(1)    The department by rule shall prescribe minimum product grade specifications for gasoline, automotive gasoline, gasoline-alcohol fuel blends, reformulated gasoline, as defined in s. 285.37 (1), and kerosene and may prescribe product grade specifications for aviation gasoline, fuel oils, and diesel fuels.

   (2)   

      (a)    Except as provided in par. (b), the rules required under sub. (1) shall prohibit gasoline, automotive gasoline, gasoline-alcohol fuel blends, and reformulated gasoline, as defined in s. 285.37 (1), beginning on August 1, 2004, from containing more than 0.5 percent, by volume, of methyl tertiary-butyl ether.

      (b)    The rules required under sub. (1) shall not prohibit racing fuel used at racing events or in preparation for racing events from containing any amount of methyl tertiary-butyl ether.

   (3)   Except as otherwise provided in this section, rules promulgated under this section shall be in conformity with nationally recognized standards, specifications, and classifications, such as those published by ASTM International, the Society of Automotive Engineers, and the U.S. Environmental Protection Agency. The department may not promulgate or enforce a rule prohibiting the placement of additional information on the dispensing device.

   (4)   

      (a)    In this subsection, “gasoline-ethanol fuel blend” includes such a fuel blend for both automotive and nonautomotive uses.

      (b)    Except as provided under par. (c), compliance with the requirements, established by the department by rule under sub. (1), of ASTM D4814-17 or the most current version of testing methods adopted by the department may be demonstrated by testing a gasoline-ethanol fuel blend or testing the gasoline base stock from which the gasoline-ethanol fuel blend is produced.

      (c)    The department may promulgate rules that require that a gasoline-ethanol fuel blend and the gasoline base stock from which the gasoline-ethanol fuel blend is produced meet the requirements of ASTM D4814-17, or the most current version of testing methods adopted by the department. A rule promulgated under this paragraph may not take effect sooner than July 1, 2019.