The Department of Government Efficiency is sifting through $1.6 trillion worth of Social Security payments — records that include a person’s name, birth date and how much they earn — in an anti-fraud effort that has advocates worried the Trump administration could start denying payments to vulnerable older Americans.

Details on the effort were confirmed in a recent letter to Congress by acting Social Security Administrator Lee Dudek and by several sources familiar with the project.

In addition to combing through sensitive data, DOGE staffers also have been inquiring about the Social Security Administration’s telephone service, sources told ABC News, which a significant portion of beneficiaries use to file initial claims. DOGE’s inquiries about the telephone service have raised concerns that it may be planning either to replace the telephone service with private call centers or eliminate it as an option for filing claims, sources said.

“Any American receiving Social Security benefits will continue to receive them. The sole mission of DOGE is to identify waste, fraud, and abuse only,” White House press secretary Karoline Leavitt said in a statement provided to ABC News on Friday.

President Donald Trump and Elon Musk both alluded to the anti-fraud project in recent public statements, claiming to have already found examples of rampant abuse.

“We’re also identifying shocking levels of incompetence and probable fraud in the Social Security program for our seniors,” Trump said in his speech to Congress on Tuesday.

Trump has promised not to cut the program unless evidence of fraud is found.

Details on the anti-fraud project though have been murky, including how DOGE staffers, who are mostly allies of Musk with no experience on complex government entitlement programs, would define what amounts to fraud, which is typically investigated by inspectors general at the agency.

The SSA did not respond to requests for comment.

“DOGE has repeatedly demonstrated a lack of understanding of what the data they are accessing actually means and whether it, in fact, represents fraud,” said Lynn Overmann, a senior adviser at the U.S. Digital Service during the Biden administration.

Overmann, the executive director of the Beeck Center for Social Impact + Innovation at Georgetown University, said she is worried wrongful fraud accusations will eliminate a crucial financial lifeline for the elderly, disabled people and children who have lost a parent.

“The public deserves strong privacy protections, not reckless data experiments with their most sensitive data,” Overmann said.

About 69 million people receive a Social Security benefit each month, totaling about $1.6 trillion in benefits expected this year, according to the agency.

Dudek, the acting Social Security administrator, has defended the effort in private communications as legal and necessary, several sources told ABC News. He said steps are being taken to protect privacy.

In a private meeting with outside groups last Tuesday, Dudek referred to DOGE staffers as “the DOGE kids” and said they would “make mistakes” but that “we have to let them see what is going on at SSA,” according to three people who attended the meeting.

Dudek said they were being given access to people’s names, birth dates and earnings information but not disability information. He also noted that the staffers were granted expedited background checks by the FBI and had been onboarded as agency employees.

“I saw what happened when DOGE had access to Treasury data,” Dudek said, according to one person’s detailed notes reviewed by ABC News. “That is not happening at SSA on my watch. It would be catastrophic.”

DOGE’s access to the Treasury Department’s payment system is tied up in the courts as outside groups insisted the staff hadn’t been properly vetted first and didn’t have authorization.

Dudek’s decision to grant DOGE access to his agency is now the subject of a separate lawsuit filed by unions and retirees.

In a Feb. 25 letter Dudek sent Sen. Ron Wyden, D-Ore., the acting SSA commissioner said the six people given access to the Social Security Administration’s master system, called the Enterprise Data Warehouse, were undergoing background checks.

He said one of them was a “special government employee” while the other were “detailees” from other federal agencies now assigned to his agency. Dudek did not name the employees granted access, citing safety concerns.

DOGE was created by Trump shortly after taking office as a way to cut government waste, and he put Musk in charge of delegating staff to the agencies.

Musk has put some of his top DOGE lieutenants at the agency, according to sources, including Ethan Shaotran, 22, who is internally listed as a “chief information officer” at the SSA and is a software engineer who specializes in artificial intelligence. He founded Spark, an AI scheduling assistant startup that received a $100,000 grant from OpenAI in 2024.

Other DOGE representatives listed as chief information officers at the SSA include Gautier “Cole” Killian, 24, and Nikhil Rajpal, 30, sources told ABC News.

Marko Elez, is also listed as working at the SSA, sources said. Elez temporarily resigned from DOGE this year following reports of past racist social media posts but was reinstated by Musk after receiving support from Vice President J.D. Vance, among others. According to court documents, Elez was among those granted access to sensitive taxpayer information at the Treasury Department earlier this year.

It was not immediately clear if Shaotran, Killian, Rajpal and Elez were among those with access to the SSA system.

Dudek said that when it comes to the SSA system, DOGE staffers were granted “read-only” access to the vast Social Security system.

“The access for these individuals does not allow for the downloading, copying, transferring, or removing data from the agency,” he wrote in the letter to Wyden.

Concerns that DOGE might mistake legitimate payments as fraudulent was evident earlier this week when Trump declared in his speech to Congress that there were millions of dead people still collecting Social Security checks.

But that isn’t accurate.

According to a 2023 report by the SSA inspector general, there are millions of people older than 100 included in a separate “master death file,” but “almost none” of them still receive benefits. The agency said fixing the file would cost between $5 million and $10 million.