Iowa agriculture’s message to the Environmental Protection Agency (EPA) last week at a hearing regarding the proposed changes to the Renewable Fuels Standard (RFS) was clear: Don’t mess with the RFS.

The EPA last week heard comments from Iowans and others on the proposed changes to the RFS, which were released May 29. In the proposed changes, the EPA lower­ed its biofuel requirements set by Congress to 15.93 billion gallons this year and 16.3 billion gallons next year.

"Biofuel refiners in Iowa and across the country have created essential markets for...