California Code, Revenue and Taxation Code - RTC § 60101

(a) Diesel fuel that is required to be dyed satisfies the dyeing requirement of this part if it meets the dyeing requirements of the United States Environmental Protection Agency and the Internal Revenue Service, including, but not limited to, requirements respecting type, dosage, and timing.

(b) Marking shall meet the marking requirements of the Internal Revenue Service.

(c) No person shall operate or maintain a motor vehicle on any public highway in this state with dyed diesel fuel in the fuel supply tank. This subdivision does not apply to uses of dyed diesel fuel on the highway that are lawful under the Internal Revenue Code or regulations promulgated thereunder, if the person is registered as a qualified highway vehicle operator, exempt bus operator, or government entity.