Teachers at Chicago’s Acero Schools have voted to authorize a strike, according to operators of the charter school network and a Chicago Teachers Union charter division social media post.

An Instagram account attributed to the CTU’s charter division posted Wednesday that 93% of more than 500 members across the Acero network voted in favor of authorizing a strike. “It’s up to Acero management to avoid a strike by meeting our demands for Supportive, Safe and Sustainable schools. They must increase staffing to support our students and provide Equal Pay for Equal Work,” the post read.

The CTU, which represents the Acero employees, has not independently confirmed to the Tribune that a strike vote has been taken but has been engaged in contract negotiations with Acero officials for weeks. The nonprofit network of 15 schools serves more than 6,500 kindergarten through 12th grade students who are predominantly Latino, Spanish-speaking and economically disadvantaged.

The union rallied in April to demand better pay, on par with Chicago Public Schools educators in district-managed schools, and also was seeking more bilingual and special education resources and social supports for students.

Melina Perayri, a mother of two students at Acero’s Sandra Cisneros Elementary School in Brighton Park, said at the CTU rally that parents have petitioned Acero leaders for a full-time, in-person school nurse. “We have a virtual nurse — really?”

Acero parents have also commended the charter operator at recent Board of Education meetings. “Both of my children are excelling academically,” Patricia Alvarez, a mother of two students at Octavio Paz Elementary in Little Village told board members in April, calling Acero Schools “a second home.”

CTU charter division chair Jen Conant told board members that in the union’s negotiations with around dozen separate charter and contract school operators, “We’re demanding the staffing we need to meet the needs of our students. ... It is unconscionable that charter operators are not meeting required services for our most vulnerable students.”

In a CPS evaluation of the district’s agreements with charter and contract schools, presented in January, CPS deemed Acero’s operational performance and the services it provides diverse learners and bilingual students as not meeting district standards. In meeting standards for academic and financial performance and student discipline, CPS extended Acero a three-year renewal, through June 2026.

In a statement emailed by a spokesperson Thursday, Acero said it was “disappointed” by CTU’s strike authorization vote. “CTU has engaged in a pattern of bad-faith bargaining in these negotiations in violation of labor laws.” The charter school operator is reviewing legal options, according to the statement.

Acero said the bargaining teams reached a tentative agreement earlier this week on the most recent of 11 proposals the union and charter school operator have agreed upon thus far. “Acero Schools remains focused on the academic excellence and financial stability necessary to serve Acero’s scholars, families and colleagues first,” Acero said in the statement, adding that it will continue bargaining in good faith.

The charter school operator said CTU has sought to combine its negotiations with all charter schools into a unified contract, “erasing Acero’s unique identity” and accused the union of delaying negotiations.

Across the city, in Archer Heights, Avondale, Brighton Park, Gage Park, Galewood, Humboldt Park, Little Village, Pilsen and Rogers Park, Acero operates 12 elementary schools, two high schools and one K-12 school.

Acero teachers walked off the job in 2018 in what was the first strike at a charter school in the country.