CHIAGO (CBS) — Chicago Teachers Union delegates voted unanimously Wednesday to schedule a date for a strike authorization vote.

The vote comes a day after the first day of school in the Chicago Public Schools – and the union complained about conditions on the first day in their announcement of the latest vote.

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The CTU said too many students either started their first day with substitute teachers or returned to oversized classes. The union said CPS is behind in hiring social workers and have school nurses only one day a week, while bringing in more than $1 billion in new annual revenue this year.

The union said CPS and Mayor Lori Lightfoot have expressed support for fixing the problems the union has highlighted, but has not put the commitments into writing with an enforceable contract.

Thus, the CTU’s rank-and-file delegates unanimously approved a strike authorization vote to be tallied Sept. 26. If a strike is authorized, the earliest it could happen is on or after Oct. 7, the CTU said.

A quote issued in a news release from CTU President Jesse Sharkey seemed to suggest that city schools do not get the same resources as schools in adjoining suburbs.

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“Our members can’t be bought – they are clear that their schools need the same things that students across Howard Street, Austin Boulevard and Cicero Avenue have,” Sharkey said in the news release. “Every one of our delegates voted today to send a clear signal to CPS and the Mayor that what’s been offered to date isn’t good enough.”

Last week, the Chicago Teachers Union rejected an independent fact finder’s contract recommendation, setting up a possible strike if they cannot reach a deal with CPS.

The recommendation that the union rejected involved an offer to boost pay checks – specifically a 16 percent pay increase over five years. Teachers are asking for more than money.

The fact finder’s also calls for a 1 percent increase in health care contributions. The raises recommended by the fact finder would cost approximately $351 million, according to the mayor’s office.

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If a strike did go ahead, it would be the first since 2012.