The US Environmental Protection Agency (EPA) is issuing an emergency fuel waiver to allow E15 gasoline to be sold during the summer driving season. (Earlier post.)

The Clean Air Act (CAA) requires the use of low-volatility gasoline during the summer months in order to limit the formation of ozone pollution. (Volatility is the property of a liquid fuel that defines its evaporation characteristics.) Reid vapor pressure (RVP) is a common measure of and generic term for gasoline volatility. EPA regulates the vapor pressure of gasoline sold at retail stations during the summer ozone season (1 June to 15 September) to reduce evaporative emissions from gasoline that contribute to ground-level ozone.

Specifically, the regulations require parties upstream of retailers and wholesale purchaser-consumers to turn over their storage tanks to low volatility summer gasoline and stop selling higher volatility winter gasoline by 1 May so that retailers and wholesale purchaser-consumers can meet the applicable low volatility gasoline standards by 1 June. Depending on the state and month, gasoline RVP may not exceed 9.0 psi or 7.8 psi. EPA provides a 1.0 psi RVP allowance for gasoline containing 10 percent ethanol (E10).

The Clean Air Act allows the EPA Administrator, in consultation with the US Department of Energy (DOE), to waive certain fuel requirements temporarily to address shortages. EPA Administrator Regan said that, as a result of the war in Ukraine, extreme and unusual fuel supply circumstances exist and has granted a temporary waiver to help ensure that an adequate supply of gasoline is available. As required by law, EPA and DOE evaluated the situation and determined that granting the waiver was in the public interest.

Currently, in roughly two-thirds of the country, E15 cannot be sold from terminals starting on 1 May and at retail stations starting on 1 June. EPA is extending the 1-psi Reid Vapor Pressure (RVP) waiver that currently applies to E10 gasoline to E15, which will enable E15 sales throughout the summer driving season in these areas, if necessary.

This action only extends the 1-psi waiver to E15 in parts of the country where it already exists for E10. E15 can already be sold year-round in parts of the country that have a Reformulated Gasoline (RFG) program.

Because the RVP of E10 and E15 gasoline used by consumers will be the same (both will be 1 psi higher than otherwise required by EPA or state regulations) EPA does not expect any impact on air quality from this limited action. EPA’s research has shown no significant impact on evaporative emissions when the 1-psi waiver is extended to E15.

EPA’s emergency fuel waiver will go into effect on May 1 when terminal operators would otherwise no longer be able to sell E15 in the effected regions of the country and will last for the statutory maximum of 20 days. EPA will continue to monitor the supply with industry and federal partners, and the Agency expects to issue new waivers effectively extending the emergency fuel waiver until such time as the extreme and unusual fuel supply circumstances due to the war in Ukraine are no longer present.