The Trump administration has laid off the entire staff of a $4.1 billion program that helps millions of low-income households pay for heat during the winter, unnerving state officials who are now wondering whether they will still receive millions of dollars in expected federal payments.

The roughly two dozen workers who ran the Low Income Home Energy Assistance Program were among 10,000 people fired as part of a dramatic restructuring of the Department of Health and Human Services, according to Mark Wolfe, executive director of the National Energy Assistance Directors Association.

He said several senior employees who oversee the program, which serves about 6.2 million households annually, told him they were locked out of their building after arriving to work Monday.

“The way they did it, there was no like warning,” he said.

On Thursday, 13 U.S. senators, including two Republicans, sent a letter to Health Secretary Robert F. Kennedy Jr. urging the administration to reverse its decision to cut the LIHEAP staff. They warned the terminations will undermine the agency’s ability to provide a “crucial lifeline” for low-income seniors and families.

The program had already delivered the bulk of its aid to the states for this fiscal year but had yet to distribute $378 million.

It also helps households pay for the cost of air conditioning during sweltering summer months.

When asked about the fate of LIHEAP and the outstanding payments, Emily Hilliard, deputy press secretary for HHS, said in a statement: “HHS will continue to comply with statutory requirements, and as a result of the reorganization, will be better positioned to execute on Congress’s statutory intent.”

Speaking about the broader overhaul of his agency, Kennedy has said it needs to be “recalibrated.”

Without any staff in place, states are questioning how and if they will get the rest of their money, especially for upcoming summer cooling programs.

“Will we receive our remaining funds? If we don’t, some states will not run their cooling programs this summer. They’ll scale them back,” Wolfe said.

State officials involved in distributing aid said they are concerned LIHEAP will collapse without federal support.

“Emails bounce back from people that we have worked with for many years, who are deeply knowledgeable of the program,” said Peter Hadler, deputy director of the Connecticut Department of Social Services, noting his state is still owed $8 million.

In Minnesota, where the northern part of the state received a foot of snow Wednesday, the state’s Department of Commerce predicted that by mid-April it will run out of money to help new applicants seeking help with heating and electric bills.

The state had been expecting an additional $12 million to $13 million in federal funding, already approved by Congress. Those funds would help more than 10,000 households pay their utility bills and prevent power shutoffs. About 130,000 Minnesota households receive assistance each year through LIHEAP.

“Winter is still happening in Minnesota. It snowed yesterday,” said Pete Wyckoff, deputy commissioner of energy resources at the department. “We do need that extra money to come through to get us through the rest of the winter season.”

Eligibility can differ by state, as well as the specific services provided. In general, the program assists families in covering utility bills or the cost of paying for home heating oil. It has received bipartisan congressional support for decades.

Sens. Susan Collins of Maine and Lisa Murkowski of Alaska were the two Republicans who signed on to the letter imploring Kennedy to reverse any staffing or funding cuts that would jeopardize the program.