* Commission assessment of law's impact still awaited
* Scientists say draft law is scientifically sound
* Oil industry says EU plan is unfair and unscientific
By Barbara Lewis
BRUSSELS, Dec 20 (Reuters) - More than 50 top European andU.S. scientists have written to the European Commissionpresident urging him to press ahead with a plan to label tarsands as more polluting than other forms of oil, in defiance ofintensive lobbying from Canada.
The draft law was kept on ice during trade talks between theEuropean Union and Canada, the world's biggest producer of oilfrom tar sands, which culminated in a multi-million-dollar pactsigned earlier this year.
EU sources, speaking on condition of anonymity, have saidpolitical momentum behind even bigger trade talks between theUnited States and Europe could freeze the EU tar sands plan forgood, as it would hobble billions of dollars' worth oftransatlantic trade in oil products.
The 53 scientists who have written to President Jose ManuelBarroso include professors from Harvard, Stanford and Columbiain the United States, Aberdeen and Edinburgh in Scotland,University College in Ireland and Heidelberg in Germany.
They say the EU draft law, which would label fuels accordingto how much carbon they emit over their entire wells-to-wheelslifecycle, is scientifically sound, after criticism from the oilindustry that it is not.
In the letter dated Dec. 16, they say the policy wouldensure investment in cleaner fuels and for the first time holdthe oil industry accountable for carbon emitted duringproduction of the fuels they sell in Europe.
"We live in an era during which it has become clear that wecannot burn all of the fossil fuels without causing dangerousclimate change," the letter, seen by Reuters, said.
Peter Smith, a professor at the University of Aberdeen, saidhe signed the letter because fuels must be assessed "on thebasis of the damage that they do".
LAW IN LIMBO
EU member states approved legislation in 2009, with the aimof cutting greenhouse gases from transport fuel sold in Europeby 6 percent by 2020, but failed to agree how to implement it.
Named the Fuel Quality Directive (FQD), the law has been inlimbo almost ever since. Oil companies, such as BP, andcountries led by Canada have spoken out against it, saying it isunfair and unscientific.
To fend off the criticism, the European Commission said lastyear it was assessing the business impact of its proposal, buthas yet to publish the results.
EU sources say they do not expect publication of theCommission's impact assessment until after a major chunk ofenvironment and energy policy set to be announced in January.
In a statement, the Commission confirmed it had received theletter and would reply.
"The Commission has consulted widely on this complex fileand is in the process of finalising the impact assessment," itsaid.