WASHINGTON — The Social Security Administration’s internal watchdog is investigating a whistleblower complaint into what it describes as a former Department of Government Efficiency worker’s potential misuse of data obtained from the Social Security Administration.

According to a document the Associated Press obtained Wednesday, the SSA’s inspector general informed the leadership of four congressional committees that it was launching the probe after receiving an anonymous complaint.

The Washington Post on Tuesday reported that a former DOGE software engineer had allegedly told several co-workers that he possessed two tightly restricted databases of U.S. citizens’ information and had at least one data set on a thumb drive that he would share with his new employer.

The SSA said the allegations have been refuted by the agency, the former employee, and the company.

Senate Finance Committee Ranking Member Ron Wyden, D-Ore., said in a statement that the allegations, if true, would represent “one of the largest known data breaches in American history” and called for a “full public accounting.”

The Social Security Administration maintains records on hundreds of millions of people — including health diagnoses, income, banking information, familial relationships and personal biographic data.

The agency has faced lawsuits over alleged mishandling of government data and DOGE’s access to sensitive personal information.

Last August, whistleblower Charles Borges, who worked as the chief data officer at the Social Security Administration filed a disclosure to the special counsel’s office, stating that more than 300 million Americans’ Social Security data was put at risk after DOGE officials uploaded sensitive information to a cloud account not subject to oversight.

In January, the Trump administration admitted in court that DOGE workers had unauthorized access to sensitive SSA data, shared SSA data using an unapproved third-party service, and engaged in activities outside the scope of SSA’s mission, including signing a “voter data agreement” with a political advocacy group.

That litigation is ongoing.