Ethanol is known as an alternative fuel, and is even renewable. But that doesn't always make it clean.
The Environmental Protection Agency, after proposing watered down emissions and fuel economy standards for cars, has now released a proposal to increase the amount of ethanol blended into pump gas year-round, including selling E15 in the summer.
Currently ethanol blending is restricted between June 1 and September 1, because a higher ratio of ethanol has been flagged by scientists and environmental groups for being a contributing factor in higher concentrations of ground-level ozone, or smog.
Ethanol blends are known by the percentage of the renewable fuel blended into ordinary gasoline, such as E10, E15, or E85.
Under existing rules, most pump gas in the U.S. contains 10 percent ethanol, and gasoline refiners are required to mix in certain amounts under the 2007 Renewable Fuels Standard.
The new rule would allow that blend to rise to 15 percent, require refiners to blend more gallons of ethanol into gasoline, and increase restrictions on renewable fuels credits, known as RINs, that refiners can trade to reduce the number of actual gallons of renewable fuels they have to blend.
Currently, only 1 percent of gas stations in the U.S. dispense E15, and the new proposal would seek to expand that. Only vehicles built since 2001 are certified by their manufacturers to run on E15.
The EPA plan hews closely to one put forward by the White House last October to expand waivers to allow more E15 sales and restrict RIN trading by limiting the length of time refiners can hold the credits.
Among other things, President Trump campaigned on expanding ethanol, and was dogged early in his administration by charges that exemptions allowing refiners to avoid blending ethanol were given out too freely.
In a statement, EPA Administrator Andrew Wheeler said, "Consistent with President Trump’s direction, EPA is working to propose and finalize these changes by the summer driving season.” A public hearing is scheduled for March 29.