Source: http://enr.construction.com, May 6, 2013
By: Candy McCampbell
One month after a pipeline rupture sent 210,000 gal of heavy crude oil through an Arkansas neighborhood, officials announced initiation of a “reentry plan” so residents can start returning to their homes.
That return will be “over the next few weeks,” according to a statement from the city-county-EPA-ExxonMobil command headquarters in Mayflower, Ark., near Little Rock.
“We are working with the construction crews and local Unified Command now to try to finalize the details around dates/times for these questions, but we don’t have that just yet,” Russ Roberts, ExxonMobil spokesman, says in response to questions about when homes would be available for occupancy and the neighborhood cleaned up.
The cause of the 22-ft gash in the Pegasus pipeline on March 29 is still under investigation. The 90,000-barrel-a-day pipeline carries diluted bitumen crude, or dilbit, from Patoka, Ill., to Nederland, Texas.
Meanwhile, the pipeline had a second, smaller breach near Doniphan, Mo., about 200 miles north of Mayflower. ExxonMobil said it was notified April 30 and that about one barrel, or 42 gal, leaked. The repair was completed May 3, but the pipeline remains shut down.
That breach is also being investigated. A preliminary investigation indicates the breach is related to action by an unspecified third party, Roberts says. The pipeline is marked.
However, Renee Bungart, Missouri Dept. of Natural Resources spokeswoman, says, “Upon excavation, Exxon has determined the release occurred from the installation of a guide wire used to support a powerline pole … located almost directly on top of the pipeline.”
In Mayflower, the 53-ft section of the pipeline that was removed has been sent to Hurst Metallurgical Research Laboratory Inc. in Euless, Texas, for testing.
One pipeline safety expert who has seen photos of the gash blames welding practices used in the 1940s, when the 850-mile-long pipeline was constructed.
“It looks like this is a seam-related weld failure,” says Richard Kuprewicz, president of Accufacts Inc. in Redmond, Wash. “They show up in pipe manufactured in the early ‘70s or earlier.”
However, he cautions, detailed metallurgical tests will have to be performed to determine the cause.
In Kalamazoo, Mich., where a pipeline break dumped more than 1 million gal of a similar heavy crude into the Kalamazoo River in July 2010, the EPA is making pipeline owner Enbridge Inc. return this summer to dredge three sites where large deposits of oil sludge still remain.
The areas are near Ceresco Dam, the Mill Ponds impoundment near Battle Creek and the Morrow Lake delta.
The new cleanup will cost an estimated $175 million, says Enbridge spokesman Jason Manshum. The company has spent $820 million on cleanup and related costs.
Work will start around July 1 and the EPA set a Dec. 31 deadline for completion.
The spill occurred after a break in Enbridge’s 30-in.-dia Line 6B pipeline near Marshall, Mich., during heavy rains that sent the oil almost 40 miles downriver.
Enbridge was hit with a $3.7-million fine. The National Transportation Safety Board, which investigated the spill, cited the company’s slow response to the break and earlier lack of attention to previously-known problems with the pipeline.
Breaks like these fuel fears by safety experts, environmentalists and residents for areas to be crossed by the proposed Keystone XL Pipeline from Alberta, Canada, to the Texas coast.
The dilbit spilled in Michigan is in a “molasses-like state” in the river and the proposed cleanup is the most invasive option, says Steve Hamilton, professor of ecology at Michigan State University who worked on a study of the river after the spill.
“The real challenge (with the bitumen crude) is you can’t see it, you can’t control it, it’s hard to measure and only makes itself known when you disturb the sediment,” he says.
The dredging involves “scooping up the whole bottom habitat,” including clams, mussels and organisms that make up the base of the food chain for fish, he says.
“It is very intrusive, with heavy equipment and a staging area on land,” he says. “It’s about as disruptive as you can imagine, short of draining the place.”
A similar but smaller situation is possible in Arkansas, Hamilton says.
ExxonMobil and Arkansas officials maintain that nearby Lake Conway has not been contaminated, but Hamilton counters that photos and videos of a lake cove show otherwise.
“They will doggedly go after any oil above the water, and get the floating oil in a matter of weeks,” he says. “The problem will be what’s lurking under the surface.”
Part of Enbridge’s Michigan cleanup cost — the company won’t specify how much — was the purchase of about 150 properties along the river that were damaged during the spill. Most of those were single-family homes.
ExxonMobil has offered to purchase the properties in Mayflower, paying for independent appraisals, closing costs and moving expenses. It is also offering $10,000 per household for “the disruption and inconvenience.”
That has not prevented homeowners from filing a lawsuit over damages resulting from the spill and seeking class-action status.
ExxonMobil also is a defendant in lawsuits by landowners in eastern Montana after a pipeline break in July 2011 dumped 63,000 gal of crude into the Yellowstone River, soiling about 70 miles of riverbank.
Plaintiffs won’t comment to reporters, but they charge the company with damage to property and livestock operations after its Silvertip pipeline broke during heavy flooding. It has since re-buried sections of the 12-in pipeline as much as 70 ft below the riverbed.
Jim Hall, former chairman of the National Transportation Safety Board, says a pipeline under a river like the Yellowstone “needs to be buried to a specific depth so the changes in water flow characteristics don’t affect the pipeline,” and the depth depends on each situation.
However, ExxonMobil spent $135 million on cleanup, $1.7 million on a PHSMA fine and $1.6 million in state fines.
While oil stains can still be observed on river rocks, the oil spilled in Montana is a lighter weight so the cleanup was faster and more complete.
The riverbanks and fields have been repaired or affected crops paid for, says Steve Lackman, Montana State University agricultural agent for Yellowstone County.
The good news: river water was not being used at that time for irrigation, though the area is heavily dependent on it, he says.
Critics have questioned the safety of transporting dilbit, which has more tar sands than conventional crude and might have a caustic effect on pipe. One possibility: a change in rules by PHMSA.
“We are working to better understand diluted bitumen,” says Damon Hill, PHMSA spokesman. The agency hired the National Academy of Sciences to determine if dilbit has a higher risk of release than other types of crude. That report is due in July.