A recently-released study by the United States-based National Academy of Sciences examining the hidden health costs of energy has concluded that corn ethanol produced fewer health threats than electric cars dependent on fossil fuel-fired power plants.
And it found that second-generation ethanol produced dramatically lower health threats than almost any other transportation fuel.
Requested by the US Congress, the report assesses what economists call external effects caused by various energy sources over their entire life cycle - for example, not only the pollution generated when gasoline is used to run a car but also the pollution created by extracting and refining oil and transporting fuel to gas stations.
Because these effects are not reflected in energy prices, government, businesses and consumers may not realise the full impact of their choices.
When such market failures occur, a case can be made for government interventions - such as regulations, taxes or tradable permits - to address these external costs, the report says.
Damages per vehicle mile travelled were remarkably similar among various combinations of fuels and technologies - the range was US1.2 cents to about 1.7c per mile traveled - and it is important to be cautious in interpreting small differences, the report says.
Non-climate-related damages for corn grain ethanol were similar to or slightly worse than gasoline, because of the energy needed to produce the corn and convert it to fuel.
In contrast, ethanol made from herbaceous plants or corn stover - which are not yet commercially available - had lower damages than most other options.
Both for 2005 and 2030, vehicles using gasoline made from oil extracted from tar sands and those using diesel derived from the Fischer-Tropsch process - which converts coal, methane, or biomass to liquid fuel - had the highest life-cycle greenhouse gas emissions.
Vehicles using ethanol made from corn stover or herbaceous feedstock such as switchgrass had some of the lowest greenhouse gas emissions, as did those powered by compressed natural gas.
Tom Buis, chief executive officer of Growth Energy, said the report confirms that ethanol is the best alternative to both gasoline and electric-driven vehicles when considering the greenhouse gas emissions of fossil fuels such as crude oil, or in the case of plug-in cars, coal.
"Although the study found E85 from corn grain ethanol had similar impacts to gasoline, that is rapidly changing as the efficiency of producing corn-ethanol improves and oil is increasingly taken from more environmentally-damaging sources like tar sands and oil shale," Buis said.
"Domestic ethanol is our best alternative to gasoline refined from oil.
"It creates US jobs, it makes the US less dependent on foreign sources of energy, and best of all, it gets cleaner and greener every year with advances in fuel and farm technology."
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