Several Congress members who recently toured a West Texas tent city housing roughly 2,700 young migrants asked that its contract not be renewed.

U.S. Rep. Beto O’Rourke, D-El Paso, and four other Democratic House members went through the facility at Tornillo, several miles southeast of El Paso, on Dec. 15. They said they were not allowed to speak with any of the children in any substantial way, and that the center’s contract, which expires Dec. 31, should be allowed to expire.

Rep. Will Hurd, R-San Antonio, whose district includes the Tornillo facility, also wants it shuttered.

Most Americans probably would agree. The shelter was opened in June to house up to 360 migrant children, most of them who arrived from Central America by themselves, for a month. The Trump administration’s “zero tolerance” immigration policy of criminal prosecution for all undocumented immigrants and consequent separation of children from their families swelled the ranks of children held at Tornillo and other facilities across the country into the thousands. It was expanded and the contract has been extended three times.

The growth has caused costs to balloon beyond original budgets; they could reach nearly $450 million.

But closing it and scattering the current residents to other, more permanent locations could create problems such as being able to track them all properly. The Department of Health and Human Services reported in April that the Office of Refugee Resettlement could not determine the whereabouts of 1,475 unaccompanied migrant children. The report was based on an effort to track unaccompanied minors in U.S. custody between October and December 2017.

A second survey conducted from April to June of this year found another 1,488 children were unaccounted for, a Senate committee revealed in September. It’s unknown how much duplication might exist between the two reports.

To be sure, the tent city’s change in function and rapid expansion created some problems. A recent Associated Press investigation found that staff at the tent city has grown to some 2,100, and none of them have gone through FBI background checks to ensure the children’s safety. The facility’s contractors have hired a private company to screen applicants, but the company doesn’t have the same access to criminal information as the FBI.

Facility staff reportedly don’t have enough mental health clinicians; federal policy calls for one clinician for every 12 children, while Tornillo might have one for every 100 residents.

And more permanent facilities don’t have room for 2,700 new residents.

At least at their present location the children are accounted for and interested parties can continue to monitor their well-being. Similar oversight must be assured before the teens are moved to other facilities. And with those facilities already at or near capacity it might be hard to assure that their whereabouts, much less their welfare, will always be known.

Until those assurances can be made, it might be best to leave these children where they are, where concerned advocates, lawmakers and others can keep an eye on them and their guardians.