The hospital refused to allow this and sent her home. Her future is unclear.

Weill Cornell told me in a statement that it issues “appropriate” P.P.E. and that it can’t allow doctors to bring their own “of unknown provenance and safety.” That’s a pretty patronizing way for hospital executives to treat professionals who are risking their lives.

In Chicago, a nurse, Lauri Mazurkiewicz, warned colleagues that standard face masks distributed by the hospital were not safe. She brought in her own higher grade N95 mask — and was fired by Northwestern Memorial Hospital. She is now suing the hospital, which declined to comment except to tell me that its practices are safe.

In Texas, my colleague Matt Richtel reported on an anesthesiologist, Dr. Henry Nikicicz, who in effect was suspended without pay because he wore a mask in public places in the hospital. The hospital relented after it was asked for comment.

Tension arises not only because of shortages of P.P.E. but also because of uncertainty about how much protection is optimal. No one knows. The Centers for Disease Control and Prevention have given conflicting advice, and other countries have varying standards. Singapore avoided infections with modest P.P.E., while Chinese doctors and nurses now use full-body coverings much more substantial than the protective clothing in America.

Meanwhile, American health workers see colleagues falling sick. At Weill Cornell, a former E.R. doctor is now fighting for her life on a ventilator.

“We’re seeing our fellow caregivers getting sick, and we’re stressed out,” said another Weill Cornell emergency room physician, who feared being fired if his name were published. “Within one morning, I saw a gastroenterologist, an internist, a nurse and a pulmonologist” — he was talking about his patients — “and you want to protect yourself.”

It’s baffling that the richest country in the history of the world fails so abysmally at protecting its health workers, especially when it had two months’ lead time. And for hospitals now to retaliate against health workers who try to protect themselves — ousting them just when they are most needed — is both unconscionable and idiotic.