Teachers at the District’s only unionized charter filed a federal labor complaint against their bosses Wednesday, six weeks after the charter network announced it would close its middle school campus.

The complaint, lodged with the National Labor Relations Board, is the latest clash between employees and management at Cesar Chavez Public Charter Schools, one of the District’s oldest and most prominent charter networks.

The network’s board announced unexpectedly in January that it would close Chavez Prep Middle in Columbia Heights at the end of the academic year amid dwindling enrollment. It also said it would merge its two high schools into a single campus. A second middle school will close in 2020 for low performance.

Chavez Prep Middle is the only one of the network’s four campuses with a union, which formed in June 2017 and is represented by the American Federation of Teachers.

The complaint alleges that the middle school’s closing is an act of retaliation against unionization efforts — a violation of federal labor laws.

The Chavez network’s board denies the allegations, saying it decided to close the school, which serves more than 200 students, because of a projected $5 million budget shortfall next year across all four of its campuses. School leaders say the closure would allow the school to continue operating its high school.

“The Prep building is half-empty and cannot be sustained as a Chavez school — union or no union,” Bethany Little, co-chair of the Chavez Schools Board of Trustees, said in a statement. “It is vitally important that Chavez Schools continue to serve students and families in the District of Columbia for many years to come.”

Other fights have been unfolding across the country between unions and charter schools, which are publicly funded and privately operated. In Los Angeles, teachers went on strike last month and used it as an opportunity to bring attention to what the union viewed as charter schools draining resources from the traditional public school system.

In the District, the city’s charter regulating board is debating how much access the public should have to data and information from charter schools. Charters in the District are not subject to the same freedom of information and open-meeting laws as traditional public schools.

The battle at Chavez Prep Middle could test whether unionized charter school employees are given the same protections as teachers in the traditional public school system, who are unionized. In the District’s traditional public school system, closing schools is a last resort and city regulations call on leaders to engage the public before any decisions are made — a process that has come under fire in the past.

“Chavez Schools has become Exhibit A in how unregulated charters routinely ignore the transparency and accountability that public schools are bound to uphold,” Randi Weingarten, president of the American Federation of Teachers, said in an email. “We are asking that management respect both the law and the educators who have worked so hard to give their kids a shot at a better life.”

The union complaint also names TenSquare, a consulting firm that has been a flash point between the union and school leaders. The charter network said it hired the firm to boost lagging performance of students, though the union says the consultants have come at the expense of core classroom positions.

The Chavez network has a four-year, $5.3 million contract with TenSquare, according to Chavez leaders. The annual budget at the four schools combined was more than $26 million last year. School leaders have publicly stated that the money awarded to TenSquare was not a factor in the decision to close the school.

The 30-member union and Chavez network operators have been unable to negotiate a contract. Such labor impasses are not uncommon: Teachers in the traditional public school system went without a contract for five years until they reached an agreement with city leaders in 2017.

But teachers at Chavez allege that even without a collective contract, school leaders have not been following federal labor policies, including bargaining with the union as they determine what would happen to employees once the school closes.

The school provided information to employees about how they could apply to transfer to another Chavez campus, according to teachers, but the union says that those procedures should have been negotiated.

Jennie Tomlinson, Chavez Prep Middle’s librarian and technology coordinator, said staff and families were shocked when they learned about the closure. The union, she said, should have been included in discussions.

“We honestly felt that the board intentionally kept us in the dark throughout the process,” Tomlinson said. “It seems they were talking to everyone else except for the people who work in the building and the families who choose to send their children there.”

The National Labor Relations Board has three other open complaints that the union filed against Chavez, though no rulings have been made yet. The board had found merit to allegations that Chavez school administrators had made changes to the workplace without negotiating with the teachers.