Wednesday, April 10, 2013
All eyes are now on Mayflower, a quaint little suburban town in rural Arkansas surrounded by streams, lakes and wetlands. And now, tar sands crude.
On March 29, Exxon’s underground Pegasus Pipeline ruptured, spilling as much as 294,000 gallons of dirty tar sands crude in and around Mayflower. And by “in”, I mean down streets, across lawns, and into gardens, canals, storm sewers, creeks, wetlands and even into nearby Lake Conway, a popular among locals for its fishing and other recreational activities.
If Mayflower has taught us anything, it’s that pipeline spills can happen anytime, anywhere, with disastrous consequences (especially when it’s in the path of tornado). “All of us are in shock,” David Fox, the pastor of the local First Baptist Church, told Inside Climate News. “Manmade disasters are so rare in our state … you don’t think this kind of thing can happen to you.”
But there are a few more specific lessons to be mulled over by those, like President Obama, who must decide whether to allow new tar sands pipelines to be built, and like the NEB, who are deciding whether to allow old oil and gas pipelines to carry more corrosive tar sands crude, through communities across the United States and Canada.
Tar sands crude is nasty stuff
Seven years ago, Exxon reversed the flow of the pipeline and turned it into a higher-volume line carrying diluted bitumen, or dilbit, flowing under greater pressure from Canada to refineries on the Gulf Coast.
Dilbit, you may be interested to know, is much more dangerous to transport by pipeline than conventional oil. Dilbit is created by diluting bitumen, a heavy tar-like substance containing numerous toxic substances, with either conventional light crude or diluent, a cocktail of natural gas liquids. In this form, it has the consistency of conventional crude and can be pumped through pipelines, but it carries additional risks. The exact composition of diluents are secret, but the mixture often includes benzene, a known human carcinogen.
The secret and not-so-secret ingredients in dilbit may mean it’s even more toxic than regular old light crude. “Without more information on the chemical characteristics of the diluent or the synthetic crude, it is difficult to determine the fate and transport of any spilled oil in the aquatic environment,” wrote the EPA in response to the U.S. State Department’s Draft Environmental Impact Statement for the Keystone XL Pipeline. “For example, the chemical nature of dilutent may have significant implications for response as it may negatively impact the efficacy of traditional floating oil spill response equipment or response strategies. In addition, the Draft EIS addresses oil in general and as explained earlier, it may not be appropriate to assume this bitumen crude/synthetic crude shares the same characteristics as other oils.”
Dilbit, unlike synthetic crude, also is more acidic and corrosive than conventional oil. This increases the risk of pipeline leaks, something Congress recently ordered the Pipeline and Hazardous Materials Safety Administration (PHMSA) to study. Studies also indicate that pipelines operating at temperatures above 100 degrees Fahrenheit spill up to 23 times more often due to external corrosion than conventional oil pipelines. The State Department estimates the proposed Keystone XL tar sands pipeline would operate at between 130 to 150 degrees. It was corrosion that caused an Enbridge pipeline to rupture and spills not once, but twice near Marshall, Michigan.
It is also harder to clean up when, inevitably, it spills. When Enbridge’s Pipeline 6B split open in 2009 and spilled one million gallons of dilbit into the Kalamazoo River, near Marshall, Michigan, the dilbit initially floated on the water like conventional crude. But once the volatile diluents evaporated into the atmosphere, the heavy bitumen sank into the water. Because you can’t see it, it’s more difficult to remove.
“[It's] not something a lot of people have dealt with,” said an Environmental Protection Agency (EPA) official at the Kalamazoo River clean-up site. “When you can’t see [the oil], you don’t know where it is, so it’s very hard to clean it up.”
Old pipelines leak more than new ones
The Pegasus Pipeline was 65 years old when it ruptured. Older pipelines, which have undergone decades of wear and corrosion, can be more prone to leaks, and thus less safe, than new pipelines—especially pipelines carrying corrosive dilbit at higher temperatures.
According to the corrective action order issued by the U.S. Pipeline and Hazardous Materials Safety Administration, the “age of the pipeline”, as well as the reversal of its flow and its location near water resources and populated areas, makes the Pegasus Pipeline “hazardous to life, property, and the environment” until “corrective measures” are taken. Even Canada’s Minister of Natural Resources, Joe Oliver blamed the spill on the pipeline’s age.
Reversing pipelines can be dangerous
When Exxon reversed the Pegasus Pipeline in 2006, it was the first time it had ever been done, a feat of engineering Exxon (ironically, in hindsight) called “historic”. According to federal rules, no permit application or safety review was required to reverse the flow of the Pegasus Pipeline.
The Pipeline and Hazardous Materials Safety Administration (PHMSA) sees things differently now. After the spill, PHMSA issued a corrective action order that admits “a change in the direction of flow can affect the hydraulic and stress demands on the pipeline.” (Woops. Should have thought of that before I guess.)
The Mayflower-Pegasus spill now brings into focus, perhaps for the first time, the increasingly popular industry practice of reversing and repurposing existing pipelines in order to transport booming supplies of heavy crude out of the tar sands region north of the border.
Think tar sands pipelines are safe? Think again.
All of these characteristics make transporting tar sands crude by pipeline much more dangerous than conventional crude. Just ask the people in Mayflower, Arkansas. This is something decisionmakers must carefully consider when they review permits for the growing network of new and repurposed tar sands pipelines that will run through, over or near hundreds of communities and thousands of streams, rivers, wetlands, lakes and aquifers in British Columbia, Ontario, Quebec, New Hampshire, Vermont, Maine, Montana, South Dakota, Nebraska, Missouri, Kansas, Oklahoma and Texas.
‘Cause really, no one should have to live with the risks and consequences of tar sands oil spilling into their own backyard, local water supply or favourite fishing hole. I mean, really.
(Read more about dilbit in Inside Climate News’s Dilbit Primer, and about the enhanced risks dilbit poses to pipelines at NRDC’s website.)