Rev. & Tax. Code, § 6480.6

(a) The following persons who have paid prepayment amounts either directly to the board or to the person from whom the motor vehicle fuel, aircraft jet fuel, or diesel fuel was purchased shall be refunded those amounts:

(1) Any person who exports the fuel for subsequent sale outside this state.

(2) Any person who sells the fuel which is exempt from the sales or use tax pursuant to Sections 6352, 6357, 6381, and 6396.

(3) Any person who has lost the fuel through fire, flood, theft, leakage, evaporation, shrinkage, spillage, or accident, prior to any retail sale.

(4) Any supplier who has removed fuel from an approved terminal at the terminal rack, but only to the extent that the supplier can show that tax on the same amount of fuel has been paid more than one time by the same supplier.

(5) Any person who is unable to collect the prepayment from the purchaser insofar as the sales of the fuel are represented by accounts which have been found to be worthless and charged off for income tax purposes, or, if the person is not required to file income tax returns, accounts which have been charged off in accordance with generally accepted accounting principles. If partial payments have been made, the payments shall be prorated between amounts due for fuel and amounts due for the related prepayment. If any of those accounts are thereafter in whole or in part collected by the seller, the gallons of fuel represented by the amounts collected shall be included in the first return filed after that collection and the amount of the prepayment thereon paid with the return.

(b) In lieu of a refund, the board may authorize a credit to be taken by the person to whom the refund is due upon his or her prepayment form or sales and use tax return.