Mich. Comp. Laws § 423.502

Sec. 2. Personnel record information which was not included in the personnel record but should have been as required by this act shall not be used by an employer in a judicial or quasi-judicial proceeding. However, personnel record information which, in the opinion of the judge in a judicial proceeding or in the opinion of the hearing officer in a quasi-judicial proceeding, was not intentionally excluded in the personnel record, may be used by the employer in the judicial or quasi-judicial proceeding, if the employee agrees or if the employee has been given a reasonable time to review the information. Material which should have been included in the personnel record shall be used at the request of the employee.