At five small Chicago networks, 94 percent of teachers casting ballots this week voted to authorize a strike if needed, banding together to boost their bargaining power ahead of what could become the largest strike of teachers of multiple operators the city has seen so far.

The 134 educators work for four charter or contract-school operators but have common demands including wage hikes, increased student supports and sanctuary protections for their students. They could be joined later by teachers at other schools that are planning strike votes.

“Our teachers said yes to fully staffed classrooms … and being held accountable to provide services for our diverse learners,” Eralda Horton said at a press conference outside of her school, Instituto Health Science Career Academy, one of two Instituto del Progreso Latino high schools that took a strike authorization vote this week. “Our teachers said yes to your students and parents — we will fight for your kids, we will fight for you.”

Building on momentum from two successful strikes at charter networks, strike authorization proposals at two Instituto del Progreso Latino schools, the Chicago High School for the Arts, Latino Youth High School and Youth Connection Leadership Academy easily surpassed the majority needed to position teachers for a walkout if contract negotiations reach an impasse.

The educators are negotiating several contracts. All are asking for more money for special education, wage hikes, bilingual services and for contract language to include sanctuary protections.

“Our issues are the same and our interests are the same — student interest,” said Chicago Teachers Union charter division President Chris Baehrend. “Charter industry, your notice is served. We are going to change how you operate.”

Here’s a rundown of where teachers have voted in favor of authorizing a strike:

  • Chicago High School for the Arts, also known as ChiArts, is an an independently run school on the West Side that contracts with the school district. ChiArts is negotiating its first labor agreement. The 38 teachers in the union have a particular focus on asking management to pay into their pension fund.
  • The two Instituto del Progreso Latino high schools have 72 teachers. The network runs two high schools serving nearly 1,000 mostly Latino students on the Southwest Side. Both schools are bargaining on the same contract.
  • Youth Connection Leadership Academy, where 11 educators are union members, belongs to the Youth Connection Charter School network, which contracts with several entities to run its 19 charter schools around the state. Teachers argue that special education doesn’t receive enough funding, and that executive pay is too high.
  • Teachers Pilsen Wellness Center runs one high school, Latino Youth High School, with 13 unionized educators. The school is owned by Youth Connection Charter School. The union says management is asking for a longer school day and school year, and has refused demands for a wage hike.

José Ochoa, the executive director of ChiArts, said his administration was disappointed in the strike authorization vote and would do everything it could to avoid a walkout by its teachers.

“We believe much can be accomplished and resolved through additional dialogue and negotiations,” Ochoa said in a statement, noting that there were two upcoming mediation sessions in the next several weeks. “ChiArts is fully committed to working through the mediation process in hopes of achieving a fair and sustainable contract with our academic teachers whom we greatly value.”

A spokesperson representing the two Instituto schools took a slightly different approach in its statement on the vote, accusing staff of engaging in ballot tampering. “We are in the process of exploring our legal options to ensure that our teachers are fairly and legally represented and that we protect our students’ experience at our schools,” spokesperson Teri Argos said in a statement.

Instituto teachers vehemently denied ballot stuffing, saying that they had gone out of their way to keep a sign-in sheet to ensure the integrity of the process. “We were there and we have signatures,” said Gema Gaete, a teachers at Instituto Justice and Leadership Academy.

The strike vote comes as the political landscape for charter schools looks set to change under mayor-elect Lori Lightfoot, who promised on the campaign trail to freeze charter expansion, a dramatic departure from her predecessor Rahm Emanuel, who oversaw the opening of a parade of charter schools.

Meanwhile, the Chicago Teachers Union is urging its 21,000 members at district-run schools to put aside money in anticipation of a potential strike, part of a two-pronged strategy that the union hopes will change the education industry in Chicago at large. But bargaining will likely be stalled until Lightfoot makes a decision about whether to keep Janice Jackson as CEO.

Chicago has been at the forefront of the charter labor movement. It was home to the first-ever charter teachers strike, at Acero schools in December, and a second one at four Chicago International Charter Schools in February.

The five charter and contract schools announcing strike votes represent only a small portion of the charter networks currently in negotiations. Nearly all are either trying to reach agreement on a new contract or negotiating after previous contracts expired over the summer.