The definition of renewable fuel in 80.1401 specifies that the maximum amount of denaturant in ethanol that can be treated as renewable fuel is 2 volume percent. If lab results indicate that the concentration of denaturant is higher than 2%, then any denaturant in excess of 2% cannot be treated as renewable fuel, and RINs cannot be generated to represent it.

However, conventional rules of rounding apply since the regulations specify the limit as 2%, not 2.0% or 2.00%. Thus, for example, if the denaturant concentration was tested and found to be 2.44%, this would be deemed equivalent to 2% and RINs could be generated for the entire volume. However, if the denaturant concentration was tested and found to be 2.66%, this would be deemed equivalent to 3% and RINs could only be generated to represent 99% of the volume of denatured ethanol.