By Stephanie Kelly

A bipartisan group of U.S. farm-state lawmakers have urged the Environmental Protection Agency to eliminate a proposed retroactive cut to biofuel blending requirements for 2020, arguing the proposal undermines the nation's biofuel laws.

The lawmakers, a group of 14 senators from states including Iowa and Minnesota, also asked the EPA in a letter to deny all pending petitions from oil refiners that would waive them from the requirements. The EPA right now is finalizing a proposal for blending requirements for 2020, 2021 and 2022.

Under the U.S. Renewable Fuel Standard, oil refiners must blend billions of gallons of biofuels into the nation's fuel mix, or buy compliance credits from those that do. Refiners can receive an exemption to the requirements, known as a Small Refinery Exemption, if they can prove the obligations cause them financial harm.

The biofuel law has been a battleground for years between two major political constituencies, the corn and oil lobbies. Independent refiners argue that the RFS is too expensive and threatens their businesses. Meanwhile, the law has helped to create a multi-billion gallon industry for farmers and biofuel producers.

In December, the EPA announced a proposal that included a retroactive cut to obligations for 2020, the requirements for which had already been finalized in 2019.

"Re-opening RVOs (Renewable Volume Obligations) that have already been finalized while setting a precedent that future Administrations and EPA Administrators may retroactively lower previously finalized RVOs does the opposite of providing more certainty in the program," said the senators, including Senator Joni Ernst from Iowa and Senator Amy Klobuchar from Minnesota, in the letter, dated Jan. 31.