The White House coronavirus task force on Sunday dangled new CDC guidance that might suggest some Americans with exposure to the 2019 novel coronavirus could return to work wearing a mask.

Vice President Pence on Sunday said the guidance “will make it possible for people that have been exposed to return to work more quickly with—by wearing a mask for a certain period of time.” He suggested it would be spelled out in more detail this week.

When asked about the potential guidance on Monday, Pence said it was still in the works, and might be targeted at a small subset of workers deemed critical.

“We're specifically looking at people that work in critical infrastructure—people in law enforcement, people in critical transportation,” he said. “The guidance we're looking for unpacking is how the people who may have come into contact with someone who tested positive for coronavirus, if they have no symptoms, [may] be able to return to work [and] wear a mask for a certain period of time.”

Pence said the proposed guidance would be before the president and possibly even before the public on Tuesday. But experts had already begun to blast Pence’s floated proposal as a dangerous one.

William Haseltine, president of the global health think tank ACCESS Health International, who recently chaired the U.S.-China Health Summit in Wuhan, called the potential guidance “deadly, deadly advice” as U.S. cases of the virus climbed to more than 40,000 infections and more than 500 deaths.

Most Americans have been told by federal agencies to avoid large gatherings—even if they have not been exposed to the deadly virus. Orders to stay inside except for essential needs like grocery runs and trips to the pharmacy have also been issued in a slew of states.

“That is so bad,” said Haseltine, of the prospect of the guidance. “If you want to really spread this infection like crazy, that’s what to do. It’s near insanity.”

“No health expert would have ever told them that, unless it’s a Trump sycophant,” continued Haseltine. “If you want to kill hundreds and thousands of Americans, he’s found a good way to do it.”

Pence’s idea, if it came to fruition, would also surely raise eyebrows considering the widely reported nationwide shortage of key supplies for medical professionals, including surgical masks. But even if there were enough to provide to every American who might be exposed, they aren’t a cure-all for contagiousness.

Masks aren’t perfect for preventing exposure, mainly because of user error, according to Dr. Jeffrey Klausner, an adjunct professor of epidemiology at the University of California Los Angeles who previously worked for the Centers for Disease Control and Prevention. He noted that someone who is infected and paying close attention may still, without thinking, touch their mouths or nose.

Klausner said “true exposure” should be met with a quarantine and then a test, for which access is improving “every single day.”

“That’s basic public health 101—that someone who has been exposed to a contagious disease be quarantined,” said Klausner. “That’s a much more scientifically rigorous approach.”

Still, it was clear from the briefing Monday the president remained fixated on the prospect of long-term damage to the economy. Just how that might impact future guidance from the nation's leading health authority remained to be seen.

“It would be much better and scientifically sound to test people before they return back to work, particularly if they’re in a work setting where they may come into close contact with other individuals,” said Klausner. “My concern with the masking is just that it’s not an evidence-based, scientifically sound approach.”