Cal. INS § 11658

(a) A workers’ compensation insurance policy or endorsement shall not be issued by an insurer to any person in this state unless the insurer files a copy of the form or endorsement with the rating organization pursuant to subdivision (e) of Section 11750.3 and 30 days have expired from the date the form or endorsement is received by the commissioner from the rating organization without notice from the commissioner, unless the commissioner gives written approval of the form or endorsement prior to that time.

(b) If the commissioner notifies the insurer that the filed form or endorsement does not comply with the requirements of law, specifying the reasons for his or her opinion, it is unlawful for the insurer to issue any policy or endorsement in that form.

(c) The withdrawal of a policy form or endorsement by the commissioner pursuant to this section shall not affect the status of the policyholder as having secured payment for compensation or affect the substitution of the insurer for the policyholder in workers’ compensation proceedings as set forth in the provisions of Chapter 4 (commencing with Section 3700) of Part 1 of Division 4 of the Labor Code during the period of time in which the policy form or endorsement was in effect.

(d) This section shall not apply to limited policies submitted for approval to the commissioner pursuant to Section 11657.