Two websites offer information about the chemicals found in dilbit: CrudeMonitor.ca and Environment Canada's oil properties database. But those websites only list the kinds of chemicals found in diluents, not the exact chemical composition.
For instance, CrudeMonitor.ca lists the volume of octanes found in specific dilbit blends. Octanes are a class of chemicals, and there are at least 18 different octane compounds, each with its own chemical properties. "They talk about the type of molecules and not the specific molecules, and that [makes] a big difference when it comes to the dangers" of those chemicals, said Anthony Swift, a policy analyst at the Natural Resources Defense Council.
Swift said there are health and safety reasons for encouraging better disclosure of the chemicals found in diluents. It's harder to clean up an oil spill if you don't know what you're dealing with, he said, and "first responders need to be aware of what they're encountering."
What Happens in a Dilbit Oil Spill?
After a spill, some of the dilbit will float on the water and it can be skimmed off just like oil from a conventional oil spill. But over time, many of the light hydrocarbons found in the diluents will gas off into the atmosphere, leaving behind the heavier bitumen, which will sink below the water surface. Cleanup crews must scoop up the bitumen from beneath the water to prevent further damage to the river.
The Enbridge spill on the Kalamazoo River was the largest dilbit spill in U.S. history. In various media interviews, EPA personnel have said that the nature of the oil made it harder to clean up the spill. Mark Durno of the EPA told reporters that the heavy submerged oil was "a real eye-opener ... In larger spills we've dealt with before, we haven't seen nearly this footprint of submerged oil, if we've seen any at all." The EPA originally believed it would take two months to clean up the spill. But in October, the agency announced that the cleanup will continue through the end of 2012.
Are Pipelines the Only Place Where Dilbit's Corrosiveness Is a Concern?
Some researchers believe that the risks posed by dilbit will be borne out not only in the pipelines, but also in refineries, where the substance is processed at extremely high temperatures. The intense heat could release sulfur from the oil molecules in dilbit, corroding refinery equipment and possibly creating leaks or explosions.
If information about dilbit is so hard to find, where are environmentalists getting their data?
Both supporters and opponents of dilbit rely on industry materials, government data and academic articles in their arguments. Here are some of the sources used by the National Resources Defense Council, which is leading the crusade against dilbit, in its oft-cited report, "Tar Sands Pipelines Safety Risks": information from the U.S. Department of Transportation Pipeline Hazardous Material Safety Administration and the Canadian Energy Resources Conservation Board, articles in the scholarly journal Petroleum Science and Technology, and documents from the Canadian Association of Petroleum Producers.
What Data Is the Industry Using to Support Its Position That Dilbit Is Safe?
Industry groups point to the lukewarm evidence of dilbit's danger as proof of its safety. Peter Lidiak, pipeline director for the American Petroleum Institute, told InsideClimate News that the API has reviewed Department of Transportation data from 2002 and found no instances of internal corrosion in pipelines carrying dilbit.
"Dilbit has very similar characteristics to other types of heavy crudes," Lidiak said. "Most refineries have been upgraded to handle the heavier products like dilbit. I'm not worried about any potential safety issues there."
What Is the State Department's Position on Dilbit?
At the end of August, the State Department released its final environmental review of the Keystone XL project. The report did not explore concerns related to dilbit's corrosiveness or the lack of information about its composition.
What Would a Comprehensive Study of Dilbit Require?
Swift said a study would need to focus on three areas: the frequency of spills in pipelines carrying dilbit, the effects of dilbit on leak detection systems and any additional risks and cleanup challenges. He estimated that such a study would take about a year and would involve a review of the historical data available on dilbit pipelines as well as testing of existing pipelines.