EPA to release biofuels proposal by June 1

Authorities are set to shake up the nation's complex and contentious renewable fuels policy in the coming days, issuing requirements that are expected to affirm that the use of ethanol in motor fuels has hit a saturation point.

The Environmental Protection Agency has pledged by June 1 to release proposals for the amount of ethanol, biodiesel and cellulosic fuels — made of plant waste — that must be mixed into motor fuel for 2014, 2015 and 2016 — targets that are as long as a year and a half behind schedule.