The last migrant child to be held at the Homestead facility for unaccompanied minors left on August 3 – but, since then, the U.S. government has likely spent more than $33 million to staff the massive, empty space.

The spending was revealed Wednesday during congressional testimony with Jonathan Hayes, director of the Office of Refugee Resettlement.

Hayes said Homestead remains staffed to support up to 1,200 children. "I think it's about $600" per day, Hayes estimated — a total of roughly $720,000 per day, or more than $33 million in the nearly seven weeks since it stopped sheltering children.

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"So $600 a day for 1,200 invisible, imaginary, nonexistent human beings at Homestead right now?" asked Wisconsin Democratic Representative Mark Pocan.

"It's the beds, but yes sir," Hayes replied.

Hayes explained that because the site is intended for use in case of a sudden influx of unaccompanied migrant children, his agency prefers to keep it staffed.

"What I was told by my planning and logistics team, the senior career professionals at ORR, you're looking at a minimum of 90 to 120 days in order to reactivate the staff back for that," Hayes said. "And again, given the extreme uncertainty of referrals coming across our nation's southern border, and how many kids we might have to care for, that wasn't a switch that was turned off at this point."

Hayes was speaking at a House Appropriations subcommittee hearing on the mental health needs of migrant children in custody, and two inspector general reports that found migrant children receive insufficient mental health care in government custody.

ORR currently has about 5,700 unaccompanied migrant children in custody. That is down from a high of about 16,000 in December 2018, a significant spike that accompanied a wave of migration from Central America and a policy change that increased the average duration of custody.

That policy change, implemented in June 2018 and discontinued in December, required fingerprint background checks of all household members of a relative seeking to sponsor a child in U.S. custody. Previously, only the sponsor was required to be fingerprinted. Officials have since said they do not believe it improved the vetting process for sponsor families.

Policies by the Trump administration — in particular, those that led families to be separated – received repeated criticism during Wednesday's hearing. They were implemented during the tenure of former White House Chief of Staff John Kelly, who in April joined the board of directors of the company that operates the Homestead facility, Caliburn International. That relationship, which was first reported by CBS News, was also criticized during the hearing.

"What troubles me deeply about Homestead is that this is a private contract with Caliburn International, where Secretary John Kelly sits on the board," said Congresswoman Katherine Clark, a Democrat from Massachusetts. "And they wrote in their SEC filings as they announced plans to go public 'border enforcement and immigration policy is driving significant growth for our company.' Significant growth at what cost to the human experience?"