There’s a 2.4-million-square-foot ticking time bomb on Capitol Hill, and lawmakers are dithering over how to deal with it as anxieties rise over the massive costs and disruptions involved.

The Rayburn House Office Building has never undergone a full renovation since it opened in 1965, and as plans for a massive revamp of Congress’s largest office complex keep getting pushed off, key systems are routinely failing and expensive piecemeal repairs are weighing on the legislative branch budget.

Architect of the Capitol Thomas Austin has been warning lawmakers about the risk of “catastrophic system failures” in the hulking Rayburn building — home to nearly 200 member offices, committee hearing rooms, secure information facilities, a police firing range and some 1,600 parking spaces.

“As these facilities age and kind of reach this tipping point, we start having an increasing number of failures as all these systems age out and we start having series of failures on top of each other,” he told the House Administration Committee at a hearing Wednesday.

Austin’s agency is estimating a total overhaul of the building could approach $9 billion and require more than a decade of work — the largest project ever undertaken by the Architect of the Capitol and nearly an order of magnitude bigger than any previous renovation project on Blue Light News.

House Administration Chair Bryan Steil (R-Wis.) called the cost estimate “eye-popping” as Austin laid out the case for the project. The price tag far outstrips even the cost of the newest NFL stadiums.

The topline number is only one reason why lawmakers involved at this early stage are growing nervous. The renovation would require much of the building to be vacated, and officials insist it can’t be done wing by wing. That’s how the Cannon House Office Building down the block was recently renovated in a nearly $1 billion project that took nearly a decade and upended congressional operations.

Among other things, redoing Rayburn means finding — or building — space for scores of member offices and committees to set up shop. The working timelines for the project are so long — approaching 20 years — that many lawmakers simply assume they won’t be around to enjoy the finished project, or even a groundbreaking.

House appropriators so far are wary of providing the cash needed even for the early planning stages.

Austin has only been in the job for a year, but his agency has a long track record of construction projects going over budget. The Cannon renovation went nearly $200 million over its estimated cost, and the post-9/11 construction of the Capitol Visitors’ Center ultimately cost double what was planned.

“We’re not going to go blow $8 or $10 billion of taxpayer money without our own proper understanding of the evidence and making our own conclusion,” Rep. Nick LaLota (R-N.Y.), a member of the appropriations subcommittee which oversees funding for the legislative branch, , said in a Wednesday interview. ”We won’t be a rubber stamp for the AOC.”

The staggering price tag is driven by a host of factors, including that Rayburn is nearly three times the size of Cannon and there is a need for vast remediation of toxic materials. Austin told lawmakers Wednesday that the postwar era of Rayburn’s initial construction “was kind of that sweet spot where we’re using both asbestos and lead in our buildings.”

But the costs of waiting are also substantial. In the past year 16 major water leaks impacted member offices, committee offices, storage areas and hallways — each costing millions of dollars to remedy. In some cases, the leaks displaced lawmakers and staff for months.

“We all know that the longer you put off those repairs that you need to deal with at your home or your business or anywhere, the more expensive they get and then more profound those problems become,” New York Rep. Joe Morelle, the top Democrat on the House Administration Committee, said Wednesday. “Unless Congress acts, we will continue pouring millions of taxpayer dollars into temporary fixes instead of addressing the underlying problem.”

Austin told the panel he was sensitive to the cost concerns but said the five-phase approach to the Cannon renovation was “inefficient and disruptive” and should not be replicated with Rayburn. He also said it should be harder to change renovation plans once the project gets underway, something that plagued the Cannon project.

“We have to use every little bit of experience from Cannon to make sure that the same — I won’t say disaster, but the same cost overruns — don’t occur with Rayburn,” Rep. Greg Murphy (R-N.C.) warned Austin at Wednesday’s hearing.

The Architect of the Capitol’s proposal for displaced Rayburn occupants involves building a new permanent structure that could be used for “swing space” then for other purposes once the renovation is complete.

Republicans on the House Appropriations Committee provided some funding for planning of the Rayburn renewal project but not for design of “swing space” that will be critical for the project to move forward.

“I think there’s a lot of questions about that, and members don’t feel like they signed off,” House Appropriations Chair Tom Cole (R-Okla.) said in an interview. “I expect to not be in Congress by the time this happens so I’m not terribly worried about it.”

