Cal. Penal Code § 24680

Any firearm detection equipment newly installed in a nonfederal public building in this state shall be of a type identified by either the United States Attorney General, the Secretary of Transportation, or the Secretary of the Treasury, as appropriate, as available state-of-the-art equipment capable of detecting an undetectable firearm, while distinguishing innocuous metal objects likely to be carried on one’s person sufficient for reasonable passage of the public.