LANSING, Mich. (AP) — Gov. Gretchen Whitmer on Friday toughened a requirement to wear masks during the coronavirus pandemic, mandating that businesses open to the public deny service or entry to customers who refuse to wear one.

The governor also expanded where people must have a face covering beyond indoor public spaces. Starting immediately, they have to wear one outdoors if they cannot consistently keep 6 feet from non-household members, and while using public transportation, a taxi or a ride-sharing vehicle — with some exceptions.

Violators will now be subject to a misdemeanor fine.

“No shirts, no shoes, no mask — no service,” Whitmer wrote in an order.

Businesses must comply beginning Monday or risk losing their license. Five other states have imposed similar requirements on businesses, she said.

Face coverings reduce the chance of spreading COVID-19, Whitmer said. She pointed to “stalled” progress in suppressing the virus — cases have risen again in Michigan — and contended that spotty compliance with her monthslong mask requirement is a “big part of the reason.”

“The heroes on the front lines of this crisis have gone hours without taking their masks off every day — doctors, nurses, child care workers, grocery store workers. We owe it to them to wear our masks when we’re on a trip to the grocery store or pharmacy,” the Democratic governor said in a statement.

There are exceptions for children under age 5 and, as before, people who cannot medically tolerate a mask. Those eating or drinking while seated at a restaurant remain exempt. So too are people exercising, officiating a religious service, communicating with the hearing-impaired, giving a speech, and police, firefighters and paramedics engaged in public safety work.

The temporary removal of a face covering is allowed when necessary to receive a service or for identification purposes. Child care centers and overnight camps are not considered public spaces under the order.

Michigan Retailers Association President and CEO Bill Hallan said the industry appreciates Whitmer’s efforts to increase mask wearing inside stores but expressed frustration “that she did not leave the policing to law enforcement officers. This puts retail employees in potentially dangerous situations when they’re forced to confront unmasked customers.”

He also said it is “impossible” for stores to determine the validity of “ambiguous” exemptions, such as when people say they cannot medically tolerate a face covering, and even retailers acting in good faith could face severe licensing sanctions based on the actions of noncompliant customers.

“When shopping, please wear a mask and understand that retailers are not to blame for the state’s mask requirement,” Hallan said.

Whitmer, who has acknowledged the difficulty of actually enforcing the mask requirement and businesses’ reluctance to turn away or confront customers, said Thursday that businesses were asking for tougher rules they could point to and say “this is the law of the land.”

Some local law enforcement agencies have refused to enforce other restrictions the governor ordered to curb the virus.