Teachers union rally in front of the Board of Ed and then marching to the Chicago Board of Trade Tuesday, Sep. 11, 2012.
Teachers union rally in front of the Board of Ed and then marching to the Chicago Board of Trade Tuesday, Sep. 11, 2012. (E. Jason Wambsgans, Chicago Tribune)

CHICAGO (Reuters) - The Chicago Teachers Union has sued the nation's third largest school district, saying Mayor Rahm Emanuel's campaign to reform or close underperforming public schools discriminates against African-American teachers and staff.

The federal lawsuit filed on Wednesday and announced on Thursday is the latest battle with the city since teachers staged a week-long strike in September. It alleges that more than half of the tenured teachers fired in the most recent round of school closings and turnarounds were African American.

But blacks make up less than 30 percent of the tenured teaching staff in the district and 35 percent of the tenuredteacher population in the failing schools, the lawsuit claims.

The suit in U.S. District Court for the Northern District of Illinois seeks an immediate moratorium on any additional school closings in the city.

The school district declined to comment on the lawsuit while it is pending, but said, "We have an obligation to expand high quality school options to all families and children in every neighborhood and turnarounds is just one tool that allows us to provide those options."

Emanuel, a former top White House adviser to President Barack Obama, and the school district are expected to close more schools in the coming years because of declining enrollment and a huge budget deficit.

The school district has until the end of March 2013 to say which schools it wants to close, and it has appointed acommission to study the matter.

The district's enrollment has fallen nearly 20 percent in the last decade, mainly because of population declines in poor neighborhoods. The district said it can accommodate 500,000 students, but only about 400,000 are enrolled. About 140 schools are half empty, according to the district.

The union argues that while the school district is closing existing neighborhood schools, primarily in minority neighborhoods, it is simultaneously approving new, mostly nonunion charter schools.

This fall, public teachers in Chicago staged the first strike against the district in 25 years to protest reforms supported by Emanuel, including teacher evaluations. The teachers were given a pay raise as part of the strike settlement.

The case, filed on behalf of three fired teachers, is Chicago Teachers Union, Terri Fells, Lillian Edmonds and Josephine Hamilton Perry v. Board of Education of the City of Chicago 12-cv-10338.