"Dilbit" is a contraction of "diluted bitumen", a little word loaded with controversy that has recently entered the English vocabulary. This is because "bitumen", a word in long existence, has entered popular use as the peanut butter-like concentrate extracted from Alberta's tar sands. Since bitumen is too thick to move through pipelines, it is diluted with benzene, naphtha, hydrogen sulphide and other proprietary ingredients — "diluent" — to make the bitumen fluid enough to be pumped. The result is dilbit, usually about 70 percent bitumen and 30 percent diluent. Although often compared to crude oil, it is categorically different.
This was illustrated on July 25, 2010, when 3 million litres of dilbit burst from Enbridge's 6B pipeline into Michigan's Kalamazoo River. Unlike crude oil, dilbit only floats for about nine days — more or less, depending on temperature and weather conditions. Then the solvents of the diluent evaporate, the dilbit reverts to bitumen and usually sinks if the spill is in water. At this point the traditional methods of recovering crude no longer work. (As a comparison, about 10 percent of conventional crude oil sinks.) Even the 15 percent recovery of a marine oil spill — the usual measure considered a "successful" cleanup — is unlikely. After the volatile, toxic and carcinogenic components of the diluent release into the air, the bitumen migrates to the bottom of the river or ocean, where its dispersal is essentially unstoppable and cleanup is nearly impossible. River ecologies pose a special problem because removing the bitumen from the bottom usually causes irreparable trauma to the sediment and gravel of the living bed.
This dilbit is the material that Enbridge's $6 billion Northern Gateway pipeline would move over and under 773 of BC's creeks, streams and rivers on its way from Alberta to Kitimat. And this is the material that tankers would be transporting along 230 km of the narrow and winding Douglas Channel, past the shoals and reefs of Caamano Sound, then through the waves and storms of Hecate Strait on its way to offshore markets in Asian.
The imagination boggles at the environmental implications of a spill occurring anywhere along this route. How is bitumen to be recovered from any of the remote watercourses along the 1,172 km of the pipeline? The delays caused by remote and inaccessible locations would mean that bitumen would be dispersed along countless kilometres of pristine rivers before — or even if — cleanup crews could arrive. This is treasured wilderness, nature's heaven, salmon country, the indispensable heartland of BC's marine ecology. Enbridge discovered that the bitumen spill in the Kalamazoo River, conveniently in a flat, populated and accessible region of Michigan, could be 18-times more expensive to clean up than conventional light crude. (During the last decade, industry's average cost of cleaning up a barrel of spilled crude was $2,000; the cost of cleaning up a barrel of dilbit is estimated at $29,000.) And even after two years of effort and an expenditure of over $800 million, the Kalamazoo cleanup is not complete — whatever “complete” means for an oil spill. In all likelihood, a comparable spill in BC's wilderness could not be contained and would probably never be cleaned up.
Then consider a tanker spill of dilbit anywhere in BC's marine environment. At least the largest proportion of crude floats and a small portion of this is recoverable. Sunken bitumen would soon submerge to unrecoverable depths, its gummy and sticky black mass dispersed along the ocean bottom by tides to become a permanent and toxic fixture of the benthic ecology. It could eventually travel for hundreds of kilometres, washing ashore unexpectedly in distant places, perhaps for decades after the initial spill — the time delay a nearly perpetual reminder of the consequences of some unforeseen natural disaster or, much worse, of the gross stupidity of some engineering miscalculation or preventable mistake.
The silence on the dilbit issue is deafening. Significantly, Enbridge took weeks to notify US authorities that their spill on the Kalamazoo River was not light crude but dilbit. No wonder. No one has had any experience dealing with a major dilbit spill. The Kalamazoo experience was the first. As Robyn Allan, the former CEO of the Insurance Corporation of BC, noted on CBC radio's The House (Aug. 11/12), no risk analysis of the Northern Gateway pipeline project by Enbridge includes any reference to the Kalamazoo River spill, suggesting that no experience has been gleaned from it and applied to BC's rivers. "So far," Allan said, "it's as if Kalamazoo never happened."
Which is probably what Enbridge would prefer. Dilbit and bitumen present complications that are incompatible with their promotion of the Northern Gateway project. As their Kalamazoo mishap has established, a dilbit spill in an aquatic environment cannot be properly addressed with known technology, the cost of cleanup is horrendous, the damage to corporate profit is considerable, the stigma on reputation is lasting, and the public relations dimensions are lethal. The challenge of cleaning up ordinary crude is bad enough without having to consider a mix of diluent and bitumen. The wisest strategy for a corporation that is constantly spinning a positive message and opportunely escalating safety assurances is just to pretend that Kalamazoo didn't happen. And then, when the subject of the Northern Gateway arises, hope than no one will notice the sound of its silence.
Postscript: The recent and surprising proposal by newspaper mogul David Black for a $13 billion refinery in Kitimat complicates rather than solves the bitumen problem.