The National Resources Defense Council responds to the most recent spill of tar sands oil — from the very pipeline that the proposed Keystone XL line will connect to — and point out that this is just the latest in a long line of spills from a line that is less than a year old. Over the last year we’ve had many recent indications of the risks of tar sands diluted bitumen pipelines – an 840,000 gallon spill in Michigan, a 250,000 gallon spill outside Chicago, a 1.3 million gallon spill in Alberta, as well as our recent report examining the safety of tar sands pipelines . On May 7 , the Keystone tar sands pipeline provided yet another warning when it spilled approximately 21,000 gallons of crude in North Dakota. This is its eleventh and most significant spill.