Enbridge failed to grasp the significance of the cracks or to put together findings from separate tests of pipe wall thickness in a way that would have led them to dig up the pipe for a visual inspection, he said.
The report urged the pipeline agency to strengthen its rules for inspecting cracked lines and to develop training requirements for control center staff. It also called for public awareness campaigns in areas with underground pipelines and better planning to deal with pipeline emergencies.
Hersman said the Michigan spill raised some of the same issues as the 2010 Pacific Gas & Electric Co. pipeline explosion that killed eight people and injured 58 others in San Bruno, Calif.
"While our findings raise red flags about the safety of these two companies, they should also force us to ask hard questions of this vital industry," she said. "With more than 2.5 million miles of pipeline running through this country — enough to circle the Earth 100 times — we have to ask, 'Are these companies representative of others?' If the answer is yes, we can expect to be back here again discussing the same issues with a different company."
Deb Miller, 57, who lives near the Ceresco dam on the Kalamazoo River, watched parts of the NTSB meeting online.
"We know and realize now that our river is never going to be the same," Miller said. "What can we learn from this and share with the rest of the country so nobody has to go through what we went through?"
Flesher reported from Traverse City, Mich. AP reporter Joan Lowy in Washington contributed to this story.
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