The EU’s proposal to assign oil from tar sands a ranking reflecting greater carbon intensity has stirred intense lobbying by Canada.
Home to the world's third-largest oil reserves, almost all of which are in the form of tar sands, Canada argues that the EU is unfairly discriminating against it.
Previous EU meetings have failed to get as far as a vote, but the agenda for a fifth sitting of the fuel quality committee later this month schedules a vote on an amendment to the Fuel Quality Directive proposed by the European Commission.
EU sources close to the talks said a stalemate is likely, with no majority either way.
If that happened, the debate would transfer from the level of EU technical experts to open discussion among EU ministers, and the Commission could decide to amend its proposal.
"It's very unlikely to get a qualified majority, which means that this will go the Council," one source said, speaking on condition of anonymity.
EU ministerial talks are also expected to be difficult as objections to the high polluting default value given to tar sands have provoked opposition in European nations where oil majors active in Canada such as Royal Dutch Shell, BP and Total are based.
Environmentalists say there is a body of scientific evidence supporting the EU view that oil sands crude is more carbon-intensive than oil from other sources and that a shift to greener forms of energy should avert the need to extract every last drop of oil.
The oil industry has countered that the proposed law could create an unreasonable administrative burden.
With Canada, it also argues that tar sands are a crucial energy source from a politically stable nation, able to fuel a world will that will remain oil dependent for decades.
Under the draft EU proposal, tar sands are assigned a default greenhouse gas value of 107 grams of carbon per megajoule, compared to conventional crude’s 87.5 grams.
If finalized, the ranking would complete legislation introduced in 2008, when the EU agreed to reduce the carbon intensity of its transport fuels by 6% by 2020 as part of wider goals to cut carbon emissions by 20% by 2020.