The sense of déjà vu was as strong as the smell of oil fumes in the Chicago suburb of Romeoville. Parking lots were full of vacuum trucks and other large vehicles emblazoned with the names of environmental remediation companies. The tents were stocked with bottled water and protective gear for cleanup workers. The EPA had brought in a mobile emergency response unit -- a trailer outfitted with air-monitoring equipment and a whiteboard listing briefings and logistics.

Nearby residents voiced fear and incredulity that a large oil pipeline ran below their homes or businesses and was now leaking heavy crude. They speculated about when the oil flow would be stemmed, how widespread the damage would be, and how much the cleanup would cost. The Canadian company Enbridge Inc. offered assurances that it would compensate all stakeholders and pay all cleanup costs, while emphasizing the overall safety and integrity of the Lakehead System which delivers a bulk of the nation’s oil imports from Canada to Midwestern refineries.

The spill that sprung from Enbridge’s punctured “6A” pipeline below a warehouse complex in Romeoville on September 9  ultimately proved significantly smaller and less damaging than the spill from its pipeline into Michigan's Kalamazoo River that threatened to reach Lake Michigan six weeks earlier. The Romeoville spill clocked in at about 250,000 gallons, compared to about 830,000 gallons in Michigan. The Romeoville spill was largely contained in a retention pond, though it did contaminate banks along a storm water ditch, ooze over a road, and reach the town’s wastewater treatment plant, causing a shutdown. Cleanup of the Kalamazoo spill, which saturates a 30-mile stretch of marshy flood plain, will take well into next year.

But both spills bolstered a growing public awareness that the pipeline network underlying America’s heartland is quite vulnerable to leaks and spills for any number of reasons. There were 89 spills on Enbridge Inc. pipelines last year, and four days after the Romeoville spill, another leak required an Enbridge pipeline to be closed near Buffalo.

Investigations into both Enbridge spills are still ongoing, but preliminary reports indicate that the Michigan spill was possibly a result of corrosion causing a six-foot-long break, while the Romeoville pipeline suffered a 2.5-inch-long puncture on its bottom side, likely from a rock. National Transportation Safety Board investigator Matt Nicholson said investigators were surprised to find that pipeline 6A, a half century old, lays on a bed of large, sharp rocks. Nowadays pipelines are nestled in soft sand or gravel.

Since the Michigan spill, legislators, environmental groups and residents have increasingly raised concerns about the safety of an aging pipeline network. Enbridge has countered that five decades is only “middle-aged” for a pipeline and with proper maintenance, should not be a cause for concern. But legislators and watchdog groups are also questioning whether current federal oversight of pipeline monitoring and maintenance is adequate. The Pipeline and Hazardous Materials Safety Administration (PHMSA), part of the Department of Transportation, is in charge of pipeline safety. This primarily involves overseeing pipeline companies’ own monitoring efforts.  In January PHMSA sent Enbridge a letter warning it had violated requirements for monitoring the integrity of its 6B pipeline.

“This web of pipelines have a remarkable tendency to not deliver their product where it’s supposed to go,” says NRDC Midwest program director Henry Henderson. “They dump it in rivers, in cities. It’s an insecure infrastructure  on many points -- there are issues of how pipelines have been sited, how they are monitored, how they are tested, how they are regulated. We’ve got a system that is not delivering what it promises to deliver, and putting people at risk.”

The oil in pipeline 6A in Romeoville was headed for a large holding facility in Griffith, Indiana, a quaint historic town nestled amidst heavy industry in northwest Indiana about 20 miles south of Chicago. The oil in pipeline 6B was headed from Griffith to a refinery in Sarnia, Ontario. Enbridge said the oil that spilled from 6A was heavy crude from Saskatchewan. The oil in 6B was from Cold Lake, Alberta, and appears to have been from the controversial tar sands, though Enbridge initially denied this was the case. Environmental groups including the NRDC point out that Enbridge’s Lakehead System is a primary conduit from the tar sands to the Great Lakes, running through pipelines built before the growth of the tar sands industry. They note that little research has been done about the effect that carrying tar sands has on pipelines.

Henderson asks: “What were these pipelines built to carry, what kind of pressure can they withstand, what kind of corrosive issues are presented by a heavy crude that has a different chemical base” than conventional oil? “These are questions that have to be probed and reviewed. Analysis needs to be undertaken by appropriate authorities and made clear to the public. The general public is remarkably uninformed about the infrastructure that makes its way through their communities, and what’s inside it. That’s not accidental.”