After the administration finalized a standard to require fuel refiners to blend in record amounts of biofuels, a refining trade group sued the administration in late May.

In a May 29 lawsuit filed in D.C. Circuit Court, American Fuel & Petrochemical Manufacturers (AFPM) challenged the administration’s renewable fuel standard for 2026 and 2027. The standard set in March requires refiners and fuel importers to blend in record-high amounts of plant-based diesel fuel, while maintaining an existing mandate to blend 15 billion gallons per year of corn ethanol into motor gasoline.

The standard “creates a larger, more stable, and more reliable domestic market for U.S. crops, strengthening farm income and rural economies,” EPA Administrator Lee Zeldin said in a March statement.

The standard has pitted the interests of fossil fuel refiners and importers against those of renewable fuel producers and farmers. Under Trump, farmers have struggled due to rising fertilizer costs due to war with Iran and the dismantling of the U.S. Agency for International Development, a major buyer of U.S. crops.

However, refiners have chafed at the standard, with AFPM’s CEO saying that the cost of complying with the standard “has reached a new all-time high,” according to trade publication Oils & Fats International. The price of credits for biomass-based diesel and ethanol have doubled since the start of the year, according to the U.S. Energy Information Administration.