Tenn. Code § 47-25-2003
All refiners, suppliers and permissive suppliers in this state shall make available to wholesalers gasoline or gasoline blending stock that has not been blended with, but is suitable for blending with, ethanol. All refiners, suppliers and permissive suppliers in this state shall make available to a wholesaler diesel that is suitable for blending with biodiesel. Diesel sold by refiners, suppliers and permissive suppliers to wholesalers may contain up to five percent (5%) biodiesel. Gasoline and gasoline blending stock, as applicable, must be made available with detergent additives in sufficient concentrations such that after the addition of ethanol at the maximum volume percent permitted by state and federal law, the final product meets or exceeds the lowest additive concentrations as required by the federal environmental protection agency (EPA).
T.C.A. § 47-25-2003