The tenure of a person holding a position under the provisions of ORS 241.016 to 241.990 shall continue only during good behavior. Any person may be dismissed for any of the following causes:

1. (1) Incompetency, inefficiency or inattention to or dereliction of duty.
2. (2) Dishonesty, intemperance, immoral conduct, insubordination or discourteous treatment of the public or of fellow employees.
3. (3) Any other willful failure of good conduct tending to injure the public service.
4. (4) Any willful violation of the provisions of ORS 241.016 to 241.990 or the rules or regulations adopted pursuant thereto.