Susceptible to Deterioration and Rupture

detail of a pipeline joint showing some rust

NAS Reports Dilbit in a pipeline acts like some other types of oil

In December 2011, Congress passed legislation requiring that a study of diluents be conducted. "TRB Special Report 311: Effects of Diluted Bitumen on Crude Oil Transmission Pipelines ( 2013 )" was released by the National Academy of Sciences June 25, 2013. The study narrowly confines its purpose to determining whether diluted bitumen is more likely to cause a pipeline to leak than are any other types of crude oil. The study does not address the size, toxicity or difficulty of remediation of spills of this type of oil.
Pipelines Susceptible to Deterioration and Rupture

The additional sulfur can lead to the weakening or embrittlement of pipelines.[1] Tar sand oil’s high concentrations of chloride salts can lead to stress corrosion in high temperature pipelines.[2] Higher quantities of abrasive quartz particles can also be found.[3]

This combination of chemical and physical abrasion can dramatically increase the rate of pipeline deterioration.[4]

The resulting corrosion and abrasive nature of tar sand crude is heightened by the relatively high heat and pressure by which these pipelines are used to transport the thick Dilbit.

While industry defines high pressure at 600 psi, tar sands pipelines operate at up to 1440 psi and temps up to 158°.[5]

The pipeline industry and the National Academy of Sciences study (see text box at left) say that other types of crude oil than diluted bitumen have these same properties. Environmentalists consider such a narrow conclusion to be irrelevant.[6]


1.^William Lyons and Gary Plisga, Standard Handbook of Petroleum and Natural Gas Engineering, Burlington, MA: Gulf Professional Publishing, 2005, p. 4-521

2.^Planning Ahead for Effective Canadian Crude Processing, Baker Hughes, 2010, p. 4,; A.I. Williams, Degradation Mechanisms in the Oilsands Industry, Calgary, Alberta: Ammonite Corrosion eng. Inc. 2006

3.^2008 NPRA Q&A and Technology Forum: Answer book, Champion's Gate, FL: National Petrochemical and Refiners Association, 2008, Question 50, Desalting, (no longer available at this address; see

4.^Henry Liu, Pipeline engineering, Boca Raton, FL: CRC Press LLC, 2003, p 317

5.^"Keystone Pipeline, USA" Net Resources International, 2011, Draft Environemtnal Impact Statement for Keystone XL, Appendix L: Pipeline Temperature Effects Study, U.S. Dept. of State, 2010,

6.^"NAS Dilbit Study Fails to Study Tarsand Spill Effects" Mark Hefflinger, Bold Nebraska, June 24, 2013.