California Code, Government Code - GOV § 11450.30

(a) A person served with a subpoena or a subpoena duces tecum may object to its terms by a motion for a protective order, including a motion to quash.

(b) The objection shall be resolved by the presiding officer on terms and conditions that the presiding officer declares. The presiding officer may make another order that is appropriate to protect the parties or the witness from unreasonable or oppressive demands, including violations of the right to privacy.

(c) A subpoena or a subpoena duces tecum issued by the agency on its own motion may be quashed by the agency.