The letter cited estimates that oil from tar sands produces 14 per cent to 40 per cent more greenhouse gas than conventional oil because of the energy consumed in extracting and refining it. The law was drafted in response to US air force plans to build its own "coal-to-liquids" fuel plants, the letter said.

But lawyers warn that, though they apply equally to domestic and imported fuels, such policies could be seen as an unfair restraint on trade if they have a disproportionate impact on exporters of oil from tar sands. "The US could end up being accused of de facto discrimination based on where these petroleum deposits are found."

The Pentagon said it would comply with federal guidelines but claimed the legislation did not rule out buying fuel from coal-to-liquids or tar sands. It could not say why it disagreed with Congress on this point. The US trade representative's office did not respond to a request for comment.

U.S.Military Denied Canadian Fuel By "The Energy Independence and Security Act of 2007"

It’s quite ironic that a bill entitled, "The Energy Independence and Security Act of 2007" would actually sabotage one significant path to weaning ourselves from Middle East oil. Canadian tar sands, after all, hold two-thirds the oil reserves of Saudi Arabia (175 vs. 262 billion barrels).

Democrat presidential candiates Sens. Hillary Clinton (D-NY) and Barack Obama (D-IL) voted for the bill; Sen. John McCain (R-AZ) was not present for the vote.

http://junkscience.com/blog_js/2008/02/18/us-military-denied-candian-fuel-by-energy-bill-climate-worries/