There's an election going on up here in Canada, right now. Current Conservative PM Stephen Harper, perhaps feeling pressure on environmental issues from the Green and New Democratic parties, recently made a promise to 'restrict' the exports of raw bitumen, which is the primary product of the Athabasca tar sands projects;
"If re-elected [a] Harper government will prohibit the exportation of bitumen outside of Canada for upgrading in order to take advantage of lower pollution or greenhouse gas emissions standards elsewhere," the Conservatives said in a statement. "We cannot allow companies to increase exports of raw bitumen simply in order to avoid Canadian emissions standards as they are strengthened over the next few years. Nor can we afford to export the jobs and spin-off industrial opportunities by the upgrading of bitumen."
Currently, the only country currently receiving exports of raw tar sands bitumen is the United States - Which could prove a problem for the World's Dirtiest Oil...
From the same National Post article, above;
Should Canada's pollution targets be considered to better those in the United States, this could serve as a blow to the oil sands industry -- a pillar of the Western Canadian economy.
While most of the bitumen mined out of the tar sands is upgraded in Alberta, about 30% is exported - around 500,000 barrels per day. This exported bitumen, which must be upgraded before it can be used, is processed at such facilities as the BP Whiting refinery, near Chicago, and the ConocoPhillips plant near Billings, Montana.
This is the second move in as many months that has threatened to turn off the tap of tar sands oil to the United States; this past June, at the U.S. Conference of Mayors meeting in Miami, delegates moved to restrict fuels derived from bitumen mined in the Tar Sands Projects.