The Chicago Teachers Union voted Tuesday night in favor of going to remote learning for the nation’s third-largest school district amid the COVID-19 surge, CBS Chicago reports.

Chicago Public Schools Chief Executive Officer Pedro Martinez said if the CTU voted for remote learning and not to return to classrooms, there would be no classes Wednesday.

Martinez said school buildings will be open and teachers, staff and students are welcome to come to classrooms – but classes will be called off.

“If they do take a vote to do a walkout tomorrow, I have to cancel classes,” Martinez said earlier Tuesday. “I am not closing the schools. The schools are going to be open. And so again, all staff will be welcome to come to school because we are going to have a plan for our families. I am not going to let our parents down.”

CPS officials asserted that a CTU vote to authorize teachers to work remotely beginning Wednesday would amount to an illegal strike.

The CTU told its teachers in a memo that January 18 will be the next day of in-person instruction, but CPS hasn’t yet addressed the plan beyond canceling classes Wednesday -– and Mayor Lori Lightfoot earlier said the union doesn’t get to make such a decision.

When a reporter asked late Tuesday whether CPS would go ahead and switch to remote learning if a CTU action had teachers not showing up to school for multiple days, Mayor Lightfoot said: “The CTU doesn’t make decisions about how our CPS system works. The CEO does. He’s the boss.”

The union said the vote in favor of remote-work-only was 73 percent.

In a statement, the CTU said in part that its members “understand the frustration that is felt by tonight’s decision, and assure our families that we will continue to work diligently, as we have for months, to encourage the mayor and her CPS leadership team to at last commit to enforceable safety protections centered on the well-being of our students, their families and our school communities.”

“A vote to stop reporting to work would cause profound harm to children’s learning and health and be another damaging blow to the well-being of our students and their families,” CPS added.

CTU President Jesse Sharkey said the “teachers are being put in the unfortunate situation where we are trying to keep people safe and we aren’t being given the tools to do so.”