After announcing its plan last week, the Nova Scotia government employees' union filed the paperwork on Thursday to formally begin its legal battle for Heather Vidito.
She was fired after a video posted on YouTube last week showed her repeatedly swearing as she stopped students from fighting on her bus.
Stock Transportation said Vidito's actions violated bus company policies and procedures, but the union contends firing is too severe.
Joan Jessome, president of the Nova Scotia General Employees Union, said it has had several discussions with Stock this week and she's hopeful they can reach a settlement without going to arbitration.
"We've had good conversations with the employer this week. So the employer has been willing to speak with us and meet with us. There's reason to believe… there might be a resolution at some point sooner than later," said Jessome.
A Facebook group also supporting her reinstatement has grown to almost 5,000 members.
There is also a fundraising drive to help Vidito pay some Christmas bills.
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