Just 2.86 million gallons of E15 was sold in July, the lowest volume recorded since September 2017, according to data from the Minnesota Department of Commerce. 

The volume in July was 26 percent lower than the volume in June (3.63 million gallons). The RVP ban began on June 1 and ends on Sept 15.

Prior to the ban in May, E15 sales in Minnesota hit an all time high of 6.74 million gallons. In fact, monthly E15 sales in the first five months of 2018 averaged 5.99 million gallons 

To recap, the EPA sets the RVP limit to 9.0 in the summer months to reduce evaporation of fuel from cars and storage and transfer equipment during the summer months. When gasoline evaporates, it contributes to smog. The PSI for E10 increases by 1 during the summer months but Congress-imposed an RVP waiver for E10. According to the Department of Energy's National Renewable Energy Laboratory (NREL), the RVP for E15 is indistinguishable from E10.

Since the RVP limit doesn't apply to flex fuels, many gas stations in Minnesota label E15 as a flex fuel during the summer months. 

Despite repeated promises from President Donald Trump and Agriculture Secretary Sonny Perdue to lift the ban, there has been no indication that there is actually any momentum at the EPA to provide RVP parity for E15. 

Meanwhile, E85 sales in July hit its highest volume of the year at 1.89 million gallons.