and caught some lawyers off guard because they weren’t given enough notice to come to the new location and represent their clients.

Beth Fertig is a senior reporter covering courts and legal affairs at WNYC. You can follow her on Twitter at @bethfertig.