The environmental cost of Obama not letting oil pipelines be built

If you don't allow pipelines to be built, the oil gets shipped by railroad.  Unfortunately, because of many government regulations, the railroads have a lot of accidents.  Delaying the Keystone Pipeline for years means a lot more oil gets shipped by the Burlington Northern railroad (his supporter Warren Buffet owns the railroad).  From the WSJ:

From 2010 to 2012, 112 oil spills were reported from U.S. rail tanker cars, up from just 10 in the previous three years, according to the Pipeline and Hazardous Materials Safety Administration, a part of the Department of Transportation that tracks most releases of hazardous materials. But the amount of crude leaked in spills has declined since 2008, when a big accident in Oklahoma released more than 1,900 barrels. On August 22, 2008, a BNSF Railway Co. train carrying crude derailed northeast of Oklahoma City; five tanker cars leaked oil that caught fire, leading to an evacuation of nearby residents. 

Questions about the safest way to transport crude are bubbling up as President Barack Obama considers whether to approve an expansion of the Keystone pipeline, which would move crude from the oil sands of Alberta, Canada, to the U.S. Gulf Coast. Pipelines carry much more crude than trains and have fewer leaks per mile, though failures can be serious. In 2010, for example, an Exxon Mobil Corp. pipeline spilled 1,500 barrels of oil into Montana's Yellowstone River in an hour. The possibility of oil spills from derailments is only beginning to be on the public's radar. . . .