This was the scene in Mayflower, Arkansas, yesterday. A ExxonMobil pipeline, dating to the 1940s, apparently ruptured between two houses in a cul-de-sac in the corner of a housing development.

One resident drove past the spill on his way to his house.

It's a scene straight out of the beginning of a post-apocalyptic movie — thick, black oil running down a suburban street. From an environmental standpoint, the spill was even more dangerous than it looks. That oil, according to a map provided by the city, flowed down the street, past a highway, and encroached on the shore of Lake Conway.

Exxon moved quickly to put up oil containment booms, and there are no reports that any oil has entered the lake. Or, rather, not oil. What spilled is a product called "diluted bitumen," or "dilbit" — the watered-down product of a fuel extracted from oil sands in Alberta, Canada. It's precisely the product that TransCanada hopes to ship through its proposed Keystone XL pipeline.

Such spills have happened before. In 2010, a pipeline operated by the Canadian company Enbridge ruptured near the Kalamazoo River in Michigan, spilling at least a million gallons of dilbit into the river and other nearby waterways — the largest on-land spill in American history. The company was eventually found to be at fault for the accident, in large part for failing to act to contain the spill for over 17 hours. That same year, ExxonMobil was bumped out of the number-one spot on the list of the worst offshore spills, thanks to BP.

Nor was that even Enbridge's most recent spill. Last July, a pipeline operated by the company leaked 67,000 gallons of dilbit in a rural area of Wisconsin.

It's been impossible not to draw comparisons between this weekend's spill and the proposed Keystone XL pipeline. That pipeline, for which the State Department recently signed off on a revised environmental plan, would vastly increase TransCanada's current dilbit transport capacity between Alberta and Oklahoma. The primary point of environmental concern cited in the TransCanada report was the possibility of a major spill. In that regard, TransCanada comes out looking pretty good. Enbridge, however, has seen three leaks in three years.

President Obama still has veto authority over Keystone XL — a decision he is still mulling. Meanwhile, Enbridge's pipelines continue to operate, criss-crossing the United States. Even if that's not preventable, maybe we can make a rule: Shipping dilbit should only happen in pipelines that are younger than World War II.

Correction: This article originally indicated that ExxonMobil and Enbridge were working together on the Pegasus pipeline. This is incorrect. A 2007 article originally included in the piece referred to a partnership that was never finalized. Enbridge also does not own the fuel it transports through its pipelines.