Nov 1 Tesoro Logistics LP on Friday
said it is restarting the 20-year-old North Dakota pipeline that
spilled 20,600 barrels of oil onto farmland in September after
it secured permission from federal regulators.
The U.S. Department of Transportation's Pipeline and
Hazardous Materials Safety Administration (PHMSA) had issued a
safety order on Thursday, ordering Tesoro to make fixes on the
pipeline and the larger North Dakota system of which it is a
A local farmer discovered the leak, the biggest in North
Dakota since the oil boom took off a few years ago and the
biggest spill on U.S. soil since an Exxon Mobil pipeline
leaked 5,000 to 7,000 barrels of heavy Canadian crude in
Mayflower, Arkansas last March.
There are no indications that corrosion or other defects led
to the leak, Tesoro said in statement. Preliminary results of
the investigation point to a small hole that was created by an
electrical discharge, the company added.
"The source of the electrical current remains under
investigation," Tesoro's statement reads in part.
The federal regulator echoed Tesoro's statements on the
cause of the leak.
"Lightning could be the source, but the metallurgical
examination will look at all possible factors that may have
caused the failure," Damon Hill, a PHMSA spokesman said in an
A routine inspection had detected some anomalies on the
pipeline a few days before the leak.
The ruptured pipeline runs 35 miles from Tioga to Black
Slough in North Dakota. It was built by BP Plc BP.L in 1993.