Way too little and way too late.

That was the reaction from Iowa lawmakers, farm leaders and biofuel groups following the announcement of the En­­vironmental Protection Ag­­ency’s (EPA) recent proposal for 2014-2016 biofuel requirements in the Renewable Fuel Standard (RFS).

The EPA did say it plans to raise the volumes of ethanol required to be blended into the nation’s gasoline supply from its original proposal way back in 2013, the critics acknowledged. But the new biofuel requirements are far short of what Congress called for when it passed the RFS back in 2005 and 2007, they said.

That reduction...