Renewed dilbit investigation faces similar hurdles of past debate

A correction was made to this article on Dec. 9.

A National Research Council committee opened a second investigation of potential environmental consequences from diluted bitumen (dilbit) spills from pipelines. It quickly became apparent that this committee would encounter similar problems balancing the need to keep the inquiry manageable while addressing a sufficiently wide range of questions.

Committee members noted that available incident data have improved since the earlier committee issued its findings in late June 2013 based on information from 2002 to 2011. NRC is one of the National Academies of Science, an independent, nonprofit organization.

Information was still being gathered from a 2010 dilbit spill from an Enbridge Inc. pipeline rupture near Marshall, Mich., while the first committee was doing its work. It issued its final report a few months after an ExxonMobil Corp. pipeline carrying dilbit began to leak on Mar. 29, 2013.

Findings from investigations of both of these incidents are significantly more informative than what previous inquiries produced, according to University of Michigan Energy Institute Director Mark Barteau, who helped lead the earlier NRC committee’s investigation.

“There’s more detail in the [National Transportation Safety Board’s] report on the Marshall, Mich., spill than what we had,” he said via teleconference from his Michigan office during the new committee’s Dec. 3 meeting. “It’s a deeper dive.”

Barteau said members of the earlier committee quickly discovered incident reports were not very detailed or useful. “They didn’t even specify the material which was released,” he added. Dilbit also is transported in the same pipelines as other crudes so it was hard to definitely identify residual characteristics, he said.

Wider scope

“In some ways, the scope grows wider when we talk about the uncontrolled environment outside the pipeline than what it’s like inside,” Barteau said. “You may need to look closely at several different issues we couldn’t consider.”

Like its predecessor, the new committee came into being in response to Congress passing a law that ordered a scientific investigation of dilbit transportation. The earlier study, requested by the US Pipeline and Hazardous Materials Safety Administration, examined whether dilbit could be more corrosive, and the committee ultimately concluded its properties are roughly comparable to other heavy crudes.

This time, the new committee, including a few members who worked on the 2013 study, will analyze whether dilbit’s stated properties differ enough from other crudes commonly shipped in US transmission pipelines to warrant modifications of PHMSA’s regulations governing spill response plans, preparedness, or cleanup requirements.

As part of its stated task, it will:

• Review available literature and data, including any available data from oil spill responses or cleanup, to determine the current state of knowledge of the transport, fate, and effects of dilbit once it’s spilled into an onshore or offshore environment.

• Identify relevant properties and characteristics that influence the transport, fate, and effects of commonly transported crudes, including dilbit, in the environment.

• Compare those identified relevant properties between dilbit and a representative set of crudes commonly shipped by pipeline.

• Analyze and determine, based on those comparisons, whether differences in environmental properties of dilbit and other crudes warrant modifications to regulations covering spill response, preparedness, or cleanup.

The new study already does not consider the full US crude oil transportation picture because it won’t address rail or other modes that have emerged as carriers since Congress made its request. “We’re really talking about pipeline transportation,” said Jeffrey D. Wiese, PHMSA’s associate administrator for pipeline safety.

Enough new pipeline issues have emerged since the earlier study for the committee’s 11 members to consider, he told them at the Dec. 3 meeting. Encroachment, as formerly rural land through which pipelines extend turns into residential communities, creates new high consequence areas where operators must take additional safety steps, Wiese said.

He said inadequate response prestaging was one issue that emerged during the 2010 Michigan leak. “But the biggest problem was lack of early recognition that there even was a leak,” he said. “If it had been discovered 10 hours earlier, we wouldn’t even be talking about it now.”

Wiese said officials at Enbridge radically revised their leak detection procedures following the Michigan pipeline rupture, and urge committee members to bring them in to discuss the changes. Training 911 telephone operators to more aggressively follow up leak reports is harder because it does not become a high priority until an incident occurs, he said.

“Most important, get out into the field where you’ll begin to understand what these communities face,” Wiese said. Marshall, Mich., site of the 2010 Enbridge leak, would be a good place to start, but Flower, Ark., where the ExxonMobil pipeline ruptured and leaked in 2013, might be better because part of the line remains shut down while remediation is completed, he said.

Poorly understood

Representatives from four other federal agencies told the committee its work would be appreciated because both responders and the general public poorly understand how dilbit behaves once it is spilled.

Steve Lehmann, scientific support coordinator in the National Oceanic and Atmospheric Administration’s Response and Restoration Office, said officials there are interested in dilbit’s fate and behavior effects, worker health considerations, relative toxicity to wildlife, and suitable shoreline and coastal alternatives.

Title 7 of the 1990 Oil Pollution Act created the Interagency Coordination Committee on Oil Pollution Research (ICCOPR), which works alongside a national response team of 14 different agencies, he said.

“My concern is if you look purely at pipelines, we won’t be looking enough at marine environments, which can be more dynamic,” Lehmann said. “Detection becomes more important at that point. There also have been several other spills which haven’t been widely reported. Some involved intermediate oils which make a big difference in toxicity, particularly when they are cut with other fuels.”

Brian Schlieger, a preparedness and removal team leader at the US Environmental Protection Agency, said protection of both the public and emergency response workers is important.

Benzene hazard

“At Marshall, we did a lot of urban benzene readings that led to a public evacuation over a fairly large area for about a week,” he told the committee. “In the intermediate spill area, there were persistent high benzene levels which made it necessary for response workers to wear respirators.”

Mark Howard, who works in EPA’s Emergency Management Office, said, “It’s not only crude that has variable benzene levels. Diluent does too. We need to know whether it has a high benzene content as we go to work.”

US Coast Guard Lt. Sara Booth, assistant to ICCOPR’s chair, said the US Department of Homeland Security agency is interested in differences between how dilbit and conventional crudes respond in sand and sediments so it can determine whether different types of spill response equipment are needed. “Information about dilbit transportation modes beyond pipelines also would be helpful,” she said.

It’s also important to learn how dilbit behaves when it is mixed with sediment, suggested Faith Fitzpatrick, a research hydrologist specializing in fluvial geomorphology at the US Geological Survey. “We learned at Marshall that it doesn’t sink on its own, but takes sediment on quickly, causing sheens and globules,” she told the committee. “Not only did it submerge, but it responded and migrated. That’s where we needed new science to collect it while it’s at the bottom.”

She said there is not much information about how oil behaves in inland water bodies, where flows and temperatures can vary, channels can be wide or narrow, and slopes can be shallow or steep. “The Kalamazoo River was not pristine at the time of the Marshall spill,” Fitzpatrick said. “There were a lot of industries along it. Oil fingerprinting was needed to definitively identify contaminant sources.”

Enbridge used as an agitation technique in the Kalamazoo River following the 2010 leak to bring most of the spilled dilbit to the surface, she noted. It also drove some of what was submerged 2 ft deeper into sediment at the channel’s bottom, Fitzpatrick said.

The committee will confront other wide ranging questions as it refines the scope of its research and pursue its inquiries, confirmed Robert Smith, research and development manager in PHMSA’s Pipeline Safety Office who is helping manage the new study. “We have a 21-month timeline, but there is some urgency to report on this,” he said.

Contact Nick Snow at

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