If the wrong person gained access to personal financial information held by the U.S. Treasury, it would constitute the biggest data breach in history.

News that Department of Government Efficiency led by Elon Musk now has access to a government payment system that is responsible for $6 trillion in annual federal payments — including Social Security and Medicare benefits — has prompted criticism from Democratic lawmakers and advocates.

Officials at Musk-led DOGE were given access to the inner workings of the Centers for Medicare and Medicaid Services (CMS), an agency with a $2 trillion budget.