Cal. Labor Code § 132

The superior court in and for the county in which any proceeding is held by the appeals board or a workers’ compensation judge may compel the attendance of witnesses, the giving of testimony and the production of papers, including books, accounts, and documents, as required by any subpoena regularly issued hereunder. In case of the refusal of any witness to obey the subpoena the appeals board or the workers’ compensation judge, before whom the testimony is to be given or produced, may report to the superior court in and for the county in which the proceeding is pending, by petition, setting forth that due notice has been given of the time and place of attendance of the witness, or the production of the papers, that the witness has been subpoenaed in the prescribed manner, and that the witness has failed and refused to obey the subpoena, or has refused to answer questions propounded to him or her in the course of the proceeding, and ask an order of the court, compelling the witness to attend and testify or produce the papers before the appeals board. The court shall thereupon enter an order directing the witness to appear before the court at a time and place fixed in the order, the time to be not more than 10 days from the date of the order, and then and there show cause why he or she had not attended and testified or produced the papers before the appeals board or the workers’ compensation judge. A copy of the order shall be served upon the witness. If it appears to the court that the subpoena was regularly issued hereunder and that the witness was legally bound to comply therewith, the court shall thereupon enter an order that the witness appear before the appeals board or the workers’ compensation judge at a time and place fixed in the order, and testify or produce the required papers, and upon failure to obey the order, the witness shall be dealt with as for contempt of court. The remedy provided in this section is cumulative, and shall not impair or interfere with the power of the appeals board or a member thereof to enforce the attendance of witnesses and the production of papers, and to punish for contempt in the same manner and to the same extent as courts of record.