The Trump administration says it will allow sales of gasoline with 15% ethanol in it year-round, and it says that will give customers more choices at the pump.
Former administrations banned its sale during the summer, says David DeGennaro of the National Wildlife Federation.
"And that's because ethanol in gasoline actually increases the amount of smog relative to gasoline with no ethanol in it," says DeGennnaro.
He says the public health risk is one big problem with the change. Smog can trigger asthma attacks.
Problem two: people may end up buying more gas, because ethanol is a less efficient fuel than gasoline.
And problem three: farmers could convert wildlife habitat to corn production to make ethanol.
"There really isn't a lot of upside to this, unless you're a corn farmer," says DeGennaro.
For years, some lower Michigan counties have periodically exceeded summer smog limits based on a separate EPA rule.
DeGennaro says now, those counties may exceed the limits more often.
Meanwhile, it could take a long time for gas stations that do not already sell E15 to add the equipment necessary for its delivery to customers. E15 requires special mixing pumps, along with a separate underground storage tank for the ethanol, because it is more corrosive than gasoline.
Oil industry groups are expected to sue to try to stop the EPA from allowing summer sales of E15, and health and environmental groups may also sue.
