Members of the U.S. ethanol industry, along with several airlines and other aviation companies, sent a joint letter to the Biden Administration on Wednesday demonstrating their support for tax incentives on sustainable aviation fuel (SAF) derived from corn ethanol.

Under the Inflation Reduction Act (IRA) of 2023, SAF producers are required to use a carbon lifecycle assessment developed by ICAO to determine their qualification for SAF production incentives. According to the letter’s signatories—which include Boeing, GE Aerospace, major U.S. airlines, Honeywell UOP, and Gevo—the legislation’s language left room for the use of “any similar methodology” in determining the sustainability quotient derived from corn-based SAF.

The letter addressed to Treasury Secretary Janet Yellin, Transportation Secretary Pete Buttigieg, Energy Secretary Jennifer Granholm, Agriculture Secretary Thomas Vilsack, and others instead urges the adoption of the Department of Energy’s Greenhouse Gases, Regulated Emissions, and Energy Use in Technologies (GREET) standard. According to the group, GREET will more favorably weigh ethanol-derived SAF and make it eligible for subsidies under the IRA.

“Our ability to attract investment and build out U.S. SAF capacity will depend on how the program determines credit eligibility and valuation,” the letter stated. “This is especially true for a performance-based tax regime that ties the size of the incentive to a product’s life cycle score.”