As many as 35 percent of enrollments in the Affordable Care Act, also known as “Obamacare,” might “not be legit,” according to the administrator of the Centers for Medicare & Medicaid Services (CMS), Dr. Mehmet Oz.

Oz laid out the eyebrow-raising projection during Tuesday’s White House press briefing while filling in for press secretary Karoline Leavitt, who is out on maternity leave.

When asked about expired Obamacare subsidies and whether there are any policy adjustments he would like to see, Oz emphasized that the number of people on Obamacare has more than doubled over the last decade.

“Let’s take a step back; 2015, ’16, ’17, ’18, 2020, there were nine million people on Obamacare, nine million. Today, it’s more than 20 million… What happened was we completely took the guardrails off, and I know this because I’m working in the agency that actually was told to take the guardrails off,” Oz said.

“Because there wasn’t an earnest desire to keep track of whether you were appropriately on it or not, but more importantly, just get the number to where we all feel good about ourselves, we had massive increases of people joining the program,” he added.

Oz then gave the estimate that more than one in three people are fraudulently on Obamacare.

We believe that 35 percent roughly, of the people that are using the Affordable Care Act, Obamacare exchanges—because they never used the program once, they’ve never filed a claim—may not be legit. And that actual number may translate to… five, six million people we could be paying premiums for because they don’t have to contribute anything, so they don’t even know they’re getting it. These are people who have Medicaid, and someone often a broker dishonestly enrolling them in Affordable Care Act, or they’re in two states at once getting full insurance paid for by us in multiple states at once, so we have evaluated these numbers. They’re extremely concerning.

Oz said that the federal government implemented a rule two weeks ago to target fraud in the ACA program.

“We had tried to do this when we first came into office; a court enjoined us, did not feel we followed appropriate… APA guidelines, government guidelines, and so we redid it, and now went back out again,” he said

“If you care about the ACA, then you’ll want us to take the fraud out,” he added.

His comments come as CMS has been a key agency through which the Vice President J.D. Vance-led Task Force to Eliminate Fraud has waged its war on fraudsters.