Obama's own former deputy press secretary is leading the charge to push the president to stop the pipeline.
Bill Burton quit his job before the 2012 election to head up the super PAC Priorities USA, which worked for the president's re-election. In January, he joined the PR firm Global Strategy Group as an executive vice president.
He is now representing a new coalition, "All Risk, No Reward," which opposes Keystone XL. It goes after the additional greenhouse gases but also showcases the damage to Americans in the heartland caused by spills.
Obama must decide
Obama has promised to decide soon on whether or not to allow the TransCanada oil company to lay the 835-mile long Keystone XL pipeline from Alberta, Canada, to Steele City, Neb.
The Keystone XL would pump 830,000 barrels of oil sands crude per day through America's heartland, connecting crude producers in Canada with refineries and shipping companies in the United States.
TransCanada would cover all the costs, proponents argue, making it practically a gift to the U.S. oil infrastructure.
On its way to Nebraska, where it would connect with other, already existing pipelines, Keystone XL would pick up additional oil produced in Montana and North Dakota and stream it south, TransCanada said on its website.
It would reduce "American dependence on oil from Venezuela and the Middle East by up to 40 percent," TransCanada extols.
But the EPA is also concerned about oil spills, particularly since sands crude is different from conventional crude.
It cites a 2010 pipe break in Michigan, which spurted out 20,000 barrels of sands crude. Some of it sank to the bottom of the Kalamazoo River and could not be completely cleaned up in three years' time, the EPA said.
"Spills of diluted bitumen may require different response actions or equipment," the letter stated. "These spills can also have different impacts than spills of conventional oil."
The State Department's assessment represents its second go-round with the Canadian company. It originally rejected a permit from TransCanada, last year, over the proposed route through Nebraska. TransCanada came up with a new route that the State Department approved of, but the EPA says it misses the mark.
Nebraska's Republican Gov. Dave Heineman has approved the project, and U.S. Rep. Lee Terry, R-Neb., has called for the Keystone XL's construction in a Republican radio address.
The pipeline "is primed to give our economy a shot in the arm and make energy more affordable -- and it won't cost the taxpayers a dime," he argued.
Terry spoke a day after an apparent pipeline rupture in the Arkansas town of Mayflower in late March, about 20 miles north of Little Rock.
Black torrents of diluted bitumen flowed through the community, forcing the evacuation of 22 homes.