Chicago Teachers Union President Karen Lewis is embraced by a teacher during an unexpected appearance at a rally of thousands of public school teachers Sept. 11, 2012, in Chicago. (Sitthixay Ditthavong/AP)

This story has been updated

The Chicago Teachers’ Union filed two complaints in federal court Wednesday trying to stop the city from closing 53 elementary schools, arguing that the closures disproportionately affect African American students and would also cause great harm to special education students.

The city’s board of education, appointed by Mayor Rahm Emanuel (D), is poised to vote on the closures May 22. If approved, the shutdown would be the largest mass school closing in any major U.S. city.

The country’s third largest school system, Chicago is facing a $1 billion budget shortfall. Declining enrollments have led to inefficient, half-empty schools where too much money has to be directed to maintenance and operations instead of classroom activities, officials said.

School officials say they will take the savings from the school closures and redirect them for the 2013-2014 school year to remaining schools that receive displaced students.

The first lawsuit filed Wednesday argues that the city is violating the American with Disabilities Act because the short time frame does not allow for an orderly, methodical transition to new schools for about 2,315 special education students who will be affected. The suit seeks a temporary injunction to delay the closures for one year.

“They made these decisions at the 11th hour without having in place an orderly process, supportive services, time that teachers need to prepare these children with special needs to move out of environments where they know their classmates and their neighborhoods,” said Tom Geoghegan, an attorney for the union, which filed both class-action lawsuits on behalf of parents. “There is simply not enough time to provide the kind of reasonable transition that this fragile population of students needs.”

The second complaint charges that the closings violate the ADA by harming thousands of special education students and also charges that the action is racially discriminating because 88 percent of the children who would have to transfer to new schools are African American, while African Americans make up 42 percent of all Chicago public schools students.

A spokeswoman for the Chicago Public Schools said the union was trying to protect “the status quo.”

“Too many children today are trapped in underutilized, under-resourced schools cheating them of the investments they need to succeed in the classroom,” said Becky Carroll of CPS. “Instead of offering up solutions, CTU continues to protect a status quo that doesn’t put our children first. Consolidating underutilized schools is necessary to give children the resources they need to access a quality, 21st century education.”

The union, which led teachers in a bitter, high-profile strike last year that disrupted school for seven days and ended with concessions from Emanuel, plans three days of protests over the school closings starting Saturday.