Cal. Rev. & Tax. Code § 7404

If a purchaser gives an exemption certificate for motor vehicle fuel pursuant to this chapter to the effect that the motor vehicle fuel purchased will be used in an exempt manner, and sells the motor vehicle fuel or uses the motor vehicle fuel in some other manner or for some other purpose, the purchaser will be liable for payment of the tax under Chapter 2 (commencing with Section 7360) of this part. The tax, applicable penalties, and interest shall become due and payable and shall be ascertained and determined in the same manner as the backup tax under Section 7727.