29 C.F.R. § 2.21
Whenever an employee or former employee of the Department receives a demand for the production of material or the disclosure of information described in § 2.20(a) , he shall immediately notify the appropriate Office of the Solicitor. The appropriate Office of the Solicitor shall be furnished by the party causing the subpoena to be issued with a written summary of the information sought and its relevance to the proceeding in connection with which it was served. The Associate Solicitor, Regional Solicitor, or Associate Regional Solicitor, whichever is appropriate, may waive the requirement that a written summary be furnished where he or she deems it to be unnecessary. The election to waive the requirement of a written summary in no way constitutes a waiver of any other requirement set forth in this subpart.
29 C.F.R. §2.21