A manufacturing defect dating from the 1940s was the primary factor that caused an Exxon Mobil pipeline to rupture in a Mayflower subdivision more than three months ago, spilling more than 100,000 gallons of heavy crude oil into yards, a street and a cove of Lake Conway, a company spokesman said Wednesday.
The long-defunct manufacturer, Youngstown Sheet and Tube Co., also made pipe segments that are in use elsewhere in the roughly 850-mile-long Pegasus pipeline, which runs from Patoka, Ill., to refineries along the Gulf Coast of Texas, Exxon Mobil Corp. spokesman Aaron Stryk said.
Youngstown, started in the Ohio town of that name in 1900, was “one of the largest manufacturers … in the 1940s,” Stryk said. “They were a large supplier to this industry, and we do have other pipe segments manufactured” by Youngstown in the Pegasus and other pipelines.
But Stryk said, “It’s premature to conclude at this time that those pipe segments are susceptible to failure.”
The Youngstown company’s exact date of closure is unclear, though a Wikipedia posting says the steel manufacturer remained in business until 1977. The Pegasus pipeline, built in 1947 and 1948, has been shut down since the March 29 spill.
It’s not yet known what other oil companies may have Youngstown-made pipe segments still in use.
Stryk’s comments came just hours after an independent laboratory that had examined the damaged pipeline section submitted a report detailing its findings to Exxon Mobil and the federal Pipeline and Hazardous Materials Safety Administration.
Agency spokesman Damon Hill said the administration would review the report before releasing it.
Stryk said the report cites the primary cause and factors that contributed to the rupture between two houses in the Northwoods subdivision.
“The root cause of the failure can be attributed to original manufacturing defects, namely hook cracks near the seam,” he said. He defined those cracks as “metal separations resulting from imperfections at the edge of the plate, parallel to the surface, which turn toward the inside diameter or outside diameter pipe surface when the edges are upset during welding.”
Contributing factors, Stryk said, included the pipe segment’s “extremely low-impact toughness and elongation properties across the … seam.” Those properties refer to the pipe’s flexibility or ability to stretch.
“It’s sort of like a trash bag,” he said: If the bag is tough enough, it won’t tear if it’s stretched.
The laboratory is still studying such things as the pipe’s toughness, Stryk said. There were no findings of corrosion, he added.
According to the pipeline agency’s website, this kind of pipe - called electric resistance welded, or ERW, pipe - is longitudinally welded.
“A failure in the weld seam of this type of pipe can propagate for a distance along the pipe and can quickly release large quantities of product to the environment,” the website says. “Low-frequency … ERW pipe installed prior to 1970 in particular can be susceptible to such failures. [The Pipeline and Hazardous Materials Safety Administration] issued advisory bulletins in 1988 and in 1989 on [low-frequency] ERW pipe that was prone to failure, alerting industry of the need to have a monitoring and replacement program for [low-frequency] ERW pipe. PHMSA conducted further studies in 2000 and 2003 on ERW pipe. Integrity management regulations have special provisions for evaluation of integrity threats for this type of pipe.”
Regarding the manufacturing defects in the Pegasus pipeline section, Stryk said in an email that Exxon Mobil officials “had no indication [beforehand] that this particular manufacturer’s pipe was more susceptible to failure than others during that period.”
“The integrity of any line depends on its type of service, ongoing maintenance and inspections and a variety of other factors. The supplemental testing being conducted in coordination with [the pipeline agency] should help us understand the factors associated with the pipe failure and allow for the verification of the integrity of the Pegasus Pipeline,” he added.
Asked if retirement of the Pegasus line was among Exxon Mobil’s options, Stryk said, “We are evaluating all options.”
He said he could not speculate on specific options because there still is much testing and analysis still to do. He stressed, however, that before the company resumes “full operation of the pipeline, we will establish the integrity of the ENTIRE pipeline, and if we need to make modifications to our integrity management program, we will.”
One thing the development does mean, Stryk confirmed, is that the Pegasus line will remain shut down for the next 90 days and probably longer.
That’s how many days Exxon Mobil has to report back to the pipeline agency, Stryk said, on supplemental testing, results from an inline inspection run in February and mitigation steps - “what we need to do to keep this from happening again.”
“The work plan must provide for verification of integrity” of the entire pipeline “and must address all factors known or suspected in the failure,” he said.
Bernard Weinstein, associate director of the Maguire Energy Institute at Southern Methodist University’s Cox School of Business in Dallas, said he suspected that “the pipeline agency, based on this report, may actually mandate pipeline inspections” of the seams or seals of all companies that bought pipe from the Youngstown company.
The rupture took place on the afternoon of Good Friday and sent an estimated 147,000 gallons of thick Canadian oil rushing into residential yards, a street, a creek and a cove of Lake Conway. Of the many homes evacuated immediately after the spill, 22 remained vacant for months. Just recently, the residents of two of those houses have moved back and “several” others plan to do so, Stryk said. He said he did not know if the moves were permanent.
Hundreds of animals from ducks to snakes died as a result of the spill and cleanup efforts, and several lawsuits are pending. About 20 workers remain at the site compared with a peak of about 750.
Aaron Sadler - spokesman for Arkansas Attorney General Dustin McDaniel, who along with U.S. Attorney Christopher Thyer has sued Exxon Mobil over the spill - declined comment on the reported causes of the rupture. Sadler said the office had not received a copy of the laboratory’s findings.
Glen Hooks, senior campaign representative for the Sierra Club and a Little Rock resident, said in an email that if the causes Exxon Mobil cited are accurate, “then we have even more reason to be concerned about the integrity of the Pegasus Exxon Mobil pipeline-especially the 13.5 miles that fall within the Lake Maumelle watershed and threaten our drinking water in Central Arkansas.”
“The Exxon Mobil pipeline was never designed to carry this volume of dirty tar sands [oil] at high pressure and high heat. Today’s report should further strengthen the arguments by a growing number of people against ever restarting the Pegasus pipeline,” Hook added.
John Tynan, watershed protection manager for Central Arkansas Water, said he had not seen the report but said, “We need to know more about what led to this rupture” and what actions Exxon Mobil “will take to ensure this will not happen” again.
Further, he said, “If there are manufacturing defects present in the Lake Maumelle watershed, certainly we need to be aware of that.”
Stryk said three or four homes still have oil inside or beneath them.
“We are continuing to take samples under and beside these homes and watching to see what happens,” he added. “This is part of normal remediation work. … We are now looking for small droplets of oil.”
Exxon Mobil has offered to buy the 22 homes at pre-spill appraisal prices, but it had bought none of them as of this week, Stryk said. “However at least 10 of the evacuated residents have initiated the appraisal process and are close to reaching a purchase agreement” with the corporation, he said.
Among the residents still wanting to sell their homes is Joe Bradley, who with his 9-year-old daughter is living in a small home provided by Exxon Mobil.
“They need to shut the whole pipeline down,” said Bradley, noting he and his daughter have been sleeping on air mattresses because he doesn’t feel safe using the furniture from his Northwoods home.
Correction: In the article published Thursday, a comment was incorrectly attributed to Bruce Bullock, director of the Maguire Energy Institute at the Cox School of Business at Southern Methodist University. The comment should have been attributed to Bernard Weinstein, associate director of the institute, who said he suspected that “the pipeline agency, based on this report, may actually mandate pipeline inspections” of the seams or seals of all companies that bought pipe from a Youngstown company. The change has been made in the story above.
Front Section, Pages 1 on 07/11/2013