The ballooning costs have also prompted officials to prepare to shift more than $200 million from other HHS accounts, even as the White House weighs a request for additional funding for the Department of Homeland Security — a politically explosive move almost certain to antagonize fiscal hawks in the run-up to the midterm elections.

“We have a public health emergency like Ebola, Zika, hurricanes — except this one is man-made,” said Emily Holubowich, executive director of the Coalition for Health Funding, who says HHS should request emergency funding too. “We should not be taking discretionary funding away from programs that need it.”

HHS didn’t respond to questions about spending on the crisis.

Frustration over the lack of transparency and the slow pace of family reunifications spilled over as appropriators marked up a Labor-HHS-Education funding bill last week. Republicans joined Democrats to unanimously back penalties for the health department if it didn’t detail its efforts to reunite families.

“This is not a policy we should be pursuing,” said Rep. Tom Cole (R-Okla.), the Labor-HHS-Education subcommittee chairman, criticizing the administration’s plan to split families at the border.

“We have sent letters demanding answers with regards to the costs ... [and] we have received no answers from OMB or from HHS,” said Rep. Rosa DeLauro (D-Conn.), subcommittee ranking member. “The Trump administration is withholding information from the Congress.”

HHS Secretary Alex Azar last week extolled his department’s work to house and care for separated children, calling it “one of the great acts of American generosity and charity” in a CNN interview.

But the services haven’t come cheap. Simply housing more than 2,500 children separated by the Trump administration has cost more than $30 million in the past two months, say two individuals with knowledge of the refugee office’s operations.

One major spending driver is that HHS has been forced to use “influx shelters” — temporarily contracted facilities — because of the surge in migrant children separated from their parents. The cost to care for a child in an influx shelter is reportedly nearly $800 per child per night, more than triple the cost of standard shelters.

“We were forced to turn to influx shelters when there was no choice,” said Mark Greenberg, a senior fellow at the Migration Policy Institute who led the Administration for Children and Families from 2013 through 2015. “That’s really different from deciding to expand influx shelters because you’ve chosen to forcibly separate families.”

The frenzied effort to reunite families after a court order and Trump’s executive order halting separations has added considerable costs — particularly because HHS and DHS hadn’t prepared for the possibility of putting families back together and now have staff working overtime to meet the court‘s deadlines.

HHS spent $10 million to hire an additional 100 case managers and about 50 support staff to help handle children’s cases for the next two months. In addition, Azar’s decision to tap his emergency response team has added hundreds of thousands of dollars in spending by deploying public health workers and other specialized staff to the refugee centers.

More logistical spending looms: HHS needs to transport separated children to immigration centers where they’ll be reunited with their parents, although the agency is trying to control costs by grouping the children’s trips together.

HHS leadership has approved the spending, although it’s created deficits for the Administration for Children and Families, which oversees the refugee office.

The agency has dipped into nearly $200 million in funds that were initially steered to the refugee office in the waning days of the Obama administration, including at least $17 million in unspent funds on the Ryan White HIV/AIDS program.

The Obama administration was moving the funds because leaders were concerned about rising and unpredictable pressures at the border. “We faced costs because of unanticipated increases in rising children,” said Greenberg, the former ACF director. “Now the additional costs are being faced because the Trump administration decided to implement family separation — and they used the refugee shelters to facilitate it.”

Greenberg said he’s worried that shifting the funds inside ACF could put the division’s funding for other programs, including unemployment services and other supports for newly arrived refugees, at risk.

Health care advocates also said they’re frustrated the funds have been rapidly drained under the Trump administration’s new policies.

“If there’s leftover money from Ryan White, it should go to support programs for poor people with HIV and AIDS, not this outrageous separation policy,” Holubowich said.

She added that “public health agencies still aren’t where they need to be” after budget sequestration in 2010 and other recent cuts, pointing to a controversial decision this week to eliminate an HHS database on medical guidelines because officials said they couldn’t come up with $1.2 million in funding.

They’re also concerned the Trump administration — by forcibly separating thousands of children — may have created significant, costly health care problems that will linger for years.

HHS in June was preparing to transfer an additional $263 million to the refugee office’s unaccompanied children program, according to a draft letter from Azar to DeLauro and first obtained by Bloomberg. However, the letter was never sent and the transfer never made amid rising scrutiny of agency operations and overall spending. “We’re still so in the dark on what’s going on,” said a spokesperson for the Appropriations Committee Democrats.

Transferring funds within the health department will still be necessary, said two individuals with knowledge of the reunification effort.

The Trump administration also has been hashing out a possible supplemental funding request for Homeland Security, and any additional money would need sign-off from Congress. But that kind of funding package could be a treacherous move for GOP leaders ahead of the midterms.

Trump’s immigration policy aside, Republican leaders would need to convince fiscal hawks in both chambers to back the package — just months after approving a record $133 billion for disaster aid, none of which was offset.

Lawmakers could decide to buck Congress’ strict spending caps, though they’d likely run head first into a dispute with the White House budget office. Mick Mulvaney, who leads that agency, has already refused funding increases for any program beyond this year’s massive spending caps deal.

Sarah Ferris and Adam Cancryn contributed to this report.