Possible Mix of Crudes in MT Pipeline Spill

Monday, July 18, 2011 @ 11:07 AM gHale

The Exxon Mobil pipeline that cracked and leaked 42,000 gallons of oil into Yellowstone River may have sometimes carried a heavier and more toxic crude. With a heavier crude, it could have caused the pipeline to corrode causing the rupture, federal regulators said.

The U.S. Transportation Department’s Pipeline and Hazardous Materials Safety Administration spokeswoman Patricia Klinger said her office just heard the pipeline may have carried heavier crude.

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“I just found out that apparently, and the regional folks just found out, there is an interconnect on the pipeline that possibly does carry some oil out of Canada.”

That a pipeline thought to transport only “sweet,” low sulfur crude could have carried tar sands crude from Canada raised concerns by health and environmental officials, even as Exxon officials said the heavier oil was not flowing through the Silvertip pipeline when it broke on July 1.

“The actual crude in the line at the point of the incident was a blend of crudes from Wyoming,” said Exxon spokesman George Pietrogallo.
The chemistry of tar sands oil, derived from tar sands or bitumen and sweet crude is significantly different, said Ronald Kendall, head of the environmental toxicology department at Texas Tech University.

“Tar sands oil is in itself heavier oil and it contains more compounds that are toxic and may contain heavy metals like lead,” Kendall said.
Exxon spokesman Kevin Allexon said in early July the crude carried by the pipeline “does not originate from Alberta” but from fields on the Montana-Wyoming border. Late last week Exxon revised that, saying “The pipeline carries a variety of different production fields in the U.S. and Canada.”

Tar sands crude may cause more wear and tear on pipes because of its chemical makeup, including corrosive and abrasive agents, said Tom Finch, the pipeline administration’s technical services director for the western regional office.

Federal inspectors were trying to determine if transport of tar sands crude could have triggered internal corrosion that may have played a role in the rupture, he said.

Exxon has apologized for the spill, which it estimates at 42,000 gallons, and pledged to restore a river prized for its near pristine waters, scenic beauty and abundance of wildlife.

EPA officials are analyzing the chemical fingerprint of the oil which, depending on its source, could contain anything from benzene, a known carcinogen, to hexane, a toxin that can damage the human nervous system.

Preliminary testing by the EPA shows no detectable levels of some hazardous compounds harmful to humans. But at least five residents went to the hospital for treatment of dizziness, nausea and respiratory distress, according to state environmental officials.