SACRAMENTO — California Gov. Gavin Newsom insists schools need to make their best attempt to open this fall, warning of the educational and social-emotional impacts of keeping kids out of the classroom.

He’s ordered a mountain of masks and other protective gear for schools to encourage safety amid a rash of new coronavirus outbreaks that have forced him to reinstate stay-at-home orders and shutter bars and restaurants that had barely reopened.

But the California Teachers Association, one of the largest and most powerful unions in the country, says it’s still worried. The union is insisting on prolonging distance learning instead of forcing its army of more than 300,000 educators back into schools.

“We hope we don’t have to go there, but if it comes to it, we do retain the right to refuse to work under unsafe conditions,” said David Fisher, president of the Sacramento City Teachers Association. “The virus is raging, and the circumstances that we were thinking we might be dealing with in September only a few weeks ago seem to be changing by the day. It just is looking increasingly unlikely that we will be able to teach in person at any level when schools first open.”

As President Donald Trump ramps up pressure on states to get kids back in the classroom — his education department going as far as threatening to cut aid to schools that don’t reopen — the standoff in the nation’s largest state underscores the difficult road ahead for governors and local leaders. Many are conflicted about what to do, citing the unknowns surrounding how children can spread the disease and the impact of a country without schools on the economy. But even for those who are finding a way to move toward reopening, like Newsom, one big question rises to the top: What will happen if teachers refuse?

Dozens of California teachers said in interviews they do not feel safe returning to classrooms any time soon and are trying to wrap their heads around Newsom’s messaging about stay-at-home orders and taking the virus seriously while also pushing schools to open as soon as possible. While Newsom has mandated masks statewide, K-12 students are not required to wear face coverings in schools — even as he calls school safety during the pandemic “nonnegotiable.“

Amy Sepulveda, a teacher in Fresno, lives with her 80-year-old grandmother and her father, who works at Avenal State Prison — the site of one of the state’s largest coronavirus outbreaks. She worries about both bringing the virus home and bringing it into her school. “Teachers and students are being treated as sacrificial, disposable human beings,” Sepulveda said.

About half of the state’s counties have been placed on a coronavirus watchlist in recent weeks due to an uptick in cases, putting 80 percent of California’s population on alert. Hospitalizations are rapidly increasing, with the state recording its highest single-day coronavirus death toll in recent days. There have been more than 6,800 coronavirus deaths in the state since February, according to the California Department of Public Health.

"So, we are told it’s not safe to be indoors around others except your immediate family even with a mask, and yet it’s somehow OK to be in an indoor classroom with AC and poor ventilation and kids with no masks?" said Richard Coleman, a San Diego area teacher.

Newsom, a Democrat who was praised for being among the first to shut down as Covid-19 cases began to climb in March, has proposed a hybrid approach to schooling that could include students alternating between physical and online learning. He dismissed Trump’s school funding threats, saying in a news conference, “I’m not worried about the latest tweets.”

But the governor, a father of four, has made it clear that in-person instruction is preferred. School districts in California “shall offer in-person instruction to the greatest extent possible,” according to new pandemic learning requirements outlined last month in state budget language. In April, Newsom even suggested that schools start in July to make up for the learning loss caused by Covid-19 shutdowns — a proposal quickly rebuffed by the state’s teachers unions.

“We put together statutory language in our budget that incentivizes the kind of learning that we think is more advantageous, which is in-person learning,” Newsom said at a news conference Wednesday, adding that flexibility will be allowed where there are safety concerns.

Teachers say that even a hybrid model puts people at risk, though. For schools that do choose to mandate strict protocols, teachers question their ability to enforce them, especially with younger children.

The California Teachers Association on Wednesday called for more school funding while the state grapples with budget cuts, and says districts do not have enough personal protective equipment, room to provide physical distancing or adequate ventilation and cleaning supplies to reopen. Teachers are also leery of a lack of data about childhood transmission of the virus and returning before there is a vaccine.

“We should be clear-eyed about this reality,” the union’s president, E. Toby Boyd, said in a statement. “How can we physically reopen schools with lower thresholds of safety than we currently have for restaurants or hair salons?”

And there’s no doubt that the union has power. CTA successfully negotiated a state budget deal last month that avoided deep education cuts initially proposed by Newsom and prevents school districts from laying off teachers and other staff.

“At the end of the day, teachers deciding not to go back will prevail. You can't force them,” said longtime education lobbyist Kevin Gordon. “It’s not a fight that school superintendents want to referee. What we really need is leadership from the state. They need to respond to the teachers and deal with this statewide instead of letting there be a shouting match at the local level.”

While Newsom has made it clear he wants schools open, and has offered up various guidelines for how districts can do that, he’s ultimately leaving it up to local leaders to decide how to teach kids this fall. Los Angeles County health authorities advised schools to continue learning from home, citing a surge in cases.

On Friday, the American Academy of Pediatrics, which had once urged school districts to reopen without delay, softened that stance, calling on public health agencies to be in charge of those decisions and saying science, not politics, should lead the way.

While local control is usually cherished among school leaders, especially in diverse California where a one-size-fits-all approach to anything is nearly impossible, parents and teachers alike have called on the state for clearer mandates on when and how to open schools.

Oakland Unified announced on Friday that it will begin its school year, slated to start August 10, completely online and slowly phase into blended learning. United Teachers Los Angeles, the union representing the country’s second-largest school district, made a similar demand.

“There is not enough time for the district to put together the detailed rigorous plans that must be in place to physically reopen our sites,” UTLA President Cecily Myart-Cruz said during a news conference Friday. “California is not there yet, not even close.”