The U.S. Environmental Protection Agency (EPA) sign is seen on the podium at EPA headquarters in Washington, U.S., July 11, 2018. REUTERS/Ting Shen

WASHINGTON (Reuters) - The U.S. Environmental Protection Agency (EPA) has rejected requests from the corn lobby to reallocate biofuel volumes waived under its small refinery exemption program into its 2019 mandate, an agency official told Reuters on Tuesday.

The move is likely to infuriate the powerful corn lobby and top officials in the U.S. Department of Agriculture, who have complained for months that an expansion of the EPA’s refinery waiver program under the Trump administration threatens demand for crucial farm products like corn-based ethanol.

Under the U.S. Renewable Fuel Standard, oil refiners must blend increasing amounts of biofuels into their fuel each year or purchase blending credits from those that do. But small refineries can be exempted from the RFS if they prove that complying would cause them financial strain.

The official also said the 2019 annual biofuel mandate figures were set to be largely in line with the agency’s June proposal of 19.88 billion gallons.