Gov. Gavin Newsom on Thursday ordered all Californians to wear face coverings while in public or high-risk settings, including when shopping, taking public transit, or seeking medical care, after growing concerns that an increase in coronavirus cases has been caused by residents failing to voluntarily take that precaution.

Newsom’s order came a week after Orange County rescinded a requirement for residents to wear masks and as other counties across California were debating whether to join local jurisdictions that had mandated face coverings.

“Simply put, we are seeing too many people with faces uncovered — putting at risk the real progress we have made in fighting the disease,” Newsom said in a statement. “California’s strategy to restart the economy and get people back to work will only be successful if people act safely and follow health recommendations. That means wearing a face covering, washing your hands, and practicing physical distancing.”

Under state law, residents who violate the new requirement could be charged with a misdemeanor and potentially face a financial penalty, according to a representative for the Newsom administration. However, officials have shied away from enforcing other statewide coronavirus mandates with similar actions, choosing instead to encourage compliance and educate residents about the benefits of safeguards against spread of the virus.

State agencies such as the Division of Occupational Safety and Health, which enforces workplace safety requirements, could take action, an administration official said.

The masking requirement comes as California and Los Angeles County saw single-day highs in coronavirus cases Wednesday, a clear sign that the COVID-19 pandemic shows no signs of waning in the state. More than 5,300 COVID-19 deaths have been reported in California thus far, including more than 3,000 in L.A. County.

Until now, state public health officials had only recommended that Californians wear face coverings, which, if worn by someone with the virus, have been shown to decrease the chances of spreading COVID-19.

The state mandate exempts children 2 years old and younger, and people with a medical, mental health or developmental disability that prevents them from wearing a face covering. Restaurant customers are also exempt when eating and drinking, as are residents engaged in outdoor recreation as long as they are able to keep distance from others.

Face coverings also are not required for the hearing impaired, or those communicating with them, or for workers whose health may be put at risk or who may need to temporarily remove a mask to perform a task or service.

Masks must be worn by Californians in their workplaces when serving customers or any member of the public, by all food service workers, when walking through parking facilities and hallways at work, and when riding on elevators, according to the order. People who drive buses, taxis, ride-hailing vehicles or any other service that accepts passengers also must wear masks.

Newsom in mid-March issued the nation’s first stay-at-home order, arguing at the time that the restrictions were necessary to slow the spread of the virus. Since that time, the Democratic governor has made it clear that enforcing the order, as well as deciding when to ease the restrictions, is up to counties and cities to decide.

“This is a statewide requirement and flows from the same legal authority as all of the other state orders,” Kate Folmar, spokeswoman for the California Health and Human Services Agency, said of the mask requirement.

State Public Health Officer Dr. Sonia Angell said wearing face coverings is an effective way to decrease the spread of the coronavirus.

“As Californians venture into our communities more,” she said, “wearing face coverings is another important way we can help protect one another.”

A recent study from Germany found that masks reduced the daily growth rate of reported infections by around 40%. Another study, published recently in the Proceedings of the National Academy of Sciences, concluded that “wearing of face masks in public corresponds to the most effective means to prevent interhuman transmission.”

Dr. Shruti Gohil, associate medical director of epidemiology and infection prevention at UC Irvine, said face coverings, in addition to frequent hand washing, are helpful in reducing the spread of infection as communities reopen and physical distancing becomes less possible.

“In my opinion, if we want to reengage we have to put all of our energy into figuring out how to shave off every piece of risk that we can, reasonably, without crippling our society,” she said. “I do think it’s hard for the public to digest what the right steps are, and I think in a time of pandemic it is nice to have authorities steer the ship as stably as possible. I do think that perhaps the governor’s move allows for that at some level.”

Dr. Peter N. Bretan, president of the California Medical Assn., said Newsom’s order was a reminder that the “COVID-19 crisis is not over.”

“We hope this order will offer some support and protection for local public health officers who have been placed in untenable situations in counties across California, coming under attack for only trying to do what science tells us is necessary to protect public health,” Bretan said in a written statement.

California joins New York, Illinois, Michigan, Virginia, Massachusetts, Maine, Maryland, Delaware, Rhode Island and New Mexico in implementing a mandatory face-covering requirement, according to the National Governors Assn. The Sacramento Bee on Wednesday first reported that the Newsom administration was considering a statewide face-covering requirement.

Some Californians have openly rebelled against directives to wear face coverings, which they consider to be government overreach and an infringement on their personal freedom.

Last week, the Orange County public health officer resigned after weeks of verbal attacks, including a death threat, over her mandatory mask rules. Her replacement rescinded the rules amid intense pressure from the Board of Supervisors, and now the county only “strongly recommends” wearing masks in public settings.

Board of Supervisors Chairwoman Michelle Steel said she was surprised by the governor’s statewide mandate, noting that Orange County’s infection rate and hospitalization numbers are below the state thresholds for reopening. Steel had previously advocated for the county health officer to loosen the requirement that all residents wear masks when in public.

“A mandatory order was too strong,” she said. “I think our residents in Orange County are very smart. If they feel sick, they’re going to wear a mask. It doesn’t really have to be mandatory.”

Orange County Sheriff Don Barnes indicated that he believes it’s not the responsibility of law enforcement to ensure compliance with the state’s mask order. Instead, “it is each person’s responsibility to wear a face covering, and follow other recommended safeguards, in order to stop the spread of COVID-19,” he said.

“I expect that Orange County residents will continue to use common sense approaches for the benefit of their own health, as well as the collective health of other county residents,” he said in a statement. “We must do what is necessary to stop the transmission of COVID-19, enabling us to further open remaining businesses, places of recreation, and the hospitality industry.”

Officials in Riverside County, which previously rescinded a face-covering requirement, urged residents to follow the state’s new rules.

“Social distancing, washing our hands and wearing facial coverings are all simple measures that we can all abide by to protect ourselves and our fellow neighbors,” Riverside County Board of Supervisors Chairman V. Manuel Perez said in a statement. “I am happy that our governor has made this decision.”

Though he declined to comment specifically on Newsom’s mandate, saying officials hadn’t yet had time to review it in detail, San Bernardino County spokesman David Wert said “the county is a big believer in face coverings.”

“The county’s position has been that face coverings do reduce the risk of spreading the virus, and we have strongly recommended that everyone wear them when they go out in public, and we’ve provided incentives to businesses that require them,” he said.

Fresno and San Bernardino counties have also rescinded face-covering requirements due to public opposition.

Many of California’s other most populous counties, including Los Angeles, San Diego, Santa Clara, Alameda, Sacramento, Contra Costa, San Francisco, and San Mateo, require mask-wearing in public.