California Code, Labor Code - LAB § 1151.2

(a) No person shall be excused from attending and testifying, or from producing books, records, correspondence, documents, or other evidence in obedience to the subpoena of the board, on the ground that the testimony or evidence required of him may tend to incriminate him or subject him to a penalty or forfeiture.  However, no individual shall be prosecuted or subjected to any penalty or forfeiture for or on account of any transaction, matter, or thing concerning which he is compelled, after having claimed his privilege against self-incrimination, to testify or produce evidence, except that such individual so testifying shall not be exempt from prosecution and punishment for perjury committed in so testifying.

(b) No individual shall be granted immunity pursuant to subdivision (a) unless, at least 10 calendar days prior thereto, the board has given written notice, by registered mail, to the district attorney of each county who may have reasonable grounds for objecting to such grant of immunity.  Such notice shall specify the subject matter of the inquiries to which the witness' answers are to be immunized from use.

The board may not grant immunity in any case where it finds that a district attorney has reasonable grounds for objecting to such grant of immunity provided that the board may disregard objections that are not accompanied by the declaration of the district attorney that he or she is familiar with the notice and which sets forth the grounds for resisting such grant of immunity.