Anchorage Daily News:

A pipeline leak-detection system sounded warnings on four straight days in the week leading up to last month’s record North Slope oil spill, but field workers interpreted the signals as false alarms, a new investigative report says.

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The report, prepared by a team of BP and state investigators, confirms that the leak from a large Prudhoe Bay oil field pipeline went on undetected for at least five days "and probably much longer."

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