The tenure of a person holding a position of employment under the Civil Service Act shall be only during good behavior. Any such person may be removed or discharged, suspended with or without pay, demoted, reduced in rank, or deprived of vacation, benefits, compensation, or other privileges, except pension benefits, for any of the following reasons:
(1) Incompetency, inefficiency, or inattention to or dereliction of duty;
(2) Dishonesty, prejudicial conduct, immoral conduct, insubordination, discourteous treatment of the public or a fellow employee, any act of omission or commission tending to injure the public service, any willful failure on the part of the employee to properly conduct himself or herself, or any willful violation of the Civil Service Act or the rules and regulations adopted pursuant to such act;
(3) Mental or physical unfitness for the position which the employee holds;
(4) Drunkenness or the use of intoxicating liquors, narcotics, or any other habit-forming drug, liquid, or preparation to such an extent that the use interferes with the efficiency or mental or physical fitness of the employee or precludes the employee from properly performing the functions and duties of his or her position;
(5) Conviction of a felony or misdemeanor tending to injure the employee's ability to effectively perform the duties of his or her position; or
(6) Any other act or failure to act which, in the judgment of the civil service commissioners, is sufficient to show the offender to be an unsuitable and unfit person to be employed in the public service.