California Code, Health and Safety Code - HSC § 1799.106

(a) In addition to the provisions of Section 1799.104 of this code, Section 2727.5 of the Business and Professions Code, andSection 1714.2 of the Civil Code, and in order to encourage the provision of emergency medical services by firefighters, police officers or other law enforcement officers, EMT-I, EMT-II, EMT-P, or registered nurses, a firefighter, police officer or other law enforcement officer, EMT-I, EMT-II, EMT-P, or registered nurse who renders emergency medical services at the scene of an emergency or during an emergency air or ground ambulance transport shall only be liable in civil damages for acts or omissions performed in a grossly negligent manner or acts or omissions not performed in good faith. A public agency employing such a firefighter, police officer or other law enforcement officer, EMT-I, EMT-II, EMT-P, or registered nurse shall not be liable for civil damages if the firefighter, police officer or other law enforcement officer, EMT-I, EMT-II, EMT-P, or registered nurse is not liable.

(b) For purposes of this section, “registered nurse” means a registered nurse trained in emergency medical services and licensed pursuant to Chapter 6 (commencing with Section 2700) of Division 2 of the Business and Professions Code.