Ill. Admin. Code tit. 35, § 741.130 – Discovery After an Action is Filed

a) Within time limits set by the hearing officer, each party to a proceeding in which allocation of proportionate shares is sought must compile any and all documents within its possession or control pertaining to the release or threatened release and the party's proportionate share and shall make the records available for review and copying by the parties. Documents protected from disclosure under 35 Ill. Adm. Code 101 and 103 are not subject to this Section.
b) Discovery is governed by 35 Ill. Adm. Code 101 and 103, and all discovery devices identified in 35 Ill. Adm. Code 101 and 103 are available to all parties in a proceeding to allocate proportionate shares. Sanctions for failure to comply with procedural rules, subpoenas, or order of the Board or hearing officer will be as set forth therein and as otherwise available under the Act.