Refiners who include in refinery compliance calculations the ethanol added downstream to the refinery's gasoline may assume that denatured ethanol is used, and that the denaturant comprises 5 vol% of the denatured ethanol. Such a refiner may assume that the remaining 95 vol% of the denatured ethanol is pure ethanol, with the normal properties for that product.

The refiner may include the 95 vol% ethanol in its compliance calculations, but not the 5 vol% denaturant. These assumptions would not be appropriate in a case where a refiner learns through its oversight program, or otherwise knows or should know, that these assumptions are inaccurate with regard to a specific oxygenate blending operation.

A refiner may use a different vol% ethanol in its compliance calculations, and may include the volume and properties of denaturant, where the refiner has data to establish the actual volume and properties of the ethanol and denaturant used.(10/17/94)

This question and answer was posted at Consolidated List of Reformulated Gasoline and Anti-Dumping Questions and Answers: July 1, 1994 through November 10, 1997 (PDF)(333 pp, 18.17 MB, EPA420-R-03-009, July 2003, About PDF)