The Chicago Teachers Union on Wednesday took another big step toward a teacher walkout.
The union filed the required 10-day notice of a strike Wednesday afternoon as ongoing negotiations between the union and Chicago Public Schools have failed to reach common ground, NBC Chicago reports.
The notice means that teachers could leave their classrooms as early as the end of next week, the first week of school for the majority of CPS students.
A specific strike date -- which could come as early as Sept. 10 -- will likely be a matter of discussion at Thursday's meeting of the union's House of Delegates, the Chicago Sun-Times reports.
The filing of the strike notice doesn't necessarily mean a strike will actually take place. Should the union and the district make an agreement, a walkout will take place, but CTU President Karen Lewis told CBS Chicago Tuesday evening that the two sides still have a long way to go before reaching that point.
A CPS spokesperson said Tuesday that the city's students "can't afford to be removed from their classroom at a time when they're starting to make progress with the Full School Day."
"They belong in school with their teachers, which is why we need to stay at the table and keep negotiating," the statement reads, according to ABC Chicago.
The teachers union has been enmeshed in a months-long standoff with the school district and the city over stalled contract negotiations, and a longer school day they say was implemented without necessary input from teachers.
Last week, on the heels of the first crop of CPS students started classes, members and supporters of the CTU hit the streets outside the Board of Education building in demonstrations they dubbed "practice strikes."
CPS has budgeted about $25 million to spend on its contingency plan should a strike take place, according to the Tribune.
Meanwhile, Mayor Rahm Emanuel is rumored, according to a Chicago Sun-Times report, to be preparing to step up to the plate in an attempt to alleviate a teacher walkout himself. Emanuel deflected those rumors in a conversation with the paper and said "the parties are there" in the ongoing talks.
The last time Chicago teachers went on strike was in 1987.