The In-N-Out burger chain will prohibit employees in five states from wearing masks unless they've got a note from their doctor, according to internal company emails leaked to social media, Bloomberg reports.

Workers in Arizona, Colorado, Nevada, Texas and Utah are advised in the memo of "the importance of customer service and the ability to show our Associates' smiles and other facial features while considering the health and well-being of all individuals."

The policy, which will go into effect August 14, will apply to all In-N-Out employees in those states, unless their job duties require masks or other protective gear. If they fail to comply, employees could face disciplinary action, up to and including being fired.

As Bloomberg notes, California and Oregon - not on the list, have laws which prevent employers from banning masks.

And of course, pro-maskers, who can't cite peer-reviewed studies proving their efficacy - are having a conniption.

"Requiring a doctor’s note is also a burden in terms of time and money. Many people don’t have a primary care physician or one who is readily available," wrote infections disease specialist Dr. Judy Stone in Forbes. "And requiring proof of a disability might be considered a violation of the Americans with Disability Act, depending on how one interprets masking as a request for accommodation."

Stone also pointed to statistics from the Centers for Disease Control and Prevention — which notes that 6 in 10 adults have a chronic disease, increasing their risk for severe COVID-19.

In-N-Out workers in California and Oregon also have new mask guidelines set to go into effect August 14, according to a separate leaked company memo. But in contrast to the other states, California and Oregon employees will still be able to choose to wear a mask in stores. -Bloomberg

The new masking guidelines are also subject to local health regulations.