Oregon Revised Statutes Public Officers and Employees § 243.684

A petition for representation filed under ORS 243.682 (2) alleging that a majority of employees in the unit appropriate for the purpose of collective bargaining wish to be represented by a labor organization for that purpose must include a statement of a desire by the employees to be represented for the purpose of collective bargaining and must be signed and dated by 30 percent of the employees in the unit during the 180 days prior to the filing of the petition with the Employment Relations Board.