PITTSBURGH (AP) – An election to unionize graduate student workers at the University of Pittsburgh has been declared inconclusive due to dozens of contested ballots.

The Pennsylvania Labor Relations Board issued the ruling Friday after a preliminary vote count showed 675 votes favoring the union and 712 opposed.

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But the final result will be determined by 153 contested votes that haven’t been counted. Three ballots were challenged because the school said those people were no longer employed there, while the remaining contested ballots were cast by people not on a list of eligible voters.

A specific timetable for resolving the disputed ballots has not been disclosed.

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The election came after the labor board ruled last month that the hundreds of teaching assistants, teaching fellows, graduate assistants and graduate student researchers were employees.

The university argued they were students without the right to organize.

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