WASHINGTON - The U.S. House Subcommittee on Railroads, Pipelines and Hazardous Materials, chaired by Rep. Bill Shuster (R-Pa.), held a hearing on July 14 to focus on the July 1 release of crude oil from the Exxon Mobil Silvertip Pipeline in Yellowstone County, Mont.
It will take several months to investigate the cause of the leak, the U.S. pipeline safety regulator told Congress on July 14.
"We will also ensure that the Silvertip pipeline is free of safety and environmental risks before Exxon Mobil is granted permission to restart the line," Cynthia Quarterman, head of the Pipeline and Hazardous Materials Safety Administration (PHMSA), told lawmakers at a House hearing on the leak.
Quarterman said the Yellowstone River was still too high to examine the pipe that leaked, and it "may take weeks if not months" before the pipeline can be brought up from the river bed.
She added that PHMSA has routinely inspected the pipeline for years. "As recently as June 6-10, 2011, PHMSA personnel performed an integrity management field inspection on the Silvertip pipeline," she said. It reviewed Exxon Mobil's 2009 internal inspection data for the line and found no violations. It did find, however, an anomaly at the river crossing that was below required repair conditions under federal pipeline safety regulations, she said.
ExxonMobil Pipeline Co. exceeded burial requirements for its Silvertip crude oil pipeline in Montana before it ruptured Quarterman said. PHMSA requires at least four feet of cover when a pipeline crosses a river that is 100 or more feet wide. When ExxonMobil performed a depth-of-cover survey in December 2010, it found five feet of cover in the riverbed and 12 feet of cover on the crossing's south side, she said.
On July 13, Exxon said it had begun preliminary work to replace the pipeline segment that ruptured and spilled an estimated 1,000 barrels of oil into the Yellowstone River in Montana on July 1.