A federal judge early Saturday blocked Elon Musk’s Department of Government Efficiency from accessing Treasury Department records that contain sensitive personal data such as Social Security and bank account numbers for millions of Americans.

President Donald Trump said Friday that billionaire Elon Musk and his tech team can access people’s Social Security numbers quite “easily,” an admission fueling Democrats’ efforts in Congress for new data protection legislation.

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.