Just as BP has finally succeeded in capping the ruptured Macondo well in the Gulf of Mexico, Canadian pipeline giant Enbridge has sprung a leak in the Kalamazoo River in Michigan. 2010 certainly hasn’t been a banner year for the North American oil industry.

The Enbridge leak in Michigan is a poignant reminder of the thousands of miles of pipeline that crisscross North America. The Kalamazoo spill is not the first pipeline to burst on the continent, nor will it be the last; spills are a fact of life in the business. But this one may have broad implications for the future of tar sands production.

The company’s grandiose plan to build the Northern Gateway, a 900,000-barrel-a-day pipeline from the Alberta tar sands to the BC coast for transoceanic shipment to China, is now in jeopardy. Watching cleanup crews scrambling to contain the spill in Michigan probably doesn’t endear Enbridge to British Columbia residents, who are being asked to accept the proposed pipeline in their own backyards. Enbridge’s only consolation is that its spill is likely to be equally damaging to the chances of its competitor TransCanada’s getting approval from US regulators to build its contentious Keystone XL pipeline, which would bring tar sands crude to US markets.

With oil spilling all over the place these days, natural gas should never have looked more appealing. But, as Josh Fox’s recent documentary, Gasland, vividly illustrates, the environmental challenges are no less daunting in that industry. Just as depletion has forced oil companies to take on greater and greater environmental risks, so has it affected North American gas producers. Shale gas, heralded by Boone Pickens and others as the answer to America’s future energy needs, leaves just as heavy an environmental footprint.

Not only does fracturing shale rock require an enormous amount of water (similar in that respect to tar sands), but it uses a toxic cocktail of chemicals to do the job. And those chemicals (as much as 80,000 pounds of them to fracture a well) have a nasty habit of turning up in the local groundwater. As much of 70 per cent of the chemical solution that is injected for shale fracturing stays in the ground.

But, fortunately for shale gas companies, producers can contaminate groundwater with impunity. Hydraulic fracturing, the process of tapping shale gas, was exempted from the Safe Drinking Water Act in 2005 in the interests of promoting American energy independence. Thanks to that exemption, and the environmental practices that it engendered, residents who live on top of the Marcellus Shale formation, for example, can actually light their tap water on fire.

The ability of new technology to unlock previously inaccessible hydrocarbon deposits in deep water, tar sands, or shale rock is beyond dispute. But so, too, is the staggering environmental cost that comes with our ever-increasing dependence on them.