Californians will have to remain masked at work possibly through early next year — at least if they have unvaccinated colleagues, state regulators decided Thursday during a marathon meeting that elicited hours of heated debate.

The new rules require employees, even those who have been vaccinated, to continue wearing masks indoors if they are around other workers who have not received the COVID-19 vaccine. If everyone is vaccinated, the masks can come off. The mandate drew ire from employers worried about having to police their workers’ vaccination status and from employees sick of wearing masks — even as other workers applauded the rules or said they don’t go far enough to protect their safety.

The new rules add another layer of complexity to the state’s pandemic recovery as COVID-19 cases decline, vaccination rates increase and society continues to reopen. They force employers to pry into who has gotten a shot and who has not, yet leave unclear how employers should verify their workers’ vaccination status.

The Centers for Disease Control and Prevention last month declared it safe for fully vaccinated people to resume most activities, including eating indoors and gathering with friends, without wearing masks or social distancing. Gov. Gavin Newsom plans to fully reopen the state and drop most mask mandates June 15. But the state’s Division of Occupational Safety and Health, known as Cal/OSHA, isn’t ready to follow suit.

“The COVID-19 pandemic has had a devastating impact on workers, causing death, serious illness and in many cases, long term chronic illness,” said Cal/OSHA deputy chief Eric Berg, adding that while the situation has improved thanks to vaccines, it’s not yet safe to retire face masks, social distancing and other safety measures. “We cannot rely on vaccines alone to stop transmission of COVID-19 in the workplace,” he said.

The agency’s standards board initially voted Thursday to reject the new rules, citing confusion and complaints about the proposal. But after deciding the imperfect new rules are better than the current ones — which require all employees to wear masks even if everyone is vaccinated — the board passed the proposed rules in a second vote.

The new rules will go into effect June 15 and last until early next year, though the agency has the option to revise or repeal them sooner. The board also created a subcommittee to continue working on COVID-19 workplace rules.

“This could be better and it needs to be better,” said board Chair David Thomas. “But in the meantime, this will help.”

Newsom’s office weighed in on the board’s decision late Thursday night.

“The Occupational Safety and Health Standards Board is independent,” a spokeswoman for the governor’s office wrote in an emailed statement. “We appreciate the Board’s actions to maintain worker safety and are hopeful the Board will further revise its guidance to reflect the latest science while continuing to protect workers and balancing realistic and enforceable requirements for employers.”

About 100 people called into the virtual meeting Thursday, arguing for and against the workplace mask mandate and other safety rules. Employer groups squared off against worker representatives, while some callers questioned the science behind face masks, called the mask mandate “tyrannical” and said the rules would further divide the state. Others worried the rules would single out unvaccinated workers and lead to workplace hostility and discrimination.

Many callers urged Cal/OSHA to clarify how employers are supposed to verify their workers’ vaccination status. For example, what happens if an employee loses his or her vaccination card?

Starting this week, Santa Clara County requires all employers to record the vaccination status of their workers or pay fines of up to $5,000 per violation per day. Employers don’t have to report this data to the county, so officials could not say how many businesses have complied so far. People can report violations at scccovidconcerns.org, and the county will follow up, a county representative wrote in an email.

The board first considered the workplace rules last month but postponed its vote to give regulators time to consider the latest CDC guidelines.

Cal/OSHA made changes that “consider the latest scientific evidence,” Berg said. But workplaces present unique risk factors, as workers spend long periods of time together, potentially allowing for prolonged exposure to COVID-19, Berg said.

Gina Ma, who works in a biotech lab in San Diego, on Thursday urged Cal/OSHA to follow federal guidelines and toss the workplace mask rules.

“I am tired. I am tired of rebreathing my own CO2 for eight or more hours a day,” said Ma, who is vaccinated. “I am tired of hearing, ‘Wear a mask, save lives.’ I am tired of hearing about all of the great things I can do if I’m vaccinated but only if I don’t live in the great state of California.”

Katie Hansen, senior legislative director for the California Restaurant Association, pointed out the irony that restaurant workers would have to wear a mask all day at work but after their shift they could return to the same restaurant, maskless, and order dinner.

But vaccination rates vary widely across the state, as do employers’ willingness to keep their workers safe from COVID-19, said David Barber, deputy chief counsel at the California School Employees Association. That’s why it’s crucial to continue enforcing masking rules in the workplace, he said.

“The pandemic is not over, and a deadly, highly transmissible virus is still spreading in our communities,” Barber said.

Vaccinated workers will be allowed to take off their masks outside, while unvaccinated workers must keep them on if they can’t socially distance. And after July 31, employers are required to offer unvaccinated employees N95 masks or similar respirators.

“We’re in this niche right now where we feel really good about where we’re at, but we’re not done,” Thomas said. “And I don’t want to get overconfident. And I think this is a measured step in the right direction.”