The ethanol industry is asking President Trump to restore biofuel demand that was damaged by small refinery waivers.

The Waivers exempt refineries from the Renewable Fuel Standard, and effectively reduce the blending targets set under the RFS, according to Growth Energy.

On Monday, the group, along with several workers from ethanol plants across the county, penned a letter to Trump asking the President to restore the demand.

The letter points to the billions of gallons of “lost” biofuel demand, leading to ethanol plants idling production or shutting down.

Each time a plant idles production, the letter states that “farmers are notified that biofuel producers can no longer accept grain deliveries, and the impact has been devastating for communities already on the edge.”

Farm income is now down by half since the start of this year alone, according to the Bureau of Economic Analysis.

Growth Energy CEO Emily Skor says the EPA “must immediately repair the damage from abusive refinery exemptions and get lost gallons back into the marketplace.”