An unpublished federal report appears to undermine the belief that commercially available ethanol-blended fuel produces cleaner emissions than regular gasoline.

Many Canadians believe filling up with ethanol-blended gasoline reduces the emission of greenhouse gases that damage the environment.

Advertising sponsored by the Canadian Renewable Fuels Association encourages the idea, telling Canadians renewable fuels are "good for the environment," and even some provincial governments, including Manitoba and Saskatchewan, say the fuel "burns cleaner" than gasoline.

The federal Conservative government committed $2 billion in incentives for ethanol, made from wheat and corn, and biodiesel in last week's budget.

But based on Ottawa's own research, critics say the investment is based more on myth than hard science.

'Not a lot of difference'

Scientists at Environment Canadastudied four vehicles of recent makes, testing their emissions in a range for driving conditions and temperatures.

"Looking at tailpipe emissions, from a greenhouse gas perspective, there really isn't much difference between ethanol and gasoline," said Greg Rideout, head of Environment Canada's toxic emissions research.

"Our results seemed to indicate that with today's vehicles, there's not a lot of difference at the tailpipe with greenhouse gas emissions."

The study found no statistical difference between the greenhouse gas emissions of regular unleaded fuel and 10 per cent ethanol blended fuel.

Although the study found a reduction in carbon monoxide, a pollutant thatforms smog, emissions of some other gases, such as hydrocarbons, actually increased under certain conditions.

Bill Rees, an ecology professor at the University of British Columbia and longtime opponent of ethanol, has read the report and thinks Canadians need to know its conclusions.

"I must say, I'm a little surprised at that, because it seems to fly in the face of current policy initiatives," he said.

"People are being conned into believing in a product and paying for it through their tax monies when there's no justifiable benefit and indeed many negative costs."

Other benefits: minister

Federal Environment Minister John Baird said he knows about the report, which was commissioned under the previous Liberal government. However, he said, heis looking at the big picture.

"I think there's an issue between the tailpipe and the whole cycle," he said. "The whole cycle is better than the tailpipe."

Other ethanol proponents agreed, saying tailpipe emissions are not the only statistic that matters.

Ethanol is made from a renewable resource, they noted, and— although there is much scientific debate on this point— they argue ethanol produces fewer greenhouse gases when the entire production cycle, from gathering to refinement to emissions, is taken into account.