643.080.  Investigations, when made — violation, how eliminated — hearing, procedure — final order, notice of. — 1.  The director shall investigate alleged violations of sections 643.010 to 643.355 or any rule promulgated hereunder or any term or condition of any permit and may cause to be made such other investigations as he shall deem advisable.  The department shall assume the costs of investigation of alleged violations.  The identity of the person who filed the complaint shall be made available consistent with chapter 610 and other provisions, as applicable.

  2.  If, in the opinion of the director, the investigation yields reasonable grounds to believe that a violation of sections 643.010 to 643.355 is occurring or has occurred, he shall refer such information to either or both the attorney general or the county prosecutor of the county where the violations are alleged to have occurred.

  3.  If, in the opinion of the director, the investigation discloses that a violation does exist which would not be a criminal violation, he may by conference, conciliation and persuasion endeavor to eliminate the violation.

  4.  In case of the failure by conference, conciliation and persuasion to correct or remedy any violation, the director may order abatement, suspend or revoke a permit, whichever action or actions the director deems appropriate.  The director shall cause to have issued and served upon the person a written notice of such order together with a copy of the order, which shall specify the provisions of sections 643.010 to 643.355 or the rule or the condition of the permit of which the person is alleged to be in violation, and a statement of the manner in, and the extent to which the person is alleged to be in violation.  Service may be made upon any person within or without the state by registered mail, return receipt requested.  Any person against whom the director issues an order may appeal the order to the commission within thirty days, and the appeal shall stay the enforcement of such order until final determination by the commission.  The commission shall set a hearing on a day not less than thirty days after the date of the request.  The commission may sustain, reverse, or modify the director's order, or make such other order as the commission deems appropriate under the circumstances.  If any order issued by the director is not appealed within the time herein provided, the order becomes final and may be enforced as provided in section 643.151.

  5.  When the commission schedules a matter for hearing, the petitioner on appeal may appear at the hearing in person or by counsel, and may make oral argument, offer testimony and evidence or cross-examine witnesses.

  6.  After due consideration of the record, or upon default in appearance of the petitioner on the return day specified in the notice given as provided in subsection 4 of this section, the commission shall issue and enter the final order, or make such final determination as it shall deem appropriate under the circumstances, and it shall immediately notify the petitioner or respondent thereof in writing by certified or registered mail.

  7.  Any final order or determination or other final action by the commission shall be approved in writing by at least four members of the commission.