Cal. LAB § 152

The Director of Industrial Relations and authorized employees of the department may issue subpoenas to compel the attendance of witnesses and production of books, papers, and records; administer oaths; examine witnesses under oath; take the verification or proof of written instruments; and take depositions and affidavits for the purpose of carrying out the provisions of this code and performing the duties required by this chapter. They shall have free access to all places of labor. Any person, or agent or officer thereof, who willfully neglects or refuses to furnish statistics requested by the division, which are in his or her possession, or under his or her control, or who refuses to admit the director or his or her authorized employee to a place of labor, is guilty of a misdemeanor. The director may direct the chief and the employees of other divisions of the department to transmit any statistical information in their possession, or to conduct investigations and otherwise assist in the gathering of whatever statistics the director deems desirable.