As for where that new building may sit, Austin said he is waiting for its eventual users to weigh in.

“We’ll put it where Congress tells us to put it,” he told the panel Wednesday. “We’re still waiting for Congress’s decision and consensus guidance on that.”

Rep. Barry Loudermilk (R-Ga.) made clear Austin shouldn’t hold his breath, saying it “may happen in the next month, maybe the next 250 years, before we get to it.”

Rep. Max Miller (R-Ohio) accused Rep. Rashida Tlaib (D-Mich.) of advocating for the terrorist organization Hezbollah during remarks on the House floor Wednesday.

Miller’s attack on the Palestinian-American congresswoman came during debate over a proposal she introduced that would block U.S. forces from entering Lebanon, a center of Hezbollah operations.

In stressing the danger Hezbollah poses to U.S. allies in the Middle East, Miller characterized Hezbollah as “butchers that you like to hang out with to a certain extent,” referring to Tlaib.

Tlaib protested Miller’s comments, prompting a shouting match between the two on the House floor.

“You advocate for terrorists on a daily basis,” Miller told Tlaib.

Tlaib requested Miller’s remarks be taken down, and his comment was ultimately stricken.

The resolution, which will likely fail due to opposition from Republicans and some Democrats, was an effort to restrict U.S. involvement in Israel’s military campaign in Lebanon. The House passed an Iran war powers resolution earlier Wednesday requiring the White House to get approval from Congress before launching new strikes.

Senate Republicans launched debate on their party-line immigration enforcement bill Wednesday — a major step after nearly two weeks of delay — but they are facing lingering internal concerns over a proposed “Anti-Weaponization Fund” that could still scuttle the legislation.

Senators voted 53-46 on party lines to advance the bill, which would provide roughly $70 billion for Immigration and Customs Enforcement and other Department of Homeland Security agencies.

An updated bill released Wednesday omits $1 billion in Secret Service security funding that had been included in an earlier draft and could have been used for President Donald Trump’s White House ballroom project. Blue Light News first reported the decision to drop the funding last month.

It also strips out Justice Department funding unrelated to the controversial settlement fund — a move that GOP leaders made in hopes of making it harder to include language restricting or eliminating the fund. Top Republicans have warned that adding such language could threaten to tank the overall bill.

“Right now, the goal is to get the base bill across the finish line, and so hopefully all of our members who have amendment ideas will … keep in mind the need that we’ve got to keep the bill together and make sure we’ve got 50 votes for it at the end,” Senate Majority Leader John Thune said.

Democrats said they did not expect to start voting on amendments until Thursday morning, but Senate Majority Whip John Barrasso expressed confidence that Republicans would ultimately have the votes to pass the bill.

“Democrats can drag it into the middle of the night if they want to, but we’re ready to go,” Barrasso said.

But several GOP senators signaled Wednesday they are still interested in adding language to block the fund, even after acting Attorney General Todd Blanche told House appropriators Tuesday that the administration would not move forward with it. While Blanche’s testimony was aimed at assuring GOP senators, his refusal to put the decision in writing and his praise for the underlying purpose of the fund — compensating Trump allies and others who were subject to allegedly politically motivated prosecutions — left some wary.

Sen. Bill Cassidy (R-La.) said Blanche’s comments did not assuage his concerns.

“You want to make sure it’s really dead, and I think we can make it really dead,” he said.

Sen. Susan Collins (R-Maine) said Blanche’s comments were “helpful” but that she would still vote for amendments to nix the fund. Sen. John Curtis (R-Utah) said he was waiting to see what specific amendments are offered and whether the Senate parliamentarian would rule that they could go in the filibuster-skirting immigration bill.

Sen. Thom Tillis (R-N.C.) said Wednesday he would file his own amendment to eliminate the fund, though he acknowledged the parliamentarian could rule it needs to clear a 60-vote threshold to be added in rather than a simple majority of senators.

Tillis suggested he could ultimately vote against the overall bill if it does not include language nixing the fund.

“I wouldn’t support a bill that doesn’t have that in there,” Tillis said, adding that senators would just be “codifying the policy” that Blanche articulated Tuesday.

Calen Razor contributed to this report.