It is an unfair labor practice for an employer:
(1) To interfere with, restrain or coerce employees in the exercise of the rights guaranteed in ORS 663.110;
(2) To dominate or interfere with the formation or administration of any labor organization or contribute financial or other support to it. However, subject to rules published by the Employment Relations Board pursuant to ORS chapter 183, an employer may permit employees to confer with the employer during working hours without loss of time or pay;
(3) To discharge or otherwise discriminate against an employee because the employee has filed charges or given testimony under this chapter; or
(4) To refuse to bargain collectively with the employees’ exclusive representative, as defined in ORS 663.015.