(1) The tax imposed by KRS 234.320 shall not be collected when the liquefied petroleum gas sold by the dealer is used to propel motor vehicles on the public highways, either within or without this state, when the motor vehicles using the liquefied petroleum gas are equipped with carburetion systems approved by the Energy and Environment Cabinet or a fuel system that meets federal vehicle safety standards contained in 49 C.F.R. pt.
571.
(2) The Energy and Environment Cabinet shall establish emission standards for carburetion systems.