Iowa Senator Charles Grassley, Chairman of the Senate Judiciary Committee, sent a letter on Tuesday to the U.S. Environmental Protection Agency and three other federal agencies requesting a detailed update on actions taken in response to concerns surrounding Renewable Fuel Standard refinery exemptions. The concerns were first raised by Iowa Attorney General Brenna Bird and attorneys general from neighboring states.
In October 2025, Bird joined the Attorneys General of South Dakota and Nebraska in sending a joint letter to four federal agencies, asking for an investigation into whether certain refiners may have misrepresented their financial condition while applying for exemptions under the Renewable Fuel Standard. The attorneys general questioned whether refiners were providing conflicting information to regulators by claiming disproportionate economic hardship at the same time they were publicly highlighting strong financial performance. Their letter cited numerous examples of refiner statements pointing to fiscal strength during the same periods in which RFS waiver requests were submitted.
Grassley’s letter seeks clarification on whether federal agencies have reviewed those allegations and what steps, if any, have been taken to ensure the integrity of the RFS exemption process. Supporters of renewable fuels say the issue is critical for maintaining confidence in a program designed to support domestic biofuel production and rural economies.
“Iowa Renewable Fuels Association members thank Senator Grassley for this timely letter, keeping the pressure on EPA to get answers to these very serious questions,” said Monte Shaw, Executive Director of the Iowa Renewable Fuels Association. “As we continue to see RFS waivers granted, it is imperative that the integrity of the RFS stays intact and transparency is returned to the process. The rural economy is depending on a fully and properly enforced RFS.”
Corn growers also voiced support for Grassley’s request, emphasizing the importance of strong oversight as exemptions continue to be issued. “Iowa’s corn growers applaud Senator Grassley, the Chairman of the Senate Judiciary Committee, for his letter seeking updated action on the EPA’s investigation into refiners seeking RFS exemptions, ensuring the EPA remains accountable on issues that directly affect Iowa corn farmers,” said Steve Kuiper, Vice President of the Iowa Corn Growers Association and a farmer from Knoxville, Iowa. “Protecting the Renewable Fuel Standard is vital to Iowa’s corn industry and we must ensure it is not being taken advantage of.”
