Cal. Lab. Code § 4351
Compensation provided by this division is the exclusive remedy of a disaster service worker, or his or her dependents, for injury or death arising out of, and in the course of, his or her activities as a disaster service worker as against the state, the disaster council with which he or she is registered, and the county or city which has empowered the disaster council to register and direct his or her activities. Liability for compensation provided by this division is in lieu of any other liability whatsoever to a disaster service worker or his or her dependents or any other person on his or her behalf against the state, the disaster council with which the disaster service worker is registered, and the county or city which has empowered the disaster council to register and direct his or her activities, for any injury or death arising out of, and in the course of, his or her activities as a disaster service worker.
Ca. Lab. Code § 4351