Tennessee Code Title 67. Taxes and Licenses § 67-3-512

Each person blending untaxed materials, including blendstocks and additives, with taxable petroleum products as to which taxes and fees have already been paid or accrued, shall remit the taxes and fees imposed by this chapter on the previously untaxed volumes. Should the blending process alter the specifications of the blended product according to American Society for Testing and Materials (ASTM) specifications, then applicable taxes and fees shall apply to the altered product.