Whenever the members of a hearing board conducting any hearing deem it necessary to examine any person as a witness at the hearing, the chairman of the hearing board shall issue a subpoena, in proper form, commanding such person to appear before it at a time and place specified to be examined as a witness. The subpoena may require such person to produce all books, papers, and documents in his possession, or under his control, material to the hearing.
Ca. Health and Saf. Code § 40840