How do you file a grievance against a union steward of the UFCW for harment?

My Union steward constantly yells at the employees in my department, he does little work, he publically humiliates employees in front of customers etc. I would like to know how I would go about filing a strong complaint against him in order to stop this once and for all. I know that publically humiliating someone is prohibited under the Canadian Human Rights Act. Only Canadian answers please, and no spammed answers. Thanks.