By Juan Perez Jr.

Hundreds of educators at Chicago's Acero charter schools walked off the job Tuesday morning, halting classes for 7,500 predominantly Latino students and launching the nation's first strike over a contract at the independently operated campuses.

Backed by affiliates at the Chicago Teachers Union, the charter network's teachers said they would not return to work after what they described as a series of fruitless negotiations with management.

"We're going to stay on strike until we get educational justice for the people who work in Acero charter schools," CTU President Jesse Sharkey said outside the charter network's empty Zizumbo elementary school campus as dozens of picketers settled in. "We're going to stay on strike until the students at Acero charter schools get the resources into their classrooms that they need to do their jobs."

The charter network cancelled all classes, athletics and extracurricular activities. School buildings will remain open with group activities supervised by nonunion staff members, though parents were encouraged to keep children at home or at nearby parks and community facilities.

Acero's chief executive blasted the walkout as the product of an "anti-charter political agenda."

"There is absolutely no good reason to put students and parents through the upheaval of a strike," CEO Richard Rodriguez said in a statement. "The sad fact is that interests from outside our community are using our students and our schools as a means to advance their national anti-charter platform."

Negotiations were set to continue later on Tuesday morning, Sharkey said. "We're going to keep negotiating until we get a contract, but we're also going to stay on the picket lines until we get fair treatment," he said.

Acero is the rebranded name of a 15-school network formerly known as the UNO Charter School Network. The charter management group split from its former umbrella organization, the United Neighborhood Organization, in 2013. While both sides landed a contract after a similar strike threat in 2016, there's been little word of movement in this year's negotiations.

The CTU has said key issues include reduced class sizes, maternity and paternity leave, a revamped teacher evaluation system and better pay. The union said they were also unable to secure commitments on special education services and guaranteed protections for undocumented students and families.

Tuesday's strike marks the CTU's latest move in a long effort to disrupt the charter school industry and flex its muscle ahead of expected contract negotiations for tens of thousands of educators at buildings directly operated by Chicago Public Schools.

"Whether it is a public charter, whether it is a public school, whether we are in West Virginia or in Chicago, teachers want and need a voice in order for us to assure that children get what they need," American Federation of Teachers President Randi Weingarten said as she joined the striking workers. "That is why we are walking out for our kids today."

Picketers planned to gather outside the charter management organization's headquarters later in the day.

"We have done the work, and management has not done their part. It is up to them to get their teachers back into classrooms," said Martha Baumgarten, an Acero teacher and bargaining team member. "They need to meet with us, they need to make fair deals, they need to make the right deals."

A Chicago Public Schools spokesman said the district was closely monitoring the situation, and urged both sides to come to an agreement that restarts classes as quickly as possible.

(c)2018 the Chicago Tribune