– The coronavirus pandemic is ravaging the U.S. Postal Service, with mail volume down by nearly a third already compared with same time last year and dropping quickly, as businesses drastically cut back on solicitations, advertisements and all kinds of letters that make up the bulk of the mail service’s bottom line.

The falloff comes even as package delivery has surged — but not by nearly enough to offset the losses from mail volume.

The result, the Postal Service told Congress on Thursday, is a multibillion-dollar financial shortfall that could cause one of the government’s oldest and most reliable entities to run out of cash by the end of September and throw regular delivery into doubt at a time when Americans may still be trapped at home.

Megan Brennan, the postmaster general, told lawmakers on the House Oversight and Reform Committee on Thursday that the agency believed it would need $25 billion in federal grants to cover lost revenue from the pandemic, plus an additional $25 billion to update aging infrastructure. Another $14 billion is needed to pay off long-term debt related to the Postal Service’s retirement benefits program along with $25 billion in unrestricted borrowing authority to weather the rapidly unfolding crisis, she said, according to officials familiar with the information she shared privately, who described it on condition of anonymity.

Even with an increase in online shopping and package delivery to Americans cooped up at home, the agency could see a 50% reduction in total mail volume by the end of June, compared with the same period last year, Brennan told lawmakers. Postal officials fear a sizable portion of that lost business may never return.

In total, the Postal Service anticipates losing $13 billion in revenue this fiscal year because of the pandemic and another $54 billion in losses over 10 years.

“They are chilling numbers,” said Rep. Gerald Connolly, D-Va., who leads the House subcommittee responsible for the Postal Service. “The reaction of a lot of my colleagues — their jaws were dropping. It is one thing to say the Postal Service is suffering. It is another to hear these specifics.”

As Congress spends trillions of dollars to try to save private businesses with loans and grants, the Postal Service has emerged as an unusual sticking point, bogged down by a long-running debate over its future. The agency does not normally use taxpayer money, but it has struggled in recent years under mounting debt.

House Democrats are ready to give the Postal Service most of what it is asking for. But President Donald Trump has so far rejected direct relief, repeatedly saying the Postal Service could solve its own woes simply by raising prices on packages delivered for big online retailers such as Amazon.

Steven Mnuchin, the Treasury secretary, squashed a bipartisan attempt to send the agency emergency funds last month, insisting instead that his department be given new authority to lend up to $10 billion to the Postal Service on terms it helps set, other officials familiar with the negotiations said.

Brennan told lawmakers Thursday that the agency was already in talks with the Treasury about the potential loan, but its revenue predictions suggest that money would not be enough if the crisis continues.

For now, the mail service, which operates under government-mandated service requirements, has continued uninterrupted. Even as scores of its more than 600,000 person workforce have fallen ill and some have died, mail sorters and carriers have continued to walk their routes in every corner of the country, in many cases the only physical lifeline Americans now have to the outside world. They deliver medicines, election ballots, coronavirus test kits and packages ordered online.

But the administration’s position has fanned fears among some lawmakers, postal union representatives and others who rely on the service that Trump administration officials are willing to let the postal network essentially go bankrupt to force its leaders to accept an overhaul to the postal business model that many conservatives have long sought — one that could limit delivery service and aid commercial competitors such as FedEx and UPS.

Negotiators on Capitol Hill had reached a tentative deal last month to provide the Postal Service around $13 billion in direct relief as part of the $2 trillion CARES Act.

But Mnuchin said the administration would not have it.

Connolly said Thursday that he would recommend House leadership promptly back the new, higher figures presented by the Postal Service. “We were just trying to get them through,” Connolly said. “The question is, will the Republicans join us?”