Cal. VEH § 2402.6

(a) The commissioner may adopt and enforce regulations and standards with respect to fuel containers and fuel systems on vehicles using compressed or liquefied natural gas and liquefied petroleum gas used in conjunction with a propulsion system certified by the State Air Resources Board as producing as few or fewer emissions as a State Air Resources Board approved system using compressed or liquefied natural gas or liquefied petroleum gas and with respect to the operation of vehicles using any of those fuels to ensure the safety of the equipment and vehicles and of persons and property using the highways.

(b) The commissioner may also adopt and enforce regulations and standards with respect to fuel containers and fuel systems on vehicles using compressed or liquefied hydrogen gas or liquid fuels that generate hydrogen gas.

(c) All motor vehicles with compressed natural gas fuel systems used for propulsion shall comply either with the regulations adopted pursuant to subdivision (a) or with National Fire Protection Administration Standard NFPA 52, “Compressed Natural Gas (CNG) Vehicular Fuel Systems” in effect at the time of manufacture, until standards for those fuel systems have been incorporated into the Federal Motor Vehicle Safety Standards by the United States Department of Transportation. Whenever those Federal Motor Vehicle Safety Standards include requirements for gaseous fuel systems, all motor vehicles with gaseous fuel systems which are manufactured after the effective date of those requirements shall comply with those requirements.

(d) It is an infraction for any person to operate any motor vehicle in violation of any provision of a regulation adopted pursuant to this section.

(e) The operator of every facility for filling portable liquefied natural gas or liquefied petroleum gas containers having a capacity of four pounds or more but not more than 200 pounds of gas shall post in a conspicuous place the regulations applicable to that filling procedure.