20 ILCS 3955/18
In the course of an investigation, a regional authority may inspect and copy any materials relevant to the investigation in the possession of a service provider or state agency. However, a regional authority may not inspect or copy materials containing personally identifiable data which can not be removed without imposing an unreasonable burden on the service provider or State agency, except as provided herein. The regional authority shall give written notice to the person entitled to give consent for the identifiable eligible person under Section 5 of the "Mental Health and Developmental Disabilities Confidentiality Act", enacted by the Eightieth General Assembly, as now or hereafter amended, or under any other relevant law, that it is conducting an investigation and indicating the nature and purpose of the investigation and the need to inspect and copy materials containing data that identifies the eligible person. If the person notified objects in writing to such inspection and copying, the regional authority may not inspect or copy such materials. The service provider or State agency may not object on behalf of an eligible person.
20 ILCS 3955/18