(1) The commission or the division may hold public hearings, which shall be held pursuant to and in conformity with article 4 of title 24, C.R.S., and with this article.

(2) The commission may adopt such rules and regulations governing procedures and hearings before the commission or division as may be necessary to assure that such procedures and hearings will be fair and impartial. Such rules and regulations shall be consistent with the pertinent provisions of article 4 of title 24, C.R.S.

(3) In all proceedings before the commission or the division with respect to any alleged violation of any control regulation, permit, or order, the burden of proof shall be upon the division.

(4) Except for classification and water quality standard-setting proceedings, the commission or the department of public health and environment may designate a hearing officer or an administrative law judge pursuant to part 10 of article 30 of title 24, C.R.S., subject to appropriations made to the department of public health and environment. When appropriate, the hearing officer may be an employee of the department of public health and environment or a member of or the administrator of the commission.

(5) (a) Any request for a variance with respect to a permit condition shall be made within thirty days after issuance by the division of the final permit. Requests for variances from any other application of a control regulation shall be made within thirty days of legal notice by the division of the regulation or prior to operation of any new or expanded facility which would be affected by the control regulations. A variance may also be sought within thirty days of facts becoming available which had not been reasonably available to the applicant prior to that time or upon application to the commission for good cause shown.

(b) The division shall approve or disapproveany variance request and issue its decision within ninety days after receipt of the variance request. Notice of a variance request shall be sent to anyone who has requested such notice and shall be included on the next commission agenda. In the case of a variance being granted prior to the final permit being issued, the division shall publish for public notice and comment the entire draft permit with the variance incorporated therein. In the case of a variance granted after a final permit has been issued, the division shall publish for public notice and comment the variance as a proposed modification to the permit. Within forty-five days of issuance of a variance decision by the division which does not involve discharge permit conditions required by the federal act, the commission on its own motion or on the motion of the division or any interested person may decide to review the variance decision. In such event, a hearing pursuant to section 24-4-105, C.R.S., shall be held, and the commission may affirm, modify, or deny the decision. Variance decisions of the division which involve discharge permit conditions required by the federal act shall be subject to review by an administrative law judge of the department of personnel pursuant to section 24-4-105, C.R.S., as part of any challenge to the conditions of a final discharge permit issued by the division.