A recording of the hearing shall be made. A copy of the recording shall be supplied to the appellant whenever the appellant takes a further appeal. The recording, together with all exhibits and papers admitted into evidence, shall constitute the exclusive record for decision. Nonrecorded or confidential information which the appellant does not have an opportunity to hear or see may not be made a part of the hearing record. The recording and copies of all exhibits and papers shall remain in the custody of the hearing officer for a period not to exceed 2 years, or until all litigation involving the decision is terminated.