The Federal Reserve’s inspector general has concluded that the central bank failed to effectively oversee a massive headquarters renovation, allowing costs to more than double without ever establishing a firm price ceiling.

The watchdog’s report, released Wednesday, identified a series of management missteps that contributed to a roughly $1 billion cost overrun on the renovation of the Fed’s two historic buildings on the National Mall in Washington.

The project was initially budgeted at $1.3 billion in 2020 and has since ballooned to approximately $2.4 billion, making it a lightning rod for political attacks from the White House.

The Office of Inspector General’s report stated: “Our review found that the Board has not effectively managed and executed its contract and repeatedly deviated from its cost-management provisions.”

Despite the damning management findings, the inspector general said it found no grounds for a criminal referral or administrative misconduct tied to the cost overruns.

The report noted that “at no point during our evaluation did we find reasonable grounds to believe that a violation of federal criminal law had occurred requiring a referral to the US attorney general.”

The IG also found that design elements such as marble, water features, and a garden terrace, which critics in the White House had seized upon, “did not materially contribute” to the cost overruns.

President Donald Trump had latched onto the renovation’s spiraling costs as a fresh focal point for his long-running campaign to oust former Fed Chair Jerome Powell and gain greater influence over monetary policy.

Trump visited the construction site last July, where Powell corrected Trump’s estimate of the project’s expected costs as the two stood in hard hats before television cameras.

The building project subsequently became the focus of a criminal investigation by Trump’s Justice Department into whether Powell had committed perjury during Senate testimony about the renovation, though that probe was dropped in April after a judge quashed subpoenas issued by Jeanine Pirro, the U.S. attorney for the District of Columbia.

Pirro said at the time she would await the outcome of the inspector general’s investigation before deciding whether to pursue further action.

Powell’s term as Fed chair ended in May, but he took the unusual step of remaining on the board as one of seven governors, with his term as governor lasting until January 2028.

Powell said earlier this year he would remain on the board at least until he was convinced Pirro’s investigation was concluded, and by keeping his seat he has prevented the Trump administration from filling another vacancy on the board.

Powell declined to comment on the inspector general’s report following its release Wednesday.

Trump wasted little time in seizing on the findings to renew his call for Powell’s resignation, writing on Truth Social: “He can’t manage a Building, and he certainly shouldn’t be allowed to manage his High Interest Rate Policy. And no, I do not want this Building named after President Donald J. Trump, ME!”

Republican Senator Tim Scott, who chairs the Senate Banking Committee, called the cost overruns “egregious” and promised “rigorous oversight” of the Fed, adding: “Inflation does not change the Fed’s responsibility to manage its resources prudently and be accountable to Congress.”

Democratic Senator Elizabeth Warren, the committee’s ranking member, countered that the report showed “no basis to restart the president’s witch hunt” against Powell.

New Fed Chairman Kevin Warsh, who succeeded Powell in May, said he would follow the inspector general’s recommendations on project management and hire an independent auditor to “verify accuracy and compliance” of all awarded costs to date.

Trump is separately seeking to remove Fed Governor Lisa Cook over alleged wrongdoing in an unrelated matter, keeping pressure on the central bank’s leadership on multiple fronts.