A member of billionaire Elon Musk’s Department of Government Efficiency [DOGE] showed up to Internal Revenue Service headquarters on Thursday, drawing concern from critics who fear the agency’s involvement will complicate IRS operations, including the timeliness of tax refunds, during the busy tax season.

DOGE’s Gavin Kliger met with senior tax executives at the IRS’ Washington, D.C. offices to examine the agency’s operations, sources told multiple news outlets Thursday.

While there were few specifics about Kliger’s appearances at IRS headquarters, Reuters reported the visit “suggests that Musk, who President Donald Trump has tasked with cutting costs, waste and fraud across the federal government is now scrutinizing the IRS as part of that effort, even as the ongoing tax season squeezes its resources.”

Among Kliger’s requests to IRS officials, according to CNN, were “a description of what each business unit in the IRS does, what it’s looking to deliver on in the next 90 days and what risks each unit currently faces.”

Sen. Ron Wyden, D-Ore., said his office heard about DOGE’s IRS visit, suggesting the appearance raises concerns about the privacy of taxpayer data.

“That means Musk’s henchmen are in a position to dig through a trove of data about every taxpayer in America,” the senator tweeted Thursday afternoon. “And if your refund is delayed, they could very well be the reason.”

DOGE’s efforts to access Treasury Department records containing sensitive personal data for millions of Americans has been temporarily stalled by a New York federal judge, who set a hearing in the matter for Friday.

Musk’s Department of Government Efficiency was created to find and eliminate wasteful government spending. Its access to Treasury records and its inspection of government agencies has led critics to criticize Musk while his supporters praise the idea of reining in bloated government finances.

The Associated Press contributed to this report.