Cal. Ins. Code § 11590
Except as provided in Section 11591, no policy providing comprehensive personal liability insurance may be issued or renewed in this state on or after January 1, 1977, unless it contains a provision for coverage against liability for the payment of compensation, as defined in Section 3207 of the Labor Code, to any person defined as an employee by subdivision (d) of Section 3351 of the Labor Code. Any such policy in effect on or after January 1, 1977, whether or not actually containing such provisions, shall be construed as if such provisions were embodied therein. However, such coverage shall not apply if any other existing, valid and collectible, workers' compensation insurance for such liability is applicable to the injury or death of such employee.
Ca. Ins. Code § 11590