Federal environmental officials say hundreds have signed up to testify on a renewable fuels proposal that ethanol supporters say would have stifling implications for their industry.
Last month the Environmental Protection Agency announced a plan to reduce renewable fuels requirements by 4 billion gallons in 2015 and more than 3 billion in 2016. The agency says volumes required by a 2007 law are impossibly high.
The EPA is conducting the hearings Thursday in Kansas City, Kansas, with plans to announce its final decision in November.
At least two governors, busloads of FFA members and farmers from several states are planning to rally against the proposal at a nearby park.
Ethanol backers say the EPA caved in to the demands of the petroleum industry, which is generally opposed to the standards.