Cal. Bus. & Prof. Code § 13431
The following persons shall pay to the secretary a maximum fee of five cents ($0.05) for each gallon of motor oil sold or purchased on or after January 1, 2010, as hereinafter provided:
(d) The assessment provided for in this section shall only be paid once on any particular motor oil.
The secretary may apply a fee of three cents ($0.03) for each gallon of motor oil sold or purchased, as provided in subdivisions (a) to (d), inclusive, prior to the adoption of regulations.
The provisions of this section shall not apply to motor oil exported for sale outside this state.