Tony Clark, the chairman of the North Dakota Public Service Commission, speaks during a commission meeting on Friday, May 13, 2011, in the commission's hearing room on the 12th floor of the North ... more 
Tony Clark, the chairman of the North Dakota Public Service Commission, speaks during a commission meeting on Friday, May 13, 2011, in the commission's hearing room on the 12th floor of the North Dakota Capitol in Bismarck, N.D. The commission voted Friday to order a formal investigation of a May 7, 2011, oil spill from the TransCanada Corp. pipeline in southeastern North Dakota. less 
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Associated Press | Photo By Dale Wetzel
Fri, May 13, 2011 1:36 PM EDT