The San Francisco Fire Department and San Francisco Metropolitan Transit Agency are departments of the City and County of San Francisco, not independent public agencies. Hence, a fireman was a city employee and when he was injured by an MTA bus driver who drove through an active fire scene, severing a fire hose which caused the fireman serious injuries, the fireman was entitled to Workers Compensation benefits for his injuries but could not sue the City and County, the MTA or driver for their tortious conduct.